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PubMed1981

Identification of a 32-34-kilodalton polypeptide as a herbicide receptor protein in photosystem II.

Photosystem II particles which retained high rates of herbicide-sensitive activity were used to examine the site(s) of action of various herbicides. A polypeptide of 32-34 kdaltons was identified as the triazine-herbicide binding site based upon: (a) parallel loss of atrazine activity and the polypeptide during either trypsin treatment or selective detergent depletion of protein in the Photosystem II complex, and (b) covalent labeling of the polypeptide by a 14C-labeled photoaffinity triazine. In Photosystem II particles depleted of the 32-34-kdalton polypeptide, electron transport was still active and was slightly sensitive to DCMU and largely sensitive to dinoseb (urea and nitrophenol herbicides, respectively). On the basis of this result it is proposed that the general herbicide binding site common to atrazine, DCMU and dinoseb is formed by a minimum of two polypeptides which determine affinity and/or mediate herbicide-induced inhibition of electron transport on the acceptor side of Photosystem II.

Chloroplasts↗
PubMed1993

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.

Chromatography↗
PubMed1992

Effect of pesticides on oestradiol-receptor complex formation in rat uterus cytosol.

The effect of gamma-1,2,3,4,5,6-hexachlorocyclohexane (lindane), 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2-methylthio-4,6-bis-isopropylamino-s-triazine (prometryne) on the formation of a specific oestradiol-receptor complex in the rat uterus cytosol has been examined in vitro and in vivo. Both in vitro and in vivo, the pesticides significantly (P < 0.001) inhibited the formation of the complex in the rat uterus cytosol. The decrease in the number of free specific binding sites on the receptors was determined. The affinity of binding was not modified under the influence of pesticides, and the Kd value was of the same order of magnitude (10(-9) M). The inhibition was found to be fully non-competitive.

Animals↗
PubMed1988

Urinary atrazine metabolites as indicators for rat and human exposure to atrazine.

Rats were given atrazine (2-chloro-4-ethylamino-6-(isopropylamino)-s-triazine) in drinking water for 1 or 3 weeks at 0.1 (0.45 mM), 0.2 (0.9 mM) or 0.5 g/l (2.3 mM) concentrations of the commercial agent. They excreted at both time points as the principal metabolite 2-chloro-4-ethylamino-6-amino-s-trazine in a dose-dependent fashion. The same urine test was applied on 6 railway men engaged in the weeding operation of railway lines with known atrazine exposure measured with hygienic techniques in their breathing zone. The spectrum of their atrazine metabolites was comprised of fully N-dealkylated atrazine and 2-chloro-4-ethylamino-6-amino-s-triazine. The sum of the two urinary metabolites reflected quantitatively the exposure.

Administration, Oral↗
PubMed1989

Suitability of DTAF as a fluorescent labelling reagent for direct analysis of primary and secondary amines--spectral and chemical reactivity considerations.

DTAF has been used successfully to prepare fluorescent labelled reagents for fluorescence polarization immunoassays. Its applicability as a derivation reagent for direct fluorescence analysis of primary and secondary amines was evaluated. DTAF was shown to have spectral properties that closely resemble those of fluorescein and that are apparently insensitive to the presence of the triazine nucleus. Spectrally determined pKa values also closely resemble those of fluorescein and other amino aryl-s-triazines. DTAF is prone to hydrolytic degradation with the rate of reaction increasing with increasing pH, until a pH value is reached at which ionization of the amine bridging the two aromatic nuclei occurs; at this pH the rate reaches a plateau value. Both primary and secondary amines react efficiently with DTAF, and the reactivity increases with the increasing basicity of the amine reactants. The reaction is pH-dependent, proceeding most efficiently at pH values at which both the "bridging amine" of DTAF and the amine substrate are unionized. Methyl substituted secondary amines were consistently more reactive than the corresponding primary amine, but further imposition of steric bulk about the amine nitrogen significantly reduced the reactivity of amines toward DTAF. In cases where such steric bulk is minimal. DTAF appears to be a suitable fluorescent labelling reagent for direct analytical applications.

Amines↗
PubMed1991

Dye-ligand and immobilized metal ion interaction chromatography for the purification of enzymes of prenyl pyrophosphate metabolism.

