US3888628A

US3888628A - Analytical method and apparatus

Info

Publication number: US3888628A
Application number: US277775A
Authority: US
Inventors: J Wallace Graham
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-08-03
Filing date: 1972-08-03
Publication date: 1975-06-10
Anticipated expiration: 1992-06-10

Abstract

The presence of volatile material, such as ethanol, in biological fluids, such as blood, is determined qualitatively and semiqualitatively by placing a drop of the biological fluid on a porous support so as to vastly extend the surface area of the sample of biological fluid. The expanded sample is confined in a small vapor-tight chamber with a liquid colorimetric agent. Changes in the colorimetric agent are noted.

Description

United States Patent [1 1 Graham June 10, 1975 ANALYTICAL METHOD AND APPARATUS [76] Inventor: J. Wallace Graham, 1501 N. Bundy Dr., Los Angeles, Calif. 90049 [22] Filed: Aug. 3, 1972 21 Appl. No.: 277,775

[52] US. Cl. 23/230 B; 206/205 [51] Int. Cl ..G01n 31/22; G0ln 33/16 [58] Field of Search 23/230 B, 259, 292, 232 R,

23/258.5, 230 R, 253 TP, 253 R; 206/1 R [56] References Cited UNITED STATES PATENTS 3,150,932 9/1964 Ogg 23/259 X 3,389,967 6/1968 l-lrabinski 23/230 R Primary Examiner-Robert M. Reese [57] ABSTRACT The presence of volatile material, such as ethanol, in biological fluids, such as blood, is determined qualitatively and semiqualitatively by placing a drop of the biological fluid on a porous support so as to vastly extend the surface area of the sample of biological fluid. The expanded sample is confined in a small vaportight chamber with a liquid colorimetric agent. Changes in the colorimetric agent are noted.

13 Claims, 6 Drawing Figures ANALYTICAL METHOD AND APPARATUS Often, when a patient is admitted to an emergency ward, that patient is unconscious. It often appears, probable that some chemical agent is responsible for the patients condition; however. it is usually difficult, if not impossible, to determine which chemical agent or combination of chemical agents is responsible for the patients condition. The treatment necessary to save the patients life is dependent upon determining quickly and accurately which chemical agents are involved and approximately how much of the chemical agent the patient has consumed. Speed, simplicity, and accuracy are essential in making the qualitative and semiquantitative determination of the chemical agent that is responsible for the patients unconscious condition.

Many of the chemical agents that frequently contribute to the unconsciousness of persons who are admitted to emergency wards are volatile. Probably the most common of these volatile chemicals is ethanol.

Previous solutions to the problem of qualitative and semiquantitative analysis of chemical agents is biological fluids have generally required too much time or have been too complicated for rapid use under emergency conditions with an unconscious patient.

According to the present invention, these and other difficulties of the prior attempts to solve the problem of quickly analyzing biological fluids under emergency conditions for volatile chemical agents have been overcome, and the advantages of a rapid, simple, and accurate qualitative and semiquantitative analysis have been achieved.

The present invention provides a quick, simple, and accurate procedure and the physical kit for carrying out that procedure for determining the presence of volatile materials; such as ethanol, methanol, and isopropanol, in biological fluids, such as blood and urine. A quick qualitative and semiquantitative indication of the volatiles in the biological fluid is obtained within minutes of the time that the sample is withdrawn from the patient.

In general, a drop or two of biological fluid that is suspected of containing a volatile material is placed on a porous support member that vastly extends the surface of the biological fluids sample so as to promote the rapid volatilization of the volatile chemical agent. The expanded sample is placed in a small vapor-tight chamber so that the volatilized chemical agent is confined to a small vapor space. An analytic reagent is also placed in the same chamber so that the volatilized chemical agent in the vapor phase contacts the analytic reagent. The analytic reagent is chosen so that it gives a detectable indication responsive both to the presence and concentration of the volatile chemical agent in the vapor phase. Preferably, the analytic reagent is liquid, and the vapor-tight reaction chamber is proportioned so that the liquid analytic reagent presents a large surface area to the vapor phase space that is shared in common with the expanded sample of biological fluid. Preferably, the analytic reagent is a colorimetric reagent that changes color responsive to the presence of the volatile material being tested for. Preferably, the color change takes place at a rate proportionate to the concentration of the volatile material in the sample of biological fluid.

