TY - JOUR
T1 - Determination of lipoic acid and dihydrolipoic acid in human plasma and urine by high-performance liquid chromatography with fluorimetric detection
AU - Haj-Yehia, Abdullah I.
AU - Assaf, Peter
AU - Nassar, Taher
AU - Katzhendler, Jehoshua
PY - 2000/2/18
Y1 - 2000/2/18
N2 - A highly sensitive method for the determination of α-lipoic acid (LA) and dihydrolipoic acid (DHLA) in human plasma and urine has been developed. Samples were acidified and extracted with organic solvent, and the free sulfhydryls of DHLA protected as the dicarboxyethylate by treatment with ethylchloroformate. The free carboxylic function of LA and the SH-protected DHLA were converted into their amide derivatives with the strong fluorophore 2-(4-aminophenyl)-6-methylbenzothiazole in the presence of a coupling agent and a base catalyst. The resulting fluorescent amides of both LA and DHLA were separated on a reversed-phase column (Ultrasphere C8) using simple isocratic elution with acetonitrile-water (80:20) and detected fluorimetrically (excitation 343, emission 423 nm). The method is highly sensitive, reproducible, and is easily applied for the simultaneous determination of LA and DHLA in biological samples. Copyright (C) 2000 Elsevier Science B.V.
AB - A highly sensitive method for the determination of α-lipoic acid (LA) and dihydrolipoic acid (DHLA) in human plasma and urine has been developed. Samples were acidified and extracted with organic solvent, and the free sulfhydryls of DHLA protected as the dicarboxyethylate by treatment with ethylchloroformate. The free carboxylic function of LA and the SH-protected DHLA were converted into their amide derivatives with the strong fluorophore 2-(4-aminophenyl)-6-methylbenzothiazole in the presence of a coupling agent and a base catalyst. The resulting fluorescent amides of both LA and DHLA were separated on a reversed-phase column (Ultrasphere C8) using simple isocratic elution with acetonitrile-water (80:20) and detected fluorimetrically (excitation 343, emission 423 nm). The method is highly sensitive, reproducible, and is easily applied for the simultaneous determination of LA and DHLA in biological samples. Copyright (C) 2000 Elsevier Science B.V.
KW - Aminophenylmethylbenzothiazole
KW - Derivatization, LC
KW - Dihydrolipoic acid
KW - Lipoic acid
KW - Thiols
UR - http://www.scopus.com/inward/record.url?scp=0033956027&partnerID=8YFLogxK
U2 - 10.1016/S0021-9673(99)00857-2
DO - 10.1016/S0021-9673(99)00857-2
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 10722093
AN - SCOPUS:0033956027
SN - 0021-9673
VL - 870
SP - 381
EP - 388
JO - Journal of Chromatography A
JF - Journal of Chromatography A
IS - 1-2
ER -