Dye-ligand and immobilized metal ion interaction chromatography were shown to be efficient techniques for the rapid batchwise fractionation, from crude plant extracts, of a series of enzymes of prenyl pyrophosphate metabolism. Isopentenyl pyrophosphate isomerase, two prenyltransferases, and a number of terpene cyclases (synthases) were readily adsorbed to Matrex Gel Red A (a dimeric triazine dye coupled to cross-linked agarose beads), and desorbed in good yield with relatively high concentrations of KCl and increasing pH. Although all of these enzymes exhibit the common feature of employing a pyrophosphorylated substrate, selective elution could not be achieved with substrate or substrate analogues bearing a pyrophosphate function. Nor could the strong binding of these enzymes to triazine dyes be attributed solely to metal ion interactions or to hydrophobic effects. In a similar way, the isomerase, the prenyltransferases, and all of the terpene cyclases bound to a column of iminodiacetate-immobilized Ni(II) and were desorbed in relatively high fold purity with 15 mM imidazole. Although all of these enzymes bear accessible histidine residues, the interactions with the chelated metal ion were not sufficiently different to permit selective enzyme desorbtion by imidazole gradient elution. However, the use of columns charged with Zn(II) or Co(II) did allow some separation of the different cyclase and transferase types. While empirical in nature, these techniques offer simple, effective, and high-capacity methods for the preliminary concentration and purification of a group of enzymes that utilize prenyl pyrophosphate intermediates of isoprenoid biosynthesis.

Chromatography, Affinity↗
PubMed2005

Comparison of different heterocyclic scaffolds as substrate analog PDE5 inhibitors.

Several different heterocyclic systems were compared as PDE5 inhibitor scaffolds. In addition to the known 3H-imidazo[5,1-f][1,2,4]triazin-4-ones and pyrazolopyrimidinones, isomeric imidazo[1,5-a][1,3,5]triazin-4(3H)-ones were also shown to be potent and selective PDE inhibitor scaffolds with in vivo activity. SAR trends were elucidated for sulfonamide derivatives with generality across different scaffolds.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2006

Nucleotide-mimetic synthetic ligands for DNA-recognizing enzymes One-step purification of Pfu DNA polymerase.

The commercial availability of DNA polymerases has revolutionized molecular biotechnology and certain sectors of the bio-industry. Therefore, the development of affinity adsorbents for purification of DNA polymerases is of academic interest and practical importance. In the present study we describe the design, synthesis and evaluation of a combinatorial library of novel affinity ligands for the purification of DNA polymerases (Pols). Pyrococcus furiosus DNA polymerase (Pfu Pol) was employed as a proof-of-principle example. Affinity ligand design was based on mimicking the natural interactions between deoxynucleoside-triphosphates (dNTPs) and the B-motif, a conserved structural moiety found in Pol-I and Pol-II family of enzymes. Solid-phase 'structure-guided' combinatorial chemistry was used to construct a library of 26 variants of the B-motif-binding 'lead' ligand X-Trz-Y (X is a purine derivative and Y is an aliphatic/aromatic sulphonate or phosphonate derivative) using 1,3,5-triazine (Trz) as the scaffold for assembly. The 'lead' ligand showed complementarity against a Lys and a Tyr residue of the polymerase B-motif. The ligand library was screened for its ability to bind and purify Pfu Pol from Escherichia coli extract. One immobilized ligand (oABSAd), bearing 9-aminoethyladenine (AEAd) and sulfanilic acid (oABS) linked on the triazine scaffold, displayed the highest purifying ability and binding capacity (0,55 mg Pfu Pol/g wet gel). Adsorption equilibrium studies with this affinity ligand and Pfu Pol determined a dissociation constant (K(D)) of 83 nM for the respective complex. The oABSAd affinity adsorbent was exploited in the development of a facile Pfu Pol purification protocol, affording homogeneous enzyme (>99% purity) in a single chromatography step. Quality control tests showed that Pfu Pol purified on the B-motif-complementing ligand is free of nucleic acids and contaminating nuclease activities, therefore, suitable for experimental use.

Amino Acid Motifs↗
PubMed2005

Synthesis, molecular structure, and in vitro antitumor activity of new 4-chloro-2-mercaptobenzenesulfonamide derivatives.

