MX2008007070A - Apparatus for determining the presence of a contaminant in a sample of water or other fluid - Google Patents

Abstract

Apparatus for testing the quality of a fluid sample, the apparatus comprising a main body including a plurality of sample compartments, characterised in that the apparatus further comprises a contaminant reagent retention means arranged to retain a plurality of doses of contaminant reagent within the apparatus and arranged to allow a dose of contaminant reagent to be added to a fluid sample in a respective one of the sample compartments.

Description

APPARATUS TO DETERMINE THE PRESENCE OF A CONTAMINANT IN A WATER SAMPLE AND ANOTHER FLUID FIELD OF THE INVENTION As recognized by the Development Goals of the Millennium for water, microbially contaminated drinking water is a leading cause of diarrheal disease, responsible for the deaths of 1.8 million people each year (WHO, 2004) of which the majority are children in developing countries. In contrast, the development of new water testing technologies is driven by the needs of water companies in North America and Europe to adhere to the strict standards set by regulatory authorities and, more recently, to concerns about bioterrorism. Even basic water testing equipment, experienced technicians and appropriate laboratory facilities are rarely available in developing countries. As a result, there is a poor correlation between the objectives for technological development and the burden of diseases. This failure to develop appropriate diagnostics is analogous to the lack of investment by pharmaceutical companies to develop drugs to attack common diseases only in developing countries.

BACKGROUND OF THE INVENTION When natural disasters occur, such as tsunami and earthquakes, agencies report that many of the attributable deaths are not the direct result of the disaster itself, but may be caused by subsequent outbreaks of disease, particularly contaminated drinking water. . The testing of drinking water sources after disasters presents particular problems due to the critical lack of equipment, resources and communications and transportation infrastructure.

SUMMARY OF THE INVENTION The World Health Organization issues guidelines for the Quality of Drinking Water. For the bacteriological quality of drinking water, the WHO website states' (En) All the water intended to drink, the bacterium E. col i or the thermotolerant coliform should not be detectable in any sample of 100 mi '. Although adherence to this strict standard is required and achieved by most developing countries in the North, it is likely to be an unreachable goal for most developing countries within the foreseeable future. This is particularly true where water is extracted from community sources in rural areas such as rivers or natural springs.

Currently, many of the other available water testing technologies have been designed for use in developed countries. This is because the size of markets for water testing products is much higher in developed countries than in developing countries, where governments have only limited funds available for water testing. Many water testing technologies, such as the standard membrane filtration procedure, require that water samples be collected in the field, stored under ice in shipping containers, and then transported to a microbiological laboratory. This microbiological laboratory needs to have appropriate facilities to test samples such as glass incubators, laboratory benches, facilities for the disposal of potentially hazardous waste, refrigerators and trained technicians capable of carrying out water tests. In remote areas of developing countries, many of those facilities are simply not available. Ice to transport water samples back to the laboratory may be impossible to obtain. The nearest microbiological laboratory may be at a considerable distance and there may be only very limited transport available for very pressured governmental environmental health technicians. Establishing a laboratory locally can also be difficult. Power plants may not be available or available only sporadically and even buildings with work tables and running water can be difficult to find. In many organizations in developing countries they may be unable to afford the high consumable costs associated with some water tests. In many rural districts in developing countries, there is a lack of trained personnel capable of carrying out some of the more complex water testing procedures, such as calculating the Most Probable Numbers of indicator bacteria or performing dilutions of appropriate samples. In recent years there has been some progress in the development of field equipment to test water. The University of Surrey developed the "DelAgua" team and it is still sold and used in the field, both in developing countries and by disaster relief agencies. It is based on the membrane filtration technique, requires an experienced technician and requires a lot of time. In more recent years, tests using Hydrogen Sulfide (H2S) have been developed to provide a simple result of 'Presence / Absence'. An evaluation of these tests (Sobsey and Pfaender, 2002) concluded (p37) 'The H2S method in various modifi cations has been tested in many places in different waters and produced reported results as indicating that it was a reasonable procedure to test treated and untreated waters for fecal contamination. It offers advantages that include low cost (estimated at 20% of the cost of coli formes tests), simplicity and ease of application to environmental samples'. However, the report noted several deficiencies in the reported H2S test assessments and commented 'Because of these deficiencies, it is not possible to widely and unequivocally recommend H2S tests for the determination of faecal contamination in drinking water. There are still too many uncertainties about the reliability, specificity and sensitivity of the test to detect faecal contamination of drinking water and its sources'. Traditional