Residue Surveillance Research Articles

Determination of Three Nitroimidazole Residues in Royal Jelly by High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method for analysis of trace metronidazole (MTZ), dimetridazole (DMZ) and ronidazole (RNZ) residues in royal jelly was developed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After samples were dissolved in sodium hydroxide solution to disassociate target analytes from matrix, liquid-liquid extraction methods by ethyl acetate solvent were used. Matrix effects were minimized and good quantitation results were obtained by using highly-selective reaction monitoring (H-SRM) technology when deuterated dimetridazole (dimetridazole-D3) was selected as internal standard. Limits of detection (LODs) were 1.0 microg/kg for DMZ, 0.5 microg/kg for MTZ and RNZ (S/N > 5). Limits of quantitation (LOQs) were 2.0 microg/kg for DMZ, 1.0 microg/kg for MTZ and RNZ (S/N > 10). The linear ranges were 2.0 - 200 microg/L for all target analytes. Recoveries and relative standard deviations (RSDs) were in the ranges of 96.6% - 110.6% and 2.1% -7.4%, respectively. This method is suitable for statutory residue testing in the National Residue Surveillance Plan in China and meets the requirement for export.

Development and validation of an HPLC confirma‐tory method for the determination of tetracycline antibiotics residues in bovine muscle according to the European Union regulation 2002/657/EC

A high-performance liquid chromatographic method with diode-array detection, at 351 nm, was developed and validated for the determination of five tetracyclines (TCs): minocycline, tetracycline, oxytetracycline, chlortetracycline, and doxycycline in bovine muscle. Samples were macerated with a buffer solution, centrifuged, and purified using Abselut Nexus SPE cartridges. The separation of the examined TCs was achieved on an Inertsil ODS-3 5 microm, 250 x 4 mm analytical column, at ambient temperature. A multistep gradient elution was followed using 0.05 M oxalic acid and CH3CN, at a flow rate of 1.65 mL/min. The procedure was validated according to the European Union regulation 2002/657/EC determining selectivity, stability, decision limit, detection capability, accuracy, and precision. The results of the validation process demonstrate that the method can be readily applied to European Union statutory veterinary drug residue surveillance programmes. Mean recoveries of TCs from bovine muscle samples spiked at three concentrations (100, 250, and 400 ng/g) were in the range of 98.7-103.3%. Method's LOQ values achieved were 40 microg/kg for MNC, CTC, and DC and 25 microg/kg for OTC and TC. The decision limits (CCalpha) were in the range of 104.7-109.8 microg/kg, while the detection capability (CCbeta) was in the range of 108.4-116.7 microg/kg for all compounds.

Veterinary pharmacovigilance. Part 2. Veterinary pharmacovigilance in practice – the operation of a spontaneous reporting scheme in a European Union country – the UK, and schemes in other countries

Veterinary pharmacovigilance, as it operates in the European Union (EU), covers a very broad remit, including adverse effects in treated animals, exposed humans and the environment, and in addition, it extends to cover the violation of maximum residue limits. The mainstay of veterinary pharmacovigilance is the spontaneous reporting scheme working along side other systems such as those reporting on residues surveillance. One of the most well established schemes in the EU is that operating in the UK and this paper examines the evolution of that scheme and some of its findings, data from other countries, and information available from the literature. It also tentatively examines the ways that pharmacovigilance can be used for regulatory purposes, and the contribution from pharmacoepidemiology.

Tissue Distribution, Metabolism, and Residue Depletion Study in Atlantic Salmon Following Oral Administration of [3H]Emamectin Benzoate

Atlantic salmon (approximately 1.3 kg) maintained in tanks of seawater at 5 +/- 1 degrees C were dosed with [3H]emamectin B1 benzoate in feed at a nominal rate of 50 microg of emamectin benzoate/kg/day for 7 consecutive days. Tissues, blood, and bile were collected from 10 fish each at 3 and 12 h and at 1, 3, 7, 15, 30, 45, 60, and 90 days post final dose. Feces were collected daily from the tanks beginning just prior to dosing to 90 days post final dose. The total radioactive residues (TRR) of the daily feces samples during dosing were 0.25 ppm maximal, and >97% of the TRR in pooled feces covering the dosing period was emamectin B1a. Feces TRR then rapidly declined to approximately 0.05 ppm by 1 day post final dose. The ranges of mean TRR for tissues over the 90 days post dose period were as follows: kidney, 1.4-3 ppm; liver, 1.0-2.3 ppm; skin, 0.04-0.09 ppm; muscle, 0.02-0.06 ppm; and bone, <0.01 ppm. The residue components of liver, kidney, muscle, and skin samples pooled by post dose interval were emamectin B1a (81-100% TRR) and desmethylemamectin B1a (0-17% TRR) with N-formylemamectin B1a seen in trace amounts (<2%) in some muscle samples. The marker residue selected for regulatory surveillance of emamectin residues was emamectin B1a. The emamectin B1a level was quantified in individual samples of skin and muscle using HPLC-fluorometry and was below 85 ppb in all samples analyzed (3 h to 30 days post dose).

