Determination of Chromium in Environmental Samples

Chromium trivalent is essential to the human body. It takes part in insulin metabolism. However, higher concentrations of chromium trivalent can cause dermatitis and respiratory cancer. In addition, other forms of chromium (especially chromium hexavalent) can damage the kidneys, liver, and blood cells. The World Health Organisation has issued limits for the presence of chromium in soil (0.05 ppm), water (0.1 ppm), and plant samples (1.3 ppm).

It is important to accurately determine the quantity of chromium (in various forms) in soil, water, and plant samples. One of the most accurate and reliable methods for the determination of chromium is high-performance liquid chromatography (HPLC) coupled with inductively coupled plasma – mass spectrometry (ICP-MS).

In this method, the samples are being run into HPLC columns and each compound is then detected through ICP-MS. The HPLC method coupled with ICP-MS showed limit of detection (LOD) lower than 1 µg/L.

Aside from HPLC coupled with ICP-MS, analysts also use other techniques such as atomic absorption spectroscopy (LOD: <1 µg/L), neutron activation analysis (LOD: 30 µg/L), spectrophotometry (LOD: 3 - 400 µg/L depending on sample type), X-ray fluorescence (LOD: 1.5 µg/g for geologic samples), and emission spectroscopy (LOD: 0.5 ng/g in environmental samples).

To obtain reliable data, analysts must be careful during sampling, sample handling, and selection of analytical technique. Analysts should also take note of the formation and volatility of chromium complexes.