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Chapter 11 Some other applications of test methods
Chapter 11
Some Other Applications of Test Methods
There are other areas where test methods are being employed but which have not been mentioned so far in this book. Two of them determination of noble metals by the use of the touchstone and application of test methods in the teaching process - are briefly considered in this chapter.
11.1
DETERMINATION OF GOLD AND SILVER BY THE TOUCHSTONE
This technique has been known since ancient times. Probably, the first mention of such a method of gold assessment was made in Theophrastus's work "On Stones" (372-287 B.C.). The method has been in use for many centuries. In the early 1600s it was improved by the introduction of reference samples, viz. 23 needles containing different amounts of gold from 1 to 23 carats and an additional one made of pure gold. Procedure To test gold specimens, a strip of uniform geometry and density 15-20 mm long and 2-3 mm wide is formed on the touchstone by scratching with the tested golden specimen. A similar strip is made in close vicinity with an appropriate reference needle. The strips are wetted width-wise by a special gold reagent using a glass rod and the reaction progress is closely watched for 15-20 seconds, after which the reagent is gently removed with filter paper, the test and reference strips are finally dried and colour-matched against each other. If the colours of the reaction spots on the strips are more or less identical then the gold 293
contents of the tested and reference samples are assumed to be also identical. If the colour intensity of the test strip is lower (or higher) than that of the reference one then the gold content of the test specimen is lower (or higher) than that of the reference sample. The method has the advantage over other methods requiring dissolution of the sample that it is very quick and simple and causes almost no damage to the tested gold articles. It allows not only qualitative but also quantitative determination of gold, silver, platinum in alloys and golden articles. Its accuracy is high, e.g. when testing a gold article of 583 per mille (p.m.) gold content the measurement error may be 2-5 p.m. 11.1.1 The touchstone and test needles The touchstone refers to silicon slate, is black in colour, has a uniform small-grained composition without quartz films or cracks, is sufficiently hard, and allows obtainment of uniformly dense strips of noble metals. It is chemically stable and is resistant to mineral acids (HNO3, HCl, H 2SO4 ) and their mixtures. The test needles are alloys of gold, silver and platinum taken in different but strictly defined proportions. The gold needles are usually alloys of gold, silver, copper, and less frequently those of gold, silver or gold, copper. For testing gold articles the needles of the following p.m. gold content are used: 333, 375, 500, 578, 583, 750, 900, 916 and 958. Additionally, needles with intermediate gold contents are prepared (Table 11.1). Silver needles are made of silver-copper alloys of the following p.m. gold content: 500, 550, 600, 650, 700, 750, 800, 875, 900, 916. The 500 and 900 p.m. needles are used to test coin alloys, and 750, 800, 875, and 916 p.m. needles are used for testing silver articles manufactured in Russia. 11.1.2 Reagents Reagents for gold are prepared in the following manner. Gold chloride solutions are obtained by dissolving 23 g H[AuCl 4 ] 4H2 0 in 1000 ml distilled water. It is used for testing alloys and articles of the 583 p.m. gold content and lower. Those of the 375-958 p.m. gold content are tested with acid reagents whose composition is indicated in Table 11.2. Although the touchstone is employed for testing silver and platinum articles, besides gold ones, in this book attention is given only to its use with golden alloys and articles just for the sake of an example. 294
TABLE 11.1 Chemical composition of test needles used for testing gold articles and alloys with the touchstone (%) Gold
Silver
Copper
Gold
Silver
Copper
Needles of 375 p.m. gold content
Needles of 750 p.m. gold content
37.5
62.5
-
75.0
25.0
-
37.5
50.0
12.5
75.0
18.7
6.3
37.5
37.5
25.0
75.0
12.5
12.5
37.5
25.0
37.5
75.0
6.2
18.8
37.5
12.5
50.0
75.0
-
25.0
37.5
-
62.5
75.0
Needles of 500 p.m. gold content
Needles of 833 p.m. gold content
50.0
50.0
-
83.3
50.0
40.0
10.0
Needles of 916 p.m. gold content
50.0
30.0
20.0
91.6
50.0
20.0
30.0
Needles of 958 p.m. gold content
50.0
10.0
40.0
95.8
4.2
-
50.0
-
50.0
95.8
2.1
2.1
95.8
-
4.2
8.3
8.4
4.2
4.2
TABLE 11.2 Composition of acid reagents for testing gold articles and alloys Gold contents (p.m.)
