CA2214715A1 - Assays for compounds in consumable items - Google Patents
Assays for compounds in consumable items Download PDFInfo
- Publication number
- CA2214715A1 CA2214715A1 CA 2214715 CA2214715A CA2214715A1 CA 2214715 A1 CA2214715 A1 CA 2214715A1 CA 2214715 CA2214715 CA 2214715 CA 2214715 A CA2214715 A CA 2214715A CA 2214715 A1 CA2214715 A1 CA 2214715A1
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- CA
- Canada
- Prior art keywords
- indicator
- caffeine
- lactose
- segment
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/02—Food
- G01N33/14—Beverages
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
- C12Q1/54—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving glucose or galactose
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/02—Food
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/94—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving narcotics or drugs or pharmaceuticals, neurotransmitters or associated receptors
- G01N33/946—CNS-stimulants, e.g. cocaine, amphetamines
Abstract
The present invention relates to simple indicators that allow a consumer to determine the presence or absence of particular compounds, such as cafeine and lactose, in foods and beverages. The indicators include portions which provide rapid visual indication of the presence (or absence) of the subject compounds. The indicators are sized to permit them to be carried whithin a pocket or purse allowing portability and discreet use.
Description
= =
CA 0221471~ l997-os-o~
ASSAYS FOR COMPOIJNDS IN CONSUMABLE ITEMS
Field of the Inventio~
This invention is in the field of assays for specific compounds in consumable items such as foods and beverages. In particular, the invention relates to simple assays by which an individual can deterrnine the presence of caffeine or lactose in consumable items using a simple non-automated technique.
Bal~k~round of the Invention The detection of compounds in various foods and beverages is a well-developed 0 technology practiced in analytical chemistry laboratories. Producers of foods and beverages typically require laboratory services to determine the quality and safety of their products, and also to insure that their products remain substantially uniform regardless of raw materials, seasonal variations, etc.
It is relatively easy to ~1Ptermine the presence of a wide variety of compounds using 15 analytical chemistry techniques. However, such methods often are not available, or practical, for individual consumers seeking to cleterrnine the presence or absence of certain compounds in their food and beverages. For example, although "decaffeinated" coffees, teas, and soft drinks have become increasingly popular over the past several years, the average consumer has no way of verifying the absence (or presence) of caffeine in such beverages when receiving them in 20 re~l~uld~ and other public and private settings. It should be understood that the term "decaffeinated" as used herein is a relative term referring to beverages having a reduced caffeine content. For example, a cup of coffee typically contains about 100 mg of caffeine (approximately 400mg/L) whereas a cup of decaffeinated coffee typically contains about 4 mg of caffeine (approximately 16mg/L), and a cup of tea typically contains about 35 mg of caffeine 25 (approximately 1 40mg/L) whereas a cup of decaffeinated tea typically contains less than about 2 mg of caffeine (approximately 8mg/L). Additionally, since most people find caffeinated and decaffeinated beverages to be very similar in taste, a consumer has very limited ability to o ~1eterrnine whether a beverage received in a re~l~ul~ut or other setting lacks (or contains) caffeine. Thus, if a group of diners orders a combination of caffeinated and decaffeinated 30 beverages, it becomes very difficult to assure that the server properly distributed the caffeinated and decaffeinated beverages to the proper persons.
In a related example, a significant percentage of the population lacks the enzymes necessary to digest lactose. This "lactose-intolerance" increases dramatically with age, starting in infancy and progressing through adolescence. The prevalence of lactose-intolerance is known to vary according to ethnicity. For example, virtually all Vietnamese adults arelactose-intolerant, as are approximately 95% of Native American adults, 65% of African-American adults, 22% of C~llc~ci~n adults, and 7% of Northern European adults.
5 Lactose-intolerant individuals often experience a significant level of gastrointestinal distress if they consume milk or other products cont~ining lactose. Although milk and other food and beverage products that are said to have reduced lactose content or to be free of lactose are available in supermarkets, grocery stores, restaurants and the like, those consuming such products cannot guarantee that the products consumed actually are free of lactose until a o significant time period has elapsed following consumption of the products.
Additionally, some foods (such as sorbet) may or may not contain milk or milk products, and it is often verv difficult to tell if such are present at all, let alone in a lactose-reduced form.
Numerous methods are known to analytical chemists for dete- " ~ i "; l Ig the presence of caffeine and lactose in various media. For example, in the case of caffeine, the scientific 15 lileldLu~ includes methods such as electrometric determination in which a caffeine-specific electrode is prepared from a caffeine-picrylsulfonate ion-pair complex dissolved in octanol, fluorimetric det~ lhldlion in which a buffered solution of caffeine is oxidized with N-bromosuccinimide and then re~cted with dimethyl o-phenyleneAi~mine followed by a fluorescence measurement at 480 nm; colormetric cletermin~tion in which an ethenolic solution 20 of caffeine is oxidized by potassium bromate, dried and then redissolved in dimethylformamide followed by an absorbence measurement at 500 nm; Fourier Transform Infrared Spectrophotometry (FTIR), thin-layer/gas chromatography; enzyme-linked immunosorbent caffeine assays in which a caffeine-cont~inin~ sample of plasma or serum is dissolved in a buffered solution and incubated in a vessel where it competes with peroxidase-labeled caffeine 25 for the binding sites on caffeine antibodies followed by detection of a visible color change with the addition of o-phenylenç~ mine, imm-m~-assay of theophylline with cross-sensitivity for caffeine; and immunoliposome assay of theophylline with cross-sensitivity for caffeine.
Likewise, numerous assays exist for determining the presence of lactose in various media. These include the lactose enzyme electrode in which a lactose specific electrode is 30 prepared using either galactose oxidase or a beta galactosidase/glucose oxidase combination in conjunction with an H20~ electrode, whereby lactose reacts with the galactose oxidase or galactosidase/glucose oxidase combination to liberate peroxide which produces an CA 022147l~ lss7-os-o~
electrochemical response; lactose detçrmin~tion by micro-calorimetry in which the reaction of lactose with beta galactosidase (lactase) to produce glucose and galactose is used; Benedict's reagent in which a cupric citrate z~lk~line solution is used to detect re~ cin~ sugars, and the method specified in U.S. Patent No. 3,814,668 for the semi-4uaulil~live detçrmin~tion of glucose s in a sample fluid in which a sample cont~ining glucose reacts with glucose oxidase to liberate oxygen, the peroxidase accelerates the release of oxygen (peroxide), and the peroxide reacts with potassium iodide releasing iodine and producing a color change to brown.
~ The problem inherent in most test procedures for lactose is that the majority are not lactose-specific. Rather, most will also react with glucose. Furthermore, each of the caffeine o and lactose assays described above requires the use of laboratory instrllment~tion and techniques in carrying out the assay and, as such, they are not well suited for consumer use.
In view of the above, a need exists for a simple, inexpensive test that can be used by a consumer to clçtennine the presence (or absence) of compounds such as caffeine and lactose in con~u.l.able food and beverage products.
Furthermore, a need exists for a simple assay which can be carried out without the need for instrllment~tion or laboratory techniques.
A need also exists for an assay which can determine the presence (or absence) ofcompounds such as caffeine and lactose in a food or beverage portion without adulterating the portion (or at least a .~ipnific~nt amount thereof).
