[Analysis of the response factors of different quinolones detected by evaporative light-scattering detector].
OBJECTIVE
To analyze the response factors of different quinolone antibiotics detected by evaporative light-scattering detector (ELSD).


METHODS
The response factors of five different quinolones (enoxacin, levofloxacin, ciprofloxacin, lomefloxacin and gatifloxacin) detected by ELSD were determined by using a YMC-Pack ODS-AM cloumn (150 mm x 4.6 mm ID, 5 microns) as analytical column and 0.5% triethylamine (adjusting pH 2.5 with trifluoroacetic acid)-acetonitrile (48:12) as mobile phase at a flow rate of 0.6 mL.min-1, the temperature of the drift tube was set at 117 degrees C, and the flow of carrier gas at 3.0 L.min-1. Detector responses (A) and the amount of injection of each substance (m) were fitted to the logarithmic regression: log A = b log m + log a.


RESULTS
The linear regression equation obtained were: enoxacin: Y = 1.0799X + 2.7611, r2 = 0.9996; levofloxacin: Y = 1.0913X + 2.7235, r2 = 0.9997; ciprofloxacin: Y = 1.0828X + 2.7523, r2 = 0.9994; lomefloxacin: Y = 1.0891X + 2.7391, r2 = 0.9993; gatifloxacin: Y = 1.0878X + 2.7392, r2 = 0.9995. The differences between them were negligible.


CONCLUSIONS
Different quinolones can give the same responses with ELSD detection. So, the HPLC-ELSD methods can be applied to the determination of new substances by using another substance as reference.
Hong
Jian-wen
JW
Guangdong Province Institute for Drug Control, Guangzhou 510180, China.
Hu
Chang-qin
CQ
Sheng
Long-sheng
LS
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002939:Ciprofloxacin / Q000032:analysis; D015365:Enoxacin / Q000032:analysis; D024841:Fluoroquinolones / Q000032:analysis; D000077734:Gatifloxacin; D064704:Levofloxacin; D008027:Light; D016014:Linear Models; D015242:Ofloxacin / Q000032:analysis; D015363:Quinolones / Q000032:analysis*
D024841:Fluoroquinolones; D015363:Quinolones; D015365:Enoxacin; D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin; D000077734:Gatifloxacin; C053091:lomefloxacin