NOM and alkalinity interference in trace-level hexavalent chromium analysis

作者：Parks Jeffrey L^*; McNeill Laurie; Edwards Marc

来源：Talanta, 2014, 130: 226-232.

DOI：10.1016/j.talanta.2014.06.052

• Alkalinity
• Chromium
• HPLC
• ICPMS
• Ion chromatography
• Organic carbon

Three analytical methods were evaluated for hexavalent and trivalent chromium analyses in the presence of natural organic matter (NOM) and alkalinity. Each method was tested using a simulated tap water with 1 mu g L-1 Cr(VI) and 0.8 mu g L-1 Cr(III) and several concentrations of NOM and/or alkalinity. An ion chromatograph with post column reaction cell conforming to USEPA Method 218.7 could accurately quantify Cr(VI) in the presence of up to 8 mg C L-1 NOM and up to 170 mg L-1 as CaCO3 alkalinity, and no oxidation of chromium was observed when 0.8 mu g L-1 Cr(III) was also present A high-performance liquid chromatography coupled with inductively coupled plasma (HPLC-ICPMS) method and a field speciation method were also evaluated. Each of these methods was unaffected by the presence of alkalinity; however, the presence of NOM created issues. For the HPLC-ICPMS method, as the concentration of NOM increased the recovery of Cr(VI) decreased, resulting in a %26apos;false negative%26apos; for Cr(VI). However, for the field speciation method, Cr(III) was complexed by NOM and carried through the ion exchange column, resulting in a %26apos;false positive%26apos; for Cr(VI).

• 出版日期2014-12-1
• 单位Virginia Tech; 美国弗吉尼亚理工大学(Virginia Tech)