A need also exists for a simple assay which is easily portable and may be performed quickly and discreetly.
Summary of the Invention The present invention relates to simple assays to detect the presence (or absence) of materials such as caffeine and lactose in con~-lm~ble items such as foods and beverages. The assay materials may be easily carried in a pocket or purse, and the assay can be performed in a simple and discreet manner. Each assay comprises an indicator, in the form of a wick, a capillary tube, a dipstick or the like having ~I!lol)-iate reagents thereon, which can be contacted with a sample taken from a food or beverage portion and can provide rapid visual fee~lb~ck indicating the presence (or absence) of the subject compound, or in sime cases, its concentration.
In one pler~;lled embodiment, caffeine and lactose indicators are enclosed in a matchbo.ok-type package which includes a plurality of caffeine indicators, lactose indicators, or a combination thereof. Such a construction offers a simple. disposable, inexpensive package that is easily used by a consumer. In that embodiment, a consumer ordering a cup of, for example, decaffeinated cappuccino or caffe latte, would open the matchbook, tear off indicators for caffeine and lactose, and briefly contact those indicators with a sample of the beverage. Shortly thereafter, colored portions on the indicators could be viewed to determine the presence or 5 absence of caffeine and lactose in the beverage.
Brief Description of the Dr~wi-~s FIG. 1 is a schematic depiction of one embodiment of an indicator for caffeine;
~ FIG. 2 is a sçhem~tic depiction of one embodiment of an indicator for lactose;
FIG. 3 is a schematic depiction of a package cont~ininp: a plurality of indicator strips.
FIG. 4a and 4b depict a housing conts~ininp: an indicator and illustrate its method of use.
Detailed De~e~ tion of the Invention The present invention provides a simple assay for ~leterrnining the presence (or absence) of compounds such as caffeine or lactose in a food or beverage sample. In one embodiment, the subject assays provide a system using a sample "dipstick" which allows a consumer to verify 5 whether the target species are present simply by contacting the dipstick with the food or beverage sample and observing an indication, typically a colormetric indication, thereon.In the case of caffeine, d~L~ ation is made using an immlmoassay. In particular,caffeine-specific antibodies, raised in various laboratory ~nim~l~, can bond to a specific number of caffeine molecules at a limited number of binding sites. By ~iml1lt~neously introducing a 20 caffeine sample taken from a beverage and a control standard such as a labeled caffeine sample to a caffeine-specific antibody, a competitive assay results in which the labeled and unlabeled caffeine molecules compete for the available binding sites on the antibody. Any unbound, labeled caffeine is then available to contact an indicator to provide an indication of the presence of caffeine in the consumable sample. For example, if a control standard of caffeine is labeled 25 with an agent that causes a color change in an indicator and introduced to a caffeine-specific antibody simultaneously with a beverage sample which does not contain caffeine, all available binding sites on the antibody would be occupied by the labeled caffeine, thereby leaving few of the labeled moieties available in an unbound form to induce a color change in the indicator.
Thus, little color change in the indicator would be expected to develop. Likewise, if equal 30 concentrations of labeled and unlabeled caffeine were provided to the antibodies, about half of the maximum possible color change would be expected, since about half of the antibody binding sites would be occupied by labeled caffeine with the other half being occupied by unlabeled CA 022147l~ lss7-os-o~
WO 96l27795 PCT/USg6/02828 caffeine. The unbound labeled caffeine complexes would remain available to induce a visual change in the indicator. Thus, as the concentration of caffeine in the sample increases, the number of binding sites on the antibody occupied by labeled-caffeine decreases, thereby freeing more labeled caffeine for interaction with the indicator. The result is a greater color change on 5 the indicator. In one preferred embodiment, these effects can be produced by labeling caffeine with peroxidase and using o-phenylenerli~min~? or other suitable indicating reagents to detect the presence of unbound, labeled caffeine.
One ~lefelled embodiment of a caffeine indicator is depicted in FIG. 1. In that Figure, the indicator 10 comprises a test strip 12 formed of a material having the ability to wick fluids.
0 One preferred material is filter paper. The indicator 10 includes five separate portions: a sample liquid portion 14, a labeled caffeine portion 16, a caffeine antibody portion 18, an indicator portion 20, and a grip portion 22.
In use, the liquid sample portion 14 is contacted with a liquid, such as coffee, to be tested. The portion 14 may either be immersed in the coffee or the coffee may be dripped onto 5 the liquid sample portion using a spoon, dropper or the like. It is ~ler~ ~led that only the liquid sample portion be contacted with the beverage being tested. If the entire indicator is immersed in the beverage, caffeine present in the sample will be able to bind with the antibody faster than the labeled caffeine, thereby providing inaccurate results. Additionally, such immersion raises the possibility of introducing unwanted chemical reagents into the beverage. Each of these effects 20 could be avoided by providing a relatively impermeable sheath or jacket around the indicator except in the sample liquid portion 14. Suitable jacket materials include any of a wide variety of transparent polymeric m~teri~l~ approved by regulatory agencies for food and beverage contacting applications.
As the sample liquid wicks upward along the indicator strip, it first encounters and mixes 2s with a labeled caffeine, such as peroxidase-labeled caffeine, that has been impregnated into the wickable material in the labeled caffeine portion 16. The labeled caffeine mixes with any caffeine contained in the liquid sample and is carried upward along the wick as the wicking process cc-ntinl-~s As the sarnple liquid enters the caffeine antibody portion 18, labeled and non-labeled caffeine compete for binding sites on the caffeine antibodies. As noted above, if the 30 sample liquid is ~l~b~ lly free of caffeine, substantially all ofthe labeled caffeine will become bound to the caffeine antibodies. In contrast, as the amount of caffeine in the sample liquid increases, a greater amount of the labeled caffeine will be unable to attain a binding site on CA 0221471~ 1997-09-0~
the antibody and will be free to continue wicking along the indicator strip.
The sample liquid, now cont~ininp a lower percentage of labeled c~ffeine as a result of interaction with the caffeine antibodies continues to wick along the indicator strip into the indicator portion 20. Based upon the amount of labeled caffeine interacting with the indicator 5 (o-phenylenerli~mine or the like), the color of the indicator will react. If the sample is relatively free of caffeine, only a small amount of, for example, peroxidase-labeled caffeine will be available to interact with the indicator and thus, no significant color change will occur in the ~ indicator. In contrast, if the sample beverage contains a significant amount of caffeine, a greater amount of unbound peroxidase-labeled caffeine will be available for interaction with the o indicator and the color change of the indicator will be significant. By ex~minin~ the color response of the indicator, the consumer thus has an indication as to whether the sample beverage contains or lacks caffeine. Likewise, by ex~mining the amount of color change, the consumer can determine not only the presence (or absence) of caffeine, but the relative amount present as well. The entire indicator strip can be easily manipulated by the consumer via the gripping 15 portion 20.
