Matrix Solid-Phase Dispersion (MSPD) Isolation and Liquid Chromatographic Determination of Oxytetracycline, Tetracycline, and Chlortetracycline in Milk

Abstract

A multlresldue method for the isolation and liquid chromatographic determination of oxytetracycline (OTC), tetracycline (TC), and chlortetracycllne (CTC) antibiotics In milk Is presented. Blank and tetracycline (OTC, TC, and CTC) fortified milk samples (0.5 mL) were blended with octadecylsllyl (C18, 40 /an, 18% load, endcapped, 2 g) derivatized silica packing material containing 0.05 g each of oxalic acid and dlsodlum ethylenedlamlnetetraacetlc. A column made from the C18/milk matrix was first washed with hexane (8 mL), following which the tetracyclines were eluted with ethyl acetate-acetonltrlle (1 + 3; v/v). The eluate contained tetracycline analytes that were free from Interfering compounds when analyzed by liquid chromatography with UV detection (photodiode array, 365 nm). Correlation coefficients of standards curves for Individual tetracycline isolated from fortified samples were linear (from 0.982 ± 0.009 to 0.996 ± 0.004) with average percentage recoveries from 63.5 to 93.3 for the concentration range (100,200,400,800,1600, and 3200 ng/ mL) examined. The Inter-assay variability ranged from 8.5 ± 2.4% to 20.7 ± 13.0% with an Intra-assay variability of 1.0- 9.3%.

Determination of oxamyl and methomyl by high-performance liquid chromatography using a single-stage postcolumn derivatization reaction and fluorescence detection

“…A matrix solid-phase dispersion (MSPD) method has been successfully used to isolate oxamyl and methomyl from animal matrices and milk (Long et al, 1990, and references cited therein). An ongoing Du Pont study has confirmed that MSPD is very effective in extracting oxamyl from both fresh and aged spiked plant leaf tissue (data not shown; Du Pont Agricultural Products study AMR-1825-90).…”

“…Matrix solid-phase dispersion (MSPD) isolation technology was first introduced by A. R. Long and his coworkers (Long et al, 1990). This technique involves blending a small amount of biological matrices with Cis (octadecylsilyl derivatized silica) followed by a small amount of solvent washing and elution to extract a wide range of compounds.…”

“…This technique involves blending a small amount of biological matrices with Cis (octadecylsilyl derivatized silica) followed by a small amount of solvent washing and elution to extract a wide range of compounds. This technology has been successfully used to extract several pesticides (e.g., organophosphates, sulfonamides, cephalosporins, and benzimidazoles) from liver, muscle tissue, kidney, milk, and fat (Long et al, 1990). The high-performance liquid chromatography (HPLC) method for postcolumn derivatization and fluorescence determination of residues, developed by Moye et al (1977), was widely recognized for its sensitivity and selectivity in determining residues of IV-methylcarbamate pesticides in the late 1970s and early 1980s.…”

SFE-plus-C18 Lipid Cleanup and Selective Extraction Method for GC/MS Quantitation of Polycyclic Aromatic Hydrocarbons in Smoked Meat

“…Alternative sorbents, such as basic alumina (26,33,34) or activated carbon (35), have also been used in the SFE extraction chamber to remove lipids from the extracts of spiked samples. Barker and co-workers (41)(42)(43)(44) have used C 18 as a nonpolar adsorbent in a variety of biological matrixes employing the technique of matrix solid-phase dispersion (MSPD). In these studies, C 18 beads were used to adsorb nonpolar to slightly polar analytes from matrixes such as milk (42,43), animal fat (44), and animal tissues (41).…”

“…Barker and co-workers (41)(42)(43)(44) have used C 18 as a nonpolar adsorbent in a variety of biological matrixes employing the technique of matrix solid-phase dispersion (MSPD). In these studies, C 18 beads were used to adsorb nonpolar to slightly polar analytes from matrixes such as milk (42,43), animal fat (44), and animal tissues (41). Recently, Amigo et al (45) reported extraction of PAHs from bird (Tyto alba) liver.…”