Liquid chromatographic method for nicarbazin in broiler feeds and premixtures: development, validation, and interlaboratory study.

A reversed-phase liquid chromatography method for nicarbazin in broiler feeds and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was an acetonitrile-methanol (1 + 1) mixture. For feedingstuffs, water was also added.

Fate of ivermectin residues in ewes' milk and derived products.

The fate of ivermectin (IVM) residues was studied throughout the processing of daily bulk milk from 30 ewes (taken up to 33 d following subcutaneous administration of 0.2 mg IVM/kg b.w.

Ivermectin pharmacokinetics in lactating sheep.

Ivermectin (IVM) concentrations in plasma and milk were studied in six Istrian Pramenka dairy sheep after a single subcutaneous dose of 0.2 mg/kg b.w.

Development and validation of a method for the determination of sub-additive levels of virginiamycin in compound animal feeds by liquid chromatography.

A method for the detection of virginiamycin M1 as a marker compound of virginiamycin at sub-additive level in pig, calf, piglet, sow, poultry, cattle and laying hen feeds was developed and validated. Both UV detection at 230 nm and MS detection were applied. Virginiamycin M1 was extracted from animal feeds with ethyl acetate after wetting of the feed with water followed by clean-up on Sep-Pak silica gel and OASIS HLB cartridges.

Polymyxin E-1 (colistin sulphate) (neuro-)intoxication in young ostriches ( Struthio camelus spp.).

Colistin (polymyxin E) is a cyclic polypeptide with a potent bactericidal action against most gramnegative bacilli. When used parenterally, polymyxins should be given with great care as they have a very small safety range, and easily induce neurotoxicity and nephrotoxicity. A dose of 39.

Immunochemical detection of aminoglycosides in milk and kidney.

In 1996, the European Union established provisional maximum residue limits (MRL) for gentamicin, neomycin, streptomycin and dihydrostreptomycin in milk and tissue (0.1-5 mg kg-1). For the detection of these four aminoglycosides, three enzyme linked immunosorbent assays (ELISA) for applications in milk and kidney were developed.

Flubendazole residues in eggs after oral administration to laying hens: determination with reversed phase liquid chromatography.

Flubendazole residues in eggs were experimentally induced by providing groups of 8 laying hens feed with approximately 3, 10 and 30 mg kg-1 flubendazole for 21 days. Eggs were sampled during this period and one week after the administration. Samples of both whole egg and egg white/yolk were analysed separately.

Suitability of the Charm HVS and a microbiological multiplate system for detection of residues in raw milk at EU maximum residue levels.

In this paper we assessed the suitability of the Charm HVS and a newly developed microbiological multiplate system as post-screening tests to confirm the presence of residues in raw milk at or near the maximum permissible residue level (MRL). The multiplate system is composed of Bacillus stearothermophilus var. calidolactis plate at pH 8.

Testing of raw milk for tetracycline residues.

A newly improved Bacillus calidolactis tube diffusion test and two postscreening test systems--a receptor assay (Charm HVS; Charm Sciences, Inc., Malden, MA) and a newly developed Bacillus cereus ATCC 11778 mycoides test system--were evaluated for the detection and identification of tetracycline residues using 973 samples of bulk milk taken at random in The Netherlands. All milk samples were assayed with the B.

Application of an enzyme immunoassay for the determination of sulphamethazine (sulphadimidine) residues in swine urine and plasma and their use as predictors of the level in edible tissue.

The potential of an enzyme immunoassay (EIA) with high cross-reactivity towards the major metabolite (N4-acetyl-sulphamethazine) of sulphamethazine was tested for screening fluids and tissues. Healthy pigs were given 20 mg sulphamethazine per kg body weight per day in their drinking water for 2 days. Groups of four pigs were slaughtered after 3, 4 and 7 days withdrawal.

Ivermectin detection in serum of onchocerciasis patients: relationship to adverse reactions.

Ivermectin treatment of onchocerciasis patients can be accompanied by adverse reactions. Not much is known concerning the pathogenesis of these reactions. Previous studies have demonstrated that the occurrence and extent of adverse reactions are related to infection intensity.

Optimization and ruggedness testing of the determination of residues of carbadox and metabolites in products of animal origin. Stability studies in animal tissues.

A method developed for the determination of residues of carbadox and its metabolites in swine tissues using high-performance liquid chromatography with on-line precolumn enrichment and postcolumn derivatization with UV-VIS detection was optimized and the applicability of the method was extended to plasma and eggs. With the optimized method, more than twenty samples per person per day can be analysed. In the matrices investigated, the observed limit of determination for carbadox is 0.

