The ECHO technique--the more effective way of data evaluation in liquid chromatography-tandem mass spectrometry analysis.

The aim of this study was to evaluate the applicability of ECHO technique in pesticide residue analysis using LC/MS/MS instruments with atmospheric pressure chemical (APCI) and electrospray (ESI) ionization. The technique is based on simultaneous injections of reference standards and samples in one run. First and second injections are made ahead and behind a precolumn, respectively, thus resulting in a short difference of retention times between standard and sample peak.

Determination of tocopherols, tocopherolquinones and tocopherolhydroquinones by gas chromatography-mass spectrometry and preseparation with lipophilic gel chromatography.

Lipophilic gel chromatography using Sephadex LH-20 helps in separating alpha-, beta- + -gamma, and delta-tocopherol and also in separation of their oxidation products e.g. the tocopherolquinones or other oxidation products.

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Tests with various clean-up materials after optimisation of different parameters showed that the use of Oasis® material resulted in matrixless chromatograms in HPLC-FLD. The selectivity and detection limit of the method was improved by using LC-MS/MS as the detection system. Mean recovery was 100%, and no negative food matrix effects could be observed.

Comparative analysis of the biosorption of cadmium, lead, nickel, and zinc by algae.

Thirty strains of algae were examined for their biosorption abilities in the uptake of cadmium, lead, nickel, and zinc from aqueous solution. A wide range of adsorption capacities between the different strains of algae and between the four metals can be observed. The cyanophyceae Lyngbya taylorii exhibited high uptake capacities for the four metals.

Isolation of n-decyl-alpha(1-->6) isomaltoside from a technical APG mixture and its identification by the parallel use of LC-MS and NMR spectroscopy.

The identification of n-decyl alpha(1-->6)isomaltoside as a main component of technical alkyl polyglucoside (APG) mixtures by the parallel use of liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy is described. Following enrichment on a styrene-divinylbenzene-based solid-phase extraction material, unknown components were separated by reversed-phase liquid chromatography (LC). Chemical characterization was achieved by both mass spectrometry and NMR spectroscopy.

Pesticide residue analysis in foodstuffs applying capillary gas chromatography with mass spectrometric detection. State-of-the-art use of modified DFG-multimethod S19 and automated data evaluation.

This paper focuses on recent developments in the author's laboratory and reports on the "ultimate" analysis scheme which has evolved over the last 20 years in our laboratory. This demonstrates the feasibility of screening analyses for pesticide residue identification, mainly by full scan GC-MS, down to the 0.01 ppm concentration level in plant foodstuffs.

Determination of ethylenethiourea in food commodities by a two-step derivatization method and gas chromatography with electron-capture and nitrogen-phosphorus detection.

Ethylenethiourea (ETU) is a decomposition product from ethylene-bis-dithiocarbamates (EBDCs), the most widely used class of fungicides in the world. ETU has been classified as a possible human carcinogen. The maximum permitted residue level (MRL) in the European Union was set at 0.

Pesticide residue analysis in foodstuffs applying capillary gas chromatography with atomic emission detection state-of-the-art use of modified multimethod S19 of the Deutsche forschungsgemeinschaft and automated large-volume injection with programmed-temperature vaporization and solvent venting.

Atomic emission detection (AED) provides high element-specific detection of all compounds amenable to gas chromatography (GC). The heteroatoms nitrogen, chlorine, phosphorus, sulfur, bromine and fluorine, which are important elements in pesticide residue analysis, are of major interest. A main drawback of AED is its lower sensitivity with respect to other selective detection methods used in pesticide residue analysis such as electron-capture and nitrogen-phosphorus detection.

Determination of resin acids in pulp mill EOP bleaching process effluent.

Resin acids are tricyclic diterpenoids which are natural constituents of the wood from conifers. They are released from the wood during the manufacture of pulp and paper. These acids are very resistant to chemical degradation and survive the pulping and also the EOP bleaching process (EOP=alkaline extraction, oxygen and peroxide, the chemicals used in the bleaching process).

Rapid micro liquid-liquid extraction method for trace analysis of organic contaminants in drinking water.

The applicability and performance of a micro liquid-liquid extraction method for trace analysis of organic compounds in drinking water is reported. Tap water samples of 400 ml are saturated with sodium chloride and extracted once with 500 microliters of toluene. Extracts are analyzed directly without further treatment by gas chromatography using simultaneous electron-capture and nitrogen-phosphorus detection.

Screening analysis of pesticide residues in plant foodstuffs by capillary gas chromatography using the DFG multiresidue method S19: a comparison of customary detection by ECD/NPD with the novel atomic emission detector (AED).

Over a period of 7 months nearly 240 plant foodstuffs taken fresh from the market were analysed for pesticide residues using the Deutsche Forschungsgemeinschaft (DFG) multiresidue method (MRM) S19. The analysed foodstuffs were a representative cross-section of different fruits and vegetables offered on sale on the German market. With the slightly modified MRM S19, up to 400 pesticides and metabolites amenable to gas chromatography (GC) can be determined.