Validation of a confirmatory method for the determination of sulphonamides in muscle according to the European Union regulation 2002/657/EC

A simple multiresidue method is described for assaying 10 sulphonamides (SAs) (sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfachlorpyridazine, sulfamethoxazole, sulfaquinoxaline and sulfadimethoxine) in muscle samples. Samples were prepared by homogenizing the tissue, extracting with ethyl acetate and cleaning up with a cation-exchange solid-phase extraction (SPE) column. The detection of analytes was achieved by HPLC–diode array detection (DAD) at 270 nm. The procedure was validated according to the European Union regulation 2002/657/EC determining specificity, decision limit, detection capability, trueness and precision. The results of validation process demonstrate that the method is suitable for application in European Union statutory veterinary drug residue surveillance programmes.

Landscape-Scale Simulation of Pesticide Behavior in River Basin due to Runoff from Paddy Fields Using Pesticide Paddy Field Model (PADDY)

A landscape-scale simulation model (PADDY-Large) based on PADDY was developed for predicting pesticide concentrations in drainage canals and rivers due to runoff from paddy fields. Based on the irrigation systems used in agrohydrology, a rice-producing area was classified into a “field plot”, “farm block”, “district”, and “river basin” and pesticide behavior was estimated focusing on the main drainage canals in the “district” area. To validate the model, a surveillance of pesticide residues was carried out in a rice-producing area. Herbicide concentrations in a main drainage canal in the area increased in early May, reached a maximum in mid May, and declined to below detection limits by early July. The correlation between simulated and observed concentrations of a herbicide mefenacet in the main canal were obtained by considering actual pesticide use and environmental conditions in the rice-producing area.

Liquid chromatography/electrospray tandem mass spectrometric analysis of incurred ractopamine residues in livestock tissues.

Ractopamine HCl is a beta-adrenergic agonist (beta-agonist) recently approved by the U.S. Food and Drug Administration, but not other governmental agencies, for use in finishing swine. For these reasons, it was important to develop and validate mass spectrometric methods for the detection and confirmation of ractopamine residues in livestock marker tissues. Incurred tissues in cattle, sheep, turkeys, and ducks were generated during 7-day ractopamine feeding (20 ppm in diets) periods. Disposition of ractopamine residues in liver and pigmented retinal epithelium was determined in animals slaughtered with withdrawal periods of 0, 3, and 7 days. Ractopamine residues, purified using solid-phase extraction, were measured using liquid chromatography (LC) and electrospray with detection by tandem mass spectrometry (MS/MS) in the multiple reaction-monitoring (MRM) mode. Total ractopamine residues (parent ractopamine + hydrolyzed conjugates) in liver were detected in all species on withdrawal day 0 (2-97 ppb) and were greatly diminished in all species by withdrawal day 7 (<1 ppb). Bovine and ovine retina had lower levels of ractopamine (0.5-3 ppb) than liver, and occular residues increased with withdrawal time, suggesting redistribution into this tissue. Lower limits of quantification were found to be approximately 0.1 ppb in liver and retina. Incurred ractopamine residues were confirmed by the precise and accurate agreement of MRM intensity ratios of diagnostic fragment ions (m/z 284, 164, and 121) from the protonated molecule between ractopamine residues in incurred samples and an authentic ractopamine standard. The limits of confirmation in liver and retina using recognized acceptance criteria were below 1 ppb. The high sensitivity and specificity for measurement and confirmation of ractopamine residues suggests this method will be applicable for regulatory residue surveillance programs.

Development and validation of a liquid chromatography-electrospray tandem mass spectrometry method for mebendazole and its metabolites hydroxymebendazole and aminomebendazole in sheep liver.

