Vesicle-mediated high-performance liquid chromatography coupled to hydride generation inductively coupled plasma atomic emission spectrometry for speciation of toxicologically important arsenic species

Abstract

The use of vesicles as mobile phases can provide a synergic combination for high-performance liquid chromatographic (HPLC) separation when coupled to hydride generation inductively coupled plasma atomic emission spectrometric (HG-ICP-AES) detection, as illustrated here for arsenic speciation. The more toxic arsenic species including arseneous, arsenic, monomethylarsonic and dimethylarsinic acids can be separated within 10 min by using didodecyldimethylammonium bromide (DDAB) vesicles in phosphate buffer containing 0.5% methanol and a C₁₈ reversed-phase column, which had previously been modified by DDAB solution. In addition, the sensitivity of detection on-line by HG-ICP-AES of the four separated arsenic species was enhanced by the presence of DDAB vesicles. The normalized detection limits for arsenic with the proposed speciation method were down to the sub-ng level and the observed precisions were always better than ±5% for the four forms of arsenic at the 10 ng level of the element in water. Arsenic recoveries (full procedure) were found to range from 93 to 108% for tap water and human urine samples by this vesicle-mediated HPLC–HG-ICP-AES technique for arsenic speciation.