Analysis of poly-beta-hydroxybutyrate in environmental samples by GC-MS/MS.
Application of gas chromatography-mass spectrometry (GC-MS) can significantly improve trace analyses of compounds in complex matrices from natural environments compared to gas chromatography only. A GC-MS/MS technique for determination of poly-beta-hydroxybutyrate (PHB), a bacterial storage compound, has been developed and used for analysis of two soils stored for up to 319 d, fresh samples of sewage sludge, as well as a pure culture of Bacillus megaterium. Specific derivatization of beta-hydroxybutyrate (3-OH C4:0) PHB monomer units by N-tert-butyl-dimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) improved chromatographic and mass spectrometric properties of the analyte. The diagnostic fragmentation scheme of the derivates tert-butyldimethylsilyl ester and ether of beta-hydroxybutyric acid (MTBSTFA-HB) essential for the PHB identification was shown. The ion trap MS was used, therefore the scan gave the best sensitivity and with MS/MS the noise decreased, so the S/N was better and also with second fragmentation the amount of ions increased compared to SIM. The detection limit for MTBSTFA-HB by GC-MS/MS was about 10(-13) g microL(-1) of injected volume, while by GC (FID) and GC-MS (scan) it was around 10(-10) g microL(-1) of injected volume. Sensitivity of GC-MS/MS measurements of PHB in arable soil and activated sludge samples was down to 10 pg of PHB g(-1) dry matter. Comparison of MTBSTFA-HB detection in natural soil sample by GC (FID), GC-MS (scan) and by GC-MS/MS demonstrated potentials and limitations of the individual measurement techniques.
Institute of Soil Biology Academy of Sciences of the Czech Republic, Ceské Budejovice. danael@upb.cas.cz
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Elhottová
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Tríska
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Petersen
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Santrůcková
D001410:Bacillus megaterium / Q000737:chemistry / Q000254:growth & development; D004785:Environmental Pollutants / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006017:Glycolipids / Q000032:analysis; D006885:Hydroxybutyrates / Q000032:analysis*; D011091:Polyesters / Q000032:analysis*; D012680:Sensitivity and Specificity; D012722:Sewage / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis; D000094122:Polyhydroxybutyrates
D004785:Environmental Pollutants; D006017:Glycolipids; D006885:Hydroxybutyrates; D011091:Polyesters; D012722:Sewage; D012989:Soil Pollutants; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates