[Simultaneous determination of three beta-lactamase inhibitor residues in dairy products by high performance liquid...

An improved method has been developed for the determination of clavulanate potassium, tazobactam and sulbactam in dairy products. High performance liquid chromatography with photodiode array detector (HPLC-PAD) was used in this method. The separation was performed on a CAPCELL PAK MG-C18 column (150 mm x 4.6 mm, 5 microm). The mobile phase was 0.03% (volume fraction unless otherwise specified) phosphate-acetonitrile. This method offered effective sample preparation procedures including dissolution with water, protein isolation with acetone, clean-up and enrichment by solid-phase extraction (SPE) with PWAX cartridges (60 mg/3 mL) under weak acidic condition and further elution with 0.05% ammonia-methanol solution. The analytical method was well validated and good results were obtained with the RSDs of 2.2% - 7.4% and the recoveries of 84.6% - 101.7%. The detection limits of clavulanate potassium, tazobactam and sulbactam were 0.03 mg/L. All of the target compounds exhibited good linearities (r > 0.999) over the mass concentration range of 0.05 - 5 mg/L. With the advantages of good purification effect, high sensitivity, good recovery and repeatability, the method is suitable for the detection of beta-lactamase inhibitors in dairy products.