bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid Method for Trace Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Yogurt
Authors: Yagüe Cristina , Herrera Antonio , Ariño Agustín , Lázaro Regina , Bayarri Susana , Conchello Pilar 
Published: February 2020

Abstract
A new multiresidue method was developed for the analysis of 19 organochlorine pesticides and 6 polychlorinated biphenyls in yogurt. The sample was extracted twice with acetone by homogenization with an Ultra-Turrax dispersing unit, and the combined extracts were filtered. The extract was then purified by reversed-phase C18 columns and subjected to further cleanup with neutral alumina columns. The residues were determined by gas chromatography with electron capture detection. After the method was optimized, it was validated by determination of recovery percentages, precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) with yogurt samples fortified at 10 and 1 μg/kg concentration levels. The recovery of 23 organochlorine residues ranged from 77 to 95% at a level of 10 μg/kg, from 74 to 102% at a level of 1 μg/kg, and between 54 and 61% for dieldrin and α-endosulfan. The method is repeatable and reproducible, with relative standard deviation values &lt;19% for all residues except dieldrin. Detection and quantitation limits were between 0.02 and 0.62 μg/kg. The analytical method proposed was quick, accurate, repeatable, and reproducible for the determination of organochlorine residues in yogurt samples.
Determination of Phosphorus in Fertilizers by Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Yang Wei Min , Boles Rhonda L , Mawhinney Thomas P 
Published: February 2020

Abstract
An inductively coupled plasma atomic emission spectrometry (ICP-AES) method was developed for the determination of phosphorus in fertilizers. Total phosphorus, direct extraction available phosphorus (EDTA), and water-soluble phosphorus, reported as phosphorus pentoxide (P2O5), in 15 Magruder check fertilizers were measured by ICP-AES, and the results were compared with those obtained by the AOAC official method. Five analytical wavelengths of phosphorus, 177.499, 178.287, 213.618, 214.914, and 253.565 nm, were tested for the determination of phosphorus in fertilizers, and their detection limits were obtained. Acid effects of perchloric acid and possible matrix effects of aluminum, calcium, magnesium, potassium, and sodium were negligible for phosphorus determination. Wavelength 213.618 nm was the best analytical wavelength for phosphorus determination by all 3 sample preparation methods for the selected Magruder fertilizers. The results demonstrated that the accuracy and precision of the ICP-AES method were comparable with those of the official methods.
Sequential Determination of Salicylic and Acetylsalicylic Acids by Amperometric Multisite Detection Flow Injection Analysis
Authors: Catarino Rita I L , Garcia M Beatriz Q , Lapa Rui A S , Lima José L F C , Barrado Enrique 
Published: February 2020

Abstract
An amperometric multisite detection flow injection analysis (FIA) system was developed for sequential determination of 2 analytes with a single sample injection and single detector. Tubular composite carbon electrodes with an inner diameter similar to that of the FIA manifold tubing were constructed so that measurements could be made without impairing the sample plug hydrodynamic characteristics. The electrochemical behavior of the tubular voltammetric cell in a low-dispersion FIA manifold and the behavior of the FIA system incorporating this type of voltammetric cell intended for multisite detection were evaluated by performing measurements with potassium hexacyanoferrate(II). Feasibility of the approach was demonstrated in the sequential determination of salicylic and acetylsalicylic acids in pharmaceutical products at a fixed potential of 0.98 V. The system allows sequential determination of salicylic acid concentrations ranging from 1.0 × 10−5 to 5.0 × 10−5M and acetylsalicylic acid concentrations between 1.0 × 10−3 and 5.0 × 10−3M with good precision on both detection sites and with relative standard deviations (RSDs) ≥ 1.5% (n = 10) and 2.1% (n = 10), respectively. A comparison of these results with those of the U.S. Pharmacopeia procedure showed RSDs &lt;5.0 and 1.0% for salicylic acid and acetylsalicylic acid, respectively. The proposed method enables 15 determinations per hour, which corresponds to the analysis of approximately 8 samples per hour. The detection limits of the methodology were approximately 3.5 × 10−6 and 1.1 × 10−5M, respectively, for the first and second monitoring sites.
Spectrophotometric Investigations of the Assay of Physiologically Active Catecholamines in Pharmaceutical Formulations
Authors: Nagaralli Basavaraj S , Seetharamappa Jaldappa , Melwanki Mahaveer B , Ramesh Kunabevu C , Keshavayya Jathi 
Published: February 2020