It should be noted that the present invention is not intçncle~l to be limited to the specific competitive assay method described above. For example, other approaches may be employed including apoenzyme reactivated immnno~s~y (ARIS) and "enzyme ch~nnelling". In the ARIS
assay, caffeine is linked to the enzyme prosthetic group flavin adenine dinucleotide (FAD), the 20 co-factor for glucose oxidase. The FAD-caffeine complex competes with free caffeine for binding to anti-caffeine antibodies. As with the competitive assay described above, the lligher the content of caffeine in the beverage, the more unbound FAD-caffeine is available for interaction with apoglucose oxidase, thereby converting it to active enzyme to metabolize glucose in the presence of peroxidase and tetramethylbenzidine as color reagents. The result is 25 an increasing blue color with increasing caffeine concentration. In this embodiment, the test device may comprise a plastic strip having filter paper impregnated with an aqueous phase followed by drying and secondary application of an organic phase. The aqueous dip includes anti-caffeine antibodies, apoglucose oxidase, anti-glucose oxidase (for enzyme stabilization), peroxidase and glucose. The organic phase contains FAD-caffeine and tetramethylbenzidine or 30 similar color reagents. Further description of the ARIS procedure may be found in Greenquist, AACC TDM-T. Vol. 6, No. 6, pp. 1-8, December, 1984, the te~rhing~ of which are incorporated herein by reference. Of course other enzyme systems may be employed.
CA 02214715 l997-os-05 In connection with ARIS arrays, a multilayer immunochemical dipstick employing multifilm technology may be used. The result is that the reagents are spacially separated in various parts of the reaction. Such a device is depicted schematically on page 7 of the Greenquist reference.
In the enzyme channelling reaction, caffeine linked to peroxidase is again used. Free caffeine in a beverage competes with caffeine-peroxidase for binding to caffeine antibodies which are linearly spaced along a wicking path. The higher the amount of caffeine in the sample, the greater the competition for binding sites along the wicking path. As a result, if the sample has a high caffeine concentration, labeled caffeine is likely to wick further along the path. By o determining the length of kavel ofthe labeled caffeine, the relative caffeine concentration ofthe sarnple can be determined. The assay can be achieved in a multilayer dipstick model, sequential impregn~ted papers on a plastic dipstick, or within a thin plastic "thermometer"-type device where the height of the color (i.e., distance traveled by free caffeine-peroxidase) is proportionate to the amount of caffeine in the beverage. Further description of the enzyme ch~nnelinp assay may be found in Wagman et al., AACC TDM-T, Vol. 7, No. 8, pp. 1-6, February, 1986, the te~f hin~s of which are incorporated herein by reference.
For each assay, multiple impregn~tt?rl paper strips aligned along a plastic support above a chemical-free "wick" may be employed. Multifilm layer technology, or a defined volume capillary tube capable of being immersed in the beverage may be used as well. In the latter case, the capillary tube can have the a~ ;ate reagents immobilized upon the interior walls of the lumen. The result is a hollow "thermometer"-type device. The test strips or "thermometers" may be packaged either in a matchbook like device or in a small container readily carried by a consumer. Depending upon size and configuration of each device, a small preme~nred plastic sampling spoon may also be provided or physically incorporated into the assay device. Also, a strip of a support material such as a semi-rigid plastic may be affixed to each indicator to provide some level of physical support and ease of manipulation.
In the case of the lactose-indicating devices, the ~lef~ d embodiment includes indicators for the presence of both glucose and lactose. This is because many of the lactose indicators are also sensitive to the presence of glucose, but not necess~rily vice-versa. Thus, a glucose indicator can be compared (as a control) to a lactose indicator with a ~iirr~rellce between the two being indicative of the presence of lactose. In one ~ler~ d embodiment shown in FIG.
CA 0221471~ l997-os-o~
ASSAYS FOR COMPOIJNDS IN CONSUMABLE ITEMS
Field of the Inventio~
This invention is in the field of assays for specific compounds in consumable items such as foods and beverages. In particular, the invention relates to simple assays by which an individual can deterrnine the presence of caffeine or lactose in consumable items using a simple non-automated technique.
Bal~k~round of the Invention The detection of compounds in various foods and beverages is a well-developed 0 technology practiced in analytical chemistry laboratories. Producers of foods and beverages typically require laboratory services to determine the quality and safety of their products, and also to insure that their products remain substantially uniform regardless of raw materials, seasonal variations, etc.
It is relatively easy to ~1Ptermine the presence of a wide variety of compounds using 15 analytical chemistry techniques. However, such methods often are not available, or practical, for individual consumers seeking to cleterrnine the presence or absence of certain compounds in their food and beverages. For example, although "decaffeinated" coffees, teas, and soft drinks have become increasingly popular over the past several years, the average consumer has no way of verifying the absence (or presence) of caffeine in such beverages when receiving them in 20 re~l~uld~ and other public and private settings. It should be understood that the term "decaffeinated" as used herein is a relative term referring to beverages having a reduced caffeine content. For example, a cup of coffee typically contains about 100 mg of caffeine (approximately 400mg/L) whereas a cup of decaffeinated coffee typically contains about 4 mg of caffeine (approximately 16mg/L), and a cup of tea typically contains about 35 mg of caffeine 25 (approximately 1 40mg/L) whereas a cup of decaffeinated tea typically contains less than about 2 mg of caffeine (approximately 8mg/L). Additionally, since most people find caffeinated and decaffeinated beverages to be very similar in taste, a consumer has very limited ability to o ~1eterrnine whether a beverage received in a re~l~ul~ut or other setting lacks (or contains) caffeine. Thus, if a group of diners orders a combination of caffeinated and decaffeinated 30 beverages, it becomes very difficult to assure that the server properly distributed the caffeinated and decaffeinated beverages to the proper persons.
In a related example, a significant percentage of the population lacks the enzymes necessary to digest lactose. This "lactose-intolerance" increases dramatically with age, starting in infancy and progressing through adolescence. The prevalence of lactose-intolerance is known to vary according to ethnicity. For example, virtually all Vietnamese adults arelactose-intolerant, as are approximately 95% of Native American adults, 65% of African-American adults, 22% of C~llc~ci~n adults, and 7% of Northern European adults.
5 Lactose-intolerant individuals often experience a significant level of gastrointestinal distress if they consume milk or other products cont~ining lactose. Although milk and other food and beverage products that are said to have reduced lactose content or to be free of lactose are available in supermarkets, grocery stores, restaurants and the like, those consuming such products cannot guarantee that the products consumed actually are free of lactose until a o significant time period has elapsed following consumption of the products.
Additionally, some foods (such as sorbet) may or may not contain milk or milk products, and it is often verv difficult to tell if such are present at all, let alone in a lactose-reduced form.
Numerous methods are known to analytical chemists for dete- " ~ i "; l Ig the presence of caffeine and lactose in various media. For example, in the case of caffeine, the scientific 15 lileldLu~ includes methods such as electrometric determination in which a caffeine-specific electrode is prepared from a caffeine-picrylsulfonate ion-pair complex dissolved in octanol, fluorimetric det~ lhldlion in which a buffered solution of caffeine is oxidized with N-bromosuccinimide and then re~cted with dimethyl o-phenyleneAi~mine followed by a fluorescence measurement at 480 nm; colormetric cletermin~tion in which an ethenolic solution 20 of caffeine is oxidized by potassium bromate, dried and then redissolved in dimethylformamide followed by an absorbence measurement at 500 nm; Fourier Transform Infrared Spectrophotometry (FTIR), thin-layer/gas chromatography; enzyme-linked immunosorbent caffeine assays in which a caffeine-cont~inin~ sample of plasma or serum is dissolved in a buffered solution and incubated in a vessel where it competes with peroxidase-labeled caffeine 25 for the binding sites on caffeine antibodies followed by detection of a visible color change with the addition of o-phenylenç~ mine, imm-m~-assay of theophylline with cross-sensitivity for caffeine; and immunoliposome assay of theophylline with cross-sensitivity for caffeine.