HNO3 (sp.w. 1.4)
HC (sp.w. 1.19)
Water
375
59.5
-
40.5
500
100.0
-
-
750
59.3
1.1
39.6
833
68.7
1.3
30.0
900
78.7
1.3
20.0
958
69.2
2.0
28.8
295
The above-mentioned highly sensitive and specific gold chloride solution is employed for testing, besides gold alloys, two-component gold-silver or gold-copper alloys, as well as three-component goldsilver-copper ones with less than 583 p.m. gold content. The scientific technology centre Tekhnokom-AS (Moscow) has developed a portable instrument "Gold Detector" for detecting gold in alloys and gold wares. The instrument scale has nine divisions corresponding to gold contents from 300 to 750 p.m., it shows the presence of platinum or a complete absence of gold (RF Patent 2057410). 11.2
USE OF TEST METHODS IN EDUCATION
One of the main objectives of ecological education is to overcome the passive attitude of pupils and students to ecological problems and inculcate in them an active and creative desire to defend the environment. Making them participate in research projects aimed at environmental monitoring and control raises their awareness, develops individual skills and awakens an interest in scientific work. The analyses and tests performed by them with their own hands and the results obtained are the best argument in favour of the necessity to protect and improve the environment. Test systems are an excellent means of teaching chemistry and ecology in schools and other educational institutions. They are convenient to use in the chemistry schoolroom, for out-of-the-class studies, expeditions, and excursions. They are quite valuable for teaching students ecological and foodstuffs control, and ecological monitoring of lakes and rivers during expeditions. Students of non-chemical departments learn the simplest methods of soil assessment, of bio- and mineral testing. As an example, one may cite the teaching test kits manufactured by Krismas+ (St. Petersburg, Russia) - Pchelka-U, Pchelka-U/M, and Pchelka-U/Khim. For example, the "Pchelka-U" kit allows the following experiments to be carried out: 296
rapid analysis by means of indicator tubes of such air pollutants as nitrogen oxides and sulphur dioxide; rapid non-aspiratory analysis of ammonia vapours; rapid analysis of contaminants in water and water extracts, e.g. active and total chlorine, pH, nitrates and chromates; rapid analysis of soil contamination using soil extracts;
-
rapid analysis of salts and fertilizers; rapid analysis of nitrates in beverages and fruits.
The Pchelka-U/Khim kit allows determination of carbonates and hydro carbonates, chlorides, sulphates and total water hardness. The kit's weight is no more than 3 kg; it is a hand-carried case measuring 330 x 170 x 160 mm. It includes five indicator tubes for air analysis, test means for 100 analysis of each specified water parameter. There are also ecological kits for practical work intended for use by students in Forms 9-11 of schools and supplementary learning establishments. The practical work kit is a modular-based didactic methodological complex including equipment and tools for carrying out experiments in ecology, environmental monitoring, geography, chemistry, biology with elements of ecology, and also the methodological literature. The practical work kit covers the main themes included in the ecological practical course, namely: -
-
-
assessment of water bodies' ecological status using test-kits and tests; the tested parameters are: organoleptic characteristics, pH, sulphates, carbonates, chlorides, dissolved oxygen, nitrates, nitrites, total hardness, chromates, copper, potassium, sodium, active chlorine, and others; assessment of the ecological status of air; determination of carbon dioxide, sulphur dioxide, nitrogen oxides, dust, bio indication of atmospheric precipitates; assessment of the ecological status of soil; determination of pH, salt content in water extracts; modelling of chemical contamination of air and water media and their rapid chemical analysis; determination of nitrates in vegetables, fruits, beverages, and water.
