bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pesticide Residues in Milk and Fish Samples Collected from Upper Egypt
Authors: Dogheim Salwa M , Almaz Monir M , Kostandi Samir N , Hegazy Mohamed E 
Published: February 2020

Abstract
In Egypt, buffalo milk is much preferred by consumers over cow's milk, while small catfish and bolti fish are common in the diet of farmers. Samples of buffalo milk, catfish, and bolti fish collected from Beni-Suef Governorate (Upper Egypt) were analyzed for organochlorines and polychlorinated biphenyls. The results obtained by gas chromatography and confirmed by thin-layer chromatographic techniques revealed high amounts of organochlorines in milk; residues were lower but occurred more frequently in fish samples. Pesticide contaminants found most often were HCH isomers including lindane, DDT complex, aldrin and dieldrin, heptachlor and heptachlor epoxide, hexachlorobenzene, and oxychlordane. Polychlorinated biphenyls were not detected in any of the analyzed samples.
Determination and Depletion of Residues in Carbadox, Tylosin, and Virginiamycin in Kidney, Liver, and Muscle of Pigs in Feeding Experiments
Authors: Lauridsen Milter Green , Lund Carl , Jacobsen Merete 
Published: February 2020

Abstract
The results of residue determinations of the growth promotors carbadox, tylosin, and virginiamycin in kidney, liver, and muscle from pigs in feeding experiments are described as well as the analytical methods used. Residues of the carbadox metabolite quinoxaline-2- carboxylic acid were found in liver from pigs fed 20 mg/kg in the diet with a withdrawal time of 30 days. No residues were detected in muscle with zero withdrawal time. The limit of determination was 0.01 mg/kg for both tissues. No residues of virginiamycin and tylosin were found in pigs fed 50 and 40 mg/kg, respectively, in the diet, even with zero withdrawal time. Residues of tylosin of 0.06 mg/kg and below were detected in liver and kidney from pigs fed 200 or 400 mg/kg and slaughtered within 3 h after the last feeding.
Determination of Arsenic and Selenium in Environmental and Agricultural Samples by
Hydride Generation Atomic Absorption Spectrometry
Authors: Hershey J Wilson , Oostdyk Timothy S , Keliher Peter N 
Published: February 2020

Abstract
Agricultural and environmental samples are digested with acid, and arsenic and selenium are determined using hydride generation atomic absorption spectrometry. Interelement interferences are eliminated by high acid concentrations or cation-exchange resins. Agreement with standard reference material is excellent. The technique is also applied to actual samples
Confirmation of Levamisole Residues in Cattle and Swine Livers by Capillary Gas
Chromatography-Electron Impact Mass Spectrometry
Authors: Stout Steven J , Dacunha Adrian R , Tondreau Robert E , Boyd John E 
Published: February 2020

Abstract
Capillary gas chromatography-electron impact mass spectrometry is used to confirm the presence of levamisole in cattle and swine livers at the 0.1 ppm tolerance level. Use of a fused silica capillary column from injector to detector solved chromatographic problems encountered with the analyte. Of the mass specrrometric techniques evaluated, electron impact mass spectrometry provided the most satisfactory data for a confirmatory method. Recoveries from swine and cattle livers fortified at 0.1 ppm averaged 74.9 and 72.7%, respectively, indicating potential utility of this methodology as a quantitative method. Apparent levamisole residues in control livers were less than 0.01 ppm
Analysis of Natural Coloring Matters in Food. III. Applications of Methylation with Diazomethane for the Detection of Lac Color
Authors: Yamada Sadaji , Noda Naoki , Mikami Eiichi , Hayakawa Junko , Yamada Masuo 
Published: February 2020

Abstract
A new method has been proposed for detection of lac color in food. Lac color is a natural color additive derived from a secretion of the insect Coccus Laccae (Laccifer lacca Kerr). It is extracted from food with methanolic oxalic acid and eluted from a column of Amberlite XAD-2 with the same solvent. The fraction containing the lac color is treated with diazomethane to produce 2 reddish-orange markers. The marker species in the reaction mixture are detected by both thinlayer chromatography and reverse-phase liquid chromatography.
Determination of Fluazifop-Butyl and Fluazifop Acid in Soybeans and Soybean Oil Using Liquid Chromatography with Oxidative Amperometric Detection
Authors: Worobey Brian L , Shields J Brian 
Published: February 2020

