bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Five Pesticide Residues in Oranges by Matrix Solid-Phase Dispersion and Liquid Chromatography to Estimate Daily Intake of Consumers
Authors: Valenzuela Ana I , Picó Yolanda , Font Guillermina 
Published: February 2020

Abstract
Residues of benzoylphenylurea insecticides (diflubenzuron, hexaflumuron, and flufenuxuron), carboxamide acaricides (hexythiazox), and carbamate insecticides (benfuracarb) were determined in 150 orange fruit samples from September 1998 to June 1999, to estimate exposure of the Valencian population to oranges contaminated with these newly developed pesticides. The method for monitoring these residues is based on matrix solid-phase dispersion and liquid chromatography with UV or atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) detection. Orange samples representing 11 varieties were collected from an agricultural cooperative and examined for the 5 pesticides. In 74.6% of all analyzed samples, the pesticide residues were below detection limits, which ranged from 0.002 to 0.05 mg/kg. Residues were detected in 25.4% of the samples, with higher incidences of diflubenzuron, flufenuxuron, hexythiazox, and benfuracarb; hexaflumuron residues were detected only occasionally. Two different pesticides exceeded maximum residue limits (MRLs) in 4 (2.7%) of the orange samples. Diflubenzuron surpassed 1 mg/kg MRL in 3 samples and flufenuxuron exceeded the 0.3 mg/kg MRL in 3 samples. The estimated daily intake of the 5 pesticide residues during the period was 0.077 μg/kg body weight per day. This value is much lower than the total admissible daily intake proposed by the Food and Agricultural Organization and the World Health Organization.
Examination of Proficiency and Control Recovery Data from Analyses for Pesticide Residues in Food: Sources of Variability
Authors: Horwitz William , Jackson Terry , Chirtel Stuart J 
Published: February 2020

Abstract
We examined a number of large proficiency and control databases supporting the values reported for pesticide residues in agricultural commodities at fractions of a part per million (mg/kg). The average recovery from &gt;100 000 recovery records in 13 databases was 94%. The overall average single-value relative standard deviation (RSD) of the reported recoveries was 17% at a mean concentration (C) of about 10−7 (0.1 mg/kg). The average apparent HORRAT value (RSD found/RSDR predicted from the Horwitz formula [2*C−0.1505]) was 0.8. Analysis of variance indicated that about 60–70% of the variance could not be associated with any particular factor or combination of factors–analyte, commodity, method, laboratory, concentration, database, or their interactions. The most predominant factor, analyte, and its third-order interaction with laboratory and concentration contributed most of the assignable variance. These findings suggested that most of the variability of trace analysis for pesticide residues is “random” in the sense of being inherent and not assignable to specific factor fluctuations.
Liquid Chromatographic Determination of Nystatin in Pharmaceutical Preparations
Authors: Wilson Phyllis , Stewart Ann , Flournoy Valerie , Zito S William , Vancura Ales 
Published: February 2020

Abstract
A rapid, reversed-phase liquid chromatographic method was developed for the assay of nystatin in the bulk drug and a variety of dosage forms. Analysis was performed on a Symmetry C18 reversed-phase column using a mobile phase of methanol–water–dimethylformamide (DMF; 55 + 30 + 15, v/v/v), with detection by UV at 305 nm. Quantitation is based on the sum of the peak areas of the 2 major isomers of nystatin. The linearity of the assay was determined for a concentration range of 0.05 to 0.2 mg/mL (correlation coefficient &gt; 0.999). Accuracies and precision showed good reproducibility.
Separation and Quantitation of Alkylphosphocholines and Analogues of Different Liposome Formulations by HPTLC
Authors: Ratz Hannelore , Schnell Horst , Rischer Matthias , Eibl Hans-Jörg 
Published: February 2020

Abstract
High-performance thin-layer chromatographic (HPTLC) analysis of non UV-active phospholipids in biological matrixes is a common method for separation, detection, and quantitation. Liposomes containing new alkylphosphocholines and analogues with enhanced cytostatic activity had been prepared. The liposomal formulations were designed to enable the intravenous application of the alkylphosphocholines and analogues and to reduce dose-limiting toxicities observed after oral administration. For quality control the liposomes were analyzed by HPTLC for content of 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG), cholesterol, alkylphosphocholines, and analogues and their related compounds (main degradation products). Due to the differences in lipophily of the compounds, different mobile phases were necessary to achieve separation. Automated Multiple Development was used to reduce the number of plates and to improve the selectivity and the capacity of the chromatographic system to separate the described alkylphosphocholines and analogues from DPPG and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine in one chromatographic system.
Determination of Clopidol Residues in Chicken Tissues by Liquid Chromatography: Part I. Optimization of Analytical Conditions and Comparison with AOAC Gas Chromatography Method
Authors: Pang Guo-Fang , Cao Yan-Zhong , Fan Chun-Lin , Zhang Jin-Jie , Li Xue-Min , Jia Xi , Song Wen-Bin 
Published: February 2020