laboratory tests include taking a sample of 100 ml of water and passing it through a filter membrane. The residue remaining on the filter membrane is then cultured with staining reagents. After an incubation period, the stained colonies are counted manually. In recent years, several manufacturers have produced reagents that use nutrient indicators to detect total coliforms and E. coli. Coliforms produce an enzyme that metabolizes nutrient indicators and causes a color change or fluoresces. These reagents are thus able to identify E. coli by visual or laser inspection. A well-known sample test kit uses a nutrient indicator together with large sealable blisters with large quantities of individual sample receiving wells (50-97). The nutrient indicator is mixed with a water sample which is then emptied into the blister and the blister is subsequently sealed so that the individual wells are all filled with the mixture of the sample and the nutrient indicator. After an appropriate incubation period, the number of sample wells that show a positive result (indicated contamination) is counted and the statistical analysis is applied to estimate the level of contamination in cfu / 100 ml. However, the mixture of sample and nutrient, the filling of the blister, the counting of the positive results and the statistical analysis all require experienced or educated personnel and such are not suitable for use by untrained or uneducated individuals as is generally the case. case for example in developing countries. Therefore, there is a need for a method and apparatus for testing the quality of a fluid sample that substantially solves the aforementioned disadvantages.

According to a first aspect of the present invention, an apparatus for testing the quality of the fluid sample is provided, the apparatus comprises a main body including a plurality of sample compartments, characterized in that the apparatus further comprises a retention means of contaminant reagent arranged to retain a plurality of doses of contaminant reagent within the apparatus and arranged to allow a dose of contaminating reagent to be added to a fluid sample in the respective sample compartments. Preferably, the volume of at least one of the sample compartments differs from the volume of the other sample compartments. This allows an indication of the quality of the sample to be inferred simply from the number of sample compartments in which contamination is detected, since at low levels of contamination only the sample compartments have the greatest volumes of contamination, while At higher levels of pollution, the smaller compartments will also spread pollution. Additionally or alternatively, the contaminant reagent retention medium can comprise a breakable membrane that separates the plurality of contaminant reagent doses from the respective sample compartments. Alternatively, the contaminant reagent retention means may comprise a permeable membrane located in each sample compartment, so that the contaminating reagent is permanently located within the sample compartment and may even be mixed with the water sample. In a further embodiment, the contaminant reagent can be retained within a cartridge mechanism arranged so that individual doses can be mechanically distributed from the cartridge in the sample compartments, for example by means of linear or rotational movement of a dispensing member with respect to the cartridge. Additionally or alternatively, at least a portion of the sample compartments is transparent, or at least is not opaque, so that any visual indication provided by the contaminant reagent can be readily observed with the naked eye. In preferred embodiments, the apparatus may further comprise a first visual indicator arranged to indicate whether the temperature of the apparatus at any point has fallen below a first threshold temperature value. Additionally, the apparatus may further comprise a second visual indicator arranged to indicate whether the temperature of the apparatus has risen at any point on a second threshold temperature value. The lower and higher threshold values represent the extremes of temperature within which polluting organisms have a significant growth rate (above the upper threshold at which organisms are killed, while below the lower threshold their proportion of Growth effectively stops). In preferred embodiments, the visual indicators comprise a temperature-sensitive chemical substance that undergoes a non-reversible change in appearance, such as color, when a particular temperature threshold, either higher or lower, is exceeded. The chemical substances may comprise liquid crystals sensitive to temperature or leuco dyes. In additional preferred embodiments, the apparatus may further include a third visual indicator arranged to indicate when the incubation period of the contaminating organism is complete. The third visual indicator of preference may be sensitive to the temperature of the apparatus, and thus the temperature of the samples that are incubated. Additionally, the third visual indicator of preference may include a chemical that changes the visual appearance, such as color, at a rate equal to the growth rate of the contaminant. In other words, the third visual indicator mimics the temperature depending on the behavior of the pollutant. Since chemical substances include Time Temperature Indicators (TTI) such as diffusion-based indicators, enzymatic indicators or reaction indicators by polymerization. Additionally or alternatively, the apparatus may further include a heat source compartment arranged to receive a heat source, the heat source being provided to facilitate the incubation process. The apparatus may additionally comprise a heat source itself, such as a heating pad, one or more portions of exothermic chemicals, one or more portions of phase change materials, or any combination thereof. In the case of exothermic chemicals, these may be encapsulated in a soluble material, preferably of varying thickness, so that