In the drawings there is illustrated:

FIG. 1, a broken side elevation view of an analytic package according to the present invention;

FIG. 2, a cross-sectional plan view taken along line 2-2 in FIG. 1;

FIG. 3, a plan view similar to FIG. 2 except that the porous member is shown in the expanded configuratron;

FIG. 4, a side elevation of a further embodiment of the analytic package shown in FIG. 1, including an optical filter;

FIG. 5, a cross-sectional side elevation of the embodiment shown in FIG. 4 taken along 55 in FIG. 4; and

FIG. 6, a partially broken side elevation view ofa further embodiment of an analytic package according to the present invention.

Referring particularly to the drawings) there is illustrated an analytical package indicated generally at 10, comprising a reaction chamber 12 and a sample structure 22. Reaction chamber 12 is defined by a generally cylindrical upright transparent chamber 14, which is closed at its open end by removable cap 16. Cap 16 and chamber 14 are so configured at their junctures so that they define together a seal 18. The center of cap 16 is configured so as to define a receptacle 20. Receptacle 20 projects inwardly so that it opens into reaction chamber 12 whencap 16 is in sealed relationship with chamber 14.

A sample support structure indicated generally at 22 comprises a shaft 24 that is received in receptacle 20 at one end and is provided with transversely extending slot 28 at its remote end. Porous member 26 is received in slot 28.

With particular reference to FIGS. 4 and 5, there is illustrated a filter holder 30 that is mounted to the closed exterior end of chamber 14. Filter holder 30 receives and positions optical filter 32 so that the contents of reaction chamber 12 may be viewed through optical filter 32. I

With particular reference to FIG. 6, there is illustrated a cap 34 that replaces cap 16 in sealed relationship with chamber 14. A hollow shaft 36 is mounted in port 40 that extends axially through the center of cap 34 from the exterior to the interior of reaction chamber 12. The exterior; end of hollow shaft 36 is sealed with rubber seal 38, and porous member 26 is received in a slot in the innermost end of shaft 36. Hypodermic needle 42 is shown inserted through rubber seal 38 so as to discharge sample fluid into the interior of hollow shaft 36.

In use a body of liquid indicating reagent 46 is confined within the reaction chamber 12 so that liquid indicating reagent 46 rests on the circular lower horizontal wall of chamber 14. The surface 48 of liquid indicating reagent 46 is exposed to the vapor phase that is confined within reaction chamber 12. A sample of the body fluid that is being tested for its volatile content is placed on porous member 26. Porous member 26 im- -mediately expands to approximately 10 times its dry volume so that the surface of the sample of body fluid is greatly attenuated, thereby promoting the rapid vaporization of any volatile substance that may be in the liquid sample. The liquid indicating reagent 46 is preferably swirled at predetermined time intervals so as to bring fresh reagent from the body of the liquid indicating reagent 46 to the surface 48 where it will react with the volatiles in the vapor phase space within reaction iamber 12. The rounded lower corners 44 on reaction iamber 12 aid in swirling the liquid indicating reagent 6. The length of shafts '24 and 36 are adjusted so that hen porous member 26 is received in the transverse 5 ots in these respective shafts, it will be supported ithin reaction chamber 12 out of contact with the alls of the reaction chamber and liquid indicating rea- :nt 46. Only the vapor phase is in common contact ith both the porous member 26 and the surface 48 of uid indicating reagent 46. The spacing between the .rface 48 of liquid indicating reagent 46 and porous ember 26 is sufficient to prevent liquid indicating rea- :nt 46 from coming into contact with porous member 5 when liquid indicating reagent 46 is agitated by genswirling. In utilizing the analytic package 10 illustrated in FIG. the sample of body fluid which is to be tested for volile content is placed on porous support 26 while the lp 16 is separated from chamber 14. Cap 16 is then imediately placed over chamber 14 so as to effect al 18. When utilizing the analytic package 10 illustrated lrticularly in FIG. 6, the sample of body fluid is incted into the sealed reaction chamber 12 by inserting podermic needle 42 through rubber seal 38 and forcg the sample of body fluid out of the hypodermic neee 42, down hollow shaft 36, onto porous member 26. tilizing the embodiment particularly illustrated in G. 6, any volatile material that flashes into the vapor iase immediately on the expansion of the surface area 'the liquid sample is trapped in reaction chamber 12. An optical filter, illustrated particularly in FIGS. 4 Id 5, is employed when color changes in the indicatg reagent are either not visible to the unaided eye or e much easier to detect when observed through an itical filter having optical characteristics that are prelected for this purpose. Preferably, the surface 48 ofliquid indicating reagent i should be as large as possible in relation to the volne of the vapor space in reaction chamber 12. The mple of body fluid is generally quite small, being usuy not larger than one-half of a milliliter. If the vapor lase space in reaction chamber 12 is large, the volae component that is volatilized from the liquid samon porous member 26 is diluted to such an extent at the reaction with the liquid indicating reagent 46 unreliable. In a preferred embodiment the exterior diameter of amber 14 is 27 millimeters, and the total exterior ight with cap 16 in place is 32 millimeters. The disice from the inwardly disposed side of cap 16 to the note end of shaft 24 is 18 millimeters; the diameter shaft 24 is 2 millimeters; slot 28 is l millimeter wide d 5 millimeters deep; porous member 26 is 10 milli- :ters long, 6 millimeters wide, and l millimeter thick; d the transparent walls of chamber 14 are about 1 llimeter thick. ?referably, analytic package 10 is proportioned so it for every square centimeter of surface 48, there is m about 2 to 3 cubic centimeters of vapor phase ace within reaction chamber 12; however, the ratio liquid reagent surface area to vapor phase volume ty range up to as much as 1 square centimeter to 5 more cubic centimeters. In general, the proportion surface area to vapor space volume in reaction chamber 12 should be no greater than approximately 1 square centimeter to 5 or 6 cubic centimeters.

