DETERMINATION OF LOW PARTS PER BILLION LEVELS OF AMINES IN URINE BY LIQUID MEMBRANE SAMPLE CLEANUP DIRECTLY COUPLED TO A GAS-LIQUID CHROMATOGRAPH

被引:86
作者
AUDUNSSON, G [1 ]
机构
[1] UNIV LUND, DEPT ANALYT CHEM, S-22100 LUND, SWEDEN
关键词
D O I
10.1021/ac00164a020
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
An automated sample preparation by the liquid membrane technique directly coupled to a gas chromatograph is demonstrated for the determination of amines in urine. The alkalized sample comes into contact with n-undecane immobilized in a membrane made of Teflon wherein the amines are extracted. On the opposite side of the membrane a stagnant buffer taps solely those amines which become protonated at the prevailing pH. After the sample passes, the accumulated plug of amines is swept from the membrane separator to an interface which injects a heartcut of the plug into the gas chromatograph. The presented technique lowers the detection limit of the manual gas chromatographic method for pure aqueous solutions by more than 2 orders of magnitude for urine as a matrix, while the availability of sample limits the enrichment obtainable for simpler matrices. The overall repeatability is 3.4-4% for concentrations down to 1 ppb in urine. More than 600 urine samples were analyzed without any noticeable change in performance of the liquid membrane system and no unusual changes in the gas chromatography system were observed.
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页码:1340 / 1347
页数:8
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