Likewise, numerous assays exist for determining the presence of lactose in various media. These include the lactose enzyme electrode in which a lactose specific electrode is 30 prepared using either galactose oxidase or a beta galactosidase/glucose oxidase combination in conjunction with an H20~ electrode, whereby lactose reacts with the galactose oxidase or galactosidase/glucose oxidase combination to liberate peroxide which produces an CA 022147l~ lss7-os-o~
electrochemical response; lactose detçrmin~tion by micro-calorimetry in which the reaction of lactose with beta galactosidase (lactase) to produce glucose and galactose is used; Benedict's reagent in which a cupric citrate z~lk~line solution is used to detect re~ cin~ sugars, and the method specified in U.S. Patent No. 3,814,668 for the semi-4uaulil~live detçrmin~tion of glucose s in a sample fluid in which a sample cont~ining glucose reacts with glucose oxidase to liberate oxygen, the peroxidase accelerates the release of oxygen (peroxide), and the peroxide reacts with potassium iodide releasing iodine and producing a color change to brown.
~ The problem inherent in most test procedures for lactose is that the majority are not lactose-specific. Rather, most will also react with glucose. Furthermore, each of the caffeine o and lactose assays described above requires the use of laboratory instrllment~tion and techniques in carrying out the assay and, as such, they are not well suited for consumer use.
In view of the above, a need exists for a simple, inexpensive test that can be used by a consumer to clçtennine the presence (or absence) of compounds such as caffeine and lactose in con~u.l.able food and beverage products.
Furthermore, a need exists for a simple assay which can be carried out without the need for instrllment~tion or laboratory techniques.
A need also exists for an assay which can determine the presence (or absence) ofcompounds such as caffeine and lactose in a food or beverage portion without adulterating the portion (or at least a .~ipnific~nt amount thereof).
A need also exists for a simple assay which is easily portable and may be performed quickly and discreetly.
Summary of the Invention The present invention relates to simple assays to detect the presence (or absence) of materials such as caffeine and lactose in con~-lm~ble items such as foods and beverages. The assay materials may be easily carried in a pocket or purse, and the assay can be performed in a simple and discreet manner. Each assay comprises an indicator, in the form of a wick, a capillary tube, a dipstick or the like having ~I!lol)-iate reagents thereon, which can be contacted with a sample taken from a food or beverage portion and can provide rapid visual fee~lb~ck indicating the presence (or absence) of the subject compound, or in sime cases, its concentration.
In one pler~;lled embodiment, caffeine and lactose indicators are enclosed in a matchbo.ok-type package which includes a plurality of caffeine indicators, lactose indicators, or a combination thereof. Such a construction offers a simple. disposable, inexpensive package that is easily used by a consumer. In that embodiment, a consumer ordering a cup of, for example, decaffeinated cappuccino or caffe latte, would open the matchbook, tear off indicators for caffeine and lactose, and briefly contact those indicators with a sample of the beverage. Shortly thereafter, colored portions on the indicators could be viewed to determine the presence or 5 absence of caffeine and lactose in the beverage.
Brief Description of the Dr~wi-~s FIG. 1 is a schematic depiction of one embodiment of an indicator for caffeine;
~ FIG. 2 is a sçhem~tic depiction of one embodiment of an indicator for lactose;
FIG. 3 is a schematic depiction of a package cont~ininp: a plurality of indicator strips.
FIG. 4a and 4b depict a housing conts~ininp: an indicator and illustrate its method of use.
Detailed De~e~ tion of the Invention The present invention provides a simple assay for ~leterrnining the presence (or absence) of compounds such as caffeine or lactose in a food or beverage sample. In one embodiment, the subject assays provide a system using a sample "dipstick" which allows a consumer to verify 5 whether the target species are present simply by contacting the dipstick with the food or beverage sample and observing an indication, typically a colormetric indication, thereon.In the case of caffeine, d~L~ ation is made using an immlmoassay. In particular,caffeine-specific antibodies, raised in various laboratory ~nim~l~, can bond to a specific number of caffeine molecules at a limited number of binding sites. By ~iml1lt~neously introducing a 20 caffeine sample taken from a beverage and a control standard such as a labeled caffeine sample to a caffeine-specific antibody, a competitive assay results in which the labeled and unlabeled caffeine molecules compete for the available binding sites on the antibody. Any unbound, labeled caffeine is then available to contact an indicator to provide an indication of the presence of caffeine in the consumable sample. For example, if a control standard of caffeine is labeled 25 with an agent that causes a color change in an indicator and introduced to a caffeine-specific antibody simultaneously with a beverage sample which does not contain caffeine, all available binding sites on the antibody would be occupied by the labeled caffeine, thereby leaving few of the labeled moieties available in an unbound form to induce a color change in the indicator.
Thus, little color change in the indicator would be expected to develop. Likewise, if equal 30 concentrations of labeled and unlabeled caffeine were provided to the antibodies, about half of the maximum possible color change would be expected, since about half of the antibody binding sites would be occupied by labeled caffeine with the other half being occupied by unlabeled CA 022147l~ lss7-os-o~
WO 96l27795 PCT/USg6/02828 caffeine. The unbound labeled caffeine complexes would remain available to induce a visual change in the indicator. Thus, as the concentration of caffeine in the sample increases, the number of binding sites on the antibody occupied by labeled-caffeine decreases, thereby freeing more labeled caffeine for interaction with the indicator. The result is a greater color change on 5 the indicator. In one preferred embodiment, these effects can be produced by labeling caffeine with peroxidase and using o-phenylenerli~min~? or other suitable indicating reagents to detect the presence of unbound, labeled caffeine.
One ~lefelled embodiment of a caffeine indicator is depicted in FIG. 1. In that Figure, the indicator 10 comprises a test strip 12 formed of a material having the ability to wick fluids.
0 One preferred material is filter paper. The indicator 10 includes five separate portions: a sample liquid portion 14, a labeled caffeine portion 16, a caffeine antibody portion 18, an indicator portion 20, and a grip portion 22.
In use, the liquid sample portion 14 is contacted with a liquid, such as coffee, to be tested. The portion 14 may either be immersed in the coffee or the coffee may be dripped onto 5 the liquid sample portion using a spoon, dropper or the like. It is ~ler~ ~led that only the liquid sample portion be contacted with the beverage being tested. If the entire indicator is immersed in the beverage, caffeine present in the sample will be able to bind with the antibody faster than the labeled caffeine, thereby providing inaccurate results. Additionally, such immersion raises the possibility of introducing unwanted chemical reagents into the beverage. Each of these effects 20 could be avoided by providing a relatively impermeable sheath or jacket around the indicator except in the sample liquid portion 14. Suitable jacket materials include any of a wide variety of transparent polymeric m~teri~l~ approved by regulatory agencies for food and beverage contacting applications.