The reaction of 3-amino-2-(2-alkylthio-4-chlorobenzenesulfonyl)guanidines 2a-j with 1,2-dicarbonyl compounds are described. Depending on structure of 1,2-dicarbonyl reagent novel 2-alkylthio-5-chloro-N-(1,2,4-triazin-3-yl)benzenesulfonamides 3-15, 1-(2-alkylthio-4-chlorobenzenesulfonyl)-3-(2-oxobutane-3-ylidenoimino)guanidines 16-18 and 2-alkylthio-4-chloro-N-(1,2-dihydroxycyclobuta[e]1,2,4-triazin-3-yl)benzenesulfonamides 19-21 are obtained. The structures of these compounds were confirmed on the basis of elemental analysis, spectral data and X-ray analysis. The compounds 4, 5, 7, 9, 10, 12-15, 17, 18 and 20 were screened at the National Cancer Institute (NCI) for their in vitro activities against a panel of 56 tumor cell lines and relationship between structure and antitumor activity are discussed. The compounds 10, 12, 17 and 20 were inactive, whereas the other compounds exhibited reasonable activity against one or more human tumor cell lines. The prominent compound 18 showed significant activity against cell lines of colon cancer (HCT-116), renal cancer (786-0) and melanoma (M14) (GI50 in the range 0.33-1.08 microM) as well as good selectivity toward non-small cell lung cancer (HOP-62) cells (GI50 = 0.05 microM, TGI = 0.38 microM and LC50 = 4.83 microM).

Antineoplastic Agents↗
PubMed2006

Toward building a database of bifunctional probes for the MS3D investigation of nucleic acids structures.

This report illustrates the approaches employed to investigate critical aspects of the activity of crosslinking reagents toward nucleic acid substrates, which should be evaluated to identify candidate probes for mass spectrometric 3D (MS3D) investigations of biomolecules and macromolecular complexes. Representative members of different classes of bifunctional reagents were taken into consideration, including bikethoxal and phenyl-diglyoxal [bis-(1,2-dicarbonyls)], cisplatin (coordinative binding agents), chlorambucil and nitrogen mustard [bis-(2-chloroethyl)amines], and sym-triazine trichloride (triazines). Nanospray-Fourier transform mass spectrometry (FTMS) was applied without desalting or separation procedures to characterize the covalent products obtained by probing dinucleotide and trinucleotide substrates under a variety of experimental conditions in vitro. The carefully controlled composition of these substrates enabled us to obtain valid comparisons of probe activity toward individual nucleotides and evaluate possible base-specific effects, including the stability of the different adducts in solution under the selected reaction conditions. The gas-phase behavior of the observed products was investigated using sustained off-resonance irradiation collision-induced dissociation (SORI-CID) to obtain valuable information for guiding the design of sequencing experiments and helping the data interpretation. Structured RNA substrates, such as HIV-1 stemloop 1, were finally employed to investigate the structural determinant of adduct formation and highlight the different nature of the spatial information provided by the various candidate probes.

Cross-Linking Reagents↗
PubMed1997

Effects of dual combinations of antifolates with atovaquone or dapsone on nucleotide levels in Plasmodium falciparum.

The triazine antifolates, cycloguanil and 4,6-diamino-1,2-dihydro-2,2-dimethyl-1-[(2,4,5-trichlorophenoxy)propy loxy]-1,3,5-triazine hydrobromide (WR99210), and their parent biguanide compounds, proguanil and N-[3-(2,4,5-trichlorophenoxy)propyloxy]-n-(1-methylethyl)-imido dicarbonimidic-diamine hydrochloride (PS-15), were tested in combination with a series of antimalarial drugs for synergism against Plasmodium falciparum growing in erythrocytic culture. Four synergistic combinations were found: cycloguanil dapsone, WR99210-dapsone, proguanil-atovaquone, and PS-15-atovaquone. Cycloguanil-dapsone or WR99210-dapsone had a profound suppressive effect on the concentration of dTTP in parasites while that of dATP increased. Depletion of dTTP is consistent with cycloguanil or WR99210 inhibiting dihydrofolate reductase and dapsone inhibiting dihydropteroate synthase. For the combinations proguanil-atovaquone and PS-15-atovaquone, the levels of nucleoside triphosphates (NTPs) and dNTPs were generally suppressed, suggesting that inhibition is not through nucleotide pathways but probably through another metabolic mechanism(s). Combinations of two synergistic pairs of antimalarial drugs, (proguanil-atovaquone)-(cycloguanil-dapsone) and (PS-15-atovaquone)-(WR99210-dapsone), were tested, and it was found that NTPs and dNTPs decreased much more than for a single synergistic combination. Dual synergistic combinations could play an important role in the therapy of multidrug-resistant malaria, just as combination chemotherapy is used to treat cancer.