the exothermic chemicals are activated for a period of time as the encapsulating material dissolves. It is advantageous to provide one or more means to maintain the temperature of the apparatus at a level suitable for a good incubation of polluting organisms that is not based on the availability of an external energy source or of third parties, such as an electrical supply, since the device can be used where a power source is not available. Additionally or alternatively, the apparatus may further comprise a neutralizing agent retention means arranged to retain a neutralizing agent within the apparatus and arranged to distribute the neutralizing agent in the sample compartments when activated. The neutralization retention medium may comprise a breakable membrane which separates the neutralizing agent from the sample compartments. The purpose of the neutralization agent is to decontaminate the source of fluid after incubation, by exterminating any contaminating organisms, and to return the contaminant reagent itself harmless. In a preferred embodiment, the main body of the apparatus can be elongated and have first and second end faces, with the sample compartments comprising a plurality of elongated chambers extending between the end faces in the elongate body. This apparatus may further comprise at least one end cap arranged to be held on an end face and to seal the sample compartments in a fluid-tight manner. The contaminant reagent retention means can preferably be located within the end cap, as can additionally be the neutralization agent. In an alternative embodiment, the main body of apparatus may comprise a flat element having a plurality of depressions, or wells, formed therein, the depressions constituting the sample compartments. The dose of contaminating reagent can be retained within each depression.

BRIEF DESCRIPTION OF THE FIGURES The embodiments of the present invention will be described in the following by means of the non-limiting examples only, with reference to the attached figures of which: Figure 1 shows an exploded view of a first embodiment of the present invention; Figure 2 shows a detailed view of an end cap of the apparatus of Figure 1; Figure 3 shows a plan view of a second embodiment of the present invention; Figure 4 shows a cross-sectional side view of the embodiment of Figure 3; and Figure 5 shows a side view of a further variant of the embodiment shown in Figures 3 and 4.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 illustrates an exploded view of a first embodiment of the present invention. The water testing device comprises a main body 1 which is generally elongated in shape and has a plurality of compartments 3 of individual samples formed therein. In the illustrated embodiment, the sample compartments comprise elongated passages extending across the entire length of the main body 1 of the apparatus. In preferred embodiments, ten separate sample compartments are provided (only a small number as illustrated in Figure 1 for purposes of clarity). The main body 1 of the apparatus has first and second end faces. A first end cap 5 is provided which is arranged to fit over an end face of the main body 1 in a fluid-tight manner, thereby sealing one end of the sample compartments. A second end cap 7 is also provided which similarly is arranged to fit over the opposite end face of the main body 1 in a fluid-tight manner, thereby sealing the opposite end of the sample compartments. The first end cap 5 has a plurality of doses 9 of contaminant reagent which are held within the end cap 5 by a contaminant reagent retention mechanism. The doses of the contaminant reagent are located within the end cap 5 so that each dose is physically located adjacent one end of a respective sample compartment when the end cap 5 is sealed sealingly on one end of the main body 1 of the apparatus. To ensure this special calibration, one or more cooperative coupling lugs can be provided in the end cap 5 and the main body 1 of the apparatus (not illustrated in Figure 1). The contaminant reagent retention mechanism is arranged so that when desired, individual doses of the contaminant reagent can be introduced into the corresponding sample compartments. A first arrangement of the contaminant reagent mechanism is illustrated schematically in Figure 2. Figure 2 schematically illustrates a cross-sectional view of the first end cap 5 on which the contaminant reagent retention mechanism is located. The contaminant reagent retention mechanism comprises a breakable membrane 11, such as a thin sheet of metal, which is bonded to the lower surface of a blister 13 which is bonded to itself to the outer end face of the end cap 5. A number of blisters are formed in the blister, each blister containing a dose of the contaminant. The blister preferably is made from a deformable material, such as a deformable plastic, so that when a compressive force is applied over a certain threshold in the blister, the contaminant reagent breaks the breakable membrane 11 and thus is free to fall into the corresponding sample compartment. In an alternative embodiment, the contaminant reagent retention mechanism comprises separate mesh cavities located within each sample compartment, each mesh cavity containing a dose of contaminant reagent, so that a sample of fluid introduced into the sample compartment is free to mix with the contaminant reagent through the open pores of the mesh cavity. In a further embodiment, the doses of the contaminant reagent can be accommodated within a multi-compartment "cartridge" which is arranged to be located within an appropriate recess within the end cap and a suitable "plunger" arrangement provided in the end cap which drives the individual doses of the cartridge, the plunger is mechanically linked to the lid so that linear or rotational movement of the lid causes the plunger to be pushed towards the cartridge. Other mechanical retention and release mechanisms can be visualized by those with experience in the art.