Abstract
A simple and specific liquid chromatographic method was developed for determination of clopidol in chicken tissues. Samples were extracted with acetonitrile. The extracts were cleaned up on an alumina column and an anion exchange column. The clopidol was separated on a column (30 cm × 3.9 mm) of μBondapak C18 (10 μm) by using acetonitrile–water (20 + 80, v/v) as mobile phase, and determined quantitatively at 270 nm. Recoveries were 86.0–97.6%, with relative standard deviations of 2.14–9.42% at 0.010–2.0 mg/kg from 4 spiked matrixes of chicken muscle, egg, liver, and kidney. The limit of detection was 0.005 mg/kg. Compared with the modified AOAC gas chromatographic method, the present method is simple and fast to operate. Its results are accurate and reliable, making it favorable for environmental protection and meeting requirements for human safety. Thus, it is suitable for routine analysis of large quantities of samples.
Simultaneous Determination of Emamectin and Ivermectin Residues in Atlantic Salmon Muscle by Liquid Chromatography with Fluorescence Detection
Authors: Riet Jeffrey M van de , Brothers Natalie N , Pearce Johanna N , Burns B Garth 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for determining residues of the antiparasitic drugs emamectin (EMA) and ivermectin (IVR) in fish tissues has been developed. EMA and IVR residues are extracted with acetonitrile and cleaned up on a C18 solid-phase extraction column. Extracts are derivatized with 1-methylimidazole and trifluoroacetic anhydride and the components are determined by LC on a C18 reversed-phase column with fluorescence detection (excitation: 365 nm, emission: 470 nm). The mobile phase is 94% acetonitrile–water run isocratically. Calibration curves were linear between 1 and 32 ng injected for both EMA and IVR. The limit of detection for both analytes was 0.5 ng/g, with a limit of quantitation of 1.5 ng/g. Recoveries of EMA and IVR added to salmon muscle averaged 96 ± 9% and 86 ± 6%, respectively, at levels between 5 and 80 ng/g. The percent relative standard deviation for the described method was less than 7% over the range of concentrations studied. The operational errors, interferences, and recoveries for fortified samples compare favorably with an established IVR method. The recommended method is simple, rapid, and specific for monitoring residues of EMA and IVR in Atlantic salmon muscle.
Determination of Salicylate in Blood Serum by Flow Injection with Immobilized Salicylate Hydroxylase
Authors: Vila Marta M D C , Tubino Matthieu , Neto Graciliano de Oliveira 
Published: February 2020

Abstract
A flow injection (FI) enzymatic system, based on the use of immobilized salicylate hydroxylase in glass beads, was developed for the determination of salicylate. Salicylate hydroxylase and nicotinamide adenine dinucleotide (NADH) are used to convert salicylate to catechol. The reaction of catechol with 4-aminophenol at high pH yields a colored product which is detected spectrophotometrically at 565 nm. Ten samples of human serum containing from 5.0 × 10−4 to 5.0 × 10−3 mol/L added salicylate were analyzed and the recovery was determined. Eight additional serum samples containing salicylate were analyzed by the Trinder test and the proposed method. The results obtained with the 2 methods showed good agreement by the statistical Student's t-test. The relative precision of the method is about 3.4% (RSD of the mean recovery). Considering the lowest concentration analyzed, the quantitative limit of detection is about 0.2 × 10−5 mol/L (3 × SD). The volume of the sample used was 150 μL. The proposed method was also used to analyze medicines containing acetylsalicylic acid. The results were statistically compared with those obtained through the U.S. Pharmacopoeia procedure and showed excellent agreement.
Environmental Monitoring of Pesticides by Immunoanalytical Techniques: Validation, Current Status, and Future Perspectives
Authors: Lee Nanju A , Kennedy Ivan R 
Published: February 2020