As the sample liquid wicks upward along the indicator strip, it first encounters and mixes 2s with a labeled caffeine, such as peroxidase-labeled caffeine, that has been impregnated into the wickable material in the labeled caffeine portion 16. The labeled caffeine mixes with any caffeine contained in the liquid sample and is carried upward along the wick as the wicking process cc-ntinl-~s As the sarnple liquid enters the caffeine antibody portion 18, labeled and non-labeled caffeine compete for binding sites on the caffeine antibodies. As noted above, if the 30 sample liquid is ~l~b~ lly free of caffeine, substantially all ofthe labeled caffeine will become bound to the caffeine antibodies. In contrast, as the amount of caffeine in the sample liquid increases, a greater amount of the labeled caffeine will be unable to attain a binding site on CA 0221471~ 1997-09-0~
the antibody and will be free to continue wicking along the indicator strip.
The sample liquid, now cont~ininp a lower percentage of labeled c~ffeine as a result of interaction with the caffeine antibodies continues to wick along the indicator strip into the indicator portion 20. Based upon the amount of labeled caffeine interacting with the indicator 5 (o-phenylenerli~mine or the like), the color of the indicator will react. If the sample is relatively free of caffeine, only a small amount of, for example, peroxidase-labeled caffeine will be available to interact with the indicator and thus, no significant color change will occur in the ~ indicator. In contrast, if the sample beverage contains a significant amount of caffeine, a greater amount of unbound peroxidase-labeled caffeine will be available for interaction with the o indicator and the color change of the indicator will be significant. By ex~minin~ the color response of the indicator, the consumer thus has an indication as to whether the sample beverage contains or lacks caffeine. Likewise, by ex~mining the amount of color change, the consumer can determine not only the presence (or absence) of caffeine, but the relative amount present as well. The entire indicator strip can be easily manipulated by the consumer via the gripping 15 portion 20.
It should be noted that the present invention is not intçncle~l to be limited to the specific competitive assay method described above. For example, other approaches may be employed including apoenzyme reactivated immnno~s~y (ARIS) and "enzyme ch~nnelling". In the ARIS
assay, caffeine is linked to the enzyme prosthetic group flavin adenine dinucleotide (FAD), the 20 co-factor for glucose oxidase. The FAD-caffeine complex competes with free caffeine for binding to anti-caffeine antibodies. As with the competitive assay described above, the lligher the content of caffeine in the beverage, the more unbound FAD-caffeine is available for interaction with apoglucose oxidase, thereby converting it to active enzyme to metabolize glucose in the presence of peroxidase and tetramethylbenzidine as color reagents. The result is 25 an increasing blue color with increasing caffeine concentration. In this embodiment, the test device may comprise a plastic strip having filter paper impregnated with an aqueous phase followed by drying and secondary application of an organic phase. The aqueous dip includes anti-caffeine antibodies, apoglucose oxidase, anti-glucose oxidase (for enzyme stabilization), peroxidase and glucose. The organic phase contains FAD-caffeine and tetramethylbenzidine or 30 similar color reagents. Further description of the ARIS procedure may be found in Greenquist, AACC TDM-T. Vol. 6, No. 6, pp. 1-8, December, 1984, the te~rhing~ of which are incorporated herein by reference. Of course other enzyme systems may be employed.
CA 02214715 l997-os-05 In connection with ARIS arrays, a multilayer immunochemical dipstick employing multifilm technology may be used. The result is that the reagents are spacially separated in various parts of the reaction. Such a device is depicted schematically on page 7 of the Greenquist reference.
In the enzyme channelling reaction, caffeine linked to peroxidase is again used. Free caffeine in a beverage competes with caffeine-peroxidase for binding to caffeine antibodies which are linearly spaced along a wicking path. The higher the amount of caffeine in the sample, the greater the competition for binding sites along the wicking path. As a result, if the sample has a high caffeine concentration, labeled caffeine is likely to wick further along the path. By o determining the length of kavel ofthe labeled caffeine, the relative caffeine concentration ofthe sarnple can be determined. The assay can be achieved in a multilayer dipstick model, sequential impregn~ted papers on a plastic dipstick, or within a thin plastic "thermometer"-type device where the height of the color (i.e., distance traveled by free caffeine-peroxidase) is proportionate to the amount of caffeine in the beverage. Further description of the enzyme ch~nnelinp assay may be found in Wagman et al., AACC TDM-T, Vol. 7, No. 8, pp. 1-6, February, 1986, the te~f hin~s of which are incorporated herein by reference.
For each assay, multiple impregn~tt?rl paper strips aligned along a plastic support above a chemical-free "wick" may be employed. Multifilm layer technology, or a defined volume capillary tube capable of being immersed in the beverage may be used as well. In the latter case, the capillary tube can have the a~ ;ate reagents immobilized upon the interior walls of the lumen. The result is a hollow "thermometer"-type device. The test strips or "thermometers" may be packaged either in a matchbook like device or in a small container readily carried by a consumer. Depending upon size and configuration of each device, a small preme~nred plastic sampling spoon may also be provided or physically incorporated into the assay device. Also, a strip of a support material such as a semi-rigid plastic may be affixed to each indicator to provide some level of physical support and ease of manipulation.
In the case of the lactose-indicating devices, the ~lef~ d embodiment includes indicators for the presence of both glucose and lactose. This is because many of the lactose indicators are also sensitive to the presence of glucose, but not necess~rily vice-versa. Thus, a glucose indicator can be compared (as a control) to a lactose indicator with a ~iirr~rellce between the two being indicative of the presence of lactose. In one ~ler~ d embodiment shown in FIG.
2, the lactose indicator 50 comprises a dipstick 52 having a glucose test portion 54 and a W 0 96t27795 PCTtUS96tO282X
glucose/lactose test portion 56 mounted at the end of a plastic strip. Each test portion can consist of an absorbent paper impregnated with an indicator solution, optionally sealed within a polymeric film. A gripping portion 58 of the indicator is provided as well to allow the consumer to manipulate the indicator. In the dual indicator embodiment described above, one such formulation for the test portions is as follows: "
Chemical Name Glucose Indicator Lactose Indicator % (WM7) % (W/W) Potassium 1.0 1.0 Iodide FD&C Blue 10.0 10.0 No. 1 (0.1% aq) Water 36.4 16.4 Citric Acid, 0.6 0.6 anhyd Sodium Citrate 5.0 5.0 Methyl vinyl ether 10.0 10.0 solution (thickener, stabilizer) (10% aq) Polyvinylpyrollidone 5.0 5.0 (10% aq) Horseradish peroxidase 2.0 2.0 (5 % aq) Glucose oxidase 30.0 30.0 (1000 units/ml) Lactase - 20.0 (3000 LAU/ml) In use, the consumer will contact an indicator strip with a beverage to be tested. The 40 contacting should be such that each of the glucose and the lactose test squares are each fully contacted with the sample material. If the lactose test square undergoes a color change that is different than that of the glucose test square, the presence of lactose in the sample is indicated.
