Lianidou E S, Ioannou P C
Department of Chemistry, University of Athens, Greece.
Clin Chem. 1996 Oct;42(10):1659-65.
A novel, sensitive, and selective method has been developed for determination of p-aminobenzoic (PABA) and p-aminosalicylic (PAS) acids in the N-benzoyl-L-tyrosyl-PABA/ PAS test. PAS is measured as a ternary complex with terbium and EDTA (lambda(ex) = 324 nm, lambda(em) = 546 nm) in alkaline aqueous solution (pH approximately 12.6), whereas both compounds (PABA and PAS) are measured as ternary complexes with terbium and tri-n-octylphosphine oxide (lambda(ex) = 292 nm, lambda(em) = 546 nm) in weakly acidic aqueous solution (pH approximately 5.5). We inve stigated and implemented optimum conditions for formation of these complexes, yielding respective detection limits for PABA and PAS of 0.07 and 0.02 micromol/L and ranges of application of 0-10 and 0-40 micromol/L (final concentration). The method has been successfully applied to determinations of PABA and PAS in urine and, after alkaline hydrolysis, to determinations of PABA in serum that has been deproteinized with acetonitrile. Within-run imprecision of the PABA determination ranges from 0.8% to 4.2 % for urine samples and from 3.9% to 8.2% for serum samples; day-to-day imprecision varies from 3.2% to 10% for serum samples.
已开发出一种新颖、灵敏且具选择性的方法，用于在N-苯甲酰-L-酪氨酰-PABA/PAS试验中测定对氨基苯甲酸（PABA）和对氨基水杨酸（PAS）。在碱性水溶液（pH约12.6）中，PAS作为与铽和乙二胺四乙酸的三元络合物进行测定（激发波长λ(ex)=324nm，发射波长λ(em)=546nm），而两种化合物（PABA和PAS）在弱酸性水溶液（pH约5.5）中作为与铽和三正辛基氧化膦的三元络合物进行测定（激发波长λ(ex)=292nm，发射波长λ(em)=546nm）。我们研究并确定了形成这些络合物的最佳条件，PABA和PAS的检测限分别为0.07和0.02μmol/L，应用范围分别为0 - 10和0 - 40μmol/L（最终浓度）。该方法已成功应用于尿液中PABA和PAS的测定，以及在碱性水解后，用于测定经乙腈脱蛋白的血清中的PABA。尿液样本中PABA测定的批内不精密度为0.8%至4.2%，血清样本为3.9%至8.2%；血清样本的日间不精密度在3.2%至10%之间。
