bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Chlorobiphenyls in Seal Blubber, Marine Sediment, and Fish: Interlaboratory Study
Authors: Boer Jacob De , Meer Jaap Van Der , Brinkman Udo A Th 
Published: February 2020

Abstract
Between 1988 and 1994, the International Councilfor the Exploration of the Sea, the Intergovernmental Oceanographic Commission, and the Oslo and Paris Commissions organized a stepwise interlaboratory study for determination of chlorobiphenyls (CBs) inmarine media. The final parts of this study, in which 53 laboratories from 14 countries participated, focused on long-term precision, cleanup, and extraction. Calibration was controlled continuously by analysis of 10 CBs in an unknownsolution. Participants were requested toanalyze 3 CBs in a certified reference material fish oil (6 times); 10 CBs in cleaned and uncleaned marine sediment and seal blubber extracts; and 10 CBs in seal blubber oil, dried marine sediment, and wet, lean fish muscle tissue. The long-term precision study showed that, compared with earlier exercises in which only duplicate analyses were required, repeatability increased about 1.5-fold compared with reproducibility. The mean standard error for reproducibility of determination of 10 CBs in standard solutions improved from 1.22 to 1.15. The standard error improved from 1.36 to 1.28(without CBs 28 and 31) for seal blubberoil and from 1.36 to 1.22 for dried marine sediment. In seal blubber oil and dried marine sediment, the major CBs 118,138,153, and 180 can now bedetermined by thegroup of participating laboratories with a reproducibility of 1.5 (about 50%). No significant differences were found between results for cleaned-up and un cleaned extracts. No acceptable results could be obtained for determination ofCBs in lean fish muscle tissue. Biplots of principal component analyses are extremely helpful in evaluating the data generated by this type of study.
Determination of Tetracyclines in Animal Feeds in the Presence of Other Drugs by Thin-Layer Chromatography and Microbiological Method
Authors: Markakis Pantelis K 
Published: February 2020

Abstract
This method was developed to separate, detect, and quantitate oxytetracycline (OTC) or chlortetracycline hydrochloride (CTC HCI) in animal feeds in thepresence of 11 otherdrugs: 3 nitrofurans, 2 macrolideantibiotics,3 sulfonamides, 2 coccidiostatics, and 1 antibacterial growth promoter. OTC or CTC HCI was separated from coexisting drugs and detected by thin-layer chromatography, then quantitated microbiologically by the agar diffusion method. Analysis of 125 experimental animal feed samples fortified at 5 levels (7.5-400 ppm) with OTC or CTC HCI and at 1 level (50 ppm) with the rest of the drugs, respectively, gave a limit of quantitation of 1.25 or 0.625 ppm, a recovery of 90.6 or 92.9%, and a coefficient of variation of 2.9-6.1 or 2.3-4.4%.
Multiresidue Method for Confirmation of Macrolide Antibiotics in Bovine Muscle by Liquid Chromatography/Mass Spectrometry
Authors: DelÉpine Bernard , Hurtaud-Pessel Dominique , Sanders Pascal 
Published: February 2020

Abstract
A particle beam/liquid chromatographic/mass spectrometric (PB/LC/MS) method capable of determining 5 macrolides in bovine muscle is described. Spiramycin, tylosin, tilmicosin, erythromycin, and josamycin residues in bovine muscle are confirmed by reversed-phase LC/MS incorporating gradient elution. Macrolides are extracted from tissue with chloroform, and the extract is purified with a diol solid-phase extraction cleanup. The 5 macrolides are identified by negative and positive chemical ionization with selective ion monitoring of 2 ions in each mode. The procedure confirms the presence of each macrolide at 50 μg/kg in spiked samples.
Assay of Volatile Acids Induced by Autoxidation of Nonionic Surfactants by Liquid Chromatography with Direct Denvatization
Authors: Miwa Hiroshi , Yamamoto Magobei 
Published: February 2020

Abstract
Direction derivatization in conjunction with liquid chromatography is described for assay of volatileacids induced by autoxidation of nonionic surfactants. The method is based on the reaction of acids with 2-nitrophenylhydrazine hydrochloride to produce nonvolatile hydrazine derivatives, which are separatedisocratically on a YMC-FA (C8) column within 10 min. In this study, formic acid was produced copiously in autoxidations, principally from C-C fission of hydroperoxides or free radicals. The method is superior with regard to stoichiometric measurement of acid formation, which is related to the extent of oxidation of nonionic surfactants.
Easy Enzyme-Linked Immunosorbent Assay for Spectinomycin in Chicken Plasma
Authors: Tanaka Touichi , Ikebuchi Hideharu , Sawada Jun-Ichi , Okada Mariko , Kido Yasumasa 
Published: February 2020