One embodiment of a package for the subject indicator strips is shown in FIG. 3. In the CA 022l47l~ lgg7-o9-o~
g Figure, the package 80 is of the matchbox type having a cover 82, a plurality of indicators 84, each of which is removeably mounted to a retainer 86. The cover is secured to the retainer using a staple 88, an adhesive or the like. Each of the indicator strips 84 may be torn from the retainer and used to indicate the presence of the desired compounds in a food or beverage sample. As depicted in the Figure, the retainer 86 may include indicators for lactose 90 and caffeine 92 in combination, or the package may include simply a single type of indicator. Additionally, more than a single retainer/indicator combination can be used in each package, thereby allowing multiple indicators with each retainer/indicator combination including a single type of indicator.
In each of the embodiments shown in the figures above, an indicator strip is held by the consumer and contacted with a sample. However, as noted above, it is pler.,lr~d that the entire indicator not be contacted with the sample, but rather that the sarnple be placed only on a small portion of the indicator strip. One method for achieving this is by providing a protective jacket or sleeve around the indicator. In another embodiment, however, the indicator may inserted into (or provided within) a s~mplin~ enclosure or housing. One such embodiment is depicted in FIGS. 4a and 4b. In those figures, the sample housing 100 comprises a "U"-shaped tube having a sample collector 102 positioned at one end of the "U" . The bend 104 of the "U" forms a sample chamber in which a liquid sample 106 is caused to contact an indicator device 108. If desired, two indicators, for dirr~ materials, may be positioned back-to-back within the housing.
In the embodiment depicted in FIGS. 4a and 4b, the indicator 108 is a caffeine indicator as shown in FIG. 1. However, it should be noted that the specific indicator is not inten~lecl to be limited to caffeine indicators, but rather, may be any indicator of the type described herein. The housing may be of a single-use type having a single indicator perm~nently mounted therein, or in the alternative, the leg ofthe "U" opposite the leg co"li.i..;..~ the sample collector 102 may be 25 open or openable to allow the indicator to be replaced, thereby providing the housing with a multi-use capability. The housing may be formed of transparent glass; however, a durable, transparent polymer is ~l~;r~ d, as such materials are less likely to suffer breakage during transport and use.
In use, the sample collector 102 is dipped into a sample to be analyzed. For example, the 30 collector 102 may be dipped into a cup of coffee to obtain a small liquid sarnple 106 having a volume of, for example, approximately 1 milliliter. The sample 106 remains within the collection portion of the device (FIG. 4a) until the device is inverted (FIG. 4b). Once the device CA 0221471~ 1997-09-0~
is inverted, the sample fluid 106 flows down to the bend 104 of the "U" and contacts the a~pl~,pl;ate portion of the indicator 108. The device is m~intzlin-ocl in the position of FIG. 4b until the sample has had an opportunity to wick up the indicator and provide the consumer with the desired assay. Upon completion of the assay, the device may be either discarded (in the 5 single-use embodiment) or emptied and rinsed with fresh water to allow reuse (in the multi-use embodiment).
Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are inten~led to be within the spirit and scope of the o invention. For example, the materials employed, as well as their shapes and llimen~ions may be modified according to the requirements of the device. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto.
What is claimed is:
glucose/lactose test portion 56 mounted at the end of a plastic strip. Each test portion can consist of an absorbent paper impregnated with an indicator solution, optionally sealed within a polymeric film. A gripping portion 58 of the indicator is provided as well to allow the consumer to manipulate the indicator. In the dual indicator embodiment described above, one such formulation for the test portions is as follows: "
Chemical Name Glucose Indicator Lactose Indicator % (WM7) % (W/W) Potassium 1.0 1.0 Iodide FD&C Blue 10.0 10.0 No. 1 (0.1% aq) Water 36.4 16.4 Citric Acid, 0.6 0.6 anhyd Sodium Citrate 5.0 5.0 Methyl vinyl ether 10.0 10.0 solution (thickener, stabilizer) (10% aq) Polyvinylpyrollidone 5.0 5.0 (10% aq) Horseradish peroxidase 2.0 2.0 (5 % aq) Glucose oxidase 30.0 30.0 (1000 units/ml) Lactase - 20.0 (3000 LAU/ml) In use, the consumer will contact an indicator strip with a beverage to be tested. The 40 contacting should be such that each of the glucose and the lactose test squares are each fully contacted with the sample material. If the lactose test square undergoes a color change that is different than that of the glucose test square, the presence of lactose in the sample is indicated.
One embodiment of a package for the subject indicator strips is shown in FIG. 3. In the CA 022l47l~ lgg7-o9-o~
g Figure, the package 80 is of the matchbox type having a cover 82, a plurality of indicators 84, each of which is removeably mounted to a retainer 86. The cover is secured to the retainer using a staple 88, an adhesive or the like. Each of the indicator strips 84 may be torn from the retainer and used to indicate the presence of the desired compounds in a food or beverage sample. As depicted in the Figure, the retainer 86 may include indicators for lactose 90 and caffeine 92 in combination, or the package may include simply a single type of indicator. Additionally, more than a single retainer/indicator combination can be used in each package, thereby allowing multiple indicators with each retainer/indicator combination including a single type of indicator.
In each of the embodiments shown in the figures above, an indicator strip is held by the consumer and contacted with a sample. However, as noted above, it is pler.,lr~d that the entire indicator not be contacted with the sample, but rather that the sarnple be placed only on a small portion of the indicator strip. One method for achieving this is by providing a protective jacket or sleeve around the indicator. In another embodiment, however, the indicator may inserted into (or provided within) a s~mplin~ enclosure or housing. One such embodiment is depicted in FIGS. 4a and 4b. In those figures, the sample housing 100 comprises a "U"-shaped tube having a sample collector 102 positioned at one end of the "U" . The bend 104 of the "U" forms a sample chamber in which a liquid sample 106 is caused to contact an indicator device 108. If desired, two indicators, for dirr~ materials, may be positioned back-to-back within the housing.
In the embodiment depicted in FIGS. 4a and 4b, the indicator 108 is a caffeine indicator as shown in FIG. 1. However, it should be noted that the specific indicator is not inten~lecl to be limited to caffeine indicators, but rather, may be any indicator of the type described herein. The housing may be of a single-use type having a single indicator perm~nently mounted therein, or in the alternative, the leg ofthe "U" opposite the leg co"li.i..;..~ the sample collector 102 may be 25 open or openable to allow the indicator to be replaced, thereby providing the housing with a multi-use capability. The housing may be formed of transparent glass; however, a durable, transparent polymer is ~l~;r~ d, as such materials are less likely to suffer breakage during transport and use.
In use, the sample collector 102 is dipped into a sample to be analyzed. For example, the 30 collector 102 may be dipped into a cup of coffee to obtain a small liquid sarnple 106 having a volume of, for example, approximately 1 milliliter. The sample 106 remains within the collection portion of the device (FIG. 4a) until the device is inverted (FIG. 4b). Once the device CA 0221471~ 1997-09-0~
is inverted, the sample fluid 106 flows down to the bend 104 of the "U" and contacts the a~pl~,pl;ate portion of the indicator 108. The device is m~intzlin-ocl in the position of FIG. 4b until the sample has had an opportunity to wick up the indicator and provide the consumer with the desired assay. Upon completion of the assay, the device may be either discarded (in the 5 single-use embodiment) or emptied and rinsed with fresh water to allow reuse (in the multi-use embodiment).
Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are inten~led to be within the spirit and scope of the o invention. For example, the materials employed, as well as their shapes and llimen~ions may be modified according to the requirements of the device. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto.
What is claimed is:
Claims (39)
1. A kit for determining the presence of compounds in food or beverage samples, the kit comprising:
a) a plurality of indicator elements, each element having at least one indicator for determining the presence of a compound in a food or beverage sample and an elongate segment by which each indicator element may be manipulated, and b) a retainer removeably joined to each indicator element, to thereby maintain the plurality of indicator elements and the retainer as a single unit until indicator elements are individually removed therefrom.
a) a plurality of indicator elements, each element having at least one indicator for determining the presence of a compound in a food or beverage sample and an elongate segment by which each indicator element may be manipulated, and b) a retainer removeably joined to each indicator element, to thereby maintain the plurality of indicator elements and the retainer as a single unit until indicator elements are individually removed therefrom.
2. A kit as in claim 1 wherein the compounds are selected from the group consisting of caffeine and lactose.
3. A kit as in claim 1 which further includes a cover which may be opened to expose the indicator elements.
4. A kit as in claim 2 wherein each indicator element is constructed and arranged to determine the presence of caffeine in the food or beverage sample.
5. A kit as in claim 2 wherein each indicator element is constructed and arranged to determine the presence of lactose in the food or beverage sample.
6. A caffeine indicator which comprises:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a sample-receiving portion positioned at the distal end of the segment, c) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
d) caffeine antibodies positioned on the material proximal to the labeled caffeine, and e) an indicator capable of undergoing a visual change in the presence of the labeling material.
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a sample-receiving portion positioned at the distal end of the segment, c) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
d) caffeine antibodies positioned on the material proximal to the labeled caffeine, and e) an indicator capable of undergoing a visual change in the presence of the labeling material.
7. A caffeine indicator as in claim 6 wherein the material segment comprises an elongated strip.
8. A caffeine indicator as in claim 6 wherein the labeled caffeine is labeled with a material comprising peroxidase.
9. A caffeine indicator as in claim 8 wherein the indicator comprises o-phenylenediamine.
10. A caffeine indicator as in claim 6 wherein at least a portion of the material segment is joined to a support element.
11. A caffeine indicator as in claim 6 wherein at least one of the labeled caffeine, the caffeine antibodies, and the indicator is enclosed within a substantially fluid impermeable, transparent sheath.
12. A caffeine indicator as in claim 6 positioned within a transparent housing.
13. A caffeine test kit which comprises a plurality of caffeine indicator elements each comprising:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a sample-receiving portion positioned at the distal end of the segment;
c) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
d) caffeine antibodies positioned on the material proximal to the labeled caffeine; and e) an indicator capable of undergoing a visual change in the presence of the labeling material;
wherein each of the elements is removeably joined to a retainer, to thereby maintain the plurality of indicator elements and the retainer as a single unit until indicator elements are individually removed therefrom.
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a sample-receiving portion positioned at the distal end of the segment;
c) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
d) caffeine antibodies positioned on the material proximal to the labeled caffeine; and e) an indicator capable of undergoing a visual change in the presence of the labeling material;
wherein each of the elements is removeably joined to a retainer, to thereby maintain the plurality of indicator elements and the retainer as a single unit until indicator elements are individually removed therefrom.
14. A caffeine test kit as in claim 13 which further includes a cover which may be opened to expose the indicator elements.
15. A caffeine test kit as in claim 13 wherein at least one of the elements includes a substantially fluid impermeable transparent sheath enclosing at least one of the labeled caffeine, caffeine antibodies, and the indicator.
16. A caffeine test kit as in claim 13 which further includes at least one transparent housing.
17. A lactose indicator which comprises:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a first indicator for visually indicating the presence of glucose positioned on the material segment, and c) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator.
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a first indicator for visually indicating the presence of glucose positioned on the material segment, and c) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator.
18. A lactose indicator as in claim 17 wherein the material segment comprises anelongated strip.
19. A lactose indicator as in claim 17 wherein the first indicator comprises glucose oxidase.
20. A lactose indicator as in claim 17 wherein the second indicator comprises, in combination, glucose oxidase and lactose.
21. A lactose indicator as in claim 17 wherein at least one of the first and second indicators is enclosed within a substantially fluid impermeable, transparent sheath.
22. A lactose indicator as in claim 17 positioned within a transparent housing.
23. A lactose test kit which comprises a plurality of lactose indicator elements each comprising:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a first indicator for visually indicating the presence of glucose positioned on the material segment; and c) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator;
wherein each of the elements is removeably joined to a retainer, to thereby maintain the plurality of indicator elements and the retainer as a single unit until indicator elements are individually removed therefrom.
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a first indicator for visually indicating the presence of glucose positioned on the material segment; and c) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator;
wherein each of the elements is removeably joined to a retainer, to thereby maintain the plurality of indicator elements and the retainer as a single unit until indicator elements are individually removed therefrom.
24. A lactose test kit as in claim 23 which further includes a cover which may be opened to expose the indicator elements.
25. A lactose test kit as in claim 23 wherein at least one of the elements includes a substantially fluid impermeable, transparent sheathing enclosing at least one of the first and second indicators.
26. A lactose test kit as in claim 23 which further includes at least one transparent housing.
27. A test kit for determining the presence of caffeine and lactose in a sample, the test kit comprising at least one caffeine indicator and at least one lactose indicator, each caffeine indicator comprising:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a sample-receiving portion positioned at the distal end of the segment;
c) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
d) caffeine antibodies positioned on the material proximal to the labeled caffeine: and e) an indicator capable of undergoing a visual change in the presence of the labeling material;
and each lactose indicator comprising:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a first indicator for visually indicating the presence of glucose positioned on the material segment; and c) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator.
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a sample-receiving portion positioned at the distal end of the segment;
c) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
d) caffeine antibodies positioned on the material proximal to the labeled caffeine: and e) an indicator capable of undergoing a visual change in the presence of the labeling material;
and each lactose indicator comprising:
a) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
b) a first indicator for visually indicating the presence of glucose positioned on the material segment; and c) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator.
28. A test kit as in claim 27 wherein each of the caffeine indicators is removeably joined to a retainer, to thereby maintain the plurality of indicators and the retainer as a single unit until indicators are individually removed therefrom.
29. A test kit as in claim 27 wherein each of the lactose indicators is removeably joined to a retainer, to thereby maintain the plurality of indicators and the retainer as a single unit until indicators are individually removed therefrom.
30. A test kit as in claim 27 wherein each of the caffeine indicators and each of the lactose indicators is removeably joined to a retainer, to thereby maintain the plurality of indicators and the retainer as a single unit until indicators are individually removed therefrom.
31. A lactose test kit as in claim 27 which further includes a cover which may be opened to expose the indicator elements.
32. A test kit as in claim 27 wherein at least one caffeine indicator or at least one lactose indicator includes a substantially fluid impermeable, transparent sheath which, in the case of the caffeine indicator, encloses at least one of the labeled caffeine, the caffeine antibodies and the indicator, and, in the case of the lactose indicator, encloses at least one of the first and second indicators.
