Jozef Tekel

Pesticide residue analyses in plant material by chromatographic methods: clean-up procedures and selective detectors

This paper deals with the analysis of pesticide residues by chromatographic methods in samples of plant origin. Emphasis is put on the isolation and clean-up steps of the sample preparation for GC or LC determination. The problems of the extraction solvent selection and clean-up procedures using different types of adsorption column chromatography or gel permeation chromatography are discussed. Attention is also given to alternative techniques such as supercritical fluid extraction (SFE), matrix solid-phase dispersion (extraction) (MSPD) and sweep co-distillation that are used for sample processing prior to GC and LC analysis. Currently, pesticide residue analyses are typically multi-residue procedures with highly sensitive methods. Consumption of costly and toxic solvents is being minimized and fully automated analytical procedures can be expected in the future.

Extraction methodology and chromatography for the determination of residual pesticides in water

The contemporary state of the determination of pesticide residues and some of their transformation products is reviewed. The review covers the chromatographic determination of herbicides, insecticides and some important fungicide residues and their toxic transformation products (substituted anilines, chlorophenols, ethylenethiourea) in various types of water samples. Advantages and drawbacks of gas and liquid chromatography in this type of analysis are discussed. The emphasis is placed on multi-residue analytical methods with the required limit of quantification (LOQ < 0.1 μg l−1) and recovery. Various aspects of the isolation, preconcentration and clean-up of pesticide residue extracts from water samples are discussed (liquid-liquid extraction, liquid-solid extraction and supercritical fluid extraction). The characteristics of a modern chromatographic method for the determination of pesticide residues and their transformation products are summarized and trends in the development of GC and LC methods are discussed.

Chromatographic methods in the determination of herbicide residues in crops, food and environmental samples

The state of the art of chromatographic methods used in the determination of herbicide residues in crops, food and environmental samples is reviewed. The main structural groups of herbicides, i.e., triazines, phenyl- and sulphonylureas, carbamates, uracils and phenoxyalkanoic and arylphenoxypropanoic acids, and important degradation products (dealkylated triazines, substituted anilines, chlorophenols) are considered. Advantages and drawbacks of gas (GC), liquid (LC) and thin-layer chromatography in this type of analysis are discussed. The characteristics of a modern chromatographic method for the determination of herbicide residues are summarized and trends in the development and combination of current GC and LC methods discussed.

Composition of the Oil from the Flowerheads of Anthemis tinctoria L. Cultivated in Slovak Republic

Abstract The chemical composition of the essential oil obtained from the flowerheads of Anthemis tinctoria L(Asteraceae) was analyzed by capillary GC/MS. 86 components of the oil were separated, 48 of which were identified. The major constituents were 1,8-cineole (7.9%), β-pinene (7,3%), decanoic acid (5.4%) and α-pinene (4.4%).

Interlaboratory study of identification and quantitation of multiresidue pyrethroids in agricultural products by gas chromatography-mass spectrometry.

This paper deals with the different GC-MS analytical conditions adopted by four laboratories in an attempt to confirm the accuracy of the GC-electron-capture detection (ECD) analytical results during the international collaborative study for the establishment of the AOAC Official Method 998. 01. What is especially noted is that two laboratories have conducted comparative analysis of the respective 12 blind samples with both methods of GC-ECD and GC-MS, and the analytical results of the two methods turn out to be basically identical. This fully demonstrates that GC-MS is not only an effective confirmation tool in the analysis of the pyrethroid residues but also of sufficient sensitivity regarding the maximum residue limit of determination prescribed by FAO/WHO. Moreover, its selectivity is better than GC-ECD.

Composition of the essential oil from Melissa officinalis L. cultivated in Slovak Republic

Abstract The leaf oil obtained by hydrodistillation from Melissa officinalis L. c. v. citra cultivated at Nitra locality (Slovak Republic) was analyzed by GC and GC/MS. M. officinalis oil was found to contain geranial (33.60%), neral (22.18%), citronellal (11.30%), caryophyllene oxide (8.35%), geranyl acetate (5.89%), and β-caryophyllene (4.20%) as the major components. More than 50 components were identified in the oil.

