To determine the concentration of chromium in a water sample for assessing water quality, detecting contamination, and ensuring compliance with environmental and water standards. We followed Diphenyl carbazide method to determine it .This procedure measures only hexavalent chromium. Therefore, to determine the total chromium, convert all the chromium to the hexavalent state .
Here we take the Surface Water Sample to detect the hexavalent chromium by the following process.
Materials used in Chromium Testing in water sample:
Apparatus used
- Spectrophotometer(540nm) : It is commonly used to measure the concentration of chromium in water sample.
- pH Meter : It is used to monitor and adjust the pH in water sample.
- Standard Volumetric Glasswares (50 ml): Provides high accuracy and precision in solution preparation.
- Beaker(50ml): To hold the sample during acidification.
Chemicals used
- Sulphuric Acid — Sulfuric acid is used to provide the required acidic medium.To prepare dilute H2SO4 add 50 ml Sulphuric acid into 50 ml distilled water.
- Phosphoric Acid — It provides the required acidic medium for the reaction.
- Diphenyl carbazide Solution — Dissolve 25g of 1,5-diphenylcarbazide( 1,5-diphenylcarbohydrazide) in 50 ml acetone.Diphenylcarbazide (DPC) solution is used as a color-developing reagent that reacts with hexavalent chromium (Cr(VI)) to form a pink-violet-colored complex for spectrophotometric determination in water samples.
- Acetone — Used to prepare diphenyl acid solution.To Dissolve 25g of 1,5-diphenylcarbazide( 1,5-diphenylcarbohydrazide).
- Distilled Water-Used for reagent preparation and dilution without introducing impurities that may interfere with the reaction.The conductivity of distilled water should be <5 μS/cm to prevent contamination.
Procedure to Follow While Doing Chromium Testing in water sample:
- Take 50 ml water sample in a beaker.
- Set the sample pH±2.5 ,using dilute sulphuric acid and also add 2 drops phosphoric acid.
- Make up the sample volume up to100 ml.
- Add 2 ml of 1,5-diphenylcarbazide solution.
- It produces pink-violet colour if Chromium is present.
- Measure the absorption in 540nm on spectrophotometer .
- Chromium(Cr)= (Absorbance-Blank) X calibration factor/Sample taken
Purpose of Chromium testing in water sample:
- To protect human health and aquatic ecosystems from chromium toxicity.
- The purpose of chromium testing in water is to detect toxic hexavalent chromium .
- Verifies that drinking water stays below safety limits.
- To monitor pollution in surface water, groundwater, and wastewater.
- Check if water filters and purification systems are successfully removing chromium.
Handling mistakes should be avoided during chromium testing in water sample:
- If the sample pH is changed incorrectly can shift chromium oxidation states.
- Verify all calculations and record results correctly.
- Transfer the sample carefully to prevent material loss.
- Use the clean cuvette to get accurate absorption.
- Mixing the acid with sample properly.
- Keep all glassware clean and dry to avoid contamination .Proper cleaning Process described previously.
Conclusion of chromium testing in water sample:
Testing the chromium content helps to detect toxic hexavalent chromium. It is check if water filters and purification systems are successfully removing chromium. By following these method, you can easily test the hexavalent chromium content of water sample at laboratory & also manufacturing industry with availability of the equipments & chemicals. If you can’t understand the procedure you can check our real time photo attached with this writing or also you can reach to Pro Research & Testing Laboratory for the advance testing.
Frequently Asked Questions (FAQs) – Chromium Content Test in water sample
Q. What is chromium?
A. Chromium is naturally occurring metal found in rocks,soil and water.
Q. Why is chromium tested in drinking water?
A. To ensure the water is safe for human consumption .
Q. Which instruments is used to detects chromium content in water sample?
A. UV-visible spectrophotometer is used to detects chromium content in water sample.
Q. At what wavelength is the absorbance measured?
A. At 540 nm is the absorbance measured.
Q. What colour indicates the presence of chromium?
A. Pink-violet colour indicates the presence of chromium.
How We Verified This Testing/Research Procedure :
This testing procedure is done under qualified analyst .Continually monitored by expertise.Repeatedly testing is always done to get accurate result.
Written by
Ankita Samanta (M.Sc Microbiology,Vidyasagar University)
Designation – Junior Microbiologist
Reviewed by
Anwesha Das (M.Sc Microbiology,BU)
Designation – Microbiologist
Verified By
Dr. Jyotirmoy Kumar Dey (Phd,Chemistry)
Designation – Senior/Chief Chemist
Experience – 25 Years +