The analytical package and method described are particularly suited for rapidly detecting qualitatively and semiquantitatively ethanol, methanol, and isopropanol in blood, urine, and cerebral spinal fluid.

The surface area of the sample of fluid may be augmented or expanded to promote vaporization of its volatile components through the use of various porous materials. Suitable sample surface area expanders include, for example, clays, cotton, elemental carbon, openpore cellulosic foam, and the like. Preferably, the openpore cellulosic foam material is used because it is inert with respect to the body fluid samples, and it expands so that the surface area of the sample is vastly expanded with great rapidity. In general, it is necessary to use larger samples of body fluid when porous support members other than cellulosic foam are employed. The increased volume of the sample compensates for the decrease in sample surface area expansion. In general, the volatile component, the presence of which is to be detected, is present in the sample. It is possible, however, to provide a reagent on the porous member such that a reaction between the component being tested for in the sample and the reagent on the porous member will generate a volatile substance that may be detected by the indicating reagent.

In general, the most convenient form for the analytic package is that of an upright cylinder. If desired, however, the analytic package may be configured to meet the requirements of a particular usage. For example, if the analytic package is to be used in a spectrophotometer, it may be necessary to configure the analytic package as a square or rectangular column.

The liquid indicating reagent is preferably chosen so that upon reaction with the volatile material being tested for it will give a visually detectable indication. Suitable liquid indicating reagents include; for example, admixtures of sulfuric acid and potassium permanganate and admixtures of sulfuric acid and potassium dichromate.

In one procedure applied to detect the presence and concentration of ethanol in blood, two separate reagent solutions are prepared. A sulfuric acid solution is prepared by admixing 1 part of concentrated sulfuric acid with 2 parts of water. A dilute potassium permanganate solution is prepared by admixing potassium permanganate with water to produce a 0.02 Normal potassium permanganate solution. One milliliter of the potassium permanganate solution is diluted to 20 milliliters with the sulfuric acid solution. A microdiffusion chamber having the dimensionsdescribed above is selected for use as the reaction chamber, and 2 milliliters of the freshly prepared potassium permanganate sulfuric acid solution is added to the chamber. A 0.1 milliliter sample of .blood is applied to the cellulosic foam support member, and the cap is screwed into place on the chamber so that a vapor-tight seal between the cap and the chamber is achieved. The chamber is swirled gently, without allowing contact between the indicating reagent and the support member. It is allowed to stand for 1 minute and reswirled at 1 minute intervals for a period of 4 minutes. The disappearance of the permanganate color indicates the presence of a volatile reducing substance. Repetition of this procedure using cotton as the porous member produces the same indication when the blood sample size is increased to approximately 1 milliliter.

The indication of ethanol in blood using this procedure is such that the time required for the disappearance of the permanganate color is directlyproportional to the concentration of ethanol. Thus, if the color disappears in exactly 1 minute, the ethanol concentration is approximately 0.5 grams perlOO milliliters of blood. If the permanganate color disappears in 5 minutes, the concentration of ethanol in the blood is approximately 0.10 grams per 100 milliliters ofblood.