Composition of the essential oils from the flowers and leaves of Salvia sclarea L. (Lamiaceae) cultivated in Slovak Republic

Abstract The chemical composition of the essential oils obtained from the flowers and leaves of Salvia sclarea L. (Lamiaceae) cultivated in Slovak Republic have been studied by GC and GC/MS methods, which resulted in the identification of 34 and 23 components, respectively. The major constituents in the flower oil were linalool (18.9%), linalyl acetate (13.7%), sclareol (15.7%), α-terpineol (6.5%), germacrene D (5.0%) and geranyl acetate (4.3%), while the major components in the leaf oil were germacrene D (28.8%), bicyclogermacrene (12.5%), spathulenol (10.1%), caryophyl-lene oxide (6.2%) and α-copaene (6.0%).

Analysis of triazine herbicides residues in butter and pasteurized milk

ZusammenfassungEs wird eine Methode für die Bestimmung der Rückstände von Atrazin, Cyanazin, Prometryn, Simazin und Terbutryn in Butter beschrieben. Die Rückstände werden aus der Butter mit einem Petrolether/Methanol-Gemisch (3 + 1) und weiter aus der geschiedenen Wasser-Methanol-Phase mittels Chloroform ausgezogen. Der Extrakt wird auf einer Aluminiumoxid-Säule gereinigt. Für die End-Analyse wird Capillargaschromatographie auf einer Glasscapillar-Säule (15 m × 0,32 mm) mit der OV-1-Stationärphase und einem thermoionischen Alkaliflammenlonisations-Detektor (N/P-FID) verwendet. Die Auswertung der Analyse geschieht mit der Standardmethode, wobei Metribuzin als innerer Standard dient. Die Wiederfmdungsraten der Methode sind 68,7 bis 79,8% für die einzelnen Herbicide in Modellversuchen bei Zugabe von 0,1 mg · kg−1 und 79,2 bis 91,9% bei Zugabe von 0,02 mg · kg−1. Die Empfindlichkeit der Methode ist 0,005 mg · kg−1.Bei der Zentrifugierung von Milch wurde die Verteilung der Triazin-Herbicidrückstände zwischen der Wasser- und Fett-Phase festgestellt, wobei der Anteil der Herbicide in Milchfett 17 bis 82% betrug. In den analysierten Proben von Butter des Handels wurden medrigere Konzentrationen (0,005–0,023 mg · kg−1) von Atrazin gefunden.SummaryA method has been developed for the determination of atrazine, cyanazine, prometryn, simazine, and terbutryn residues in butter. The residues were extracted from the matrix with a mixture of petroleum ether/methanol (3 + 1), and from the separated water-methanol phase extraction was carried out with chloroform. The extract was cleaned up on an alumina column. Capillary glass liquid chromatography using a 15 m × 0.32 mm glass capillary column coated with OV-1 and an alcali flame ionization detector were employed for the analysis of the residues. The analyses were evaluated by the internal standard method, using metribuzin as the internal standard. The recovery of the method was 68.7%–79.8% for the individual herbicides under study at the fortification level of 0.1 mg · kg−1 and 79.2%–91.9% at the fortification level of 0.02 mg · kg−1. The determination limit of the method was 0.005 mg · kg−1.When centrifuging full milk, residues of triazines were partitioned between the water and fat phases, whereby 17%–82% of the residues were transferred to the milk fat. Samples of commercial butter were analysed and found to contain 0.005–0.023 mg · kg−1 atrazine.

Composition of the Essential Oil from the Flowerheads of Chamaemelum nobile (L.) All. (Asteraceae) Cultivated in Slovak Republic

Abstract The composition of the essential oil obtained by hydrodistillation from the flower heads of Chamaemelum nobile (L.) All. (Asteraceae) was analyzed by capillary GC and GC/M S. Thirty-six components of the oil were identified. The major components were esters, such as isobutyl angelate (21.6%), 2-methylbutyl angelate (14.4%), 2-methyl-2-propenyl angelate (9.1%) and 3-methylamyl angelate (8.4%).

Determination of uracil herbicide residues and components in essential oil of Melissa officinalis L. in its main development phases

Abstract Uracil herbicide residues were studied in the medicinal plant lemon balm (Melissa officinalis L. c.v. citra) grown under standard agrochemical conditions. The residues from the uracil herbicides bromacil, lenacil, and terbacil were determined at selected phases of flower development. In addition the main components of the M. officinalis oil were determined by GC/MS at the same stages of development such as bud set, at the beginning of bloom, and at full bloom. TLC on silica gel with selective biochemical detection was used for the determination of herbicide residues in the plant material. It was found that the sample of plant material harvested in full bloom state contained 0.007 mg/kg of bromacil residue, and 0.005 mg/kg of lenacil and terbacil residues. The application of the herbicide at a rate of 2 kg/ha did not affect the quality of the treated plant.