HUNGARIAN JOURNAL 
OF INDUSTRIAL CHEMISTRY 

VESZPREM 
Vol. 30. pp. 253-255 (2002) 

A NOVEL METHOD FOR DETECTION AND ESTIMATION OF COPPER (II) IN 
WATER 

M. K. BHUTRA*, A. VYAS and G. L. BHUTRA 

(Department of Chemistry, Jai Narain Vyas University, Jodhpur (Raj)- 342005, INDIA) 

Received: July 26, 2002 

An improved, simple and sensitive method for quick detection and estimation of Copper (II) in drinking water has been 
described. The method involves use of ferric thiocyanate along with optimized amount of sodium thiosulphate as field 
test reagent. The concentration of copper is determined from the time required for disappearance of red brown colour of 
reagent. The ratio of ferric thiocyanate and sodium thiosulphate solutions should be 1:3 for best results. A time chart is 
also provided for finding out concentration of copper. The sensitivity limit of reagent for visual observation is 1.0 mg/1. 
The test is simple, sensitive, rapid, economic and quantitative, hence it can be incorporated in existing water testing field 
kits. 

Keywords: copper (II), water sample, ferric thiocyanate reagent, field test 

Introduction 

Copper is widely distributed in nature. Copper salts are 
used in water supply systems to control biological 
growths in reservoirs and in distribution pipes and to 
catalyse the oxidation of manganese [1]. Corrosion of 
copper containing alloys in pipe fittings may introduce 
measurable amount of copper into the water in a pipe 
system. 

Copper is essential metal required by almost all 
living organisms in some of their enzyme systems [2]. 
The adult daily requirement has been estimated as 2.0 
mg. Deficiency of copper may lead to certain 
physiological disorders in both plants and animals, but 
in higher concentrations it works essentially as a 
pollutant. Copper poisoning occurs mostly due to 
homicidal ingestion of copper containing solutions or 
consumption of acidic beverages stored in containers of 
copper [3]. Excess of copper in human body is toxic and 
causes hypertension, sporadic fever, uremia, coma and 
even death. Copper also produces pathological changes 
in brain tissue [4]. It is also toxic to most aquatic life 
and particularly algae are very~sensitive to copper. It is 
toxic to many plants at 0.1 to 1.0 mgll nutrient 
solutions. Thus the presence of copper is to be tested in 
drinking water for suggesting its potability along with 
other physicochemical parameters. In the present 
investigation an attempt is made to detect and estimate 
copper in drinking water. The permissible limit of 

copper in drinking water is 1.0 mg/1 as laid down by 
WH0[5]. 

Experimental 

Reagents 

a. Ferric thiocyanate solution (2.0 g ferric chloride 
(AR) and 2.5 g potassium thiocyanate (AR) in 
100 ml double distilled water). 

b. Sodium thiosulphate (AR) solution - 0.1 N (freshly 
prepared). 

Method 

To 10 mi water sample add a drop of ferric thiocyanate 
reagent. A red brown colour appears. Now add 3 drops 
of sodium thiosulphate solution. Shake, if red brown 
colour disappears within 5 minutes it indicates that 
Copper (II) is present above permissible limit i.e. 
1.0 mg/1. The quantitative estimation can be done with 
the help of time chart provided for ready reference. If 
the colour of reagent does not disappear within 5 
minutes it indicates that copper concentration is well 
within permissible limit. Higher concentration of copper 
in the tests sample is determined by standard dilution 
technique. 

*Address for Correspondence: 47-NC-1, P.W.D. Colony, Jodhpur (Raj)- 342 001, INDIA 



254 

Table 2 Copper (Permissible limit = 1.0 mg/1) 

Reagents 

Characteristics Alizarin blue Benzidine+ Ammonium Dithizone 
Ferric thiocyanate + Ferric thiocyanate + 

Potassium bromide Sodium thiosulphate Sodium thiosulphate* 
bromide (in optimized ratio) 

Medium Pyridine Acetic acid Cone. H3P04 CCl4 Water Water 

Number of 2 3 2 2 3 3 
ingredients 

Sensitivity (ppm) 5.0 5.0 3.0 1.0 0.01 0.01 

Oxidation state Cu (II) Cu (II) Cu (II) Cu (II) Cu (II) Cu (II) 