Abstract
Reliable monitoring technology is an essential component of effective regulation and risk management of environmental contaminants such as pesticides. Most environmental monitoring and analysis is currently conducted using instrumental techniques such as gas–liquid chromatography (GLC) and liquid chromatography (LC). Immunoanalysis provides powerful monitoring techniques that have emerged in the last 3 decades. This paper shows they can deliver rapid, accurate, and relatively inexpensive analysis with high throughput and that have the capability to be field oriented. The technique is versatile in application and can be formatted to suit different purposes such as quantitative analysis or simple “yes/no” tests that are field-portable. While there is a range of opinion on the merits of immunoassays as an analytical tool for pesticides, we suggest that this technology is best considered as complementary to GLC and LC, extending the range of capability for field monitoring. Supporting this view, an increasing number of successful applications of immunoassays to monitoring have been reported in recent years. We also report here the implications of recent developments in the field of immunodiagnostics and their application to monitoring of environmental contaminants. We emphasise that, together with adequate validation by instrumental techniques, immunoassays provide monitoring services yielding realistic and comprehensive data for risk management, allowing decisions on appropriate action by various authorities to be made.
Determination of Fat in Raw and Processed Milks by the Gerber Method: Collaborative Study
Authors: Kleyn Dick H , Lynch Joanna M , Barbano David M , Bloom M Jeffrey , Mitchell Martin W ,   Collaborators:, Cooper L S , Cusak E , Fick M , Hanks T , Hesen M K , Johnson J , Kleyn D H , Mercer F , Monahan D , Peat B , Petit M 
Published: February 2020

Abstract
The Gerber method is used worldwide as a simple and rapid method for determining fat in raw and processed milks. However, the volume of the test portion used in the method has not been internationally agreed upon. A collaborative study was conducted to evaluate performance of the Gerber method using either a weighed test portion (11.13 g) or by a 10.77 mL test portion delivered by pipet. For each method, laboratories received 10 test samples: 5 raw and 5 pasteurized homogenized milks, 2 of which were blind duplicate pairs. Eleven and 10 laboratories participated in the evaluation of aliquot addition by weight and pipet, respectively. Mojonnier ether extraction (Method 989.05) was used as the reference method. Interlaboratory study statistics were similar between methods of test portion addition and between raw and processed materials; therefore, summary interlaboratory study statistics were pooled. The fat content of milk samples ranged from 0.96 to 5.48%. Absolute reproducibility and repeatability were not affected by fat level, and pooled statistical performance (invalid and outlier data removed) was (g fat/100 g milk) sr = 0.026, sR = 0.047, r = 0.074, and R = 0.132. Relative standard deviations increased with decreasing fat content, and were summarized by fat level: 1–2% fat milk, mean = 1.437, RSDr = 1.809%, RSDR = 3.271%; 2–6% fat milk, mean = 4.156, RSDr = 0.626%, RSDR = 1.131%. Compared with ether extraction, test results by the Gerber method were slightly lower (0.02% fat) using a weighed test portion and significantly lower (0.06% fat) using a 10.77 mL volume addition by pipet. A trend toward underestimating fat content at lower fat concentrations (1–2% fat) was observed with the weighed test portion but not when a pipet was used. The Associate Referee recommends that the Gerber method using a weighed test portion be adopted as First Action with applicability limited to whole milk.
On-Line Complexation/Preconcentration System for the Determination of Lead in Wine by Inductively Coupled Plasma–Atomic Emission Spectrometry with Ultrasonic Nebulization
Authors: Wuilloud Rodolfo G , González Alfredo H , Marchevsky Eduardo J , Olsina Roberto A , Martinez Luis D 
Published: February 2020

Abstract
An on-line lead preconcentration and determination system implemented with inductively coupled plasma–atomic emission spectrometry (ICP–AES) with ultrasonic nebulization (USN) in association with flow injection was studied. For the preconcentration of lead, a Pb–quinolin–8–ol complex was formed on-line at pH 6.8 and retained on Amberlite XAD–16 resin. The lead was removed from the microcolumn by countercurrent elution with nitric acid. A total enhancement factor of 225 was obtained with respect to ICP–AES with pneumatic nebulization (15.0 for USN and 15.0 for the column). The detection limit for Pb for the preconcentration of a 10 mL wine sample was 0.15 μg/L. The precision for 10 replicate determinations at a Pb level of 25 μg/L was a relative standard deviation of 2.5%, calculated from the peak heights obtained. The calibration graph obtained by using the preconcentration system for lead was linear with a correlation coefficient of 0.9995 for levels near the detection limit up to ≥ 1000 μg/L. The method was successfully applied to the determination of lead in wine samples.
Identification of Commercial Fish Species Belonging to the Orders Pleuronectiformes and Gadiformes: Library of Isoelectric Focusing Patterns
Authors: Tepedino Valentina , Berrini Anna , Borromeo Vitaliano , Gaggioli Daniela , Cantoni Carlo , Manzoni Paolo , Secchi Camillo 
Published: February 2020

