Direct introduction of large-volume urine samples into an on-line immunoaffinity sample pretreatment-capillary gas chromatography system

Abstract

An immunoaffinity precolumn containing immobilized antibodies raised against the synthetic steroid hormone beta-19-nortestosterone, has been used for the automated sample pretreatment of urine samples containing beta-19-nortestosterone or the related steroids norethindrone and norgestrel. The sample pretreatment system was coupled on-line to a capillary GC. The on-line connection between the immunoaffinity precolumn and the capillary GC was realized with an interface that consisted of a 10 mm X 2 mm i.d. reversed-phase pre-column and a diphenyltetramethyldisilazane-deactivated GC retention gap. After preconcentration on the immunoaffinity precolumn the analytes were eluted and reconcentrated on the reversed-phase precolumn. Subsequently, this precolumn was desorbed with 75 microL of ethyl acetate, which was directly introduced into the retention gap by using partially concurrent solvent evaporation. The system allows the automated pretreatment and GC analysis of 5-25-mL urine samples for the ppt-level determination of 19-norsteroids. The general applicability and potential of on-line immunoaffinity-capillary GC systems are discussed.

Development of an ELISA for 2,4-D: characterization of two polyclonal antisera

“…A prerequisite for this control for the protection of both man and nature is an efficient analytical tool. So far 2,4-D is analyzed by GC or HPLC, which need an extensive sample preparation to reach the required sensitivity [3,[9][10][11][12][13]. The main disadvantage of this preparation is the expenditure for a great time number of samples.…”

Approaches for on-line coupling of extraction and chromatography

“…Methods based on both SPE-GC and LLE-GC have been developed for a variety of environmental determinations, and SPE-GC has also been used for the analysis of drugs in biological fluids [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,53,54,55,56,57,58,59,60,61,62,…”

Immunoaffinity Extraction with On-Line Liquid Chromatography—Mass Spectrometry

“…To illustrate how IAC is coupled on-line with HPLC the experimental setup used by Farjam and co-workers is described (6). In a repetitive analysis mode, the first step is to flush the immunoaffinity column with water to displace the eluting solvent [e.g, methanol-water (95:5) or other solvent combination] from the previous run.…”