Optimization of Sample Preparation Procedure for Evaluation of Occupational and Environmental Exposure to Nickel

Background: Nickel is an important constituents widely used in different industrial processes for production of various synthetic materials. For evaluation of workers’ exposure to trace toxic metal of Ni (II), environmental and biological monitoring are essential processes, in which, preparation of samples is one of the most time-consuming and error-prone aspects prior to analysis. Methods: To evaluate factors influencing quantitative analysis scheme of nickel, solid phase extraction using mini columns filled with XAD-2 resin was optimized with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume (up to 500 ml), elution volume, amount of resins, and sample matrix interferences. Nickel ion was retained on solid sorbent and was eluted with followed by simple determination of analytes by using flame atomic absorption spectrometery. Results: Obtained recoveries of metal ion were more than 92%. The amount of the analyte detected after simultaneous preconcentration was basically in agreement with the added amounts. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six withinday experiments. The developed method promised to be applicable for evaluation of other metal ions present in different environmental and occupational samples as suitable results were obtained for relative standard deviation (less than 10%). Conclusion: This optimized method can be considered to be successful in simplifying sample preparation for trace residue analysis of Ni in different matrices for evaluation of both occupational and environmental exposures.