Abstract
A new method is described for the determination of the herbicide fluazifop-butyl, and its metabolite fluazifop acid, in soybeans and soybean oil as fluazifop acid. Liquid chromatography with amperometric detection (LC/AD) is used to determine fluazifop acid produced from the metabolism or base hydrolysis of fluazifop-butyl in soybeans and soybean oil. These foods were spiked with fluazifopbutyl at 0.05,0.10, and 0.50 ppm and hydrolyzed with 0.2N NaOH in methanol. The hydrolysate (adjusted to pH ≤ 1) is extracted with dichloromethane and the extract is washed with 1.0% NaHC03. The NaHCo3 is acidified to pH ≤ 1 and extracted with dichloromethane; the partitioning is repeated 2 more times. The dichloromethane is removed, mobile phase solvent is added, and aliquots are injected onto a PRP-1 liquid chromatographic column; fluazifop acid is separated from coextracted compounds and detected at an applied potential of + 1.25 V, using an amperometric electrochemical detector in the oxidation mode. Recoveries ranged from 69 ± 6.5 to 101 ± 18% and from 72 ±7.5 to 88 ± 11% for soybeans and soybean oil, respectively. Accuracy of these recoveries was confirmed by use of ^-radiolabeled fluazifop-butyl and by liquid scintillation spectrometry of the 14C-fluazifop acid released.
Ion-Exchange Chromatographic Determination of Hypoglycin A in Canned Ackee Fruit
Authors: Chase G William , Landen William O , Gelbaum Leslie T , Soliman Abdel-Gawad M 
Published: February 2020

Abstract
An ion-exchange chromatographic method was developed to determine hypoglycin A (HG-A) levels in canned ackee fruit by using an amino acid analyzer. HG-A was extracted by homogenizing the sample in 80% alcohol. An isocratic buffer system, consisting of 30% sodium citrate buffer (pH 3.15) and 70% sodium chloride-sodium acetate buffer (pH 7.40) was used to obtain baseline separation between HG-A and the other amino acids. The system can detect HGA levels as low as 4.8 μg/mh. HG-A levels in the edible portion of fruit in 6 cans ranged from 11.0 to 66.5 mg HG-A/can. Recoveries by standard addition averaged 102.5%.
Rapid Determination of Total Cholesterol in Homogenized Milk
Authors: Tsui Ida C 
Published: February 2020

Abstract
A rapid method that is amenable to automation has been developed for the determination of total cholesterol in homogenized milk. The milk sample is saponified in ethanolic KOH in the presence of an internal standard, cholestane. Cholesterol and the internal standard are then isolated by solid-phase extraction on a nonpolar adsorbent and eluted with organic solvent. The evaporated extract is derivatized and analyzed by capillary gas chromatography. Average recovery of cholesterol acetate added to milk prior to saponification was 95%. The average relative standard deviation for repeated analyses was 2%. The limit of detection for this method is 2 mg/100 g. Twenty samples can be analyzed by one analyst in a normal work day if the gas chromatograph is equipped with an autosampler. This method has been compared with a modified AOAC method for the determination of total cholesterol. At a confidence level of 95%, no difference was observed between the 2 methods.
Liquid Chromatographic Determination of Sulfamethazine in Milk
Authors: Weber John D , Smedley Michael D 
Published: February 2020

Abstract
A simple, relatively rapid liquid chromatographic method has been developed for the determination of sulfamethazine (SMZ) in milk at levels in the low ppb range. The method is based on extracting SMZ from milk with chloroform, evaporating the chloroform, dissolving the residues in hexane, extracting into buffers, and chromatographing the buffer solution. The method has been shown to determine levels as low as 5 ppb reliably. Levels ≥7 ppb have been confirmed by gas chromatography/mass spectrometry after derivatization of extracts from fortified, incurred, and shelf milk. Intralaboratory recoveries and percent coefficients of variation are satisfactory. Sulfadimethoxine and sulfaquinoxaline can also be determined by the method. Application of the method to other dairy products is being investigated.
Gravimetric Determination of Ash in Foods: NMKL Collaborative Study
Authors: Mortensen Anna Birthe , Wallin Harriet 
Published: February 2020

Abstract
A gravimetric method for the determination of ash was collaboratively studied in 14 laboratories. The food is ashed at 550 °C to constant weight and the ash is determined by weighing. Seven samples of various food commodities with estimated ash contents varying between low and high (0.07-8.0 g/100 g) were included in the study. The relative standard deviations for reproducibility varied, ranging from 1.0 and 1.3 for ash contents of 7.2 and 8.0 g/100 g, to 11 ± 1% for low ash contents of 0.07 and 0.27 g/100 g.
Diazomethane Derivatization of Sulfamethazine: Formation of Isomeric Products
Authors: Feil Vernon J , Paulson Gaylord D , Lund Anders L 
Published: February 2020