A quantitative liquid chromatography-electrospray tandem mass spectrometry method for the determination of mebendazole and its hydrolysed and reduced metabolites in sheep liver has been developed and validated. The benzimidazole substances were extracted with ethyl acetate after the sample mixture had been made alkaline. The HPLC separation was performed on a reversed-phase C18 column with gradient elution using a mobile phase consisting of water containing 0.1% formic acid and acetonitrile. The analytes were detected after atmospheric pressure electrospray ionization on a tandem quadrupole mass spectrometer in MS-MS mode. The components were measured by the MS-MS transitions of the molecular ion to the two most abundant daughter ions. The detection limits are lower than 1 microg kg(-1). For this application, the validation limit was set at 50 microg kg(-1). The examined validation parameters were in accordance with the permitted tolerances ranges stipulated in the proposed new European validation criteria for residue surveillance. For the three analytes, the overall recovery was higher than 90%. The RSD for the repeatability ranged from 5 to 11%. The range for the within-laboratory reproducibility was between 2 and 17%. The decision limits for mebendazole, the hydrolysed and the reduced metabolite were 56.6, 61.8 and 64.2 microg kg(-1), respectively. The detection capabilities for these substances were 60.0, 86.1 and 90.9 microg kg(-1), respectively.

Determination of three nitroimidazole residues in poultry meat by gas chromatography with nitrogen–phosphorus detection

A method was developed for the determination of the nitroimidazole compounds dimetridazole (DMZ), ronidazole (RNZ) and metronidazole (MNZ) by gas chromatography with nitrogen phosphorus detection. Nitroimidazole compounds were extracted with acetonitrile, followed by acidification using acetic acid and cleanup using strong cation-exchange (SCX) SPE column. Validation in chicken muscle fortified at a concentration of 5 μg/kg gave mean recoveries of 85% DMZ, 90% RNZ, 80% MNZ with RSDs of 13.0, 14.3, 11.2%, respectively ( n=6). The method is suitable for statutory residue testing and is used as a quick screening method in the National Residue Surveillance Plan in China.

Multi-residue analysis of avermectins and moxidectin by ion-trap LC-MSn.

A multi-residue method was developed and validated for the quantitation and confirmation of avermectins and moxidectin residues in bovine liver. Target analytes were extracted from liver homogenate using C8 solid phase cartridges, chromatographed under basic pH conditions in order to promote the formation of analyte anions, and detected by ion-trap mass spectrometry (MS) in negative ion mode using an atmospheric pressure chemical ionization interface (APCI). The method provided detection capabilities (CC beta, where beta = 0.05) for eprinomectin, abamectin, doramectin, moxidectin and ivermectin of 3.1, 3.2, 2.2, 4.0 and 3.2 ng g-1 liver respectively, well below their respective maximum residue limits (MRLs). The critical concentrations for MRL compliance (CC alpha, where alpha = 0.01) were 840, 28, 130, 130 and 130 ng g-1 respectively. Analysis of liver fortified at the appropriate MRLs gave recoveries (% +/- RSD) of 70.9 +/- 11.6 (n = 14), 69.1 +/- 3.9 (n = 13), 65.9 +/- 6.4 (n = 19), 69.7 +/- 9.3 (n = 19) and 73.2 +/- 10.5 (n = 19), respectively, for each analyte. Calibration curves fitted a second order polynomial function (R2 > or = 0.9978) over a wide range of concentrations (0 to 10,000 ng ml-1). The detection of two daughter-ions for each analyte allowed for quantitation and the confirmation of identity. The method is suitable for application in European Union statutory veterinary drug residue surveillance programmes, since it fulfills appropriate analytical criteria, and has the particular advantage of enabling high throughput multi-residue quantitation and confirmation of the target analytes.

Organochlorine insecticide residues in surface and underground water from different regions of Bangladesh

The use of organochlorine insecticides (except heptachlor) for all agricultural and public health purposes was banned in Bangladesh by late 1993, although stocks could be used after that time and emergency use of limited quantities of DDT for plague control was permitted in 1994. Water samples from the different regions of Bangladesh were studied for organochlorine insecticide residues (OCs) during 1992–1995, both before and after the banning of the use of OCs. Packed column gas chromatographic (Electron Capture Detector mode) techniques were used and recovery was checked by monitoring the extraction of radio-labelled compounds with a Liquid Scintillation Counter. The results indicate slight contamination of some of the water samples of both surface and underground sources with residues of DDT, heptachlor, lindane and dieldrin. The majority of the samples, were found to be free from residues. Although use of heptachlor is allowed for specific purposes, its presence in surface water and ground water at levels well above WHO-recommended limits is a matter of concern. Appropriate remedial measures and systematic surveillance of heptachlor and other OC residues in water resources of the country are necessary to check further aggravation of the situation.