The opposite end cap 7 may include a neutralization agent retention mechanism that can take a shape similar to that of the contaminant reagent retention mechanism described above and which retains one or more doses of neutralization agent that can be mixed with the contents of the sample compartments when required to return to the contents of the chemical and biologically inert sample compartment. This is preferred since it allows the contents of the apparatus to be easily discarded after use without chemically or biologically contaminating the area in which it is disposed. In alternative embodiments, only one end cap can be provided, in which case one end of the main body 1 is formed without any opening. In this case, both the contaminant reagent and the neutralization agent retention mechanisms can be located within the single end cap. To test a sample of a fluid, water for example, the individual sample compartments are filled with the sample water. This can be achieved more easily by joining one or the other of the end caps to the main body of the apparatus and immersing the apparatus in the water source, if possible. Having filled the sample compartments, both end caps are 1 secure on the respective end faces of the main body of the apparatus to seal the individual sample compartments. The reagent retention mechanism of the contaminant is then operated to introduce a single dose of contaminant reagent into each of the sample compartments. The apparatus then needs to be incubated for a period of time to allow any contaminating organisms present in the sample to multiply at a detectable level. The temperature range over which any coliforms, for example, within the water sample will establish a colony that will be between 7 ° C and 44 ° C. Where this temperature can not be maintained simply by virtue of the ambient temperature, it is necessary to provide a heat source for incubation, isolation or cooling medium. It is more likely that some form of heat source will be required instead of cooling. Due to the small size of the appliance, the necessary heating can be achieved by securing it against the human body (ideal for a single-use domestic use) or against the skin of a pet. In the embodiment illustrated in Figure 1, the main body of the apparatus is substantially cylindrical with a central passage formed along the longitudinal axis of the main body and with the sample compartments located surrounding this central compartment. In this way, the central compartment can be used to receive an appropriate heat source, for example, an autonomous package of exothermic chemicals that are activated when the device is first immersed in the sample water source. However, it will be appreciated that other sources of heat may be placed within the compartment, such as chemically heated elements activated by the mixture of two or more exothermic chemicals, preheated thermal pads (preheated by immersion in hot water, for example) or elements of heat. heating driven by the sun or battery. In some embodiments, a portion of the encapsulated exothermic chemicals is loaded into the central cavity, the encapsulation material is soluble so that in the mixture with the fluid (taken from the sample fluid) the exothermic chemicals are activated only after the has dissolved the encapsulation, thereby providing a time delay to activate the heating action. By varying the encapsulation thickness, the proportion by which the exothermic chemicals are activated can be controlled to prolong the overall heating effect. In some embodiments, one or more of the end caps provided may contain the exothermic chemicals encapsulated so that they can be released into the central cavity of the apparatus when required. In other modalities, the heat source can be provided by the inclusion of phase change materials within the apparatus, which are characterized by the property of extracting heat from or imparting heat to any surrounding material as they change phase, for example from the solid phase to liquid In this way, the cavity can be filled with a phase change material that imparts heat to its surroundings as it changes from liquid to solid phase and this can be activated simply by placing the filled apparatus in a source of direct heat, such as in the direct sunlight. Likewise, the walls of the apparatus can be formed to enclose one or more cavities of such phase change material to replace or increase the use of the central cavity. The ability to heat or cool the appliance without any external power supply (or with only a limited power supply) is particularly advantageous in circumstances where the appliance is used in very rural or remote locations where a permanent or reliable power supply may not be available. Under ideal laboratory conditions, fluid samples can be incubated at 35 ° C for a period of about 18 hours, for example. However, due to the intended use in non-laboratory conditions, it may not be guaranteed so that a constant temperature will be maintained and therefore the incubation period will vary as a function of the temperature profile to which the device is exposed during incubation. Accordingly, in preferred embodiments of the present invention, one or more visual