Lehman P A, Franz T J
Department of Dermatology, University of Arkansas for Medical Sciences, Little Rock 72205-7199, USA.
J Pharm Sci. 1996 Mar;85(3):287-90. doi: 10.1021/js950339x.
A highly sensitive assay for the measurement of all-trans-retinoic acid (tretinoin) and 13-cis-retinoic acid (isotretinoin) has been developed. Collected plasma samples were protein precipitated with 2-propanol followed by solid phase extraction. The retinoic acids were subsequently derivatized to their pentafluorobenzyl esters followed by separation and isolation by reverse phase high-pressure liquid chromatography. The HPLC eluate was directed to a mass spectrometer via a particle beam interface. Selected ion monitoring (299 m/z) for the retinoic acid's carboxylate anion produced by negative chemical ionization using methane reagent gas achieved minimum detection limits of 25 pg injected. Endogenous blood levels in 19 male and 9 female subjects were measured. It was found that females have significantly more all-trans-retinoic acid than males and that both sexes demonstrate significantly more all-trans-retinoic acid then 13-cis-retinoic acid.
已开发出一种用于测量全反式维甲酸（维甲酸）和13-顺式维甲酸（异维甲酸）的高灵敏度检测方法。收集的血浆样品先用2-丙醇进行蛋白沉淀，然后进行固相萃取。随后将维甲酸衍生化为其五氟苄酯，再通过反相高压液相色谱进行分离和纯化。高效液相色谱洗脱液通过粒子束接口导入质谱仪。使用甲烷反应气通过负化学电离产生的维甲酸羧酸根阴离子的选择离子监测（299 m/z）实现了25 pg进样的最低检测限。测量了19名男性和9名女性受试者的内源性血液水平。结果发现，女性的全反式维甲酸含量明显高于男性，并且两性的全反式维甲酸含量均明显高于13-顺式维甲酸。