Abstract
Reaction of 4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzenesulfonamide (sulfamethazine) with diazomethane yields not only 4-amino- N-(4,6-dimethyl-2-pyrimidinyl)-iV-methylbenzenesulfonamide but also 2-(4-aminobenzenesulfonimido)-1,4,6-trimethyl-1,2-dihydropyrimidine. Yields of the latter compound are highly variable and the compound does not show a response to gas chromatography. Thus, results of gas chromatographic determinations of residues of some sulfa drugs in edible meat tissues may be erroneous when diazomethane derivatization is used.
The FDA Pesticides Program: Goals and New Approaches
Authors: Lombardo Pasquale 
Published: February 2020

Abstract
The U.S. Food and Drug Administration (FDA) has carried out a large-scale monitoring program for pesticide residues in foods since the 1960s. The program has evolved continuously as evidenced by a number of recently incorporated modifications and initiatives. Included are greater emphasis on imports; increased and more specific targeting of pesticide/ commodity combinations by geographic area or country; development of individual district sampling plans for domestic and imported foods; expanded use of single residue methods; linkage of information on foreign pesticide usage with food import volumes; development of an analytical methods research plan; and increased cooperative sampling and data exchange with the states. Initiatives to acquire and utilize private sector and other monitoring data are being explored, and aggressive steps are being taken to inform the public of FDA monitoring results in a timely and understandable manner.
Reverse-Phase Liquid Chromatographic Determination of Clioquinol in Cream and Ointment Preparations: Collaborative Study
Authors: Wojtowicz Edward J 
Published: February 2020

Abstract
Seven laboratories participated in a collaborative study to analyze, in duplicate, 2 synthetic formulations and 2 commercial preparations, labeled to contain 3% clioquinol. Clioquinol is determined as its nickel (II) complex by reverse-phase liquid chromatography on a phenylbonded column with a mobile phase of acetonitrile-methanol-water, containing ammonium acetate and nickel chloride. Detection is at 273 nm and diphenylamine is added as an internal standard. Mean recoveries were 99.1 and 101.1%, respectively, for the ointment and cream synthetic preparations and 96.7 and 99.7%, respectively, for the commercial ointment and cream. All results are consistent with the variability of other methods at this concentration range. The method has been approved interim official first action
Gas Chromatographic Determination of Carbetamide Residues in Rape and Soil
Authors: Wu Jia-Lun , Fan De-Fang 
Published: February 2020

Abstract
A gas chromatographic method is described for direct determination of carbetamide residues in rape and soil. Rapeseed, leaves and stem of rape, and soil samples are extracted with acetone and the extracts are cleaned up by coagulation and partition with petroleum ether, followed by extraction with dichloromethane. Carbetamide is determined by gas chromatography using a nitrogen-phosphorus detector. Recovery ranges for rapeseed, leaves and stem of rape, and soil samples fortified with 0.1-10 ppm carbetamide were 91.4-103% [average 97.2 ± 12% (n = 9)], 94.4-102% [98.2 ± 4.4% (n = 12)], 87.9-93.9% [91.2 ± 6.5% (n = 9)1, and 86.7-102% [94.5 ± 4.5% (n = 15)], respectively.
Heavy Metal, pH, and Total Solid Content of Maple Sap and Syrup Produced in Eastern Canada
Authors: Robinson Robin A , Maclean Kenneth S , Macconnell Henry M 
Published: February 2020

Abstract
Maple sap and syrups in eastern Canada were analyzed for pH, total solids, and the heavy metals Cu, Fe, Pb, and Zn. The levels of heavy metals found were within the range normally contained in food and water samples except for Pb. The concentration factor found in reducing sap to syrup did not reflect the same concentration change for the measured parameters. This indicates removal or conversion of heavy metals and organic acids with the sugar sands. There was no statistical difference among provinces with respect to the heavy metal, pH, and total solids content of sap. The only significant difference in syrup occurred with Cu and this appeared to be the result of the processing procedure. As the season progressed, the Cu, Pb, pH, and total solids content of the sap decreased while Zn increased and Fe showed little change. Syrups reflected a similar change. Statistical differences occurred in sap composition among sites within each province.
Use of Deuterated Internal Standards for Quantitation of T-2 and HT-2 Toxins in Human Blood by Tandem Mass Spectrometry
Authors: Pawlosky Robert J , Mirocha Chester J , Wen Y , Abbas Hamed K 
Published: February 2020