Abstract
Two simple, sensitive, and accurate spectrophotometric methods are proposed for the determination of levodopa (LD), methyldopa (MD), dopamine hydrochloride (DP), and pyrocatechol (PC) in pure and pharmaceutical preparations. The methods are based on measurement of the absorbances of tris( o-phenanthroline)iron(II) (method A) and tris(bipyridyl)iron(II) (method B) obtained by the oxidation of the catecholamines by iron(III) in the presence of 1,10-phenanthroline and 2,2′-bipyridyl at 510 and 522 nm, respectively. The absorbances were found to increase linearly with increases in the concentrations of the catecholamines, results which were corroborated by the calculated correlation coefficients (0.9990–0.9996). Beer's law was valid over the concentration ranges of 0.04–0.6, 0.06–0.75, 0.06–0.65, and 0.05–0.70 μg/mL in method A and 0.02–1.0, 0.04–1.3, 0.05–1.0, and 0.06–1.1 μg/mL in method B for PC, MD, LD, and DP, respectively. The common excipients and additives did not interfere in their determinations. The proposed methods were successfully applied to the assay of LD, MD, and DP in various dosage forms. The results were validated by statistical analysis.
Concurrent Determination of Four Fluoroquinolones in Catfish, Shrimp, and Salmon by Liquid Chromatography with Fluorescence Detection
Authors: Roybal José E , Walker Calvin C , Pfenning Allen P , Turnipseed Sherri B , Storey Joseph M , Gonzales Steve A , Hurlbut Jeffrey A 
Published: February 2020

Abstract
A liquid chromatographic (LC) method with fluorescence detection was developed for concurrent determination of 4 fluoroquinolones: ciprofloxacin (CIPRO), enrofloxacin (ENRO), sarafloxacin (SARA), and difloxacin (DIFLX) in catfish, shrimp, and salmon. The procedure consists of extraction from fish tissue with acidified ethanol, isolation and retention on a cation exchange solid-phase extraction column, elution with basic methanol, and LC analysis with fluorescence detection. LC is performed by isocratic elution with acetonitrile–2% acetic acid (16 + 84) mobile phase, and a PLRP-S polymer column with fluorescence detection, excitation 278 nm and emission 450 nm. A target level of 20 ppb for each of the 4 fluoroquinolones has been established for this method. Fortified and incurred fish sample results are based on a 5-point standard curve calculation (10–160 ppb). Overall percent recoveries (% relative standard deviation) from fortified catfish were 78 (10), 80 (11), 70 (9.4), and 78 (10); from fortified shrimp, 69 (5.9), 85 (4.9), 79 (5.9), and 90 (4.5); and from fortified salmon, 56 (15), 93 (5.6), 61 (11), and 87 (5.0) for CIPRO, ENRO, SARA, and DIFLX, respectively. Data from the analysis of fluoroquinolone-incurred catfish, shrimp, and salmon are presented.
Kinetic Spectrophotometric Method for the Determination of Ranitidine and Nizatidine in Pharmaceuticals
Authors: Walash Mohamed I , Belal Fathalla , Ibrahim Fawzia , Hefnawy Mohamed , Eid Manal 
Published: February 2020

Abstract
An accurate and simple kinetic method is described for the determination of ranitidine and nizatidine in pure form and in pharmaceuticals. The method is based on the reaction of the compounds with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole in pH 7.4 borate buffer at 60°C for a fixed time of 25 min for both compounds. The absorbance of the reaction product is measured at 495 nm for ranitidine and nizatidine. Calibration graphs were linear over the concentration range of 2–20 μg/mL, with limits of detection of 0.13 (3.7 × 10−7M) and 0.25 μg/mL (7.5 × 10−7M) for ranitidine and nizatidine, respectively. The proposed method was applied successfully to the determination of ranitidine in tablets and ampoules with average recoveries of 100.26 ± 0.69 and 100.29 ± 0.59%, respectively, and to the determination of nizatidine in capsules with an average recovery of 104.26 ± 0.44%. The results obtained are in good agreement with those obtained by the other methods used for comparison. A proposal of the reaction pathway is also presented.
Detection of Salmonella in Fresh Cheese, Poultry Products, and Dried Egg Products by the ISO 6579 Salmonella Culture Procedure and the AOAC Official Method: Collaborative Study
Authors: Feldsine Philip T , Lienau Andrew H , Leung Stephanie C , Mui Linda A , Humbert Florence , Bohnert Marylène , Mooijman Kirsten , Schulten Saskia , Veld Paul In’t , Rollier Patricia , Leuschner Renata , Capps Katherine ,   Collaborators:, Agin J , Allaert C , Asmundson R , Asperger H , Bohnert M , Bound A , Dixon L , Donda S , Espersen M , Foster K , Gangar V , Hammack T , Humbert F , Humes L , in’t Veld P , James L , Jost-Keating K , Kalinowski R , Kwan J , Lamb J , Leung S , Lienau A , Littell A , Mooijman K , Mui L , Ott M , Qvist S , Roberts D , Ruby R , Rude R , Santos C , Schulten S , Sellers R , Smith M , Solis D , Stecchini M L , Stegeman H , Steneryd A , Suktankar V , Wiberg C , Young V 
Published: February 2020

