title: An improved method for analyzing chlormequat and mepiquat in source waters by solid-phase extraction and liquid chromatography-mass spectrometry.
abstract: A liquid chromatography-mass spectrometry (LC-MS) method for the identification and quantification of chlormequat (CQ) and mepiquat (MQ) in source waters with high sensitivity and specificity was established using WCX cartridges (150 mg/6 mL) for pre-concentration of the samples and using the CAPCELL PAK CR 1:4 (2.0 mm×150 mm 5 μm, SCX:C18=1:4) column containing strong cationic exchange resins and C18 for separation. The method could solve the problem for pre-concentrating ionic compounds from water samples and avoid the MS instrument fouling problem accompanied with the use of ion-pair reagents. After the optimization of analytical conditions, quantification was achieved in the positive electrospray ionization mode using selected ion monitoring. The samples were analyzed with multi-channel mode with quantification performed at 30 V cone voltage to ascertain the sensitivity and qualitative analysis performed at 60 V cone voltage simultaneously. The method detection limits (MDLs) of CQ and MQ in source water were determined to be 14 and 22 ng L(-1). Finally, the method was used to quantify CQ and MQ in several source waters, which gave a level ranging from below the quantitation limit to 28 ng L(-1).
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Yu
authors.forename: Fen
authors.initials: F
authors.lastname: Jin
authors.forename: Jianying
authors.initials: J
authors.lastname: Hu
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Jingfang
authors.initials: J
authors.lastname: Sun
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D002716:Chlormequat / Q000032:analysis* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry*; D010880:Piperidines / Q000032:analysis* / Q000302:isolation & purification; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D010880:Piperidines; D014874:Water Pollutants, Chemical; D002716:Chlormequat; C049449:mepiquat