Abstract
Deuterated acetyl derivatives (3-trideutero-acetyl-T-2 and 15-trideutero- HT-2) were prepared for use as internal standards for the quantitation of T-2 and HT-2 in blood by tandem mass spectrometry. The method used was multiple reaction monitoring (MRM), which essentially involves the selection of a parent ion for analysis followed by monitoring of the daughter ions generated by collision activated decomposition. The parent ions chosen for the trifluoroacetate derivative of T-2 and HT-2 were m/z+ 478 and 532, respectively. Both parents yield the same daughter ions, i.e., 180, 138, and 121. HT-2 and T-2 were added to blood extracts in amounts ranging from 1 to 20 ppb. The limit of detection is about 0.5 ppb with an effective detection limit of 1.0 ppb in a range of 1-20 ppb. The recovery is about 90%. This method can be used by veterinarians for purposes of diagnostics. It can be used for urine as well as blood.
Liquid Chromatographic Determination of Penicillin V Potassium in Tablets:
Collaborative Study
Authors: Mopper Barry 
Published: February 2020

Abstract
A liquid chromatographic method for the determination of penicillin V potassium in tablets was collaboratively studied by 7 laboratories. The method uses an octadecyl silane reverse-phase column, a mobile phase of acetonitrile-methanol-O.OlM potassium phosphate monobasic (21 + 4 + 75 v/v/v), photometric detection at 225 nm, and sulfadimethoxine as an internal standard. Each collaborator received 6 samples: powdered composites of 2 commercial tablet preparations and 1 synthetic tablet powder mixture, each with blind duplicates. The mean repeatability and reproducibility relative standard deviations for commercial samples were, respectively, 1.10 and 1.46% (250 mg dosage), and 0.84 and 2.82% (500 mg dosage). The average standard recovery from the synthetic formulation was 99.1%, with repeatability and reproducibility relative standard deviations of 1.30 and 3.66%, respectively. The method has been adopted official first action.
Comparison of Colorimetric Monoclonal Enzyme Immunoassay Screening Methods for Detection of Salmonella in Foods
Authors: Curiale Michael S , Joan Klatt Mary , Robison Barbara J , Beck Lisa T 
Published: February 2020

Abstract
A colorimetric enzyme immunoassay (EIA) method for detection of Salmonella in foods has been compared to the AOAC colorimetric monoclonal EIA screening method (986.35,15th ed.; 46.B21-46.B29, 14th ed.). The assays use the same monoclonal antibodies and have similar reactivity toward Salmonella. However, the new assay uses antibody-coated microtiter wells instead of coated magnetic beads to capture Salmonella antigens. Compared with the bead assay, the coated-well assay format requires significantly less time to complete, and was consistently able to detect lower levels of Salmonella In mixed culture. Compared to the standard AOAC culture method for food samples, the plate assay was as productive. No false negatives were obtained by the immunoassay; the false negative rate was 1.1% by the culture method. The rate of agreement between the 2 methods was 99.1 %. The official final action bead assay method for Salmonella in foods, 986.35, and the same assay for use with low-moisture foods, 987.11, have been modified official first action to use antibody-coated microtiter strip-wells
Determination of Total Gossypol in Cottonseed and Cottonseed Meals by Derivative UV Spectrophotometry
Authors: Botsoglou Nickos A , Kufidis Dimitrios C 
Published: February 2020

Abstract
A new method for the determination of total gossypol in cottonseed and cottonseed meals has been developed. The method Involves oxalic acid hydrolysis of the bound gossypol In a methyl ethyl ketone-water azeotrope, partitioning the liberated gossypol Into chloroform, and quantification by 2nd derivative UV spectrophotometry. The 2nd derivative transformation and measurement of the conventional analytical band around 300 nm permits direct quantification of all compounds containing naphthalene nuclei; chromogenic reaction Is not required. The method was tested at concentration levels of total gossypol normally expected for cottonseed and cottonseed meal. Precision and accuracy data suggested an overall relative standard deviation of 4.0% and an overall recovery of 89.5%. Although results for cottonseed and solvent-extracted cottonseed meal analyses were comparable to those obtained by use of American Oil Chemists' Society methods, results were lower for screw-pressed meals. The lower results were attributed to the partial conversion of gossypol, during the cooking process of these meals, to compounds that differ in composition and structure from gossypol and which react with aniline to give false readings
Enzyme-Linked Immunosorbent Assay for Microcystins in Blue-Green Algal Blooms
Authors: Chu Fun S , Huang Xuan , Wei R D 
Published: February 2020