33. A test kit as in claim 27 which further includes at least one transparent housing.
34. The apparatus of any of claims 12, 16, 22, 26, or 33 wherein the housing comprises a "U"-shaped tube.
35. The apparatus of claim 34 wherein the housing includes a sample collector positioned at an end of the "U"-shaped tube.
36. A method for determining the presence of caffeine in a beverage which comprises the steps of:
a) providing a caffeine indicator which comprises:
i) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
ii) a sample-receiving portion positioned at the distal end of the segment;
iii) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
iv) caffeine antibodies positioned on the material proximal to the labeled caffeine; and v) an indicator capable of undergoing a visual change in the presence of the labeling material;
b) contacting the sample-receiving portion with a sample of the beverage to be tested;
c) allowing the sample to be wicked until it contacts the indicator for a period of time sufficient to cause the indicator to provide a visual indication of the presence of caffeine; and d) observing the indicator to determine whether caffeine is present in the sample.
a) providing a caffeine indicator which comprises:
i) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
ii) a sample-receiving portion positioned at the distal end of the segment;
iii) caffeine labeled with a material capable of causing a visual change in an indicator, the labeled caffeine being positioned proximal to the sample receiving portion;
iv) caffeine antibodies positioned on the material proximal to the labeled caffeine; and v) an indicator capable of undergoing a visual change in the presence of the labeling material;
b) contacting the sample-receiving portion with a sample of the beverage to be tested;
c) allowing the sample to be wicked until it contacts the indicator for a period of time sufficient to cause the indicator to provide a visual indication of the presence of caffeine; and d) observing the indicator to determine whether caffeine is present in the sample.
37. A method as in claim 36 wherein a plurality of caffeine indicators is provided, each removeably joined to a retainer, to thereby maintain the plurality of indicators and the retainer as a single unit until indicators are individually removed therefrom, the method including the additional step of removing an indicator from the retainer prior to contacting the sample-receiving portion of that indicator with the beverage sample.
38. A method for determining the presence of lactose in a beverage which comprises the steps of:
a) providing a lactose indicator which comprises:
i) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
ii) a first indicator for visually indicating the presence of glucose positioned on the material segment; and iii) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator;
b) contacting each of the first and second indicators with a sample of the beverage to be tested;
c) allowing the sample to contact each of the first and second indicators for a period of time sufficient to cause the first indicator to provide a visual indication of the presence of glucose and the second indicator to provide a visual indication of the presence of glucose and lactose; and d) observing the indicators to determine whether lactose is present in the sample.
a) providing a lactose indicator which comprises:
i) a segment of a material having the ability to wick fluids, the segment having a proximal end and a distal end;
ii) a first indicator for visually indicating the presence of glucose positioned on the material segment; and iii) a second indicator for visually indicating the presence of glucose and lactose positioned on the material segment substantially adjacent to the first indicator;
b) contacting each of the first and second indicators with a sample of the beverage to be tested;
c) allowing the sample to contact each of the first and second indicators for a period of time sufficient to cause the first indicator to provide a visual indication of the presence of glucose and the second indicator to provide a visual indication of the presence of glucose and lactose; and d) observing the indicators to determine whether lactose is present in the sample.
39. A method as in claim 38 wherein a plurality of lactose indicators is provided, each removeably joined to a retainer, to thereby maintain the plurality of indicators and the retainer as a single unit until indicators are individually removed therefrom, the method including the additional step of removing an indicator from the retainer prior to contacting that indicator with the beverage sample.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US39860895A | 1995-03-06 | 1995-03-06 | |
| US08/398,608 | 1995-03-06 |
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|---|---|
| CA2214715A1 true CA2214715A1 (en) | 1996-09-12 |
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|---|---|---|---|
| CA 2214715 Abandoned CA2214715A1 (en) | 1995-03-06 | 1996-03-01 | Assays for compounds in consumable items |
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| EP (1) | EP0813681A1 (en) |
| JP (1) | JPH11502016A (en) |
| AU (1) | AU5091296A (en) |
| CA (1) | CA2214715A1 (en) |
| WO (1) | WO1996027795A1 (en) |
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|---|---|---|---|---|
| GB0100770D0 (en) * | 2001-01-11 | 2001-02-21 | Celsis Internat Plc | Hygiene monitoring |
| JP2002340898A (en) * | 2001-05-22 | 2002-11-27 | Toyota Central Res & Dev Lab Inc | Specimen substance detection method and detector |
| EP1714145A1 (en) * | 2003-12-19 | 2006-10-25 | Bloomsbury Innovations Ltd. | Apparatus for detecting drugs in a beverage |
| GB0405648D0 (en) | 2004-03-12 | 2004-04-21 | Bloomsbury Innovations Ltd | Apparatus |
| GB2418248B (en) * | 2004-09-17 | 2009-08-12 | Adam Brown | A testing device for spiked drinks |
| JP4632915B2 (en) * | 2005-09-27 | 2011-02-16 | シスメックス株式会社 | Immunochromatography kit |
| GB2438675A (en) * | 2006-05-22 | 2007-12-05 | Checkmate Organisation Ltd | An integrated liquid sampling and testing device for evaluating substances within potable liquids |
| US7569396B1 (en) | 2006-09-08 | 2009-08-04 | Purplecow Llc | Caffeine detection using internally referenced competitive assays |
| NO2491401T3 (en) * | 2009-10-21 | 2018-11-03 | ||
| US8920857B2 (en) | 2010-12-22 | 2014-12-30 | Michael T. Abramson | System and method for detection of a contaminated beverage |
| US9285352B2 (en) | 2010-12-22 | 2016-03-15 | Drinksavvy, Inc. | System and method for detection of a contaminated beverage |
| JP2014071015A (en) * | 2012-09-28 | 2014-04-21 | Taiheiyo Material Kk | Measurement instrument and measurement method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE427389B (en) * | 1981-03-02 | 1983-03-28 | Alfa Laval Ab | INDICATOR INCLUDING A CAREER AND A REACTION SYSTEM |
| US4410493A (en) * | 1981-05-11 | 1983-10-18 | Sybron Corporation | Indicator device for use in steam sterilization |
| JPS60224063A (en) * | 1984-04-20 | 1985-11-08 | Terumo Corp | Testing implement |
| US4647430A (en) * | 1985-06-20 | 1987-03-03 | Miles Laboratories, Inc. | Volume independent test device |
-
1996
- 1996-03-01 EP EP96907163A patent/EP0813681A1/en not_active Withdrawn
- 1996-03-01 JP JP8526960A patent/JPH11502016A/en active Pending
- 1996-03-01 WO PCT/US1996/002828 patent/WO1996027795A1/en not_active Application Discontinuation
- 1996-03-01 CA CA 2214715 patent/CA2214715A1/en not_active Abandoned
- 1996-03-01 AU AU50912/96A patent/AU5091296A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| WO1996027795A1 (en) | 1996-09-12 |
| AU5091296A (en) | 1996-09-23 |
| EP0813681A1 (en) | 1997-12-29 |
| JPH11502016A (en) | 1999-02-16 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Dead |