Adenosine Triphosphate↗
PubMed1992

The reaction of some dicarbonyl sugars with aminoguanidine.

The reactions of aminoguanidine (guanylhydrazine) with 3-deoxy-D-erythro-hexos-2-ulose (1a), 3-deoxy-D-glycero-pentose-2-ulose (1b), D-erythro-hexos-2-ulose (1c), and D-glycero-pentose-2-ulose (1d) were examined at 37 degrees at a solution pH of 7.0 (phosphate buffer). For 1a and 1b, two major products were observed and shown respectively to be the 5- and 6-substituted 3-amino-1,2,4-triazine derivatives. The ratios of the products were independent of the amount of aminoguanidine present or the order of mixing the reagents prior to the experiments. For 1c and 1d, only the 5-substituted triazine derivatives were formed. No evidence for hydrazone or bishydrazone formation was observed.

Guanidines↗
PubMed2002

5-HT1A receptor activation and anti-cataleptic effects: high-efficacy agonists maximally inhibit haloperidol-induced catalepsy.

Studies have shown that 5-HT1A receptor ligands modulate antipsychotic-induced catalepsy. Here, we further examined the role of intrinsic activity at 5-HT1A receptors in these effects. The anti-cataleptic effects of 5-HT(1A) receptor ligands with positive intrinsic activity [from high to low: 3-chloro-4-fluorophenyl-(4-fluoro-4-[[(5-methyl-6-methylamino-pyridin-2-ylmethyl)-amino]-methyl]-piperidin-1-yl-methanone fumaric acid salt (F 13714), eptapirone, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), 2-[4-[4-(7-methoxy-1-naphtyl) piperazino]butyl]-4-methyl-2H,4H-1,2,4-triazin-3,5-dione maleic acid salt (F 11461), buspirone, 2-[4-[4-(7-benzofuranyl)piperazino]butyl]-4-methyl-2H,4H-1,2,4-triazin-3,5-dione (F 12826), ipsapirone, and (s)-N-tert-butyl-3-(4-(2-methoxyphenyl)piperazine-1-yl)-2-phenylpropanamide hydrochloride (WAY 100135)] and negative intrinsic activity [N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide dihydrochloride (WAY 100635)] were examined. Catalepsy was induced by the classical antipsychotic haloperidol (0.63 mg/kg) and measured in the cross-legged position test and in the bar test. All 5-HT1A receptor agonists, except WAY 100135, significantly attenuated the effects of haloperidol in the cross-legged position test. All agonists had similar effects in the bar test, except ipsapirone, which failed to attenuate haloperidol-induced catalepsy. In contrast to the effects observed with the agonists, the inverse agonist WAY 100635 appeared to enhance haloperidol-induced catalepsy in both tests, in agreement with earlier findings. The maximal effects of the 5-HT1A receptor ligands to attenuate catalepsy correlated positively with the rank order of their intrinsic activity at 5-HT1A receptors (either catalepsy test: r(S)=0.92, P<0.001). F 13714, which had the highest intrinsic activity, maximally inhibited haloperidol-induced catalepsy in the cross-legged position and bar tests (100% and 99% inhibition, respectively). Because the magnitude of the anti-cataleptic effects of 5-HT1A receptor ligands correlates positively with their intrinsic activity, it is likely that F 13714 has marked anti-cataleptic effects because of its high intrinsic activity at 5-HT1A receptors.

Animals↗
PubMed2001

Characterisation of retention in micellar high-performance liquid chromatography, in micellar electrokinetic chromatography and in micellar electrokinetic chromatography with reduced flow.

