A novel method for the detection of moroxydine ( ABOB) residue in tomatoes was developed based on the enhancement of the fluorescence intensity of CdTe quantum dots( QDs) in the presence of ABOB. The factors influencing the performance of the QDs fluorescent probes were investigated, and the optimum conditions were determined:the concentration of mercaptoacidic acid ( TGA) capped-CdTe quantum dot was 1×10-4 mol/L, and the reaction time was 20 min at pH=5. 6. Under the optimum conditions, the relative fluorescence intensity increases linearly proportional to the ABOB concentration in the range of 1. 0×10-12-5. 0×10-10 mol/L with a limit of detection of 5. 2×10-13 mol/L, R=0. 9981, the recovery was 97%-106%, without obvious interference on the determinations of moroxydine from the common coexisting ions, antibiotics, and vitamins. The proposed method has been successfully applied in the detection of trace moroxydine hydrochloride residue in tomatoes.

OBJECTIVE:To establish a method for the content determination of polymer in cefatrizine propylene glycol. METHODS:High performance sephadex gel chromatography was performed on the column of Sephadex G-10 with mobile phase A of 0.01 mol/L phosphate buffer [0.01 mol/L Disodium hydrogen phosphate solution-0.01 mol/L Sodium dihydrogen phosphate solution (61∶39,V/V)](pH7.0)and mobile phase B of water at a flow rate of 1.0 ml/min,the detection wavelength was 254 nm,column temperature was 30℃,and volume injection was 200μl. RESULTS:The linear range of polymer was 2.07-103.30 mg/ml(r=0.999 4);the limit of quantitation of 10.4 ng,limit of detection was 4.1 ng;RSDs of precision and reprodicibility tests were lower than 3%. CONCLUSIONS:The method is specific with high sensitivity and good reproducibility,and can be used for the content determination of polymer in active pharmacentical ingredient cefatrizine propylene glycol.