Modular design of the practical work kit creates favourable conditions for carrying out expedition tasks, field and outdoor practical work of all or selected directions. A complex ecological monitoring can be performed by students using the kit in combination with such instruments as microscope, noise meter, lux meter, radio dosimeter, psychrometer and others. Ecology and environmental protection have long been an integral part of school curricula, especially in chemistry and biology. The Aquamerck® test kit system and, especially, the Compact Laboratory, are 297
ideal tools for illustrating ecological principles and the potential effect of our interfering with nature. The test procedures can be learned quickly and pupils soon begin to participate actively and even carry out their own measurements. Aquamerckg test kits can also be used highly effectively and in a very impressive manner to demonstrate reaction mechanisms and analytical methods. Apart from the various ecological aspects involved, the Aquamerck® test kits can be used to illustrate other principles, e.g. the solubility of gases in liquids using oxygen as an example. Many of the Aquamerck® kits are used in technical colleges; they are excellent for explaining complex technical processes and concepts. Merck also provides the schooling and "Nitrogen - a key element of life" (Junger Verlag, Offenbach: available currently only in German). Using nitrate as an example, the origin and potential effects of an environmental problem are illustrated in such a way as to cover a number of interdisciplinary curriculum subjects. The Somerset Educational Co. (SAR) manufactures laboratory equipment kits Microchem® for use in school chemistry curricula, among them a MicroScience® Minilab kit for 100 analyses of water. Analogous kits are produced by ECOTECH (Moscow) in which are included reagents for field analyses of Fe(II), Cu, total and calcium hardness, chlorides, sulphates, fluorides at maximum admissible concentration levels. A range of educational material and pertinent test systems under the rubric "Monitoring and protection of the environment" has been developed and marketed by the Vladimir State University (Vladimir, Russia) for pupils of Forms 9-11 of general learning institutions attending classes in ecology, chemistry, biology, and for faculty and group studies [3]. Emphasis is placed on developing the practical skills of pupils in analyzing the environment and drawing the right conclusions. The program corresponds with that for ecological practicum of general learning establishments. The test systems are reagent papers impregnated with appropriate ingredients and showing the presence of the target component by the change of the test strip coloured or discoloured zone length or area. Test systems are easy to use, do not contain carcinogenic substances and can be used in the field, at home and in other out-of-lab conditions. The kit includes test systems without liquid or solid reagents, syringes, glass flasks, and a dropper with a 7% HCl solution. User instructions are printed on the package cover; 50 tests can be performed with one kit batch Table 11.3). 298
TABLE 11.3 Parameters of test systems for field environmental monitoring Component to be detected
Analytical range (mg/l)
Analyzed medium
Aluminum
0.01-50
Drinking water
Ammonium
0.5-20
Natural and waste waters, soils, atm. precipitates
Aniline
0.1-5
Waste waters, air
Bromides
1-500
Ascorbic acid
50-1000
Waste waters, solutions Foodstuffs
Iron
0.01-1
Natural waters, atmospheric precipitates
Iron
0.1-40
Natural and waste waters, solutions, soils
Total hardness
0.1-10, 1-20 mM
Iodides
1-1000
Water, atmospheric precipitates Waste waters
Cadmium
0.005-1
Natural waters
0.1-200
Waste waters, soils
Cationic surfactants
0.01-1000
Waste waters
Acids
0.1-100 mM
Solutions
Copper
0.001-0.1
Natural waters and atmospheric precipitates
0.1-100
Natural, atmospheric and waste waters, soils
Arsenic
0.05-3
Natural, atmospheric and waste waters, soils
Nickel
0.05-10
Natural, atmospheric and waste waters, soils
Nitrates
40-800
Natural and waste waters, soils, foodstuffs
Nitrites
2-60
Waste waters, soils, foodstuffs
Nitrites
0.05-5
Natural and waste waters, atmospheric precipitates
Total acidity
0.1-10 mM
Waste waters
Total alkalinity
0.1-10 mM
Natural waters
pH
4-6
Atmospheric precipitates
pH
4-8
Soils
pH
6-8
Natural waters continued
299
TABLE 11.3 (continuation) Component to be detected
Analytical range (mg/l)
Mercury
0.005-1
Natural and waste waters
0.1-200
Waste waters, soils
0.01-1
Natural and drinking waters
1-500
Waste waters, technological solutions
Lead Silver
Analyzed medium
0.005-1
Natural waters
0.5-100
Waste waters, technological solutions