Abstract
Three food types were analyzed for the presence of Salmonella by the AOAC culture method and by the International Organization for Standardization (ISO 6579:2002) culture method. Paired test portions of each food type were simultaneously analyzed by both methods. A total of 21 laboratories representing federal government agencies and private industry, in the United States and Europe, participated in this interlaboratory study. Foods were artificially contaminated with Salmonella and competing microflora if naturally contaminated sources were not available. No statistical differences (p &lt; 0.05) were observed between the AOAC and ISO culture methods for fresh cheese and dried egg products. A statistically significant difference was observed for one of the 2 lots of poultry from the first trial. The poultry meat used in this run was radiation sterilized, artificially contaminated with Salmonella and competitive flora, and then lyophilized. A second trial was conducted with 2 separate lots of raw ground chicken that were naturally contaminated. The results from the second trial showed no statistical difference between the 2 culture methods. A third trial involving 4 laboratories was conducted on 2 separate lots of naturally contaminated raw poultry. Again, no statistically significant differences occurred. It is recommended that ISO 6579:2002 culture method for Salmonella be adopted Official First Action for the analysis of fresh cheese, fresh chilled and frozen poultry, and dried egg products.
Sensitivity and Specificity of the Sanita-kun Aerobic Count: Internal Validation and Independent Laboratory Study
Authors: Morita Hiroshi , Ushiyama Masashi , Aoyama Shigeyuki , Iwasaki Mihoko 
Published: February 2020

Abstract
The Sanita-kun Aerobic Count consists of a transparent cover film, an adhesive sheet, a layer of nonwoven fabric, and a water-soluble compound film, including a culture medium formula for detection of aerobic microorganisms. The Sanita-kun sheet was validated for 14 food categories in an internal study and an independent study was conducted on ground beef and hot dogs. Both studies showed no significant difference in performance between 5 or 8 replicates of the Sanita-kun sheets and AOAC Method 966.23, excluding some lots of foods. The correlation coefficient to plate count agar in the internal accuracy study was 0.99. The average relative standard deviation for repeatability of total foods was 0.26 and 0.19, respectively, excluding &lt;10 average counts. The ruggedness study, which examined the influence of incubation temperature and period, recommended incubation of the Sanita-kun sheet at 32.5 ± 2.5°C for 46 ± 2 h. Comparison of 3 lots of Sanita-kun sheets showed no decrease of performance in the older lot. The shelf-life of the sheet is at least 14 months. The Sanita-kun Aerobic Counts has been granted AOAC Performance Tested MethodSM status.
Kinetic Spectrophotometric Determination of the Macrolide Antibiotic Josamycin in Formulations
Authors: Al-Majed Abdulrahman A , Belal Fathalla , Ibrahim Kamal E E , Khalil Nasr Y 
Published: February 2020

Abstract
A simple kinetic spectrophotometric method was developed for the determination of josamycin in its dosage forms. The method is based on oxidation of the drug with alkaline potassium permanganate at room temperature for a fixed time of 20 min and measuring the produced green color at 611 nm. The absorbance–concentration plot is rectilinear over the range of 2–10 μg/mL (2.4 × 106–1.2 × 10−5M) with minimum detectability of 1.0 μg/mL (1.2 × 10−6M). The determination of josamycin by fixed concentration and the rate-constant methods is also feasible with the calibration equations obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets, and statistical analysis showed that the results compared favorably with those obtained by reference methods. The effect of sensitizers and surfactants on the performance of the proposed method was also studied. A proposal of the reaction pathway was presented.
Simultaneous Determination of Residual Antiparasitic Lactones in Bovine Muscle and Liver by Liquid Chromatography with Fluorescence Detection
Authors: Nagata Tomoko , Miyamoto Fumio , Hasegawa Yasuyuki , Ashizawa Eiichi 
Published: February 2020

