Matrix solid-phase dispersion extraction and the analysis of drugs and environmental pollutants in aquatic species

Matrix solid-phase dispersion extraction and determination by high-performance liquid chromatography with fluorescence detection of residues of glyphosate and aminomethylphosphonic acid in tomato fruit

A method based on matrix solid-phase dispersion (MSPD) is described for the quantitative extraction of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA) from tomato fruit. After application of 120 microL of HNO3 1M to the sample, the dispersion column was packed with 0.5 g of sample blended into 1 g of NH2-silica. Two aqueous fractions were obtained. First, AMPA was eluted from the column using deionized water (F1), and then a NaH2PO4 0.005 M solution was used for the elution of glyphosate (F2). Cleanup of F1 and F2 was made by ion exchange chromatography on a SAX anion exchange silica. Determination was done by HPLC with fluorescence detection after precolumn derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). Mean recoveries calculated at fortification levels of 0.5 microg/g for glyphosate and 0.4 microg/g for AMPA were 87% and 78%, respectively. The relative standard deviations (n=7) for the total procedure were 10% and 16%. Detection limits were 0.05 microg/g for glyphosate and 0.03 microg/g for AMPA.

Capillary electrophoresis in analysis of veterinary drugs

Antibiotics are extensively applied in veterinary medicine for the treatment of various bacterial infections. Because of their use in food producing animals, the risk of occurrence of unwanted residues in edible products exists. To ensure human food safety, The European Union has defined maximum residue limits (MRLs) for veterinary drug residues in food products. Analytical methods need to be developed to confirm the presence of antibiotics at the MRL level. A capillary electrophoresis (CE) method with UV detection is proposed for the quantitative determination of residues from poultry and porcine tissues. Eight of the most frequently used antibiotics and nifursol, which routinely used as poultry coccidiostat, were analysed. CE technique permitted analysing substances to be separated from muscle, liver, kidney and skin with fat after a simple extraction with acetonitrile or ethyl acetate under basic conditions. Proposed method is capable to identify drug residues in tissues at level below 20 microg/kg.

Before the injection--modern methods of sample preparation for separation techniques

The importance of sample preparation methods as the first stage in an analytical procedure is emphasised and examined. Examples are given of the extraction and concentration of analytes from solid, liquid and gas phase matrices, including solvent phase extractions, such as supercritical fluids and superheated water extraction, solid-phase extraction and solid-phase microextraction, headspace analysis and vapour trapping. The potential role of selective extraction methods, including molecular imprinted phases and affinity columns, are considered. For problem samples alternative approaches, such as derivatisation are discussed, and potential new approaches minimising sample preparation are noted.

Matrix solid-phase dispersion

Matrix solid-phase dispersion (MSPD) is a patented process, first reported in 1989, for conducting simultaneous disruption and extraction of solid and semi-solid samples. MSPD permits complete fractionation of the sample matrix components as well as the ability to selectively elute a single compound or several classes of compounds from the same sample. The method has been applied to the isolation of drugs in food animal tissues but has also found wide application in the analysis of herbicides, pesticides and pollutants from animal tissues, fruits, vegetables and other matrices. The present article provides a review of MSPD applications in these and related fields and discusses the factors known to affect MSPD methods. Both the practical and theoretical aspects of MSPD are also presented.

Applications of matrix solid-phase dispersion in food analysis

Matrix solid-phase dispersion (MSPD), a patented process for the simultaneous disruption and extraction of solid and semi-solid samples, was first reported in 1989. Since that time, MSPD has found application in numerous fields, but has proven to be particularly applicable for the analysis of drugs, pollutants, pesticides and other components in foods. The present article provides a review of these and related applications and discusses both the practical and theoretical aspects for the use of MSPD in sample processing.

Recent advances in the residue analysis of N-methylcarbamate pesticides

This paper highlights recent advances in the determination of methylcarbamate residues in water, soil and plant tissues. Chromatographic analyses (e.g., HPLC, GC, supercritical fluid chromatography and TLC) with various sample pretreatment procedures and detection methods are reviewed. More generally, some non-chromatographic techniques such as immunoassay, biosensor and spectrophotometry are included.

Multi-residue matrix solid-phase dispersion method for the determination of six synthetic pyrethroids in vegetables followed by gas chromatography with electron capture detection

An effective multi-residue matrix solid-phase dispersion (MSPD) extraction and gas chromatographic-electron-capture detection method for the determination of six synthetic pyrethroids (fenpropathrin, cyhalothrin, permethrin, cypermethrin, fenvalerate and deltamethrin) in 5 g of vegetables (West Indian gherkin, eggplant, pak-choi, cabbage and garden peas) is described. The method uses a Florisil-based MSPD column for direct in-line clean-up with n-hexane-acetone (9:1). Recoveries calculated at 0.1 and 0.5 micrograms/g fortification levels were between 92 and 113%. The method detection limits were between 5.1 and 91.5 ng/g. The method compared favourably with the traditional method in terms of the sample size, analysis time and overall cost. The method may serve as a screening protocol for the determination of pyrethroids in vegetables.

Determination of oxytetracycline in the live fish feed Artemia using high-performance liquid chromatography with ultraviolet detection

A high-performance liquid chromatographic analytical method was developed for the determination of oxytetracycline in Artemia nauplii. A solid-phase extraction protocol was used to recover oxytetracycline and the internal standard tetracycline, from the Artemia samples. Oxytetracycline was analyzed using a 150 x 4.6 mm I.D. Hypersil-ODS column, a mobile phase of acetonitrile-tetrahydrofuran-0.01 M oxalic acid buffer (pH 3.0) (15:3:82, v/v), and an ultraviolet detection wavelength of 365 nm. The calibration curve of oxytetracycline in Artemia was linear (r2 = 0.9998) from 0.1 to 6.4 micrograms/g of tissue. Using a signal-to-noise ratio of 4:1 the oxytetracycline detection limit was 10 ng/g of tissue. Mean recovery of oxytetracycline amounted to 97%, while intra-assay variability was 1.5%. Quantitative data from an in-vivo feeding study indicated an excellent uptake of oxytetracycline by Artemia, as its levels reached 25.6 micrograms per g of nauplii.