The apparatus and procedure described herein are generally applicable to analytical problems where a volatile component in an admixture of liquids must be detected qualitatively and semiquantitatively in one simple, quick step. In addition to the analysis of botanical and biological fluids, the procedure herein is applicable to various manufacturing procedures. For example, in solution polymerization where a volatile monomer is employed, it is possible to detect the progress of the reaction and the end point of the polymerization reaction by observing the decrease in the concentration of the volatile monomer over a period of time. Successive samples are withdrawn from the reaction vessel and are subjected to analysis, as described herein, with the decrease in concentration of the monomer being detectable by increasing reaction times in the reaction chamber.

The reagents and sample are chosen so that the indication is obtained at normal room temperatures. If an additional heating step is required to volatilize the volatile component, the chances for error are substantially multiplied and the objective of simplicity is defeated. Volatilization of the liquid sample is achieved by greatly expanding its surface area rather than by heating it. In general, the surface area of the liquid sample is expanded to an area at least times and preferably times greater than that of the same sample in spherical form so as to promote rapid volatilization at room temperature. Also, the proportioning of the surface area of the liquid indicating reagent to the volume of the vapor space is chosen so that a rapid, reliable indication is given by the reagent. In general, when the analytic package in its assembled form is substantially a right cylinder, the reaction chambers height should be least than approximately three times its diameter.

What is claimed is:

1. An analytical method comprising:

expanding the surface area of a liquid sample;

confining the resultant expanded sample within a closed chamber, said closed chamber also containing a vapor phase space and a liquid indicating reagent, said expanded sample being positioned in close proximity to and out of contact with said liquid indicating reagent;

allowing any volatile substance present with said expanded sample to vaporize to about room temperature into said vapor phase space and to react with said liquid indicating reagent; and

observing said liquid indicating reagent for a predetermined period of time to detect any indication of a reaction with said volatile substance.

2. An analytical method of claim 1 wherein the surface area of the liquid sample is expanded to an area at least 20 times greater than that of the same sample in spherical form.

- 3 Ananalytical method of claim 1 including observing the indicating reagent to detect any change in color in said indicating reagent.

4. An analytical method of claim 1 including placing the liquid sample on a cellulosic foam.

5. An analytical method comprising:

placing a sample of body fluid on a porous support member to expand the surface area of said sample;

confining the vapor phase surrounding the resultant expanded sample in a closed, substantially transparent, reaction chamber; providing liquid indicating reagent'in said reaction chamber, said indicating reagent and said expanded sample both being in contact with said vapor phase and out of contact with one another; allowing any volatile substance present in said expanded sample to vaporize into said vapor phase and to react with said indicating reagent; and observing said indicating reagent for a predetermined period of time and agitating said indicating reagent at predetermined intervals during said period of time to detect any indication of the reaction of said indicating reagent with said volatile substance.

6. An analytic method of claim 5 including placing a sample of blood on a porous support member, providing an aqueous admixture of potassium permanganate and sulfuric acid in the reaction chamber, allowing any alcohol present in the expanded sample to vaporize,

and observing said aqueous potassium permanganate sulfuric acid solution for a period of time to detect the disappearance of the permanganate color.

7. An analytical package comprising:

closable reaction chamber means enclosing within a common vapor phase space, a sample support means, and an indicating reagent, said sample support means and a generally liquid indicating reagent being spaced in close proximity to and out of contact with one another; and

said sample support means including a porous member for supporting a liquid sample and extending the surface area of said liquid sample to an area at least 10 times greater than that of the samesample in spherical form to promote the vaporization of a volatile substance from said liquid sample on said porous member, said indicating reagent being adapted to give a detectable indication responsive to the presence of said volatile substance in said vapor phase, the ratio of the surface area of said generally liquid indicating reagent to the volume of said common vapor phase space being in the proportion of 1 square centimeter to no more than approximately 6 cubic centimeters.

8. An analytical package of claim 7 wherein at least one wall of the closable reaction chamber means is substantially transparent.

9. An analytical package of claim 7 including means for permitting the liquid sample to be placed on the porous member while the closable reaction chamber means is in the closed configuration.

10. An analytical package of claim 7 wherein the porous member is inert to the liquid sample.

1 1. An analytical package of claim 7 wherein the porous member is a cellulosic foam.

