PubMed Health⌕ Search

PubMed · 2772221

A new method using simple solid phase extraction for the rapid gas-chromatographic mass-spectrometric determination of 11-dehydro-thromboxane B2 in urine.

Abstract

A new gas-chromatographic mass-spectrometric method for the rapid determination of 11-dehydro-thromboxane B2 in urine, the major metabolite of systemic thromboxane formation, has been developed. Excellent sample clean-up was obtained in a single step by adsorption of 11-dehydro-TXB2 on phenylboronate cartridges, vigorous polar and organic washing and elution with an acidic methanol mixture. Then the pentafluorobenzylester trimethylsilylether derivative of 11-dehydro-TXB2 was formed and quantified in isotope dilution technique by negative chemical ionisation gas-chromatography tandem mass-spectrometry. The daughter fragments m/z 243/247 of the parent ion m/z 511/515 were monitored. Recovery was linear and quantitative over a wide range, accuracy was 95 + 7% and precision was 11% down to the very low pg range in biologic samples. Independent validation of this very fast extraction method with a reference method applying extensive sample purification with consecutive reversed and straight phase extraction, precolumn derivatisation, reversed phase high pressure liquid chromatography and tandem gas-chromatography mass-spectrometry gave excellent agreement of values. Values for 11-dehydro-TXB2 excretion in 8 healthy controls were 501 + 298 (range 231 to 1141) ng/g creatinin. Excretion was suppressed by aspirin, moderately elevated in heavy smokers (range 680 to 1540) and increased in patients with venous thrombosis or pulmonary embolism (2370 to 13350 ng/g creatinin). This rapid extraction method is useful for the highly specific and sensitive determination of 11-dehydro-TXB2 in large sample numbers.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R Lorenz, P Helmer, W Uedelhoven, B Zimmer, P C Weber. 1989. A new method using simple solid phase extraction for the rapid gas-chromatographic mass-spectrometric determination of 11-dehydro-thromboxane B2 in urine.. https://doi.org/10.1016/0090-6980(89)90079-8

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

HPLC separation and NMR structural elucidation of sn-1,2-, 2,3-, and 1,3-diacylglycerols from olive oil as naphthylethylurethane derivatives.

In this study, sn-1,2-, sn-2,3-, and sn-1,3-diacylglycerols were isolated from olive oil, and their urethane derivatives (urethanes) were prepared. Normal-phase high-performance liquid chromatography (NP-HPLC) separation of the urethane isomers was performed and the separate classes were studied by nuclear magnetic resonance (NMR). The use of 1H NMR and homo- and heteronuclear 2D techniques provided a great amount of information in a very short time, particularly when a high-field NMR instrument (700 MHz) was used. Particularly diagnostic for this kind of compound was the glyceridic moiety that presents typical chemical shifts both for carbon and hydrogen. These studies show the usefulness of NMR spectroscopy to recognize clearly the sn-1,3- and, moreover, sn-1,2- with respect to sn-2,3-diacylglycerols, although very minor differences occur between them.

Chromatography, High Pressure Liquid↗

Solid-phase extraction combined with high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis of pesticides in water: method performance and application in a reconnaissance survey of residues in drinking water in Greater Cairo, Egypt.

Monitoring of water resources for pesticide residues is often needed to ensure that pesticide use does not adversely impact the quality of public water supplies or the environment. In many rural areas and throughout much of the developing world, monitoring is often constrained by lack of testing facilities; thus, collection of samples and shipment to centralized laboratories for analysis is required. The portability, ease of use, and potential to enhance analyte stability make solid-phase extraction (SPE) an attractive technique for handling water samples prior to their shipment. We describe performance of an SPE method targeting a structurally diverse mixture of 25 current-use pesticides and two common degradates in samples of raw and filtered drinking water collected in Greater Cairo, Egypt. SPE was completed in a field laboratory in Egypt, and cartridges were shipped to the United States for elution and high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis. Quantitative and reproducible recovery of 23 of 27 compounds (average = 96%; percent relative standard deviation = 21%) from matrix spikes (1 microg L-1 per component) prepared in the field and from deionized water fortified similarly in the analytical laboratory was obtained. Concurrent analysis of unspiked samples identified four parent compounds and one degradate in drinking water samples. No significant differences were observed between raw and filtered samples. Residue levels in all cases were below drinking water and "harm to aquatic-life" thresholds, indicating that human and ecological risks of pesticide contamination were relatively small; however, the study was limited in scale and scope. Further monitoring is needed to define spatial and temporal variation in residue concentrations. The study has demonstrated the feasibility of performing studies of this type using SPE to extract and preserve samples in the field. The approach should be broadly applicable in many settings.

Chromatography, High Pressure Liquid↗

Retention behavior of oligomeric proanthocyanidins in hydrophilic interaction chromatography.

A novel method was developed for the separation of proanthocyanidins (PAs; oligomeric flavan-3-ols) by hydrophilic interaction chromatography (HILIC) using an amide-silica column eluting with an aqueous acetonitrile mobile phase. The best separation was achieved with a linear gradient elution of acetonitrile-water at ratios of 9:1 to 5:5 (v/v) for 60 min at a flow rate of 1.0 ml/min. Under these HPLC conditions, a mixture of natural oligomeric PAs (from apple) was separated according to degree of polymerization (DP) up to decamers. The DP of each separated oligomer was confirmed by LC/electrospray ionization MS. In further HILIC separation studies of 15 different flavan-3-ol and oligomeric PA (up to pentamer) standards with an isocratic elution of acetonitrile-water (84:16), a high correlation was observed between the logarithm of retention factors (log k) and the number of hydroxyl groups in their structures. The coefficient of this correlation (r2=0.9501) was larger than the coefficient (r2=0.7949) obtained from the correlation between log k and log P(o/w) values. These data reveal that two effects, i.e. hydrogen bonding between the carbamoyl terminal on the column and the hydroxyl group of solute oligomer and hydrophilicity based on the high-order structure of oligomeric PAs, corporately contribute to the separation, but the hydrogen bonding effect is predominant in our HILIC separation mode.

Chromatography, High Pressure Liquid↗