Colour and nature of Blueppt Blue colour Violet colour Yellow brown Brown colour Brown colour 
complex (Stable) (Stable) (Stable) colour disappears disappears 

(Stable) (Stable) (Stable) 

Interferences Co (Ill), Ni Au (III), Many metal ions Zn (II), Cd (II), No interference No interference 
(II) interfere Fe (III) interfere Pb (II) interfere 

interfere 

Remark Liquid phase Liquid phase Liquid phase Liquid phase Liquid phase Liquid phase 

*Modified field test reagent 

Concentration of 
COPPER (mg/1) 

10.0 

5.0 

3.0 

2.0 

1.0 

<1.0 

Table 1 Time Chart 

Time required for disappearap.ce of 
reagent colours 

Instantaneous 

1 minute 

2 minute 

4minute 

5 minute 

>5 minutes 

Time chart 

Standard copper sulphate (AR) solutions were prepared 
in different concentrations ranging from 1.0 to 
10.0 mg/1. The time required by different concentrations 
of copper for disappearance of reagent colour were 
taken as reference time in the time chart, as shown in 
Table 1. 

Estimation of copper 

Standard copper solutions were made from copper 
sulphate and estimation of Copper (II) was done using 
atomic absorption spectrophotomerric method (AAS) 
(6]. 

Results and Discussion 

The methods for estimation of copper [7-20] involve the 
use of different reagents like Alizarin blue, Benzidine~ 
Dithizone. Ammonium bromide and ferric thiocyanate 
etc. Laboratory studies on these reagents were 
conducted in view of their adaptability for field 
determinations. stability, ease and sensitivity of test at 

different dilutions specially near permissible limit. The 
results are given in Table 2. 

It is clear from the Table 2 that ferric thiocyanate 
reagent is most suitable under field conditions while 
others are not suitable due to their complexity, 
unstability and other limitations. 

Chemistry Involved in Fer~ic Thiocyanate Test 

In the ferric thiocyanate test when a solution of ferric 
salt reacts with a solution of an alkali thiosulphate a 
transient red brown colour appears which is unstable, 
slowly disappears after considerable time. The reaction 
takes place in two steps: 

Fe3+ + 2S2 o;- ~[Fe(S203hr (rapid) (1) 
Red brown complex 

{Fe(S20 3 ) 2 r +Fe3+ ~2Fe2+ +S40~- (slow) (2) 
Almost colourless 

2Fe3+ +2S 2 o;- --72Fe2+ +S40~- (slow) (3) 
Copper (II) accelerate the second partial reaction and 

therefore speed up total reaction. Consequently the red 

brown colour due to [Fe(S20 3 ) 2 rion disappears far 

more rapidly when copper ions are present. The velocity 
of reaction (disappearance of colour) increases with 
increase in concentration of Copper (II). The chemistry 
involved is as follows: 

[Fe(S2 0 3 )zr +Cu
2+ --7 

--7Cu+ +Fe2+ +S 40t (rapid) 
Cu + + Fe3+ --7Cu 2+ + Fe2+ (rapid) 

Cu 2+ 
[Fe{S20 3 ) 2 r + Fe3+ --~ 
--72Fe2+ +S

4
o;- (rapid) 

(4) 

(5) 

(6) 



Table 3 Comparative studies of Rapid Field Test and Standard 
Method (AAS) using standard-copper solutions 

Parameters 

Sample No. 

Time required for 
disappearance of 
reagent colour after 
adding field test 
reagent (in minutes) 

Standard samples having different 
concentration of Cu (II) 

a b c d e 
5 4 2 inst. 

Concentration of 1.0 2.0 3.0 5.0 10.0 
copper using time chart 
in field test method 
(mg/1) 

Concentration of 0.988 2.001 3.005 5.001 10.001 
copper estimated by 
standard AAS method 
(mg/1) 

To make the test quan.titative and specific: 

The ratio of number of drops of reagent 1 (ferric 
thiocyanate solution) and reagent 2 (sodium 
thiosulphate) solution) was optimized. It was found that 
1:3 ratio is optimum. With this optimized concentration 
ratio the test becomes sensitive upto permissible limit. 

