RESUMO
A method was developed for the determination of four sulfa antibiotics in groundwater, soil and excreta using solid phase micro extraction disks coupled with high performance liquid chromatography. The influence of eluent, different solid phase micro extraction membranes on the recovery of sulfa antibiotics in groundwater was investigated and it was found that when using the mixture of methyl alcohol and 1 . 0% formic acid as eluent, HLB ( divinyl benzene-N-vinyl pyrrolidone polymer ) as extraction membranes, an optimal enrichment effect was obtained. Different pretreatment methods for the 3 kinds of samples abovementioned were also examined. It was found that the signal response values obtained by using mixture of methyl alcohol and 1 . 0% formic acid as base solution of standard or sample solution was higher 8-10 times than that by using methyl alcohol only. Under the optimal conditions, good linear relationships were obtained in the sulfa antibiotics concentrations of 0 . 005-10 . 0 mg/L with the correlation coefficients>0 . 9999;The detection limits of sulfathiazole ( ST ) , sulfadiazine ( SM ) , sulfamethazine ( SM2 ) , sulfamethoxazole ( SMX ) were 1 . 08 , 3. 56, 4. 63 and 1. 84 ng/L(S/N=3), respectively. The enrichment factors for four sulfa antibiotics were 4000 times with solid phase micro extraction disks. The RSD of matrix spiked samples were 0. 1%-0. 4%(n=7). The proposed method was applied to the determination of the four sulfa antibiotics in groundwater, soil and excreta with spiked recoveries of the four sulfa antibiotics in the range of 69 . 80%-117 . 60%.