Abstract
A direct competitive enzyme-linked immunosorbent assay (ELISA) for the freshwater blue-green algal toxin mlcrocystln (MCYST) In algae and water was developed. The assay Involves coating antl-MCYST-variant leuclne-arglnine (LR) antibody to the ELISA plate and the use of MCYST-LRperoxidase as the enzyme marker. The linear portion of the standard curve for MCYST in phosphate buffer containing saline (PBS) was 0.5-10.0 ng/mL (25-500 pg/assay). The minimum detection level for MCYST-LR was 0.20 ng/mL (10 pg/assay). Contaminated water could be directly used In the ELISA. The overall analytical recoveries for MCYST-LR added to water at levels of 1-20 ng/mL was 83.4%. For analysis of cellular MCYST, the toxin was first extracted from the algae with 0.1M ammonium bicarbonate, diluted with PBS to less than 0.5 mg dried algae/mL (&lt;5.0 mg wet welght/mL) and directly used in the ELISA. C-18 reverse-phase Sep-Pak cartridges effectively adsorbed MCYST from the toxln-containlng solutions. The toxin could be recovered from the cartridge by elutlng with 60% methanol. Using this approach, an algae extract that was relatively free of MCYST was prepared and was used in a recovery study. The overall analytical recovery of MCYST added to the algae extract In the range of 0.25-20 ppm was 83% with a coefficient of variation of 11.9%. The detection limit for MCYST In dried algae was about 0.25-0.5 pg/g (0.25-0.5 ppm) lyophlllzed algae sample. This method was applied for the analysis of several naturally occurring algal blooms. Limited samples were also analyzed for MYCST by liquid chromatography. ELISA data were in general agreement with those obtainedby liquid chromatography. MCYST concentrations from 0.006 to 2.9 fig/g (6 to 2900 ppb) and from 26 to 5200 /ig/g (26 ppm to 5200 ppm) were found In water and algae (dried weight), respectively
Survey of Residues of Organochlorine Pesticides in Some Marketable Egyptian Fish
Authors: Abdallah M A , Hassan I M , Naguib M M , Abodonia M A 
Published: February 2020

Abstract
One hundred random samples representing 34 species of marketable fish were collected from 8 Egyptian governorates during the period March 1986 to March 1988 and were analyzed for the presence of some organochlorine pesticides. The results showed the predominance of beta-BHC and lindane at maximum levels of 435.30 and 59.00 μg/kg, respectively, for fish samples obtained from Damietta governorate. The corresponding levels of aldrln, and o,p'-DDT were 34.27 and 734.10 μg/kg, respectively, for fish from the Red Sea governorate. gamma-Chlordane, p,p'-DDE, and p.p'-DDT were found in fish from Ismailla governorate at respective maximum levels of 36.17, 234.40, and 57.19 μg/kg. Heptachlor was Identified at 8.50 μg/kg In Port Said governorate fish and o.p'-DDE at 10.59 μg/kg In Suez governorate fish. Mlrex, on the other hand, could not be detected In any of the samples investigated.
In Vitro Assay for Protein Digestibility: Interlaboratory Study
Authors: Mcdonough Frank E , Sarwar Ghulam , Steinke Fred H , Slump Pier , Garcia Salvador , Boisen Sigund 
Published: February 2020

Abstract
True protein digestibilities of 17 protein sources were estimated by 6 laboratories using an in vitro, 3-enzyme digestion system In a pH stat. Samples from animal, vegetable, and mixed food sources were freeze-drled (If not already dried), ground, mixed, and shipped to each collaborator along with a sodium caselnate standard and trypsin, chymotrypsin, and peptidase. The uptake of tltrant during enzymatic digestion was used to calculate estimates of digestibility. Digestibilities ranged from 100% for casein to 89.9% for whole wheat cereal. Mean relative standard deviations for repeatability were 1.4% for rolled oats and &lt; 1 % for the remaining 16 samples. Mean relative standard deviations for reproducibility ranged from 5.0 to 0.8%; values were &lt; 2.5% for 13 of the 17 samples.
Gas Chromatographic Determination of Incurred Dimetridazole Residues in Swine Tissues
Authors: Newkirk David R , Righter Herbert F , Schenck Frank J , Okrasinski Joseph L , Barnes Charlie J 
Published: February 2020

Abstract
A gas chromatographic method for determination of 2-hydroxymethyl- 1-methyl-5-nltrolmldazole (DMZOH), the hydroxy metabolite of dimetridazole, in swine muscle has been developed. The method uses cleanup steps similar to those of an earlier polarographic method. The present method Is capable of quantltatlng levels as low as 2 ppb and detecting less than 1 ppb. Recoveries from 30 control tissues spiked at 1,2, or 4 ppb averaged 80.4%. Performance of the method In Incurred tissue was documented and limited data on the depletion of the metabolite In muscle were generated. The muscle of swine given 150 ppm dimetridazole In feed for 14 days contained less than 1 ppb DMZOH at 12 h withdrawal time.