Lead and cadmium in meat and organs of game in Slovenia

Pollution of the environment and contamination of animals including game with Pb and Cd are serious problems in most countries. Our many-years results of Pb and Cd residues in meat and organs of game show us, that the herbaceous game, which feed only with various herbs are more contaminated than other animals - cattle and pigs. They really seem to be a good environmental contamination indicator. The aim of our research was to establish contamination levels of game with Pb and Cd. Two different regions of Slovenia, an industrial region with a lead mine and smeltry in Koroska and an unindustrial one a Ilirska Bistrica were chosen to study contamination of game. Muscle tissues, heart muscles, kidneys and livers of roe-deer, chamois, red-deer and wild boards were analysed. The correlation between the animals` age and cadmium content in kidney was researched and a positive correlation was established. We have found out to which extent the meat and organs of game correspond with our available tolerances for each single residue and whether they are unfit for human consumption. The results of investigations concerning Pb and Cd content in game analysed in Slovenia in the last four years were shown, too. Resultsmore » were taken from the reports of the Residue monitoring and surveillance which is performed in the Republic Slovenia for more than ten years. 6 refs., 5 tabs.« less

Programs for surveillance and monitoring of antibacterial residues in Australia, 1989 to 1993.

The development of a State-based confirmatory testing capability for antibiotic residues in meat in Australia has allowed the rapid feedback to producers failing to comply with antibiotic maximum residue limits. The identification of problem areas in various categories of livestock, and subsequent focused surveillance programs, has reduced the prevalence of antibacterial residues in both domestic and export meat products. Failure to observe withholding periods of antibacterial drugs after treatment is the most significant cause of non-compliance. In the period July 1991 to June 1993 the compliance rate for antibacterial residues for all species was 99.9%.

Food safety and residues in Australian agricultural produce.

A brief history of food safety in Australia in the context of the development of scientific knowledge is presented. Australia's food and food commodity residue and contamination surveillance and monitoring programs are outlined. Although chemical residues are perceived as a major health risk by the general community, the risk of food causing illness or death because of chemical residues is low. The major threat to human health from food is microbiological contamination, in terms of deaths, sickness and economic loss. The emerging influences in food safety are scientific and technical developments, deregulation, social and demographic factors, and the media. The risk of disruption of domestic and export markets by food safety issues is considerable. The emergence of international standards for food production and processing will enable commercial contractual arrangements to minimise the frequency of disruptive food safety incidents.

Residues and persistence of endosulfan in Dry Tobacco leaves and cigarettes

Pesticide residue surveys in agricultural products have never been conducted in Greece and data concerning pesticide residues are circumstantial and fragmentary. These are derived from few researchprojects goingonoccasionally in Greece but mostly from national surveys and pesticide residue surveillance programs in countries importing agricultural products from Greece. Recently a research program on pesticide residues and pesticide persistence studies in different agricultural products has beeen approved and initiated with respective research in tobacco leaves and cigarettes. Tobacco is considered to be one of the main agricultural products of Greece. Many tobacco varieties (basmas, koulak, samsous, tsebel, burley, virginia et~ are cultivated in Greece and a high percentage of the annual production is exported. Therefore, data concerning the residues and behaviour of pesticides in tobacco leaves as well different tobacco products is of concern to the Greek as well to other country cigarette and tobacco smokers. The use of most organochlorine insecticides has been banned in Greece except for endosulfan and lindane which are still in use for the protection of many crops including tobacco. The residues and behaviour of these two pesticides in dry tobacco leaves and cigarettes will be discussed in the present communication. MA"I~RI~T.~S AND MR~~-IODS Samples of dry tobacco leaves consisting of approximately 500 g each were collected either from individual tobacco growers from different tobacco growing areas of Central and Northern Greece or were supplie<] by Tobacco Export Companies. These samples were taken mostly from the 1987 tobacco yield. Cigarette samples from different brands either produced in Greece or imported consisting of 200 to 60 cigarettes each were purchased from the local market (1987). Before the analysis, individual leaf samples were further dried at 45 ~ for two days and pulverized using a Wiley Mill. The cigarettes from each brand sample were opened and the already cut tobacco leaf material was mixed thoroughly and dried as previously.

Affinity Column Cleanup and Direct Fluorescence Measurement of Aflatoxin M1 in Raw Milk

Aflatoxin M1 is a carcinogen secreted in the milk of cows which ingest feed contaminated with aflatoxin B1 Surveillance of aflatoxin residues requires a simple, rapid, sensitive, and quantitative test. A test has been developed which uses an antibody affinity column to isolate aflatoxin M1 from raw milk. The skim portion is passed directly through the column. The column is then washed and the aflatoxin M1 eluted into a test tube. The affinity column provides sufficient sample cleanup to measure the aflatoxin level directly using a fluorometer. Using raw milk samples spiked with known amounts of aflatoxin M1, the method provides 97% recovery over the range 0.05ppb to 0.5ppb. The detection limit is 0.05ppb. Values obtained on the fluorometer agree with those obtained by HPLC. The time required to quantitate a prepared sample is about 8 minutes.

