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A solvent-free analytical methodology for the determination of phthalic monoesters (MPs) with diazomethane on-fibre derivatization using solid-phase microextractiongas chromatography -mass spectrometry (SPME -DOFD -GC -MS) was developed. Among the different SPME fibres evaluated, the polydimethylsiloxane/divinylbenzene (PDMS/DVB) proved to be the most suitable for the determination of four MPs. The diazomethane on-fibre derivatization (DOFD) procedure was improved, avoiding diethyl ether as solvent. Equilibrium conditions were reached (15 min) and K9 MP values were calculated. Under optimum MP extraction conditions (e. g. direct immersion, 4 mL of sample, 258C extraction temperature, stirring at 1 100 rpm, 20 min extraction time, 10 min derivatization reaction, and pH = 1.5), trace level concentrations of MPs (0.3 -8.6 ng/mL) were detected, allowing the simultaneous determination of phthalic diesters (DPs). The overall SPME -GC -MS precision was improved by using four deuterated internal standards. The developed analytical methodology was applied to different environmental water matrices and human urine samples at MP concentrations ranging from 0.1 -538 ng/mL. The developed analytical procedure is robust (50 analyses with the same fibre), rapid (40 min), and of low cost, improving the conventional analysis methods in terms of analysis time, background levels, and cost.

The qualitative analytical detection of kaurenic compounds kauradienoic (kauradien-9(11),16-dienoic acid) (1), monoginoic (2), and kaurenoic acids (3) in the infusion of Montanoa tomentosa Cerv., was carried out using GC-MS and 2D-NMR methods to resolve contradictory HPLC results from previous reports.

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Yeast species are analyzed on the basis of their lipid composition to evaluate if chemotaxonomic classification of different species is feasible. The cell walls of samples of Baker's and Brewer's yeast are disrupted by smashing the cells with glass beads at low temperatures. The liberated lipids are extracted with chloroform-methanol. Fractionation of the extract into simple lipids and complex lipids (phospholipids) is performed by column chromatography on silica gel. Elution with methanol produces the simple lipids fraction, whereas elution with methanol-chloroform-ammonium hydroxide produces the phospholipid fraction. The latter fraction is analyzed by high-performance liquid chromatography with light-scattering detection. High-temperature capillary gas chromatography of the simple lipids fraction permits the separation of waxes, sterols, squalene, sterol esters, free fatty acids, monoglycerides, diglycerides, and triglycerides.