Abstract
An easy, sensitive, competitive indirect enzyme- linked immunosorbent assay (CI-ELISA) for specti nomycin in chicken plasma was developed. Preparation of a spectinomycin-bovine serum albumin conjugate in which the hapten is linked to the carrier protein through the C-4 position is described. Antibodies raised against antigens in rabbits had excellent specificity for spectinomycin, exhibiting a cross-reactivity of 44.0% with dihydrospectinomy-cin and 13.8% with tetrahydrospectinomycin. No cross-reactivity was observed with other antibiotics. The detection limit of the CI-ELISA was 2 ng/mL (equivalent into 40 ng/mL undiluted chicken plasma) spectinomycin. Known amounts (0.1-100 μg/mL) of spectinomycin were added to chicken plasma and then analyzed. Average recoveries were 97-110%. This procedure may be used without prior extraction of samples.
A Simple and Rapid Solvent ExtractionMethod for Determining Total Lipids in Fish Tissue
Authors: Lee Chong M , Trevino Belzahet , Chaiyawat Mayuree 
Published: February 2020

Abstract
Solvent systems that have been developed for lipid extraction include chloroform–methanol, n-hexane– isopropyl alcohol, and methylene chloride–metha nol. The extraction methods are labor intensive, lack precision, or require a large volume of solvent. Correct computation of lipid content calls for full recovery of solvent after extraction, but recovery always is incomplete because of unaccounted solvent residue that remains in jar, filter paper, and homogenized tissue. A rapid and simple extraction method coupled with correct computation was developed for determining total lipids in fish tissue. The method uses chloroform–methanol and an Eberbach blending jar. Variables examined were chloroform–methanol ratio, solvent-to-sample ratio, and phase separation time. Precision was within 0.5%. Conventional computation of lipid content depends on the volume of chloroform measured after filtration. This volume does not include unaccounted solvent residue. Thus, a time-consuming second extraction is required for complete recovery. The mass balance of each extraction and filtration step confirmed that the correct volume of chloroform (measured plus unaccounted) was close to the theoretical volume. The procedure eliminates problems associated with laborious filtration and variation in chloroform volume readings and does not require an exact reading of chloroform volume. Instead it allows use of a theoretical volume, which depends on solvent volume and ratio used.
Organohalogen and Organophosphorus Pesticides in Mixed Feed Rations: Findings from FDA’s Domestic Surveillance During Fiscal Years 1989-1994
Authors: Lovell Randall A , McChesney Daniel G , Price William D 
Published: February 2020

Abstract
During Fiscal Years 1989–1994, the U.S. Food and Drug Administration (FDA) collected and analyzed 545 domestic surveillance samples of mixed feed rations (172 for cattle, 125 for poultry, 83 for swine, 61 for pets, 56 for fish, and 48 miscellaneous).All samples were analyzed by gas-liquid chromatography for organohalogen and organophosphorus pesticides. Of the 545 samples, 88 (16.1%) did not contain detectable pesticide residues. In the 457 samples with detectable pesticide levels, 804 residues (654 quantitable and 150 trace) were found. None of these 804 residues exceeded regulatory guidance. Malathion, chlorpyrifos-methyl, diazinon, chlorpyri fos, and pirimiphos-methyl were the most commonly detectedpesticides. These 5 organophosphorus pesticides accounted for 93.4% of all pesticide residues detected (malathion, 52.9%; chlorpyrifos-methyl,25.2%; diazinon, 7.7%; chlor pyrifos, 4.9%; and pirimiphos-methyl, 2.7%).Their median values in samples containing quantitable levels ranged from 0.014 to 0.098 ppm. The most commonly detected organohalogen compounds were methoxychlor, DDE, PCB, dieldrin, pentachlo- ronitrobenzene, and lindane. These 6 compounds combined accounted foronly 4.1 % of all residues detected. FDA is continuing its pesticide surveillance of feeds tohelpensure animal safety and prevent violative residues in food derived from animals.
Reliability of the Determinations of Polychlorinated Contaminants (Biphenyls, Dioxins, Furans)
Authors: Horwitz William , Albert Richard 
Published: February 2020

Abstract
Precision performance parameters from results of 34 interlaboratory performance studies of polychlorinated aromatic ring compounds (biphenyls, dioxins, and furans) (PCCs) have been recalculated by using the International Union of Pure and Applied Chemistry-1987 harmonized protocol. Most studies of 1052 test samples, 56 analytes, 19 matrixes, and 2 types of detectors (electron capture and mass spectrometers) provide among-laborato- ries relative standard deviations (RSDRs), that are considerably better than those predicted from the Horwitz equation at fractional concentrations of 10−6 down to 10−15. The explanation suggested is that supplying common reference calibration solutions, as was done in many of these studies, does not reflect realistic operating conditions. Furthermore, the ability to repeat, discuss, and reassess aberrant reported values results in underestimating the true RSDR. The commonly reported problems of preparation of standard calibrating solutions, instability of the detection system, and failure to follow quality control instructions and good laboratory practices may be important sources of interlaboratory variability in PCC determinations
Worldwide Survey of Fumonisin Contamination of Corn and Corn-Based Products
Authors: Shephard Gordon S , Thiel Pieter G , Stockenström Sonja , Sydenham Eric W 
Published: February 2020

Abstract
As part of a comprehensive risk assessment study for fumonisins, reliable data on exposure of populations to these dietary toxins must be obtained. To assess the extent of worldwide exposure, the published literature on the contamination of food and feed supplies has been reviewed and supplemented with unpublished material from various international sources. Fumonisin contamination of corn and corn-based products occurs in many countries. Animal mycotoxicoses such as equine leukoencephalomalacia and porcine pulmonary edema are caused by heavily contaminated animal feeds. For example, as much as 330 μg/g fumonisin B1 (FB1) has been found in swine feed. Although commercially available refined corn products for human consumption are generally contaminated at levels below 1 μg/g FB1, individual products in certain countries can reach far higher levels. Health risks associated with consumption of these products depend on the extent to which they are consumed in a varied diet. Home-grown corn in certain rural areas, where it also constitutes the staple diet, can be contaminated at &gt;100 μg/g. Consumption of corn contaminated at these high levels has: been associated with a high incidence of esophageal cancer in these areas.
Gas Chromatographic Differentiation of Virgin, Refined, and Solvent-Extracted Olive Oils
Authors: Jiménez De Blas Oroncio , Del Valle González Amando 
Published: February 2020

Abstract
An analytical method based on gas chromatography using a capillary column was used to determine fatty acids in olive oils. The method was applied to 50 samples of virgin olive oil, 50 of refined olive oil, and 30 of solvent-extracted olive oil. Results were compared, with special emphasis on peaks of minor fatty acids to distinguish virgin, refined, and solvent-extracted oils. Some peaks are probably due to trans Isomers of the fatty acids. Statistically significant differences were observed among the 3 types of olive oil.
Testing for Compliance with Migration Limits: Determination of 1,2-, 1,3-, and 1,4-Dihydroxybenzenes in Food-Simulating Solvents by Liquid Chromatography
Authors: Philo Mark R , Jickells Sue M , Castle Laurence 
Published: February 2020

Abstract
A method, intended for regulatory purposes, for quantitative determination of the plastics monomers 1,2-, 1,3-, and 1,4-dihydroxybenzene in foodsimulating solvents is described. Liquid chromatography is used with UV detection and 2-methyl- 1,3-dihydroxybenzene as internal standard. Repeatability, stability, and migration tests were conducted. The limits of detection were in the range 0.03–0.40 mg/kg for the 3 phenols in aqueous and fatty food simulants. Relative repeatability standard deviations at migration limits of 6,2.4, and 0.6 mg/kg for 1,2-, 1,3-, and 1,4-dihydroxybenzene, respectively, ranged from 0.8 to 4.8% for the food simulants tested. A commercial sample of polyetherketone made from 1,4-dihydroxybenzene was tested with the method. No polymer-derived interferences were found. The method is thus suitable for testing against migration limits for the 3 monomers.
Gas Chromatographic Determination of Propamocarb in Agricultural Commodities
Authors: Nagayama Toshihiro , Kobayashi Maki , Shioda Hiroko , Tomomatsu Toshio 
Published: February 2020

Abstract
A simple and efficient gas chromatographic (GC) method is described for quantitative determination of propamocarb in agricultural commodities. Propamocarb is extracted into acetone–water (or acidified solvent for dry products) and then cleaned up by extraction with diethyl ether. The analyte is extracted from the aqueous fraction under basic conditions with diethyl ether and then analyzed by GC with nitrogen–phosphorus detection. The minimum detection limit is 0.01 μg/g in original samples (signal-to-noise ratio &gt; 5). Recovery of propamocarb spiked at 0.1 μg/g into various samples is &gt;75%, except for lettuce (41%).
Determination of Aromatic Amines in Soils
Authors: Pace Christopher M , Donnelly Joseph R , Jeter Jeffrey L , Brumley William C , Sovocool G Wayne 
Published: February 2020