An interesting application of infra-red reflection photography to blood splash pattern interpretation

Infra-red reflection photography is commonly used in various aspects of forensic work including document examination, firearm residue detection and surveillance work. Its use in the visualisation of blood stains is less well documented. The nature of a recent homicide case in Victoria, Australia, made it imperative that the blood spray pattern and its direction be determined. The success of the technique in this case gives credence to the argument that every “violent” scene should be approached with this capability close at hand.

Survey of potatoes grown in New York State for aldicarb residues.

Aldicarb [2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime] (Temik) is a broad-spectrum pesticide registered for use on a wide variety of agricultural crops. A single application, in the case of potatoes at the time of seed planting, protects the crop for the entire season against a variety of insects, mites, and nematodes. Upon weathering, aldicarb is oxidized to aldicarb sulfoxide and aldicarb sulfone (Kuhr and Dorough 1976). When field-grown potatoes were exposed to in-furrow treatment with aldicarb, the expected sulfoxidation products were found but no parent compound was extracted from any portion of the plants (Andrawes et al. 1971). The tolerance in the United States for residues of aldicarb and its metabolites in potatoes is i ppm (Code of Federal Regulations 1983). As part of the Food and Drug Administration's (FDA) ongoing pesticide residue surveillance program, the FDA Buffalo District conducted a survey of potatoes grown in New York State in 1982 to determine carbamate insecticide use and residue content after harvest. The residue of particular interest was aldicarb. This insecticide is systemic, its metabolites are stable, and its application to potatoes is recommended for a variety of insect pests. Due to the contamination of groundwater with aldicarb on Long Island, the manufacturer requested from the Environmental Protection Agency (EPA) an amendment to its product label banning the use of aldicarb in Suffolk County, NY. This was granted (Zaki et al. 1982). MATERIALS AND METHODS Fifty samples, representing potatoes grown in four areas of New York State, were collected. Interviews with growers were obtained for nearly all samples. With the exception of potatoes grown on Long Island, all growers indicated that granular aldicarb had been applied at rates between 13 and 20 lb/acre at planting. No further applications of aldicarb were made.

Poliomyelitis in India: prospects and problems of control.

Based on many surveys of residual paralysis and limited surveillance, the incidence of acute paralytic poliomyelitis in India has been calculated to be 20-40 per 100,000 population per year; thus greater than 200,000 cases occur annually, or 500 every day. Although oral polio vaccine ( OPV ) has been highly effective in controlling outbreaks, its introduction in routine immunization programs has not succeeded in controlling poliomyelitis in India. This failure is the result of inappropriate immunization strategy and low rates of antibody response to vaccine virus. Injectable polio vaccine, although found to be highly effective in routine immunization programs, is very costly and in short supply. The annual immunization of the susceptible age group with OPV during a short period (pulse immunization) has been found to be highly effective; this strategy is recommended for national control of poliomyelitis.

Zur wirtschaftlichen Bedeutung des Pflanzenschutzes1

AbstractOn the economical importance of plant protection. The assessment of losses caused by plant diseases and plant pathogens is still largely dependent upon rough estimates. Therefore, it is highly desirable to learn more about the importance of individual pathogens and to develop methods for long term prognoses. The latter may be hampered by the rapid change of production methods which can cause unpredictable alterations in the prevalence of pathogens. There is abundant evidence that the problems of plant protection have not decreased during the last decades. Presently, there seems to be general agreement that plant protection measures are necessary, controversies, however, exist concerning the extent of the use of chemical plant protection agents and the choice of methods. More attention should be paid to the improvement of methods of plant cultivation without undervaluing the central importance of chemical measures which are indispensible in the control of many diseases, pathogens and weeds. The need to rationalize frequently leaves no other choice but the use of chemical plant protection measures. It is assumed that on the average the ratio of costs versus efficiency ranges between 1 : 3 to 1 : 9 for chemical plant protection agents, in favourable cases it is even better. The increase in yield resulting from chemical plant protection measures is recognized directly as an increase of the net yield. No evaluation, however, can presently be made of the costs resulting from the necessary surveillance of residues and undesirable side effects of plant protection agents.