Analytical methods for the determination of organochlorine compounds. Application to environmental samples in the Slovak Republic.

The paper deals with the isolation of chlorinated phenols, benzenes and insecticides from water, soil and vegetable samples. A review of the current procedures is presented. Solid-phase extraction on Empore extraction discs was experimentally evaluated for isolation of the compounds from surface and ground waters. For the isolation of chlorophenols from soil and vegetable samples, a method of simultaneous steam distillation/extraction was elaborated which proved to be also applicable for waste waters and sludges. Chlorinated insecticides and benzenes were extracted from soil and vegetable samples with the Soxhlet procedure. Final determinations were carried out by GC-electron-capture detection. The recoveries of the methods were well over 70%, with relative standard deviations below 14%. Samples of surface and ground waters, soil and vegetables, mostly from the vicinity of chemical and municipal waste dumping sites, were analysed. The highest contamination levels were found for chlorinated phenols in surface water from the vicinity of a former chemical waste dumping place where the concentrations of 2,6-dichlorophenol and pentachlorophenol were 4.3 and 3.9 micrograms l-1, respectively.

Chlorinated phenols in human milk.

The paper deals with the contamination of human milk with chlorinated phenols. The average and median concentrations of the chlorophenols investigated ranged from 0.75 to 9.74 micrograms.kg-1 and from being not detectable to 5.62 micrograms.kg-1, respectively, for the different compounds. The highest average and median levels were found for pentachlorophenol and 2,4,5-trichlorophenol. The concentrations determined were below the permissible levels.

Polychlorinated phenols in total diet.

A method has been developed for the isolation, separation and determination of chlorinated phenols in total diet. The isolation takes place following acid hydrolysis of the conjugates and is performed by simultaneous extraction and distillation with water vapour and toluene. The isolated chlorophenols are removed by clean-up on a Florisil column using a mixture of 15% dichloromethane in toluene for elution. The separation and determination is carried out by capillary gas chromatography with electron capture detection. The recovery of the method ranged between 70.1 +/- 5 and 96.8 +/- 4.9% for the individual chlorophenols. The determination limits were 0.5 to 1.0 microgram.kg-1. The method was applied in a study aimed at estimating the chlorophenol burden in two population groups (children up to the age of 6 years and students up to the age of 18 years). In two successive years, 80 total diet samples were analysed. Average contents of the individual chlorophenols were from 0.7 to 33.5 micrograms.kg-1 and were higher for the dichlorophenol isomers. The calculated average daily intake ranged from 0.04 to 1.69 micrograms.kg-1 body weight for the individual phenols.

Polychlorinated biphenyls in mother milk and adapted cow's milk.

In the present study, 50 samples of mother milk and 20 samples of adapted cow's milk produced for bottle feeding supplied from the lactarium of the Pediatric Hospital were examined for presence of 6 indicator congeners of polychlorinated biphenyls (IUPAC No. 28, 52, 101, 138, 153, and 180). Congeners No. 138, 153, and 180 were predominant in all samples, the highest mean as well as the maximum level was found for No. 138 for both type of samples. The average daily intake based on the sum of indicator congeners was found to be 2.56 micrograms. (kgb.w..day)-1 for mother milk, and 0.85 microgram.(kgb.w..day)-1 for adapted cow's milk.

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.

Isotachophoretic determination of herbicides prometryne, desmetryne, terbutryne and hydroxy-derivatives of atrazine and simazine in extracts of milk.

A method is described for the determination of the triazine herbicides prometryne, desmetryne, terbutryne, OH-atrazine and OH-simazine in purified extracts of milk using analytical capillary isotachophoresis. The reproducibility of isotachophoretic analyses was 3.5% and the detection sensitivity reached 2 ng. Recovery of triazines from fortified samples of homogenized full milk (0.05 mg/L) was about 65%.

Analysis of triazine herbicides residues in butter and pasteurized milk.

A 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 x 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.

Analysis of herbicide residues in sugar beet and sugar.

A simple quantitative TLC method for the determination of the residues of herbicide inhibiting photosynthesis was compared with capillary GLC for the analysis of atrazine, chloridazone, lenacil, phenmedipham and desmedipham in sugar beet and sugar. No significant differences in the determination limit and precision of the two methods were found. Monitoring of herbicide residue levels in commercial sugar revealed low levels of atrazine (0.003 mg.kg-1 on average) in all the samples. This contamination level does not present a health hazard consumers.