Automated derivatization for on‐line solid‐phase extraction‐gas chromatography; phenolic compounds

Abstract

SummaryAn automated system for derivatization was coupled on-line with solid-phase extraction-gas-chromatography (SPE-GC). The system was optimized for the determination of phenol and chlorinated phenols in aqueous samples. The test analytes were acetylated with acetic anhydride; proper buffering of the sample was a critical factor. Next, the phenol acetates were enriched on a SPE cartridge and transferred to a GC; two approaches were studied. In the first approach, the derivatives were enriched on disposable C18 cartridges (ASPEC type) and desorbed with methyl acetate. An aliquot of the final eluate was injected on-line into the GC by means OP a loop-type interface. In the second approach, trace enrichment was performed on a 10 x 2 mm i.d. LC-type precolumn packed with polystyrenedivinylbenzene copolymer (PLRP-S). This precolumn was dried with a nitrogen purge and the phenol acetates were desorbed with ethyl acetate which was injected on-line into the retention gap of the GC under partially concurrent solvent evaporation (PCSE) conditions. The derivatization-SPE-GC system which was based on the loop-type interface has the advantage of simplicity and easy operation, the main drawback is the intpossibility to determine phenol acetates which elute prior to trichlorophenol acetates. With the derivatization-SPE-GC approach using PCSEbased desorption, even the most volatile analyte of the test series, phenol acetate, can be determined successfully. The entire procedure, including the derivatization step, was fully automated and integrated in one set-up. The analytes were detected with a flame ionization detector (FID). The precision data for the integrated on-line derivatization-SP-FID system were fully satisfactory, with RSD values of 1-12 % at the 1 ~g / l level. When a sample volume of 2.2 ml was analyzed, the detection limits for the chlorinated phenol acetates were in the 0.1-0.3 pgll range.

Bisphenol A (BPA) daily intakes in the United States: Estimates from the 2003–2004 NHANES urinary BPA data

“…To achieve enhanced sensitivity and selectivity, the phenols have been derivatized to alkyl or acyl derivatives before GC-mass spectrometry (GC/MS) analysis. [23][24][25][26][27][28][29][30][31] We have developed a sensitive method for measuring BPA, 4-tert-octylphenol (tOP), benzophenone-3 (BP-3), and five chlorophenols [2,4-dichlorophenol(24-DCP), 2,5-dichlorophenol (25-DCP), 2,45,-trichlorophenol (245-TCP), 2,4,6-trichlorophenol (246-TCP) and triclosan]. The method uses solid phase extraction (SPE) coupled on-line to HPLC and tandem mass spectrometry (MS/MS).…”

On-line solid-phase extraction-gas chromatography-ion trap tandem mass spectrometric detection for the nanogram per liter analysis of trace pollutants in aqueous samples

“…under partially concurrent solvent evaporation conditions to extend the analysis range to substances of higher volatility. A retaining precolumn was used to prevent the loss of volatile analytes, and an increased retention was effeeted by the use of 50 [aL of pre-solvent to cause phase-soaking [24]. The optimum transfer temperature was 90 ~ with an additional 10 s opening time of the SVE.…”

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,…”