A simple and fast method for chlorsulfuron and metsulfuron methyl determination in water samples using multiwalled carbon nanotubes (MWCNTs) and capillary electrophoresis

A new method to determine metsulfuron methyl (MSM) and chlorsulfuron (CS) in different water samples was developed It consists in a solid phase extraction (SPE) procedure using multiwalled carbon nanotubes (MWCNTs) as sorbent material in combination with capillary zone electrophoretic determination To carry out the pre-concentration step a simple flow injection system was developed and optimized Thus 250 mu L of aqueous solution containing methanol 50% (v/v) and acetonitrile 2% (v/v) as eluent 10 mL of sample and a flow rate of 1 15 mL min(-1) were selected The CE variables also were optimized A rapid determination and good resolution of two herbicides were obtained within 9 min using a simple electrophoretic buffer (50 mmol L-1 sodium tetraborate with 3% of methanol pH = 9 0) Under the optimum conditions the calibration curves were linear between 05 and 6 mu g L-1 for MSM and CS with R-2 = 0 995 and 0 997 respectively The repeatability of the proposed method expressed as relative standard deviation (RSD) varied between 4 1% and 5 4% (n = 10) and the detection limits for MSM and CS were 040 and 036 mu g L-1 respectively Good results were achieved when the proposed method was applied to spiked real water samples The recoveries percentages of the two analytes were over the range 86-108% (C) 2010 Elsevier B V All rights reserved