Abstract
Isoelectric focusing in polyacrylamide gel was used to establish an identification archive of fish species belonging to the orders Pleuronectiformes, or flat fish, and Gadiformes, or gadoid fish. The 2 orders include species of different commercial value and interest that are frequently requested in European fish markets, but are susceptible to substitution either because they are morphologically similar or because they arrive on the markets already filleted or sliced. The sarcoplasmic protein profiles are species-specific and reproducible. The use of densitometry and image analysis coupled with a simple computer program overcomes the subjective evaluation of the patterns, making it possible to identify species correctly.
Simultaneous Densitometric Determination of Indomethacin and Its Degradation Products, 4-Chlorobenzoic Acid and 5-Methoxy-2-Methyl-3-Indoleacetic Acid, in Pharmaceutical Preparations
Authors: Krzek Jan , Starek Magorzata 
Published: February 2020

Abstract
A densitometric method was developed for the identification and determination of indomethacin and its degradation products, 4-chlorobenzoic acid and 5-methoxy-2-methyl-3-indoleacetic acid, in pharmaceuticals. To separate these compounds, silica gel-coated thin-layer chromatography plates and the following mobile phase were used: 2-propanol–25% ammonia–water (8 + 1 + 1, v/v). UV densitometric measurements were made by comparing the absorption spectra and Rf values of appropriate standards with the pharmaceutical preparations examined. The conditions for separation were established and a low detection limit was obtained. Average recoveries were 100.69, 90.09, and 91.17% for indomethacin, 4-chlorobeznzoic acid, and 5-methoxy-2-methyl-3-indoleacetic acid, respectively.
Development and Validation of a Chiral Liquid Chromatographic Method for the Determination of Atenolol and Metoprolol Enantiomers in Tablet Preparations
Authors: Singh Anil K , Kedor-Hackmann Erika R M , Santoro Maria Inês R M 
Published: February 2020

Abstract
Atenolol (AT) and metoprolol (MT) are predominantly used in the treatment of angina pectoris, certain arrhythmias, systemic hypertension, and several other cardiovascular disorders. Both compounds are produced commercially in the racemic form, although the S-form is responsible for the desired biological effect. This paper describes a simple, rapid, precise, and accurate method for separating the enantiomers of AT and MT. AT isomers are separated by using a Chiralcel OD® column (250 × 4.6 mm, 10 μm), hexane–ethanol–diethylamine–acetic acid (60 + 40 + 0.2 + 0.2, v/v/v/v) as the mobile phase, and a flow rate of 1.0 mL/min. MT isomers are separated by using a mobile phase with the same components in the following proportions (40 + 60 + 0.2 + 0.2, v/v/v/v) and a flow rate of 0.8 mL/min. Ultraviolet detection was at 276 nm for both analytes. The coefficients of variation (CVs) and average recoveries (ARs) for the R-enantiomers in samples A, B, C, D, and E were 1.15 and 101.06%, 0.74 and 99.25%, 1.05 and 102.57%, 0.84 and 101.57%, and 0.86 and 98.62%, respectively. The CVs and ARs for the S-enantiomers in samples A, B, C, D, and E were 1.33 and 98.87%, 0.99 and 100.76%, 1.17 and 101.69%, 1.26 and 100.39%, and 1.40 and 99.39%, respectively. The standard curves of R-AT, S-AT, R-MT, and S-MT showed good linearity over the concentration range studied with correlation coefficients of 0.9991, 0.998, 0.9988, and 0.999, respectively.
Production and Use of BCR Reference Materials for Quality Assurance in Environmental Analysis: An Update
Authors: Quevauviller Philippe 
Published: February 2020

Abstract
Reference materials represent an invaluable tool for analytical quality control. Certified Reference Materials (CRMs) are used for the validation of methods, whereas various types of (uncertified) Reference Materials (RMs) are used for routine quality control (establishment of control charts) and interlaboratory testing (e.g., proficiency testing). This paper provides background information on the production and use of environmental RMs and describes recent CRMs produced by the BCR (European Commission) for quality assurance in environmental analysis.
Validation of PCR Methods for Quantitation of Genetically Modified Plants in Food
Authors: Hübner Philipp , Waiblinger Hans-Ullrich , Pietsch Klaus , Brodmann Peter 
Published: February 2020