Liquid chromatographic multicomponent method for determination of residues of ipronidazole, ronidazole, and dimetridazole and some relevant metabolites in eggs, plasma, and feces and its use in depletion studies in laying hens.

A simple, rapid liquid chromatographic (LC) method that uses UV/VIS detection has been developed for the determination in eggs of residues of the histomonostats dimetridazole (DMZ), ronidazole (RON), ipronidazole (IPR), and side-chain hydroxylated metabolites of DMZ and RON. Sample pretreatment includes an aqueous extraction, purification with an Extrelut cartridge, and acid partitioning with isooctane. An aliquot of the final aqueous extract is injected into a reverse-phase LC system; detection is performed at 313 nm.

Liquid chromatographic determination of chloramphenicol residues in meat: interlaboratory study.

A liquid chromatographic (LC) method for the determination of chloramphenicol (CAP) residues in meat at the 10 microgram/kg level was tested in an interlaboratory study. The method used, based on aqueous extraction and sample cleanup with a cartridge containing Extrelut, was published earlier. A prestudy to familiarize collaborators with the method was performed before the actual interlaboratory precision study.

Determination of residues of carazolol and a number of tranquilizers in swine kidney by high-performance liquid chromatography with ultraviolet and fluorescence detection.

A rapid and sensitive method has been set up for the determination of the beta-receptor blocker carazolol and the tranquillizers acepromazine, azaperone, chlorpromazine, haloperidol, propionylpromazine and xylazine in swine kidneys. The procedure involves extraction with acetonitrile, rapid sample clean-up with a Sep-Pak C18 cartridge and high-performance liquid chromatography with ultraviolet and fluorescence detection. The mean recoveries range from 93 to 101%, with the exception of xylazine (52%), and the coefficients of variation from 5.

Determination of residues of carbadox and some of its metabolites in swine tissues by high-performance liquid chromatography using on-line pre-column enrichment and post-column derivatization with UV-VIS detection.

A high-performance liquid chromatographic (HPLC) method that uses UV-VIS detection and post-column derivatization with sodium hydroxide was developed for the determination of the growth-promoting antibiotic carbadox and three of its metabolites in swine muscle, liver and kidney tissues. Sample pre-treatment involves extraction with methanol-acetonitrile, purification over an alumina-Florisil column and partition with isooctane. A 2-ml volume of the final aqueous extract is injected into a column-switching HPLC system; detection is performed at 420 nm.

High-performance liquid chromatographic screening and confirmation methods for chloramphenicol residues in meat with off-line cartridge sample clean-up and on-line diode array UV-VIS detection.

Two high-performance liquid chromatography (HPLC) methods for the analysis and confirmation of residues of the antibiotic chloramphenicol in edible animal tissues are described. The first method consists of an aqueous extraction followed by purification through an Extrelut cartridge and toluene partition. With this simple and rapid method, meat samples can be screened at the 5 micrograms/kg level.

Procedure for the gas chromatographic-mass spectrometric confirmation of some exogenous growth-promoting compounds in the urine of cattle.

As gas chromatography-mass spectrometry is the most conclusive confirmation technique available today for the detection of ppb levels of anabolics in the urine of cattle, the following procedure was used. The urine is hydrolysed with Helix pomatia intestinal juice, extracted, and the extract cleaned by gel-permeation chromatography or with Extrelut. In one fraction are eluted diethylstilboestrol, dienoestrol, hexoestrol, methyltestosterone, ethinyloestradiol, zeranol and trenbolone.

Quantitative determination of specified chlorobiphenyls in fish with capillary gas chromatography and its use for monitoring and tolerance purposes.

A gel permeation (GPC) clean-up procedure of fish samples in combination with capillary gas chromatography is used for the determination of individual chlorobiphenyls. The described method is compared with a more universal method based on saponification. Starting from a tolerance for PCB's expressed as a technical Aroclor, tolerance for some specified individual chlorobiphenyls are derived.

Quantitative determination of individual chlorinated biphenyls in milkfat by splitless glass capillary gas chromatography.

A method is described for determining individual polychlorinated biphenyls (PCBs) in milkfat at the ppb level. Extraction and major cleanup are done simultaneously by saponification of the milkfat. After final cleanup on basic alumina, the concentrated extract is injected under splitless conditions on a capillary column coated with CPSil 7 stationary phase.