Determination of tetracycline and streptomycin in mixed fungicide productsby capillary zone electrophoresis

A method of capillary zone electrophoresis (CZE) was used to determine tetr acycline and streptomycin content in commercial agriculture products. The r esults indicated that this method was capable of analyzing the mixed fungic ide in formulated products with instrument detection limit (IDL) of 0.50 mu g/mL and a method detection limit (MDL) of 0.52 mug/mL for tetracycline, an d IDL of 1.00 mug/mL and MDL of 1.22 mug/mL for streptomycin. Precision exp ressed by relative standard deviation (RSD) ranged from 1.44 to 4.37% of te tracycline and 1.00 to 4.20% of streptomycin. Recoveries were in the region of 98.2-102.5% for tetracycline and 95.3-103.0% for streptomycin. The low detection limit, the low RSD values, and the high percentage of recovery co nfirmed that the CZE technique is a sensitive and selective method. And the CZE method can analyze both tetracycline and streptomycin at the same time without complicated extraction and further derivative reaction.