Abstract
For enforcement of the recently introduced labeling threshold for genetically modified organisms (GMOs) in food ingredients, quantitative detection methods such as quantitative competitive (QC-PCR) and real-time PCR are applied by official food control laboratories. The experiences of 3 European food control laboratories in validating such methods were compared to describe realistic performance characteristics of quantitative PCR detection methods. The limit of quantitation (LOQ) of GMO-specific, real-time PCR was experimentally determined to reach 30–50 target molecules, which is close to theoretical prediction. Starting PCR with 200 ng genomic plant DNA, the LOQ depends primarily on the genome size of the target plant and ranges from 0.02% for rice to 0.7% for wheat. The precision of quantitative PCR detection methods, expressed as relative standard deviation (RSD), varied from 10 to 30%. Using Bt176 corn containing test samples and applying Bt176 specific QC-PCR, mean values deviated from true values by −7 to 18%, with an average of 2 ± 10%. Ruggedness of real-time PCR detection methods was assessed in an interlaboratory study analyzing commercial, homogeneous food samples. Roundup Ready soybean DNA contents were determined in the range of 0.3 to 36%, relative to soybean DNA, with RSDs of about 25%. Taking the precision of quantitative PCR detection methods into account, suitable sample plans and sample sizes for GMO analysis are suggested. Because quantitative GMO detection methods measure GMO contents of samples in relation to reference material (calibrants), high priority must be given to international agreements and standardization on certified reference materials.
Trace Elements in Western Canadian Hard Red Spring Wheat (Triticum aestivum L.): Levels and Quality Assurance
Authors: Gawalko Eugene J , Garrett Robert G , Nowicki Thomas W 
Published: February 2020

Abstract
A monitoring program was conducted for trace elements in Western Canadian Hard Red Spring wheat (Triticum aestivum L.). Samples were selected from harvest survey samples submitted by producers from crop districts in Manitoba, Saskatchewan, and Alberta for 1996, 1997, and 1998 crops. The analytical quality control measures used in these surveys are described along with the results for Cd, Cu, Fe, Mn, Se, and Zn. Accuracy and precision for the analyses fell within the acceptable control limits. Year-to-year variations in grain chemistry were small for Cd, Mn, Se, and Zn, but Cu and Fe contents showed 12 and 9% decreases, respectively, over the 3 years. The overall variability for the plant-essential trace elements—Cu, Fe, Mn, and Zn—was low compared with that for Cd and Se. The spatial variation in crop chemistry across the Canadian Prairie wheat-producing region was greater than the year-to-year variations. Soil properties were major factors in controlling Cd and Se levels in grain.
Cadmium and Other Metals in Swedish Wheat and Rye Flours: Longitudinal Study, 1983–1997
Authors: Jorhem Lars , Sundström Birgitta , Engman Joakim 
Published: February 2020

Abstract
Wheat flour (sifted), wheat bran, and rye flour were sampled annually in several different areas in Sweden for 15 consecutive years (1983–1997) for a total of 105, 90, and 30 samples, respectively. These samples were analyzed for their content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn by atomic absorption spectrophotometry with background correction after dry ashing at 450° C. As part of the quality control procedures, an in-house reference material was analyzed in parallel to the samples to ensure reliability of the results. In addition, a certified reference material was analyzed to monitor accuracy of the results. The Cd level in wheat and rye flours (mean 0.029 and 0.017 mg/kg dry wt, respectively) correlated significantly with time (p &lt; 0.05) in 2 phases, tending to increase during the first half of the period and decrease during the latter half. In wheat bran, Cd (mean 0.15 mg/kg) levels did not correlate significantly with time. In wheat flour, Cu, Mn, and Zn (means 1.7, 6.2, and 7.6 mg/kg, respectively) showed a significant linear increase (p &lt; 0.05) in concentration over time. In rye flour, the levels of Cu, Fe, Mn, and Zn (means 3.8, 36, 30, and 28 mg/kg, respectively) all decreased significantly (p &lt; 0.05) over time. Similarly, in wheat bran Cu (mean 14 mg/kg) increased and Pb (mean 0.027 mg/kg) decreased significantly (p &lt; 0.05) over time, whereas Ni and Zn showed a significant curved correlation with time and peaked at about the middle of the measurement period.