CAPA--Computer Aided Pesticide Analysis. Computer program for the automated evaluation of chromatographic data for residue analysis of foods.

Pesticide residue analysis in food by means of gas chromatography with columns of different polarity and several selective detectors provides the analyst with a great number of chromatographic data. The introduction of personal computer based chromatographic data systems into research laboratories increased the efficiency of information management and organization; user designed software packages now have direct access to the stored data. The computer program CAPA (Computer Aided Pesticide Analysis) was developed for the interpretation and evaluation of chromatographic results.

Microcomputer programming in basic for the evaluation of capillary gas chromatography in the analysis of pesticide residues. I. MATRIXCOMP--a program that facilitates the recognition of interfering peaks from the biological matrix.

Chromatograms of pesticide residues in food include peaks produced by pesticides and matrix compounds. Pesticide peaks are recognized by means of relative retention times and response factors; two detectors are used and internal standard methods are applied. Chromatograms of reference samples for all types of food are stored as raw data in a reduced format, together with tables of all chromatographic data for the matrix compounds.

Automated gas chromatographic analysis of pesticide residues in food samples by means of fused-silica capillary columns and data processing.

A conventional gas chromatograph with one system for split and splitless injection and one on-column injection system for fused-silica capillary columns and the two selective nitrogen-phosphorus and electron-capture detectors is applied to pesticide residue analysis in food samples. The gas chromatograph is equipped with a two-channel data processor that can be programmed with BASIC. Additionally an autosampler is used with the splitless injector.

Automated capillary gas chromatographic analysis of pesticide residues in food.

A method for multiresidue pesticide analysis in food is described. After a conventional clean-up, gas chromatographic analysis is performed in a gas chromatograph equipped with two fused-silica capillary columns coated with methylsilicone SP 2100 and methylphenylsilicone OV-17. The effluent from each column is split to electron-capture and nitrogen-phosphorus detectors, which are connected to a dual channel integrator.

Investigation of the butyrophenone tranquilizer azaperone and its main metabolites with the Salmonella/microsome test.

In previous experiments, azaperone was found to be weakly mutagenic, after metabolic activation, in the Ames assay. In this study, we subjected metabolites found in rat and swine to the Salmonella/microsome test. 5 histidine-auxotrophic strains were used.

Investigation, with the Salmonella/microsome test, of psychopharmaceuticals used in meat production.

Azaperone, acepromazine, xylazine and diazepam were tested for mutagenic activity. To screen these veterinary drugs we used the Salmonella/microsome test on 5 histidine-auxotrophic strains, with and without metabolic activation. Azaperone and xylazine were found to be weakly mutagenic.

Microbiological studies investigation mutagenicity of deep frying fat fractions and some of their components.

In this study, the Salmonella/microsome mutagenicity test according to Ames et al. (Mutation Res. 31:347, 1975) was performed in order to detect possible mutagenicity of oxidized deep frying fat fractions.

Determination of residues of anabolic drugs in meat by gas chromatography-mass spectrometry.

The residues in meat of seven estrogenic drugs used in anabolic preparations for animal production were analysed as trimethylsilyl ethers by electron-impact gas chromatography-mass spectrometry following a simple clean-up procedure. The compounds under investigation were: 17 beta-estradiol,l diethylstilbestrol,l hexestrol, dienestrol, stilbestrol, ethynylestradiol and zeranol. The method includes extractive homogenization of 10 g of meat in tetrahydrofuran, followed by liquid-liquid partition between acetonitrile and hexane and finally a chromatographic purification step on a small silica gel column.

[Determination of trenbolone and testosterone residues in meat by high pressure liquid chromatography (author's transl)].

A new method for the qualitative and quantitative determination of trenbolone and testosterone residues in meat, liver, and kidney is described. The analytical procedure consists of the following steps: homogenisation of the meat sample with tetrahydrofurane; liquid-liquid partition first between acetonitrile and hexane, then between sodium hydroxide and petroleum ether/benzene; purification of a silica gel column. The purified sample is analysed by high pressure liquid chromatography using silica gel packings.

In vitro metabolism of the anabolic drug zeranol.

The anabolic drug zeranol, which is employed for livestock breeding was studied for its metabolic fate in vitro using isolated microsomal preparations from bovine liver, uterus, and muscle. Diethylstilbestrol and 17 beta-estradiol were investigated simultaneously for comparison. The structure of the zeranol metabolite was examined by means of TLC as well as GC-MS analysis.

[Detection of trenbolone residues in meat by thin layer chromatography and fluorimetry (author's transl)].

An new method for the qualitative and quantitative determination of trenbolone residues in meat, liver and kidney is described. The analytical procedure consists of the following steps: comminution of the meat sample; homogenisation with tetrahydrofurane; liquid-liquid partition first between acetonitril and hexane then between sodium hydroxide solution and petroleum ether/benzene; chromatography on a silica gel column. The detection on the TLC-plate is performed with 366 nm ultra violet light.