“…Ion chromatography is also used for the separation of Cr species successfully (Arar & Pfaff, 1991, Arar et al, 1992Giuriati et al, 2005) and is adopted by US-EPA in method 7199, which describes the determination of hexavalent chromium in drinking water, groundwater, and industrial wastewater effluents by ion chromatography (U. S. EPA, 1996b). Detection is mainly accomplished by spectrophotometry at 540 nm, utilizing the well-documented diphenylcarbazide method (Arar & Pfaff, 1991;Giuriati et al, 2005;Wei et al, 1982). However, in order to achieve lower detection limits, ion chromatography has been coupled with atomic spectrometric detection systems, such as flame atomic absorption spectrometry (Posta et al, 1993) and inductively coupled plasma with atomic emission spectrometry (Byrdy et al, 1995), or mass spectrometry (Arar et al, 1992;Byrdy et al, 1995).…”