indicators are provided to indicate in an unambiguous manner whether the incubation has been completed and whether it has been successful or not. In terms of incubation success when the contaminant of interest is E. coli or other coliforms, incubation will not be successful if the temperature of the device is dropped below the above-mentioned minimum temperature of about 7 ° C or above the value of upper threshold temperature of about 44 ° C. Accordingly, a first visual indicator 17 can be provided which preferably comprises an appropriate temperature-sensitive chemical that if exposed to a temperature above about 44 ° C will experience a non-reversible change in appearance. Most preferably, the chemical is selected so that upon exposure to temperature above the threshold value, it will change color to a red color, thus visually indicating that the device has been exposed to an excessive temperature and that the incubation will not be valid. A second visual indicator 19 can also be provided, preferably again comprising an appropriate chemical, which when exposed to a temperature below the lower threshold value of about 7 ° C experiences a non-reversible change in appearance, preferably changes its appearance to a blue color and in this way indicates that the device has been exposed to a temperature below the minimum accepted and thus that the incubation will have stopped prematurely. Examples of suitable chemicals include liquid crystals or leuco dyes. Liquid crystals use organic polymers such as colestril nonanoate or cyanobiphenyls that change their orientation with temperature so that the relative change in the crystal forms is in the visible light spectrum, thus resulting in a color change when observed by the human eye. Alternatively, they cut out the visible light completely and darken. These liquid crystals are encapsulated and suspended in a paint medium. Other colored transparent organic polymers (ie, leuco dyes) are spirolactans, fluorans, spiropyrans and fulgida. In the embodiment illustrated in Figure 1, the first and second visual indicators take the form of small discs or circles located on the outer surface of the main body 1 of the device, although they can be located anywhere in the device. Also located on the outer surface of the main body is a third visual indicator that is provided to indicate when the incubation process has been successfully completed. As mentioned previously, the period of time required for successful incubation, assuming appropriate temperature conditions, will nevertheless vary depending on the range of temperatures to which the device has been exposed. Accordingly, in preferred embodiments, the third visual indicator 21 comprises a chemical substance that is arranged to change visual appearance over a period of time and such that the proportion by which the substance changes appearance closely matches the incubation rate of the substance. coliforms depending on the temperature curve exposed. In other words, the proportion in which the chemical of visual appearance changes is dependent on the temperature at which it is exposed. Suitable chemical substances are Indicators / Temperature Integrators on Time (TTI). These fall into 3 main types: indicators based on diffusion, enzymatic indicators and indicators of solid state polymerization reaction. The last group are compounds that undergo addition polymerization to give a progressive irreversible color change that is indicative of the integrated time-temperature conditions. In preferred embodiments, and as illustrated in Figure 1, the third visual indicator comprises a rectangular band that changes in visual appearance in a progressive manner during the incubation period so that when the entire band has changed in visual appearance, then the incubation is considered to have been completed. Of course it will be appreciated by those skilled in the art that other non-chemical visual indicators can be provided that have the same functionality as the chemical substances described in the foregoing with respect to the first, second and third visual indicators. For example, an electronic indication mechanism can be easily conceived using one or more temperature sensors, appropriate threshold circuitry and visual displays. However, while it is possible and within the scope of the present invention, these non-chemical solutions are not preferred due to their increased complexity and cost. In additional embodiments, instead of providing a heat source or cooling source, within the central cavity of the device, a plastic sleeve may be provided which is arranged to over the exterior of the apparatus as illustrated in Figure 1, the plastic sleeve optionally includes any cavities for separate heat sources or cooling means or by itself includes an exothermic heat source. In additional embodiments, an electrically activated heating or cooling mechanism may be provided which is essentially battery driven or sun-driven, together with a solar panel provided. As previously discussed, regulatory authorities have accepted membrane filtration and Most Probable Number methods to establish a quantified estimate of the level of contamination in terms of cfu / 100 ml. Apart from being