Measurement of 18 Perfluorinated Organic Acids and Amides in Human Serum Using On-Line Solid-Phase Extraction

• Published in: Analytical chemistry (Washington) Vol. 77; no. 18; pp. 6085 - 6091
• Main Authors: Kuklenyik, Zsuzsanna, Needham, Larry L, Calafat, Antonia M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.09.2005
• Subjects: Acids; Acids - chemistry; Amides; Amides - blood; Amides - chemistry; Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid; Exact sciences and technology; Extraction processes; Fluorine Compounds - blood; Fluorine Compounds - chemistry; Human subjects; Humans; Ionization; Liquid chromatography; Mass spectrometry; Methods; Online Systems - instrumentation; Organic acids; Organic Chemicals - blood; Organic Chemicals - chemistry; Other chromatographic methods; Solid Phase Extraction - instrumentation; Solid Phase Extraction - methods; Spectrometric and optical methods; Tandem Mass Spectrometry; Trace levels; Trace analysis; Human; Solid phase extraction; Sulfonamide; Coupled method; HPLC chromatography; Isotope dilution; Organic acids; Electrospray; Chemical ionization; Protein; Chemical enrichment; Precipitation; Formic acid; Detection limit; Mass spectrometry MS/MS; Serum; Organic amide; Negative ion; Switching system; Quantitative analysis
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac050671l

We have developed an on-line solid-phase extraction (SPE) method coupled to high-performance liquid chromatography (HPLC)−tandem mass spectrometry (MS/MS) for measuring trace levels of 18 perfluorinated chemicals (3 perfluorosulfonates, 8 perfluorocarboxylates, 7 perfluorosulfonamides) in serum. Without protein precipitation, only dilution with 0.1 M formic acid, one aliquot of 100 μL of serum was injected into a commercial column switching system that allowed for concurrent SPE and HPLC−MS/MS acquisition. First, the analytes were concentrated on a C18 SPE column. Then, this column was placed automatically in front of a C8 analytic HPLC column for chromatographic separation of the analytes. Detection and quantification were done using negative-ion TurboIonSpray ionization, a variant of electrospray ionization, MS/MS. Excellent recovery was achieved for all analytes including the volatile sulfonamide derivatives that could not be determined before using traditional off-line SPE methods. The high throughput and low limits of detection (0.05−0.8 ng/mL) using a small sample volume (100 μL of serum) and isotope dilution quantification make this method suitable for large-scale epidemiologic studies.