METHODOLOGICAL VALIDATION FOR THE DETERMINATION OF TOXIC ARSENIC SPECIES IN HUMAN URINE USING HPLC WITH ICP-MS

There is a significant amount of arsenic species in the environment and in biological systems; however, the toxicity and possibly the carcinogenicity of ingested arsenic depend on the species and the oxidation state. Therefore, analytical methodologies and techniques that are fast and robust, that involve highly efficient separation and are powerful tools of detection are necessary for the correct quantification of individual arsenic species. The field of speciation analysis of arsenic in this area has grown rapidly in recent years, especially with the application of liquid chromatography and mass spectrometry with inductively coupled plasma. This study aimed to develop and apply this technique to human urine samples in order to reduce the treatment needed for speciation, maintain maximum recovery and avoid interconversion and / or degradation between species. In order to optimize the separation of species, several experiments were performed by preparing the mobile phase at different pH values. The optimal pH value and the linearity of the method were determined and the methodology was validated using a Certified Reference Material. Student's t-test and Fisher F-test for determination of accuracy and precision were applied. A simple, rapid and reliable method for the separation and quantification of several species of arsenic, As III (Arsenite), As V (Arsenate), MMA (Monomethyl Arsonic Acid), DMA (Dimethyl Arsinic Acid), AB (Arsenobetaine) was developed in human urine samples with minimal prior sample preparation. The time required for sample processing and isocratic chromatographic analysis is about 15 minutes. Detection limits of 0.020 mu gL(-1) of AsB, 0.020 mu gL(-1) of As III, 0.040 mu gL(-1) of DMA, 0.060 mu gL(-1) of MMA and 0.060 mu gL(-1) of As V were achieved under the analytical conditions mentioned above.