extremely complicated to determine in the context of non-laboratory conditions and inexperienced users, these methodologies provide a degree of quantification that is greater than that required in the context of simply providing an indication of the overall quality level of the water source sampled However, it is still desirable to provide some indication of different levels of quality beyond just an indication of the presence or absence of faecal contamination. This is desirable where it is likely that children or immunocompromised individuals will be the recipients of the waterIn any case, it is preferable that the water given to these individuals be of a higher quality than that which may otherwise be acceptable. With embodiments of the present invention, the quality of the water sample can be differentiated between three different levels of contamination, for example, from 0 to 10 cfu / 100 ml, from 10 to 100 cfu / 100 ml and 100 + cfu / 100 my. The applicant has determined that the minimum sample required to distinguish, with a 95% confidence level, between contamination of less than 10 cfu / 100 mi or more than 10 cfu / 100 mi is 37.5 mi. The applicant has also realized that at higher levels of contamination only a smaller sample size is required for the contamination reagent to provide a visual indication of contamination. Accordingly, in preferred embodiments of the present invention, ten sample compartments are provided in different volumes, for example, 2xl0ml, 2x5ml, 2x2.5ml, 2xlml and 2x0.5ml, a total volume of 38ml, i.e., above the minimum required to distinguish the lowest level of contamination at the 95% confidence level. By virtue of the different volumes of sample compartments, it is possible to simply count the number of compartments that demonstrate a visual indication of contamination to determine the likely overall level of contamination. In addition, it is not necessary to distinguish between different 2 compartment sizes that show the visual indication, only the general number of compartments. Consequently, a simple diagram can be provided with the apparatus that correlates the number of compartments that show a visual indication of contamination with the approximate level of contamination. Ten compartments are provided in preferred embodiments of the apparatus since even individuals with little knowledge are likely to be able to count to 10. Equally, when taking into account which of the sample compartments show contamination, a more accurate indication of the level of contamination can inferred by more experienced users. It will also be appreciated that the number and overall volume of sample compartments can be varied if confidence levels other than 95% are required or acceptable. For example, for a higher level of confidence, the overall volume of the sample compartments should be increased. An alternative embodiment of the apparatus of the present invention is illustrated schematically in Figures 3 to 5. A plan view is shown in Figure 3 in which a main planar element 31 is provided having a plurality of compartments 33 of samples formed in the same. The seal 35 is provided to close the apparatus after the water sample has been introduced therein. First, second and third visual indicators 37, 39 and 41 are provided in the main element and can be implemented as discussed previously with respect to the embodiment illustrated in Figure 1. Figure 4 shows a side view of the apparatus of Figure 3 taken through a cross section through a set of sample compartments 33. The sample compartments are formed as depressions or wells within the main element 31. A sealable cover 43 is provided which preferably attaches permanently at one end of the main element 31 and has a portion of the seal 35 at the opposite end thereof. In use, seal 35 is opened, thereby allowing sample fluid to enter the apparatus. The sealable cover then closes over the main element 31 and is sealed thereto by means of the seal 35, the cover 43 thereby isolating the compartments 33 of individual samples. In the embodiment illustrated in Figure 4, a permeable membrane 45 is provided separate from the side wall of the depressions forming the sample compartments, the permeable membrane is provided to restrict the individual doses of contaminant reagent 49 within the compartments of individual samples. Figure 5 illustrates a further variation of the embodiment illustrated in Figures 3 and 4, in which an additional 5 in 5 compartment can be provided, for example, by means of an additional flexible membrane, to receive a heat source to assist in the incubation as discussed previously. In preferred embodiments, the contaminant reagent comprises a nutrient indicator that produces a visible color change to indicate the presence of a contaminant after the incubation period. Therefore, in preferred embodiments, at least a portion of each of the sample compartments is transparent or opaque to allow a visual inspection of the contents. Where the sample compartments are of different volumes, it is also preferable that the non-opaque part of the sample compartments for all be the same size and appearance so that it is not readily apparent which compartment is which, since it may