The use of 1-phenyl-3-methyl-4-benzoyl-5-pyrazone as chemical modifier for low-temperature electrothermal vaporization for separation and determination of Cr(III) and Cr(VI) by ICP-MS

• Published in: Microchemical journal 2011-03, Vol.97 (2), p.196-200
• Main Authors: Chen, Shizhong, Zhu, Shengping, Lu, Dengbo
• Format: Article
• Language: English
• Subjects: 1-phenyl-3-methyl-4-benzoyl-5-pyrazone; Chromium speciation; Inductively coupled plasma mass spectrometry; Low-temperature electrothermal vaporization
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2010.09.001

Based on thermal stability and volatility of 1-phenyl-3-methyl-4-benzoyl-5-pyrazone (PMBP) chelate, a novel method was described for the determination of Cr(III) and Cr(VI) by low-temperature electrothermal vaporization (LETV) combined with inductively coupled plasma mass spectrometry (ICP-MS). It was found that Cr(III) could be rapidly formed in a graphite furnace, and quantitatively vaporized into ICP at a relatively low temperature of 1000 °C with the use of PMBP as a chemical modifier, while Cr(VI) was retained in the graphite tube. Thus, the separation of Cr(III) and Cr(VI) could be realized. The main factors affecting the formation and vaporization of Cr(III)-PMBP chelate were investigated in detail. Under the optimized conditions, the detection limit of Cr(III) for this method was 0.031 ng mL −1 and the relative standard deviation (RSD) for 1.0 ng mL −1 Cr(III) was 5.3% ( n = 9, v = 10 μL). The linear range of calibration curve spanned three orders of magnitude. The proposed method was applied to the determination of Cr(III) and Cr(VI) in water samples with satisfactory results.