Abstract
A rapid liquid chromatographic (LC) method with ultraviolet (UV) or fluorescence detection was developed for parts-per-billion levels of aromatic amines in soils. 2,4-Diaminotoluene, pyridine, aniline, 2-pi-coline, 2-toluidine, 5-nitro-2-toluidine, 2-methyl-6-ethylaniline, 4-aminobiphenyl, 4-nitroaniline, 1-naphthyl-amine, 2-methoxyaniline, and 2-naphthyiamine were tested. The method involves extraction by sonication with 1% ammonium hydroxide–acetonitrile and analysis by LC using gradient elution with aqueous 0.01 M ammonium acetate–0.0005% triethylamine and acetonitrile. Recoveries of 67–106% (9.2 and 34% for 1-and 2-naphthylamines, respectively) were obtained from sand and organic-containing soils spiked in the parts-per-million range. Recoveries from sand spiked at 8.5–25 ppb were 88–105%. Recoveries from organic soil varied from nondetectable to 86% at spikes of 85–500 ppb. Detection limits ranged from 0.5 ppb for highly fluorescent 2-naphthyiamine (by fluorescence detection) to 0.5 ppm for nonfluorescing pyridines (by UV detection).
Determination of Imazalil Residues in Lemons by Gas Chromatography with Nitrogen–Phosphorus Detection
Authors: Yamazaki Yoshie , Ninomiya Takahiro 
Published: February 2020

Abstract
A simple and reliable method was developed for determination of imazalil residues in whole lemons. Imazalil was extracted from lemon samples with ethyl acetate under basic conditions. The ethyl acetate in the extract was evaporated, and the residue was dissolved in dichloromethane. The solution was applied to a solid-phase extraction (diol- bonded silica) cartridge. Imazalil was eluted with methanol and determined by gas chromatography (GC) with nitrogen–phosphorus detection. Recoveries at 4 fortified levels (0.1,1.0,2.0, and 5.0 μg/g) ranged from 93.3 to 97.8%, with coefficients of variation ranging from 0.2 to 3.0%. The detection limit was 0.05 μg/g. Fifteen commercial lemon samples were analyzed for imazalil residues; 10 were positive. Concentrations of imazalil residues ranged from 0.22 to 4.44 μg/g. Imazalil-positive samples were confirmed by GC with mass–selective detection (m/z 173,215, and 217).
Estimating Analytical Variances in Measurement of Polycyclic Aromatic Hydrocarbons and Application to Monitoring Contaminants in American Lobster (Homarus americanus)
Authors: Uthe John F , Misra Rajendra K , King Thomas L , Musial Charles J 
Published: February 2020

Abstract
A method is presented for estimating replicate polycyclic aromatic hydrocarbon (PAH) concentrations in American lobster (Homarus americanus) digestive gland tissue based on recoveries of added perdeuterated surrogates from a single satisfactory analysis. PAH concentrations demonstrated a large interanimal variance, even in specimens captured at the same time in the same place. Principal component analysis showed that the variability of the total system of biological variables (carapace length, lobster weight, and digestive gland weight) could be adequately summarized by the first principal component alone in each data set. Ranks provide ordered classification of individuals, allowing data analysis by statistical methods for continuous variables (i.e., analysis of variance). PAH concentrations in individual lobsters were generally highly sensitive to animal size, sex, and fishing area. Efficient monitoring would result from analyzing individual animals of a single sex from a study area, using as small a geographical study area as possible, measuring a single biological variable, and using individual specimens of as narrow a size range as possible.
Determination of Heterocyclic Aromatic Amines in Process Flavors by a Modified Liquid Chromatographic Method
Authors: Perfetti Gracia A 
Published: February 2020

Abstract
A liquid chromatographic method for determining heterocyclic aromatic amines (HAAs) was modified so that it can be used to quantitate the following 5 HAAs in complex process flavors: 2-amino-3-methylimidazo[4,5-f]quinoline (IQ); 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MelQ); 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx); 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (diMelQx); and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). By changing the initial extraction procedure, PhIP recovery improved from 35 to 87%. An additional cleanup step using ion-exchange solid-phase extraction reduced the levels of interfering components, thus allowing determination of low levels of the amines. Recoveries from process flavors spiked at 25 ppb averaged 83–90%.
Optimization and Automation of AOAC Official Method 971.47 for Determination of Roxarsone in Feed
Authors: Webster Gregory K , Mandzu Rostyk , Drong Lisa A , Williams William H , Mess Brian G , Wodke Norbert 
Published: February 2020