12. An analytical package of claim 7 including an optical filter positioned so as to permit viewing of the indicating reagent through said optical filter.

13. An analytical package comprising:

cover member within said reaction chamber, said means for mounting positioning said porous memher at a location spaced from said closed end a distance sufficient to permit a body of liquid to be positioned on said closed end within said reaction chamber out of contact with said porous member, said reaction chamber being proportioned so that the ratio of the surface area of said body of liquid to the volume of the vapor space within said chamber is in the proportion of 1 square centimeter to as much as 5 cubic centimeters.

Claims

1. AN ANALYTICAL METHOD COMPRISING: EXPANDING THE SURFACE AREA OF A LIQUID SAMPLE; CONFINING THE RESULTANT EXPANDED SAMPLE WITHIN A CLOSED CHAMBER, SAID CLOSED CHAMBER ALSO CONTAINING A VAPOR PHASE SPACE AND A LIQUID INDICATING REAGENT, SAID EXPANDED SAMPLE BEING POSITIONED IN CLOSE PROXIMITY TO AND OUT OF CONTACT WITH SAID LIQUID INDICATING REAGENT; ALLOWING ANY VOLATILE SUBSTANCE PRESENT WITH SAID EXPANDED SAMPLE TO VAPORIZE TO ABOUT ROOM TEMPERATURE INTO SAID VAPOR PHASE SPACE AND TO REACT WITH SAID LIQUID INDICATING REAGENT; AND OBSERVING SAID LIQUID INDICATING REAGENT FOR A PREDETERMINED PERIOD OF TIME TO DIRECT ANY INDICATION OF A REACTION WITH SAID VOLATILE SUBSTANCE.

3. An analytical method of claim 1 including observing the indicating reagent to detect any change in color in said indicating reagent.

4. An analytical melthod of claim 1 including placing the liquid sample on a cellulosic foam.

5. An analytical method comprising: placing a sample of body fluid on a porous support member to expand the surface area of said sample; confining the vapor phase surrounding the resultant expanded sample in a closed, substantially transparent, reaction chamber; providing liquid indicating reagent in said reaction chamber, said indicating reagent and said expanded sample both being in contact with said vapor phase and out of contact with one another; allowing any volatile substance present in said expanded sample to vaporize into said vapor phase and to react with said indicating reagent; and observing said indicating reagent for a predetermined period of time and agitating said indicating reagent at predetermined intervals during said period of time to detect any indication of the reaction of said indicating reagent with said volatile substance.

6. An analytic method of claim 5 including placing a sample of blood on a porous support member, providing an aqueous admixture of potassium permanganate and sulfuric acid in the reaction chamber, allowing any alcohol present in the expanded sample to vaporize, and observing said aqueous potassium permanganate sulfuric acid solution for a period of time to detect the disappearance of the permanganate color.

7. An analytical package comprising: closable reaction chamber means enclosing within a common vapor phase space, a sample support means, and an indicating reagent, said sample support means and a generally liquid indicating reagent being spaced in close proximity to and out of contact with one another; and said sample support means including a porous member for supporting a liquid sample and extending the surface area of said liquid sample to an area at least 10 times greater than that of the same sample in spherical form to promote the vaporization of a volatile substance from said liquId sample on said porous member, said indicating reagent being adapted to give a detectable indication responsive to the presence of said volatile substance in said vapor phase, the ratio of the surface area of said generally liquid indicating reagent to the volume of said common vapor phase space being in the proportion of 1 square centimeter to no more than approximately 6 cubic centimeters.

11. An analytical package of claim 7 wherein the porous member is a cellulosic foam.

13. An analytical package comprising: a substantially transparent reaction chamber being closed at one end and open at the other end, the height of said reaction generally being less than approximately three times the diameter of said reaction chamber; a cover member for closing said open end; a porous member for supporting a liquid sample and extending the surface area of said liquid sample to an area at least 10 times greater than the surface area of the same liquid sample in spherical form; and means for mounting said porous member on said cover member within said reaction chamber, said means for mounting positioning said porous member at a location spaced from said closed end a distance sufficient to permit a body of liquid to be positioned on said closed end within said reaction chamber out of contact with said porous member, said reaction chamber being proportioned so that the ratio of the surface area of said body of liquid to the volume of the vapor space within said chamber is in the proportion of 1 square centimeter to as much as 5 cubic centimeters.