Abstract
Abamectin, doramectin, eprinomectin, ivermectin, milbemectin, and moxidectin in bovine muscle and liver were extracted with acetonitrile. The extracts were partitioned with n-hexane and then evaporated to dryness. The residue was cleaned up on Bond Elute NH2 cartridge, and the drugs were eluted from the cartridge with methanol–ethyl acetate (3 + 7). The eluate was evaporated to dryness, and residues were derivatized with N,N-dimethyl-formamide–acetic anhyride-1-methylimidazole. The derivatives were determined by liquid chromatography with fluorescence detection. Recoveries of the 6 drugs were 79.6–63.8% in muscle and 71.6–60.6% in liver at 0.01 ppm levels. The quantitation limits were 5 ppb for each drug.
Distribution of Deoxynivalenol in Wheat, Wheat Flour, Bran, and Gluten, and Variability Associated with the Test Procedure
Authors: Samar María M , Fontán Constantino Ferro , Resnik Silvia L , Pacin Ana M , Castillo Marcelo D 
Published: February 2020

Abstract
Analytical data obtained on deoxynivalenol (DON) concentration in naturally contaminated wheat during processing in an industrial mill were statistically analyzed, and the distribution functions of DON concentration in lots of wheat, bran, wheat flour, and gluten were estimated. The analytical method had acceptable precision (HORRAT 0.25—0.32) for each test sample. The total variance combined sampling, sample preparation, and analytical variances were 0.188, 0.033, 0.42, and 0.0014 ppm2 for wheat, 1.93; flour, 0.99; bran, 4.68; and gluten, 0.29, respectively. The distribution function of DON contamination presented an asymmetric tail for high values of concentration in wheat grains and wheat flour; in bran it seemed to be bimodal with 2 separated peaks of different concentrations; in gluten the normal distribution function gave a reasonably good fit to empirical data. The function η(c) = –ln(–lnp), where p (c) is the cumulative distribution function was linear with c in the so-called extreme-value type I distribution and could be fitted by a cubic polynomial in c in the distributions determined for all the products. This variability and distributional information contributes to the design of better sampling plans in order to reduce the total variability and to estimate errors in the evaluation of DON concentration in lots of wheat and wheat products.
Recent Advances in the Thin-Layer Chromatography of Pesticides: A Review
Authors: Sherma Joseph 
Published: February 2020

Abstract
Advances in the applications of thin-layer chroma-tography (TLC) and high-performance TLC for the separation, detection, identification, and determination of pesticides, other agrochemicals, and related compounds are reviewed for the period 2000–2002. Analyses are described for a variety of samples, such as food, biological, and environmental samples, and for residues of pesticides of various types, including insecticides, herbicides, and fungicides, belonging to different chemical classes. References are included for residue analysis, hydrophobicity studies, and the use of TLC and thin-layer radiochromatography for studies of pesticide metabolism, degradation, uptake, and related topics.
Comparison of the Ammonium Oxalate Extraction of Fertilizer for K2O, Method 983.02, with the Ammonium Citrate/EDTA Extraction, Method 993.31
Authors: Newlon Natalie F 
Published: February 2020