Abstract
AOAC Official Method 971.47 was optimized for use with solid-phase extraction (SPE) using the same activated carbon referenced in the original method. The optimization of AOAC 971.47 begins after the roxarsone is extracted into the 2% K2HPO4 solution of the original method; instead of 30 mL, 9 mL is pipetted into a test tube. Next, to flocculate the protein, 300 μL HCI is pipetted into the tube and mixed. After 15 min, the contents of the tube are filtered through a 0.45 μm nylon membrane filter equipped with a glass prefilter. Next, 7 mL clear filtrate is pipetted into a new test tube, followed by the addition of 234 μL NaOH, and the contents of the tube are mixed. The filtrate is then passed through a 400 mg bed of activated carbon packed in a 3 mL SPE tube at a flow rate of 1 mL/min. The spectrophotometric analysis of the eluate is not changed from the original AOAC 971.47. The optimized method was validated and semiautomated. Results of roxarsone determination by the optimized procedure were found to be acceptable at all levels of approved claims. For the commercial feed samples analyzed, recoveries by the automated method ranged from 93.7 to 104% of the results reported by an independent laboratory using AOAC 971.47.
Simultaneous Determination of Five Fasciolicides in Milk by Liquid Chromatography with Electrochemical Detection
Authors: Takeba Kazue , Itoh Takeshi , Matsumoto Masao , Nakazawa Hlroyuki , Tanabe Shinzo 
Published: February 2020

Abstract
A sensitive and specific method is described for determination of 5 fasciolicides in milk. The drugs are used to control liver flukes in cattle. The milk sample was homogenized with acetone and acetonitrile, sonicated, and centrifuged. The supernatant was extracted with dichloromethane. The extract was evaporated to dryness, dissolved in 1 % sodium hydrogen carbonate, and purified on a C18 cartridge. The 5 drugs were separated from the matrix by reversed-phase liquid chromatography (LC) and determined by dual-electrode coulometric detection on a Kaseisorb LC ODS-300-5 column. The mobile phase was acetonitrile-0.05M potassium dihydrogen phosphate (55 + 45) at pH 3.0. The flow rate was 1 mL/min at 40°C. The applied potentials of detectors 1 and 2 were set at 0.20 and 0.55 V, respectively. The average recovery of the drugs added to milk at 0.01 and 0.1 µ g/mL was 89.6%, and the coefficient of variation was 4.7%. The detection limits of the drugs in milk were 4-20 ng/mL. The method is used to monitor commercial milk samples and to determine the residual levels of these drugs in milk from cows treated with a fasciolicide.
Determination of Atrazine and Hydroxyatrazine in Agricultural Runoff Waters by Liquid Chromatography and Fast Atom Bombardment-High Resolution Mass Spectrometry
Authors: Cai Zongwei , Monson Steven J , Spalding Roy F 
Published: February 2020

Abstract
Agricultural surface water samples were collected after the first 2 major runoff events in 1994 for determination of atrazine (ATR, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and hydroxyatrazine (HA, 2-ethylamino-4-hydroxy-6-isopropylamino-striazine). After addition of. 13C3-labeled ATR and 13C3-labeled HA as internal standards, the chemicals were quantitatively extracted and eluted from water samples by liquid-solid extraction with a carbon black cartridge. Liquid chromatography and fast atom bombardment-high resolution mass spectrometry were used to analyze the sample extracts. Concentrations of ATR ranged from 8.2 to 15.1 parts per billion (ppb) in the samples collected after both runoff events from a highly agricultural watershed in south-central Nebraska. HA concentrations ranged from 0.25 to 2.7 ppb in the water samples. Results obtained from both analytical procedures agreed within a 15% deviation. As predicted from runoff events, the highest levels occurred in samples from the first collection on June 24,1994, for both ATR and HA, whereas samples collected on July 5,1994, contained much lower levels of HA.
Viscometric Determination of p-Glucanase and Endoxylanase Activity in Feed
Authors: Engelen Adrianus J , Van Der Heeft Fred C , Randsdorp Peter H G 
Published: February 2020

Abstract
A method is described for viscometric determination of enzymatic activity of β-glucanase and endoxylanase in feed samples. The method is based on determination of the decrease in viscosity as a result of hydrolysis of glycosidic bonds in β-glucan and xylan at pH 3.5. This method does not require a blank sample (feed without enzyme addition), and it does not need standard addition for reliable quantitation.