The retention (migration) behaviour of various barbiturates, phenylurea and triazine herbicides in micellar electrokinetic chromatography (MEKC) with uncoated fused-silica capillaries was compared with the behaviour in micellar electrokinetic chromatography with reduced electroosmotic flow (RF-MEKC) using capillaries modified with linear polyacrylamide. The error in the values of the retention factors caused by the neglection of the contribution of the electroosmotic flow in RF-MEKC was investigated and a method for correcting this error was suggested. The retention was characterised using the lipophilic and polar indices to characterise and to predict the retention as a function of the concentration of the surfactant (sodium dodecylsulphate) in the running buffer in MEKC and in RF-MEKC. Homologous series of n-alkylbenzenes and of n-alkan-2-ones were compared as the standard sets for the calibration of the retention (migration) index scale. The values of the lipophilic indices of a given solute measured in reversed-phase HPLC, MEKC and RF-MEKC are close to each other. Under ideal MEKC conditions, the values of the polarity indices are close to one for various sample solutes. However, for partially ionised compounds such as weakly acidic barbiturates, where the contribution of the electrophoretic migration is significant, the values of the polarity indices are significantly lower than one. Optimum conditions for separations of mixtures of triazine and phenylurea herbicides and of barbiturates using various techniques tested were compared.

Chromatography, High Pressure Liquid↗
PubMed1990

High-performance liquid chromatography of amino acids, peptides and proteins. XCV. Thermodynamic and kinetic investigations on rigid and soft affinity gels with varying particle and pore sizes: comparison of thermodynamic parameters and the adsorption behaviour of proteins evaluated from bath and frontal analysis experiments.

The thermodynamic constants, associated with the interaction of three proteins with triazine dye affinity sorbents, have been derived from bath and frontal analysis experiments. In cases where mass-transfer restrictions are very high, calculation of the thermodynamic constants directly from frontal analysis experiments could not be achieved. In such cases, a portion of the adsorbate was always present in the effluent, a situation which has its effect as the split peak phenomenon. With Fractogel-based triazine dye affinity sorbents none of the test proteins applied in frontal analysis were adsorbed. A similar behaviour was observed for a Cellufine sorbent during the adsorption of human serum albumin and the Blue Sepharose CL6B sorbent during the adsorption of alcohol dehydrogenase, which displayed much slower apparent adsorption kinetics than observed in the bath experiments. These phenomena were shown to be associated with changes in the gel structure, caused in part by the column packing procedure. Silica-based sorbents performed better in the adsorption of lysozyme in the column mode than soft-gel affinity sorbents, as was evident in the higher capacities and steeper breakthrough curves. At high protein concentrations (feedstock concentration greater than 0.2 mg/ml) breakthrough curves obtained with small- and large-particle-size sorbents, but of constant pore size, were found to be identical. This finding demonstrates that the use of small-particle-size sorbents (e.g. particle diameter, dp less than or equal to 5 microns) for the preparative isolation of proteins may not be justified when operating in the overload mode. With other higher-molecular-weight proteins and the silica-based sorbent systems examined, the small-particle-size sorbents (dp = 5 microns) displayed less symmetrical shapes of their breakthrough curves than the larger-particle-size and soft-gel sorbents. This behaviour was further exacerbated when non-porous glass or silica-based sorbents were utilized. These non-porous affinity sorbents displayed nearly rectangular breakthrough shapes at the onset of the adsorption process, but comparatively slow adsorption kinetics became evident as saturation was approached. This phenomenon has been attributed to surface rearrangement and/or reorientation of the adsorbed proteins, particularly with sorbents of high ligand densities.

Amino Acids↗
PubMed1984

Separation of plasma membrane proteins of cultured human fibroblasts by affinity chromatography on bonded microparticulate silicas.

