Solid-phase extraction with styrene-divinylbenzene sorbent for high-performance liquid or gas chromatographic determination of urinary chloro- and methylthiotriazines

New sorbents based on poly(methacrylic acid-TRIM) and poly(vinylimidazole-TRIM) for simultaneous preconcentration of herbicides in water samples with posterior determination by HPLC-DAD

In the present study, poly(methacrylic acid-trimethylolpropane trimethacrylate) (PMA-TRIM) and poly(vinylimidazole-TRIM) (PV-TRIM) have been used for simultaneous extraction of tebuthiuron, hexazinone, diuron, and ametryn with posterior determination by HPLC-DAD.

Determination of ametryn in sugarcane and ametryn-atrazine herbicide formulations using spectrophotometric method

A sensitive spectrophotometric method has been developed for determination of ametryn in agricultural samples. The proposed method was based on reaction with pyridine and further coupling with sulfanilic acid to form a colored product. The absorbance was measured at 400 nm with a molar absorptivity of 2.1 x 10(5) L mol(-1) cm(-1). The method shows a linear range from 0.2-20 μg mL(-1) with limit of detection and limit of quantification 0.16 and 0.54 μg mL(-1), respectively. The method has been successfully applied to the determination of ametryn in sugarcane juice and commercial formulations after separation of ametryn from triazine herbicides based on solvent extraction. Recovery values were found to be in the range of 96.0 ± 0.2% to 98.4  ±  0.1%.

Procedures for analysis of atrazine and simazine in environmental matrices

There is an ongoing need to monitor soil and trophic chain samples for residues of triazine herbicides, particularly atrazine and simazine, because these herbicides are among the most used members of their class, are toxic, can be persistent, and are widely distributed in the environment. The main purpose of this review is to provide an overview of principle techniques and approaches used in analyzing atrazine, simazine, and other triazine herbicide residues in environmental matrices. The methods covered generally provide low detection limits, acceptable levels of matrix interferences, and are relatively fast and inexpensive. Atrazine and simazine are popular herbicides used to control a variety of broad leaf and grassy weeds in agriculture and on industrial sites. Because they are widely and frequently used, the environmental contamination of these compounds is considerable. Atrazine, simazine, and other triazines have the ability to translocate in ecosystems. When this occurs, it is often necessary to monitor their residue content in soils, vegetation, biota, and water. There is a vast literature available that addresses the extraction and clean-up of soil, vegetation, animal tissue, and animal fluid samples; unfortunately, few of these publications compare the effectiveness of results obtained on similar matrices. In this review we endeavor to review and provide comparative information on methods dedicated to determining residues of atrazine, simazine, and other triazines in several environment matrices: soil, plants, animal tissues, and water.

Montmorillonite as an adsorbent for extraction and concentration of atrazine, propazine, deethylatrazine, deisopropylatrazine and hydroxyatrazine

Adsorption properties of the clay mineral montmorillonite in the potassium homoionic form (KMT) was investigated to achieve the extraction and concentration of the herbicides atrazine (AT) and propazine (PROP), as well as the main degradation products of atrazine, namely deethylatrazine (DEA), deisopropylatrazine (DIA) and hydroxyatrazine (ATOH). A batch approach was proposed, with recovery percentages for AT, PROP and DIA higher than 90% at concentrations of 0.50 and 2.50 microg L(-1). For DEA and ATOH, however, low recoveries were obtained. For DEA, this fact can be explained by its low K(d) with KMT, contrary to ATOH, which interacts strongly with the mineral surface, hindering the complete desorption and hence, generating low recovery percentages. The influence of pH, ionic strength and humic acid was studied, and a comparison with the C(18) phase as SPE cartridges was carried out. Montmorillonite showed a similar performance to commercial cartridge for concentrations of AT, DEA and PROP, but better recoveries for DIA was obtained using the clay mineral. For ATOH the recovery was also higher on the clay mineral, although for this compound the most suitable SPE cartridge is constituted by cation exchange resin. After the concentration and elution steps, the 0.50 and 2.50 microg L(-1) gave chromatographic peak areas that could be easily quantified with an analytical curve obtained in the concentration range between 7.5 and 100 microg L(-1). The obtained concentration factors are suitable to allow the application of the method to the monitoring of triazine residues in drinking water.

Automated solid-phase extraction and high-performance liquid chromatographic determination of nitrosamines using post-column photolysis and tris(2,2′-bipyridyl) ruthenium(III) chemiluminescence

A sensitive and selective post-column detection system for nitrosamines is described. The principle upon which the detector works is that UV irradiation of aqueous solutions of nitrosamines leads to cleavage of the N-NO bond. The amine generated is subsequent detected by chemiluminescence using tris(2,2'-bipyridyl) ruthenium(III), which is on-line generated by photo-oxidation of the ruthenium(II) complex in the presence of peroxydisulfate. Factors affecting the photochemical and chemiluminescent reactions were optimized to minimise their contribution to the total band-broadening. This detection system was tested for N-nitrosodimethylamine, N-nitroso-diethylamine, N-nitrosomorpholine, N-nitrosopiperidine and N-nitrosopyrrolidine, which were separated on an ODS column by isocratic reversed-phase chromatography with acetonitrile-water containing 5 mM acetate buffer at pH 4.0. A linear relationship between analyte concentration and peak area was obtained within the range 0.13-500 microg l(-1) with correlation coefficients greater than 0.9995 and detection limits of between 0.03 and 0.76 microg l(-1). Intra- and inter-day precision values of about 1.2% RSD (n = 11) and 2.5% RSD (n = 10), respectively, were obtained. The sensitivity may increase from 9 to 280 times with respect to UV detection, depending on the nitrosamine in question. An automated solid-phase extraction (SPE) system was used in conjunction with HPLC to determine nitrosamine residues in waters. Detection limits within the range 0.10-3.0 ng l(-1) were achieved for only 250 ml of sample.

Fast and robust simultaneous determination of three veterinary antibiotics in groundwater and surface water using a tandem solid-phase extraction with high-performance liquid chromatography–UV detection

A simple and robust analytical method is presented in which the three veterinary antibiotics oxytetracycline (OTC), sulfachloropyridazine (SCP) and tylosin (TYL) were simultaneously determined in surface water and groundwater. The three compounds were simultaneously extracted from the water samples using a mixture of methanol, EDTA and McIlvaine buffer (citric acid and sodium orthophosphate) and then cleaned-up and pre-concentrated by solid-phase extraction using sacrificial Isolute strong anion-exchange cartridges, to remove interfering organic material, and Waters Oasis hydrophilic-liphophilic balance polymer cartridges, to retain the compounds, in tandem. Analysis was performed using liquid chromatography with ultraviolet detection. Recoveries for river water samples spiked at 10 and 1 microgl(-1) were respectively 99.6+/-4.6 and 99.4+/-8.4% for OTC; 99.9+/-2.2 and 105.0+/-5.7% for SCP; and 94.9+/-2.4 and 71.6+/-8.2% for TYL. Overall limits of detection based on pre-concentrating 400 ml of sample were 0.35 microgl(-1) for OTC and TYL and 0.25 microgl(-1) for SCP.