AIMTo analyze if the response factors of different aminoglycoside antibiotics detected by evaporative light-scattering detector (ELSD) are the same. If they are, then ELSD can be applied to the quality analysis of this class of antibiotics.

METHODSThe response factors of five different aminoglycosides (amikacin, sisomicin, netilmicin, etimicin and vertilmicin) detected by ELSD were determined by using a Diamonsil C18 column (150 mm x 4.6 mm, 5 microns) as analytical column and 0.2 mol.L-1 trifluoroacetic acid-methanol (94:6) as mobile phase at a flow rate of 0.6 mL.min-1, the temperature of the drift tube was set at 110 degrees C, and the flow of carrier gas at 2.80 L.min-1. Detector responses (A) and the amount of injection of each substance (m) were fitted to the logarithmic regression: logA = blogm + loga.

RESULTSThe linear regression equation obtained were amikacin: Y = 1.46X + 5.07, gamma = 0.9997; sisomicin: Y = 1.51X + 5.03, gamma = 0.9997; netilmicin: Y = 1.52X + 4.88, gamma = 1.000; etimicin: Y = 1.46X + 4.85, gamma = 0.9999; vertilmicin: Y = 1.41X + 4.90, gamma = 0.9998. The differences between them were negligible.

CONCLUSIONDifferent aminoglycosides can give the same responses with ELSD detection. So, the HPLC-ELSD methods can be applied to the analysis of impurities, the control of the ratio of multi-components drug and the determination of new substances by using another substance as reference, etc.