Hydrogen sulphide
0.01-1
Waste waters, solutions, atmospheric precipitates
Sulphates
10-800
Water, atmospheric precipitates
Thiocyanides
1-500
Waste waters, solutions
Phenol
0.05-5
Waste waters
Phosphates
1-50
Natural and waste waters, soils
2-50
Waste waters, soils
Fluorides
0.5-500
Natural and waste waters, atmospheric precipitates, soils
Active chlorine
0.3-8
Drinking and waste waters
Chlorides
0.5-500
Natural and waste waters, atmospheric precipitates, soils
Chromium(VI)
0.05-500
Natural and waste waters, atmospheric precipitates, soils
Cyanides
1-500
Waste waters and technological solutions
Zinc
0.01-1
Natural waters, atmospheric precipitates
0.1-200
Natural and waste waters, soils
Using the test methods one can quickly detect the presence or absence of a harmful component in different media and its approximate content. The test kit was employed in the field for such tasks as: -
300
detection and assessment of different components in waste, natural, drinking, atmospheric waters, technological solutions, foodstuffs, and bio-liquids; assessment of the degree of purification of drinking water using household filters; control of wastewater purification; teaching pupils ecology, chemistry, biology in field conditions;
From 1994 to 2000 the students of Vladimir educational institutions carried out the following experiments using test systems: -
monitoring water quality in wells and springs of Vladimir; monitoring water quality in the river Rpen; quality control of vegetables and fruits by measuring their ascorbic acid, nitrate and nitrite content; monitoring the tap water quality of the eastern district of the city; assessment of atmospheric air contamination by detecting heavy metals in the foliage; assessment of atmospheric air contamination by chemical analysis of atmospheric precipitates; nitrogen biocycle in the atmosphere; micro-elemental composition of human hair and man's living conditions.
The results of this work were presented at international, all-Russian and district ecological Olympiads where the pupils received high esteem and recognition.
REFERENCES 1. 2. 3.
E.A. Marenkov and D.G. Grebenkin (Eds.), A Guide on Assay, Gosfinizdat, Moscow, 1953 (in Russian). S.V. Alekseev, N.V. Gruzdeva, A.G. Muraviev and E.V. Gushchina, PracticalCourse on Ecology, AO MDS, 1996 (in Russian). V.G. Amelin, Ecology and Industry of Russia, 1997, 43.
301
Some Other Applications of Test Methods
There are other areas where test methods are being employed but which have not been mentioned so far in this book. Two of them determination of noble metals by the use of the touchstone and application of test methods in the teaching process - are briefly considered in this chapter.
11.1
DETERMINATION OF GOLD AND SILVER BY THE TOUCHSTONE
This technique has been known since ancient times. Probably, the first mention of such a method of gold assessment was made in Theophrastus's work "On Stones" (372-287 B.C.). The method has been in use for many centuries. In the early 1600s it was improved by the introduction of reference samples, viz. 23 needles containing different amounts of gold from 1 to 23 carats and an additional one made of pure gold. Procedure To test gold specimens, a strip of uniform geometry and density 15-20 mm long and 2-3 mm wide is formed on the touchstone by scratching with the tested golden specimen. A similar strip is made in close vicinity with an appropriate reference needle. The strips are wetted width-wise by a special gold reagent using a glass rod and the reaction progress is closely watched for 15-20 seconds, after which the reagent is gently removed with filter paper, the test and reference strips are finally dried and colour-matched against each other. If the colours of the reaction spots on the strips are more or less identical then the gold 293
contents of the tested and reference samples are assumed to be also identical. If the colour intensity of the test strip is lower (or higher) than that of the reference one then the gold content of the test specimen is lower (or higher) than that of the reference sample. The method has the advantage over other methods requiring dissolution of the sample that it is very quick and simple and causes almost no damage to the tested gold articles. It allows not only qualitative but also quantitative determination of gold, silver, platinum in alloys and golden articles. Its accuracy is high, e.g. when testing a gold article of 583 per mille (p.m.) gold content the measurement error may be 2-5 p.m. 11.1.1 The touchstone and test needles The touchstone refers to silicon slate, is black in colour, has a uniform small-grained composition without quartz films or cracks, is sufficiently hard, and