Abstract
The direct available method for phosphorus in fertilizers, Method 960.03, is an Official Method for extraction of both P2O5 and K2O. Because K2O is much more soluble and easier to extract than P2O5, the conditions of the extraction procedure are set for efficient extraction of P2O5, and the extraction of K2O is, in effect, a bonus. In 1993, a modified extraction procedure, using an extractant of ammonium citrate/ethylenediaminetetraacetic acid (EDTA) solution, was evaluated for P2O5 and then collaboratively studied. This now-modified extraction procedure for phosphorus is Official Method 993.31, which is used extensively as an alternative to Method 960.03 for phosphorus because it is less labor-intensive. Method 993.31 was also evaluated in our laboratory for K2O extraction, but it was never formally collaboratively studied for K2O. To demonstrate the suitability of Method 993.31 as an extraction procedure for K2O, as well as P2O5 in fertilizers, Method 993.31 extraction for K2O was compared with Method 983.02, the traditional ammonium oxalate extraction procedure for K2O. A wide range of fertilizer samples was extracted by using both procedures. The t-test for samples containing &lt;30% K2O had a t-value of 1.23 and a probability of 0.22, which indicates there was no significant difference in the results obtained by the 2 extraction methods. The t-test for samples containing &gt;30% K2O had a t-value of 0.30 and a probability of 0.77, also indicating no significant difference. It is recommended that Method 983.02 be modified to include the ammonium citrate/EDTA extraction procedure as an additional option for extraction of K2O from commercial fertilizers.
Enumeration of Probiotic Pediococci in Animal Feed: Interlaboratory Study
Authors: Leuschner Renata G K , Bew Jan , Simpson Paul J , Ross Paul R , Stanton Catherine ,   Collaborators:, Adler A , Bertin G , Braconnier M , Coeuret V , Domig K , Durand H , Kneifel W , Krause M , Marmo S , Michard J , Mietke H , Olofson A S , Thalmann A , Vernoux J P , Voets A , Warmerdam C 
Published: February 2020

Abstract
An enumeration method to be used as official control under Council Directive 70/524/EEC for probiotic pediococci used as feed additives was validated for consideration for adoption as Comitée Européen de Normalisation (CEN) and ISO standards. Seventeen laboratories in 11 European countries carried out an interlaboratory study. A spread plate method following BS ISO 15214:1998 using 4 different agars [MRS, acidified MRS, MRS with triphenyl tetrazolium chloride (TTC), and a newly developed pediococci selective medium (PSM)] was validated. Precision data in terms of repeatability (r) and reproducibility (R) of the method for each medium using different feeding stuffs with a high and a low inoculation level were determined. Pediococci were present in the samples in mixtures with other probiotics. The enumeration of pediococci on all agars showedan RSDr value of 0.4–3.1% and an RSDR of 1.3–4.8%. MRS agar was preferred, followed by acidified MRS and MRS + TTC agar. All 4 media gave similar counts. Depending on the presence and concentration of other probiotic, such as enterococci, lactobacilli, and yeast, acidified MRS or MRS + TTC agar are recommended. The PSM was selective for pediococci and can be used if this species is present at a concentration more than 10-fold lower than other species that can grow on the MRS agars. The methodology with all 4 media is not applicable to mineral feed.
Determination of Ultratrace Bismuth in Milk Samples by Atomic Fluorescence Spectrometry
Authors: Cava-Montesinos Patricia , Cervera M Luisa , Pastor Agustín , de la Guardia Miguel 
Published: February 2020

Abstract
A sensitive procedure was developed for determination of bismuth (Bi) in milk samples by hydride generation atomic fluorescence spectrometry (HG–AFS) after microwave-assisted sample digestion with HNO3 and H2O2. The method provides a sensitivity of 1832 fluorescence units (ng/mL) with a detection limit of 0.01 ng/mL, which corresponds to 20 pg absolute limit of detection, equivalent to 0.50 ng/g in the original sample. Application of the methodology to cow milk samples from the Spanish market showed the presence of Bi at a concentration of 11.8–28.8 ng/g, which compared well with data obtained after dry ashing of samples and with data obtained by inductively coupled plasma–mass spectrometry after microwave-assisted digestion.
Application of Strategically Designed Sample Composition to the Rapid Analytical Screening of Milk Samples for Polychlorinated Biphenyls
Authors: Martínez Elena , Pazos Manuel , Carro Antonia M , Llompart Maria , Cela Rafael 
Published: February 2020

Abstract
Strategically designed sample composition (SSC) is a new technique that decreases the number of analytical determinations needed in routine screening to as few as the number of original sample specimens while providing information that is specific to them. Although this new technique has been applied to environmental studies, this paper describes its first application to food safety studies. Contamination of milk samples with polychlorinated biphenyls (PCBs) was chosen as a case study to show the usefulness and potential of the SSC technique with a fast analytical procedure that involves saponification of the samples and solid-phase microextraction of the PCBs. A total of 20 sample specimens can be analyzed in 11 determinations with excellent predictions of the positive samples and the concentration levels of the contaminants. The robustness of the strategy was investigated and demonstrated.