affect how the Test results are reported by non-premiered users. While this can be achieved by simply varying the size of the sample compartments behind the transparent 'windows', this may have the effect of varying the depth of color received between separate compartments., due to the possible variation in thickness of the fluid sample that is observed. Since this may be undesirable on its own (as a non-trained or experienced user may falsely discount a sample compartment apparently showing only a shadow of contaminant indicator light as uncontaminated), it is more preferable than the internal geometry of the compartments of Samples are such that the physical depth of the compartment opposite the transparent portion is the same regardless of the overall volume of the compartment. Although primarily intended for use in rural or remote areas of the world where complete laboratory facilities are not available, it will be appreciated that the apparatus can be used in other situations, such as military applications or in disaster areas. It will also be appreciated that although the embodiments described in the foregoing have mostly referred to the quality of drinking water, the apparatus of the present application can be used for other sources of water, such as river or lake water, or even others. fluids, such as animal milk.

Claims (17)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property.
2. CLAIMS 1. An apparatus for testing the quality of a fluid sample, the apparatus characterized in that it comprises: a main body including a plurality of sample compartments, a contaminant reagent retention means arranged to retain a plurality of reagent doses of contaminant within the apparatus and arranged to allow a dose of the contaminant reagent to be added to a fluid sample in the respective of the sample compartments, and a first cover to close the fluid under test within one or more of the compartments , wherein the retaining means is located within the first lid. The apparatus according to claim 1, characterized in that the volume of at least the sample compartments differs from the volume of the other sample compartments.
3. 3. The apparatus according to any preceding claim, characterized in that the contaminant reagent retention means comprises a breakable membrane that separates the plurality of reagent doses from the respective sample compartments. The apparatus according to any preceding claim, characterized in that the compartments shown are not opaque. The apparatus according to any preceding claim, further characterized in that it comprises a first visual indicator arranged to indicate whether the temperature of the apparatus has fallen below a first threshold temperature value. The apparatus according to any preceding claim, further characterized in that it comprises a second visual indicator arranged to indicate whether the temperature of the apparatus has been raised above a second threshold temperature value. The apparatus according to claim 5 or claim 6, characterized in that the visual indicator comprises a temperature-sensitive chemical substance that undergoes a non-reversible change in appearance when a temperature threshold is exceeded. The apparatus according to any preceding claim, further characterized in that it comprises a third visual indicator arranged to indicate when the incubation period of the contaminant reagent is complete. The apparatus according to claim 8, characterized in that the third visual indicator is sensitive to the temperature of the apparatus. The apparatus according to claim 9, characterized in that the third visual indicator includes a chemical substance that changes the visual appearance in a proportion equal to that of the contaminant reagent during the experienced temperature of the apparatus. The apparatus according to any preceding claim, further characterized in that it comprises a heat sink compartment arranged to receive a heat source. 12. The apparatus according to any preceding claim, further characterized in that it comprises a heat source. The apparatus according to any preceding claim, further characterized in that it comprises a reagent neutralizing retention means disposed to retain a neutralizing agent within the apparatus arranged to distribute the neutralizing agent in the sample compartments when activated. . The apparatus according to claim 13, characterized in that the neutralization retention means comprises a breakable membrane that separates the neutralizing agent from the sample compartments. The apparatus according to any preceding claim, characterized in that the main body is elongated and has first and second end faces and where the sample compartments comprise a plurality of elongated chambers extending between the end faces. 16. The apparatus according to claim 15, characterized in that the apparatus further comprises a second cover and wherein the covers are arranged to be clamped on the respective end faces and seal the sample compartments in a fluid-tight manner. The apparatus according to any preceding claim, characterized in that the main body comprises a flat element having a plurality of depressions formed therein, the depressions constituting the sample compartments.