allows obtainment of uniformly dense strips of noble metals. It is chemically stable and is resistant to mineral acids (HNO3, HCl, H 2SO4 ) and their mixtures. The test needles are alloys of gold, silver and platinum taken in different but strictly defined proportions. The gold needles are usually alloys of gold, silver, copper, and less frequently those of gold, silver or gold, copper. For testing gold articles the needles of the following p.m. gold content are used: 333, 375, 500, 578, 583, 750, 900, 916 and 958. Additionally, needles with intermediate gold contents are prepared (Table 11.1). Silver needles are made of silver-copper alloys of the following p.m. gold content: 500, 550, 600, 650, 700, 750, 800, 875, 900, 916. The 500 and 900 p.m. needles are used to test coin alloys, and 750, 800, 875, and 916 p.m. needles are used for testing silver articles manufactured in Russia. 11.1.2 Reagents Reagents for gold are prepared in the following manner. Gold chloride solutions are obtained by dissolving 23 g H[AuCl 4 ] 4H2 0 in 1000 ml distilled water. It is used for testing alloys and articles of the 583 p.m. gold content and lower. Those of the 375-958 p.m. gold content are tested with acid reagents whose composition is indicated in Table 11.2. Although the touchstone is employed for testing silver and platinum articles, besides gold ones, in this book attention is given only to its use with golden alloys and articles just for the sake of an example. 294
TABLE 11.1 Chemical composition of test needles used for testing gold articles and alloys with the touchstone (%) Gold
Silver
Copper
Gold
Silver
Copper
Needles of 375 p.m. gold content
Needles of 750 p.m. gold content
37.5
62.5
-
75.0
25.0
-
37.5
50.0
12.5
75.0
18.7
6.3
37.5
37.5
25.0
75.0
12.5
12.5
37.5
25.0
37.5
75.0
6.2
18.8
37.5
12.5
50.0
75.0
-
25.0
37.5
-
62.5
75.0
Needles of 500 p.m. gold content
Needles of 833 p.m. gold content
50.0
50.0
-
83.3
50.0
40.0
10.0
Needles of 916 p.m. gold content
50.0
30.0
20.0
91.6
50.0
20.0
30.0
Needles of 958 p.m. gold content
50.0
10.0
40.0
95.8
4.2
-
50.0
-
50.0
95.8
2.1
2.1
95.8
-
4.2
8.3
8.4
4.2
4.2
TABLE 11.2 Composition of acid reagents for testing gold articles and alloys Gold contents (p.m.)
HNO3 (sp.w. 1.4)
HC (sp.w. 1.19)
Water
375
59.5
-
40.5
500
100.0
-
-
750
59.3
1.1
39.6
833
68.7
1.3
30.0
900
78.7
1.3
20.0
958
69.2
2.0
28.8
295
The above-mentioned highly sensitive and specific gold chloride solution is employed for testing, besides gold alloys, two-component gold-silver or gold-copper alloys, as well as three-component goldsilver-copper ones with less than 583 p.m. gold content. The scientific technology centre Tekhnokom-AS (Moscow) has developed a portable instrument "Gold Detector" for detecting gold in alloys and gold wares. The instrument scale has nine divisions corresponding to gold contents from 300 to 750 p.m., it shows the presence of platinum or a complete absence of gold (RF Patent 2057410). 11.2
USE OF TEST METHODS IN EDUCATION
One of the main objectives of ecological education is to overcome the passive attitude of pupils and students to ecological problems and inculcate in them an active and creative desire to defend the environment. Making them participate in research projects aimed at environmental monitoring and control raises their awareness, develops individual skills and awakens an interest in scientific work. The analyses and tests performed by them with their own hands and the results obtained are the best argument in favour of the necessity to protect and improve the environment. Test systems are an excellent means of teaching chemistry and ecology in schools and other educational institutions. They are convenient to use in the chemistry schoolroom, for out-of-the-class studies, expeditions, and excursions. They are quite valuable for teaching students ecological and foodstuffs control, and ecological monitoring of lakes and rivers during expeditions. Students of non-chemical departments learn the simplest methods of soil assessment, of bio- and mineral testing. As an example, one may cite the teaching test kits manufactured by Krismas+ (St. Petersburg, Russia) - Pchelka-U, Pchelka-U/M, and Pchelka-U/Khim. For example, the "Pchelka-U" kit allows the following experiments to be carried out: 296
rapid analysis by means of indicator tubes of such air pollutants as nitrogen oxides and sulphur dioxide; rapid non-aspiratory analysis of ammonia vapours; rapid analysis of contaminants in water and water extracts, e.g. active and total chlorine, pH, nitrates and chromates; rapid analysis of soil contamination using soil extracts;
-
rapid analysis of salts and fertilizers; rapid analysis of nitrates in beverages and fruits.
