The unstable nature of hexavalent chromium Cr(VI) makes it one of the difficulties in RoHS (Restriction of Hazardous Substances) compliant test. A study on the spectrophotometric determination of Cr(VI) contained in plastics, especially focused on influence of the processing parameters and interference factors in the extract and colorific process of Cr(VI) was performed. And subsequently a set of standard procedures including sample preparation, extraction, colorific reaction were established. It was found that the mixed alkali method could effectively extract Cr(VI) from complicated plastic matrices and eliminate the interference of Cr(III), simultaneously. By the exclusion of the coexisting ions, and optimizing several parameters such as pH, temperature, time and so on, the satisfactory results were achieved because the recovery rates were in the range of 90%～110% both for samples and standard solutions, RSDs were less than 1%, and the calibration exhibited the linear relation in the low concentration range (0～500 μg/L). All the above proved that the present method provided a high accuracy and sensitivity, as well as a simple and rapid procedure, thus offering a good technical support to comply with RoHS directive for the information industry.

Key words: hexavalent chromium [Cr(VI)], spectrophotometry, RoHS compliant test, plastic, extraction