Adsorbents for high-performance affinity chromatography were prepared by bonding proteins and reactive Procion triazine dyes to 3-isothiocyanatopropyl- and 3-aminopropylsilicas. The materials prepared were used successfully in the separation of hydrophobic plasma membrane proteins of cultured human fibroblasts. The data obtained show that the reaction of 3-isothiocyanatopropyltriethoxysilane (ITCPS) with the surface hydroxyl groups of silica yields a new and convenient route to preparing an "activated carrier" that is capable of coupling with potential affinity ligands containing amino functional groups. The reaction and bonding procedures of 3-isothiocyanatopropyltriethoxysilane and 3-aminopropyltriethoxysilane with silica were optimized with regard to a controlled and reproducible ligand density by adjusting the type of solvent and organic base as reaction catalyst. The ligand content of reactive triazine dyes directly coupled to 3-aminopropylsilica was significantly higher than that of the 6-aminohexyl derivatives coupled to 3-isothiocyanatopropylsilica. The stability of Procion Blue MX-R bonded to 3-aminopropylsilica and 3-isothiocyanatopropylsilica in phosphate-buffered aqueous solution at pH 5.0 and 8.0 was examined.

Cell Membrane↗
PubMed2002

Comparison of three different poly(dimethylsiloxane)-divinylbenzene fibres for the analysis of pesticide multiresidues in water samples: structure and efficiency.

Despite the continuing development of SPME (solid-phase microextraction) fibre coatings, their selection presents some difficulties for analysts in choosing the appropriate fibre for a certain application. There are two distinct types of SPME coatings available commercially. The most widely used are poly(dimethylsiloxane) (PDMS) and poly(acrylate) (PA). Supelco has developed new mixed phases consisting of porous polymer particles, either poly(divinylbenzene) (DVB) or Carboxen suspended in a matrix of PDMS or Carbowax for extracting analytes via adsorption. In addition to the nature of the extracting phase, the thickness of the polymeric film must be taken into account and, surprisingly, the construction of the fibres when apparently they bear the same coating, as it is the case of the three PDMS-DVB fibres available. Other fibre structure properties not well explored were identified and must be taken into consideration. To elucidate their extraction efficiency, three PDMS-DVB fibres, namely 60 microm for HPLC use, 65 microm for GC use and 65 microm StableFlex for GC use, were compared with regard to the extraction of 36 compounds included in four pesticide groups. The first was particularly suited for the extraction of organophosphorus pesticides and triazines whereas the StableFlex exhibited advantages in the analysis of organochlorine pesticides and pyrethroids. An explanation for the extraction differences is suggested based on the different structure of the fibres. Detection limits in the range of 1-10 ng/l for organochlorine pesticides, 1-30 ng/l for organophosphorus pesticides, 8-50 ng/l for triazines and 10-20 ng/l for pyrethroids were attained in a method using the 60 microm PDMS-DVB fibre. The fibre maintains its performance at well above 100 extractions with between-day precision below 10%.

Chromatography, Gas↗
PubMed2002

Multiresidue method for the simultaneous determination of four groups of pesticides in ground and drinking waters, using solid-phase microextraction-gas chromatography with electron-capture and thermionic specific detection.

A common sample preparation procedure capable of efficiently concentrating various groups of pesticides, taking advantage of universal detectors like the mass spectrometer or combined techniques of group selective detectors like gas chromatography-electron capture detection (ECD)/thermionic specific detection (TSD), is desirable in environmental analysis. Six solid-phase microextraction fibres available for analysis of semi-volatiles (7, 30 and 100 microm poly(dimethylsiloxane) (PDMS), 85 microm polyacrylate, 60 microm PDMS-divinylbenzene (PDMS-DVB) and 65 microm Carbowax-DVB) were evaluated and the 60 microm PDMS-DVB was selected for the simultaneous extraction of 34 compounds, included in the organochlorine (OCPs), organophosphorous (OPPs), pyrethroid and triazine pesticide groups. All parameters affecting the extraction efficiency from water samples, namely fibre coating, sample agitation, pH and ionic strength, extraction temperature and time, were optimised. The analytical procedure involves solid-phase microextraction extraction, gas chromatographic separation and subsequent ECD and TSD via a post-column splitter adjusted to a split ratio of 1:10, respectively. Detection limits in the range of 1-10 ng l(-1) for OCPs, 1-30 ng l(-1) for OPPs, 20-30 ng l(-1) for pyrethroids and 8-50 ng l(-1) for triazines are easily attainable with the optimised procedure. The method validated for ground and drinking waters has low cost of implementation and operation although it requires careful maintenance.

Chromatography, Gas↗