The Pchelka-U/Khim kit allows determination of carbonates and hydro carbonates, chlorides, sulphates and total water hardness. The kit's weight is no more than 3 kg; it is a hand-carried case measuring 330 x 170 x 160 mm. It includes five indicator tubes for air analysis, test means for 100 analysis of each specified water parameter. There are also ecological kits for practical work intended for use by students in Forms 9-11 of schools and supplementary learning establishments. The practical work kit is a modular-based didactic methodological complex including equipment and tools for carrying out experiments in ecology, environmental monitoring, geography, chemistry, biology with elements of ecology, and also the methodological literature. The practical work kit covers the main themes included in the ecological practical course, namely: -
-
-
assessment of water bodies' ecological status using test-kits and tests; the tested parameters are: organoleptic characteristics, pH, sulphates, carbonates, chlorides, dissolved oxygen, nitrates, nitrites, total hardness, chromates, copper, potassium, sodium, active chlorine, and others; assessment of the ecological status of air; determination of carbon dioxide, sulphur dioxide, nitrogen oxides, dust, bio indication of atmospheric precipitates; assessment of the ecological status of soil; determination of pH, salt content in water extracts; modelling of chemical contamination of air and water media and their rapid chemical analysis; determination of nitrates in vegetables, fruits, beverages, and water.
Modular design of the practical work kit creates favourable conditions for carrying out expedition tasks, field and outdoor practical work of all or selected directions. A complex ecological monitoring can be performed by students using the kit in combination with such instruments as microscope, noise meter, lux meter, radio dosimeter, psychrometer and others. Ecology and environmental protection have long been an integral part of school curricula, especially in chemistry and biology. The Aquamerck® test kit system and, especially, the Compact Laboratory, are 297
ideal tools for illustrating ecological principles and the potential effect of our interfering with nature. The test procedures can be learned quickly and pupils soon begin to participate actively and even carry out their own measurements. Aquamerckg test kits can also be used highly effectively and in a very impressive manner to demonstrate reaction mechanisms and analytical methods. Apart from the various ecological aspects involved, the Aquamerck® test kits can be used to illustrate other principles, e.g. the solubility of gases in liquids using oxygen as an example. Many of the Aquamerck® kits are used in technical colleges; they are excellent for explaining complex technical processes and concepts. Merck also provides the schooling and "Nitrogen - a key element of life" (Junger Verlag, Offenbach: available currently only in German). Using nitrate as an example, the origin and potential effects of an environmental problem are illustrated in such a way as to cover a number of interdisciplinary curriculum subjects. The Somerset Educational Co. (SAR) manufactures laboratory equipment kits Microchem® for use in school chemistry curricula, among them a MicroScience® Minilab kit for 100 analyses of water. Analogous kits are produced by ECOTECH (Moscow) in which are included reagents for field analyses of Fe(II), Cu, total and calcium hardness, chlorides, sulphates, fluorides at maximum admissible concentration levels. A range of educational material and pertinent test systems under the rubric "Monitoring and protection of the environment" has been developed and marketed by the Vladimir State University (Vladimir, Russia) for pupils of Forms 9-11 of general learning institutions attending classes in ecology, chemistry, biology, and for faculty and group studies [3]. Emphasis is placed on developing the practical skills of pupils in analyzing the environment and drawing the right conclusions. The program corresponds with that for ecological practicum of general learning establishments. The test systems are reagent papers impregnated with appropriate ingredients and showing the presence of the target component by the change of the test strip coloured or discoloured zone length or area. Test systems are easy to use, do not contain carcinogenic substances and can be used in the field, at home and in other out-of-lab conditions. The kit includes test systems without liquid or solid reagents, syringes, glass flasks, and a dropper with a 7% HCl solution. User instructions are printed on the package cover; 50 tests can be performed with one kit batch Table 11.3). 298
