Long Ar

Tissue Drug Residue Extraction and Monitoring by Matrix Solid Phase Dispersion (MSPD)-HPLC Analysis

Abstract The increasing implementation of immuno-, receptor and microbial inhibition screening tests for the monitoring of drug residues in foods of animal origin also requires that we be capable of confirming and validating the results of such tests in a timely manner. Methodology for the isolation and analysis of “detected” substances must be capable of performing rapid and efficient extractions that are amenable to instrumental determinations for the presence, level and, where possible, identity of the substance in question. We present here a summary of such methodolgy utilizing matrix solid phase dispersion (MSPD) as the isolation method and several simple isocratic HPLC/UV diode array and florescence methods developed for extracts so obtained for several drug classes as well as individual drugs. The application of these methods for a variety of purposes in drug residue monitoring programs is discussed.

THE LIQUID CHROMATOGRAPHIC ANALYSIS OF VITAMIN K1 IN SOY BASED INFANT FORMULA USING MATRIX SOLID PHASE DISPERSION

A liquid chromatographic method is described for vitamin K1 in soy based infant formula. The vitamins are extracted from infant formula by matrix solid phase dispersion (MSPD) and quantitated by reversed phase chromatography with fluorescence detection. Vitamin K1 is converted to the fluorescent hydroquinone with a post column zinc reductive reactor. The limit of detection is 12 pg and the limit of quantitation is 38 pg on- column. Linear response ranged from 0.70 – 11.0 ng/mL (r2 = 0.998). Recoveries were determined on an analyte-fortified blank material for soy based infant formula and averaged 92.5% (n = 25) for vitamin K1. The method provides a rapid, specific, and easily controlled assay for the analysis of vitamin K1 in fortified soy based infant formula.

Liquid Chromatographic Method for the Analysis of All-rac-α-tocopheryl Acetate and Retinyl Palmitate in Soy Based Infant Formula Using Matrix Solid Phase Dispersion

Abstract A liquid chromatographic method is described for the analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in soy based infant formula. The vitamins are extracted from infant formula without saponification by matrix solid phase dispersion (MSPD) and quantitated by normal phase chromatography with fluorescence detection. Retinyl palmitate and all-rac-α-tocopheryl acetate are quantitated isocratically with a mobile phase of hexane containing isopropanol @ 0.125% (v/v) and 0.5% (v/v), respectively. Results compared favorably to the label declaration on a retail infant formula product.

Optimization of the analytical performance of the magnetic sector mass spectrometer for the identification of residual chloramphenicol in shrimp.

Chemical noise limits mass spectrometric detection of chloramphenicol (CAP) with electron capture ionization at low resolution, and makes CAP identification at concentrations of 5 parts per billion (ppb) difficult. Increasing the resolution from 1000 to 3500, however, was sufficient to separate the analyte signals from the noise signals, and resulted in a 100 times higher analytical sensitivity. The introduction of sweep gas in the ion source decreased the scattering of the quantitative results on average by a factor of 7, and thereby improved the precision of the analyses to an acceptable level (CV < 10%). Under such conditions, CAP residues of 1.5 and 2.1 ppb in shrimp as determined by electron capture gas chromatography/mass spectrometry can readily be identified by monitoring four diagnostic ions.

Matrix Solid Phase Dispersion (MSPD) Isolation and Liquid Chromatographic Determination of Clorsulon in Milk

Abstract A method for the isolation and liquid chromatographic determination of the anti-parasitic drug clorsulon in milk is presented. Milk samples (0.5 g) were blended with 2 grams of C-18 (octadecylsilyl-derivatized silica column packing material). A column was made from the C-18/milk matrix and first washed with hexane. The clorsulon was then eluted from this column with ethyl ether. The ether eluate was cleaned up by Florisil solid phase extraction, and clorsulon was subsequently determined by liquid chromatography with UV detection. The overall recovery of clorsulon from milk spiked at 50–200 ppm was 93.0&with a coefficient of variation of 5.6 & The MSPD method and a solid phase extraction method used by the FDA gave comparable values for milk containing incurred clorsulon residues.

The Application of Matrix Solid Phase Dispersion (MSPD) to the Extraction and Subsequent Analysis of Drug Residues in Animal Tissues

The contamination of our environment and of our food supply with industrial, agricultural and pharmaceutical agents possessing toxicologic and/or pharmacologic character are major man-made problems that must be redressed in the coming decade. The prevention, detection and elimination of such contamination constitute major challenges to our technology and our science and will result in significant financial resources being expended by private, State and National agencies to remediate and monitor these problems. Of particular concern is the use of veterinary drugs in the production and maintenance of food animals. The improper use of such drugs leaves residues of the parent and/or its metabolites in the tissues or milk of the animal so treated and, subsequently, in the food products derived from these sources. The presence of such drugs poses a potential threat to human health on toxicologic, immunopathological and microbiological grounds. Toxicological concerns relate to a direct toxic effect of the compound on the consumer, possibly resulting in physiological abnormalities, such as cancer. Immunopathological complications arise when the drug serves as an antigen, resulting in hypersensitivity reactions in sensitized individuals. Microbiological concerns relate to the transmittance of antibiotic resistance to bacteria from low level exposure to antibiotics and the possible emergence of resistant pathogenic bacteria in the natural flora of humans.

A LIQUID CHROMATOGRAPHIC METHOD FOR THE ANALYSIS OF RETINYL ACETATE IN SOY BASED INFANT FORMULA USING MATRIX SOLID PHASE DISPERSION

Retinyl acetate in soy based infant formula was extracted by matrix solid phase dispersion (MSPD) and chromatographed by isocratic normal phase chromatography on a Si 60 column with a mobile phase of 0.28% (v/v) isopropanol in hexane. Detection was by fluorescence (Ex λ=325, Em λ=470). Fluorescence response was linear (r2=0.999) from 0.10 – 2.5 μg/mL. Recoveries determined on a soy based infant formula zero control reference material (ZRM) containing added analyte at five levels averaged 94.7% (n=25) with CVs from 0.57–3.53%. The method expands the use of MSPD extraction to the analysis of retinylacetate in soy based infant formulas.