Comparative studies of standard methods like 
Atomic Absorption Spectrophotometric method and 
rapid field test undertaken on standard Copper (II) 
solutions have shown (Table 3) that the visual colour 
test exhibited by this method is quite reliable under field 
conditions. 

Laboratory and field trials on surface water, ground 
water and irrigation water using this reagent have also 
been extensively conducted during last two years 
successfully as shown in Table 4. Thus this rapid test 
can be used in field areas for assessing Copper (II) in 
drinking water. The test is simple, reliable, sensitive and 
quantitative too and can easily be performed by a person 
of normal scientific temper. So the test will be a good 
addition in existing water testing field kits [21]. 

REFERENCES 

1. CLECERRI L., GREENBERG A., ANDREW D. E.: 
Standard Methods for the Examination of Water 
and Waste Water, APHA, AWWA & WPCF, 3-71, 
1998 

2. DAS A. K.: Medicinal Aspects of Rio-inorganic 
Chemistry, 1st Ed., 18, 1990 

3. KUDESIA V. P.: Water Pollution, 1st Ed., 205, 1980 
4. SCHUBERT J.: Heavy Metal Toxicity and 

Environmental Pollution of Metal Ions in Biological 
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5. WHO, Guiidelines for Drinking Water Quality, 182, 
1984 

6. PAUS P. E.: Atomic Absorption Spectroscopy, 
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7. FEIGL F.: Sport Test in Inorganic Analysis, 6th Ed .• 
203-221, 1972 

255 

Table 4 Comparative studies of Rapid Field Test and Standard 
Methods using some natural water samples 

Source of Water sample 
Concentration of Cu (II) (rng/1) 

AAS Field test 

Tapi Baori 0.0 0.0 

Lal Sagar 0.01 < 1.0 
Fateh Sagar 0.04 < 1.0 
DevKund 0.00 0.00 

UmedBhawan 0.03 < 1.0 
Kailana 0.00 0.00 

Gulab Sagar 0.21 < 1.0 
Gorinda Baori 2.02 2.00 

Jalap Baori 3.34 3.00 

Chandpole Jhalra 0.04 < 1.0 
Nagadari Mandore 0.00 0.00 

Jhalara Mahila Bagh 0.11 < 1.0 
Kurbija Baori 4.45 5.00 

Ranisar Padarnsar 0.01 < 1.0 
Balsamand 0.00 0.00 

ShivMandir 0.02 < 1.0 
Kabutaron Ka Chowk 0.00 0.00 

Police Line Ratanada 0.01 < 1.0 
Jain Bhawan Ratanada 1.35 2.00 

Subhash Chowk Ratanadda 0.01 < 1.0 
Baiji Ka Talab 2.20 2.00 

8. BILIKOVA A.: Determination of Copper and Zinc in 
Water, Special publication, Nr. 44, Water Research 
Institute, Bratislava, 1968 

9. GAHLER A. R.: Anal Chern., 1954,26,577 
10. KocH 0. G. and KocH G. A.: Dedic, Handbuch der 

spurnanalyse, Springer- Verlag, B~rlin, 646, 1974 
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New York, 305, 1975 
12. KORKISCH J., GoDL L. and GROSS H.: Talanta, 

1975,22,289 
13. GRYS S.: Microchim Acta, 1976, 1, 147 
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Reagents for Copper, Krieger, Huntington, New 
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15. BURNS D. T., TOWNSHEND A., CARTER A. H.: 
Inorganic Reaction Chemistry, 1981, 2 

16. BUDAVARI S.: The Merck Index, llth Ed., Rahway. 
NJ, Merck, 1989 · 

17. THEROUX F. R., ELDRIDGE E. F. and MALLMANN 
W. L.: Laboratory Manual for Chemical and 
Bacterial Analysis of Water and Sewage, Agro 
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18. DE A. K.: Environmental Chemistry, 3rd Ed., New 
Age International Publication, 260-261, 1994 

19. FLANAGAN R. J., BRAITHWAITE R. A., BROWNS. 
S., WIDOOP B. and de WOLFF F. A.: Basic 
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20. KUMAR U. and KAKRANI B.: Water Environment 
and PoUution. Agrobios.India. 145.2000 

21. GOPAL R., BHARGAVA T. N., BHUTRA M. K.: J. 
IWW A. 1983, XV. 59-64 


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