TABLE 11.3 Parameters of test systems for field environmental monitoring Component to be detected
Analytical range (mg/l)
Analyzed medium
Aluminum
0.01-50
Drinking water
Ammonium
0.5-20
Natural and waste waters, soils, atm. precipitates
Aniline
0.1-5
Waste waters, air
Bromides
1-500
Ascorbic acid
50-1000
Waste waters, solutions Foodstuffs
Iron
0.01-1
Natural waters, atmospheric precipitates
Iron
0.1-40
Natural and waste waters, solutions, soils
Total hardness
0.1-10, 1-20 mM
Iodides
1-1000
Water, atmospheric precipitates Waste waters
Cadmium
0.005-1
Natural waters
0.1-200
Waste waters, soils
Cationic surfactants
0.01-1000
Waste waters
Acids
0.1-100 mM
Solutions
Copper
0.001-0.1
Natural waters and atmospheric precipitates
0.1-100
Natural, atmospheric and waste waters, soils
Arsenic
0.05-3
Natural, atmospheric and waste waters, soils
Nickel
0.05-10
Natural, atmospheric and waste waters, soils
Nitrates
40-800
Natural and waste waters, soils, foodstuffs
Nitrites
2-60
Waste waters, soils, foodstuffs
Nitrites
0.05-5
Natural and waste waters, atmospheric precipitates
Total acidity
0.1-10 mM
Waste waters
Total alkalinity
0.1-10 mM
Natural waters
pH
4-6
Atmospheric precipitates
pH
4-8
Soils
pH
6-8
Natural waters continued
299
TABLE 11.3 (continuation) Component to be detected
Analytical range (mg/l)
Mercury
0.005-1
Natural and waste waters
0.1-200
Waste waters, soils
0.01-1
Natural and drinking waters
1-500
Waste waters, technological solutions
Lead Silver
Analyzed medium
0.005-1
Natural waters
0.5-100
Waste waters, technological solutions
Hydrogen sulphide
0.01-1
Waste waters, solutions, atmospheric precipitates
Sulphates
10-800
Water, atmospheric precipitates
Thiocyanides
1-500
Waste waters, solutions
Phenol
0.05-5
Waste waters
Phosphates
1-50
Natural and waste waters, soils
2-50
Waste waters, soils
Fluorides
0.5-500
Natural and waste waters, atmospheric precipitates, soils
Active chlorine
0.3-8
Drinking and waste waters
Chlorides
0.5-500
Natural and waste waters, atmospheric precipitates, soils
Chromium(VI)
0.05-500
Natural and waste waters, atmospheric precipitates, soils
Cyanides
1-500
Waste waters and technological solutions
Zinc
0.01-1
Natural waters, atmospheric precipitates
0.1-200
Natural and waste waters, soils
Using the test methods one can quickly detect the presence or absence of a harmful component in different media and its approximate content. The test kit was employed in the field for such tasks as: -
300
detection and assessment of different components in waste, natural, drinking, atmospheric waters, technological solutions, foodstuffs, and bio-liquids; assessment of the degree of purification of drinking water using household filters; control of wastewater purification; teaching pupils ecology, chemistry, biology in field conditions;
From 1994 to 2000 the students of Vladimir educational institutions carried out the following experiments using test systems: -
monitoring water quality in wells and springs of Vladimir; monitoring water quality in the river Rpen; quality control of vegetables and fruits by measuring their ascorbic acid, nitrate and nitrite content; monitoring the tap water quality of the eastern district of the city; assessment of atmospheric air contamination by detecting heavy metals in the foliage; assessment of atmospheric air contamination by chemical analysis of atmospheric precipitates; nitrogen biocycle in the atmosphere; micro-elemental composition of human hair and man's living conditions.
The results of this work were presented at international, all-Russian and district ecological Olympiads where the pupils received high esteem and recognition.
REFERENCES 1. 2. 3.
E.A. Marenkov and D.G. Grebenkin (Eds.), A Guide on Assay, Gosfinizdat, Moscow, 1953 (in Russian). S.V. Alekseev, N.V. Gruzdeva, A.G. Muraviev and E.V. Gushchina, PracticalCourse on Ecology, AO MDS, 1996 (in Russian). V.G. Amelin, Ecology and Industry of Russia, 1997, 43.
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