bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Four Methods for Digesting Food Samples for Determination of Trace Levels
of Cadmium by Flameless Atomic Absorption Spectrophotometry
Authors: Cabanis Marie T , Cassanas Genevieve , Cabanis Jean C , Brun Suzanne 
Published: February 2020

Abstract
We compared 4 digestion procedures, namely, sulfuric-nitric acid in an open flask, nitric acid under pressure, sulfuric-nitric acid with refluxing, and nitric-hydrochloric-peroxide with refluxing, for the determination of cadmium by flameless atomic absorption spectrophotometry in 3 foodstuffs: rice, beef, and cream cheese. The foodstuffs were homogenized and divided into several batches for analysis. The results were evaluated using a 2-way cross analysis of variance. The study revealed that the digestion procedure was a highly significant factor (P &lt; 10 4) in the analysis of the 3 foods; whereas the nature of the foodstuffs was not significant for rice and meat and only slightly significant (P &lt;10~2) for cream cheese. When the foodstuffs were spiked with a known amount of cadmium, we observed a loss of the metal when the sulfuric-nitric acid procedure in an open flask and the nitric-hydrochloric-peroxide digestion procedure were used. Taken together, the results of the present study indicate that the choice of the reagents used for digestion of foodstuffs is a crucial factor for cadmium determination by flameless atomic absorption spectrophotometry.
Analysis of Selected Elements in Tobacco by Wavelength Dispersive X-Ray Fluorescence
Spectrometry
Authors: Martin John M 
Published: February 2020

Abstract
A rapid method for the determination of 16 elements in tobacco by wavelength dispersive X-ray fluorescence spectrometry has been developed. The method is accurate and precise, and requires only 9 min per sample for quantitation. Sample preparation consists of placing a portion of dried, ground tobacco in a sample cup, and pressing at 25 tons pressure to make a compressed pellet. This pellet is then automatically analyzed by X-ray fluorescence for 16 elements. The results are stored on a computer disk for future recall and report generation.
Liquid Chromatographic Determination of Sulfamethazine in Feeds
Authors: Houglum Joel E , Larson Richard D , Neal Rose M 
Published: February 2020

Abstract
A reverse-phase liquid chromatographic method for the assay of sulfamethazine (SMZ) in feeds is described. Feed samples are extracted with 50% methanol solution, centrifuged, filtered, and diluted when necessary, and chromatographed on a C-18 column. Samples are eluted with a mobile phase of 20% methanol and 80% of a solution containing acetic acid and tetramethylammonium chloride. The average recovery from spiked samples was 97.2% with a coefficient of variation of 1.2%. Linearity was very good (correlation coefficient 0.9997). Within-day and between-day coefficients of variation averaged 1.3 and 2.6%, respectively. The results for samples assayed by this method compared closely with the results from the same extracts assayed by the AOAC colorimetric method
Simplified Method for Determination of Total Dietary Fiber in Foods
Authors: Li Betty W , Andrews Karen W 
Published: February 2020

Abstract
A simplified method, based on the same principles as the AOAC enzymatic-gravimetric method for determining total dietary fiber (TDF) (43.A14-43.A20), has been tested on 12 food samples which had been used in other collaborative studies. TDF values obtained in our laboratory for these 2 methods were in good agreement (y = 0.96x + 0.39; r = 0.999). The simplified method uses a single incubation period and only 1 enzyme (amyloglucosidase), and thus yields smaller blank and ash corrections but a higher protein correction.
Liquid Chromatographic Determination of Glibenclamide in Human Plasma
Authors: Othman Sadeq , Shaheen Omar , Jalal Ibraheem , Abdullah Awidi , Al-Turk Walid 
Published: February 2020

Abstract
The oral hypoglycemic agent glibenclamide was determined in human plasma by liquid chromatography (LC). Samples, with internal standard added, are extracted with dichloromethane. The organic phase is evaporated, and the residue is reconstituted in mobile phase for injection onto the LC column. Intra- and inter-day variability of the method was assessed at high and low levels of the drug. Although coefficients of variation were similar for both intra- and inter-day studies at both levels, CVs were smaller at the higher concentration level. Recovery of the drug was good at both high and low levels. The minimum level of detection was 5 ng/mL.
Evaluation by Enzyme-Linked Immunosorbent Assay of Cleanup for Thin-Layer
Chromatography of Aflatoxin B 1in Corn, Peanuts, and Peanut Butter
Authors: Chu Fun S , Lee Rachel C , Trucksess Mary W , Park Douglas L 
Published: February 2020

Abstract
A simple, rapid enzyme-linked immunoassay (ELISA) was used to evaluate the performance of each step (extraction, filtration, solvent partition, and silica gel column chromatography) of a solvent-efficient thin-layer chromatographic (TLC) method which is undergoing interlaboratory collaborative study for the determination of aflatoxin B1 in corn, raw peanuts, and peanut butter. The apparent average recoveries using the ELISA method were about 30 to 50% higher than those using the TLC method if only the amount of B, added to the samples was used in the calculations. After the cross-reaction of the antibody with other aflatoxins added to the samples was considered, the amounts recovered approached the levels of aflatoxins added in all 3 commodities tested. With no cleanup treatment, ELISA recoveries at aflatoxin B, levels above 7.5 ng/g were 84, 79, and 103% for corn, raw peanuts, and peanut butter, respectively. The coefficients of variation were between 5.2 and 25.2%. With each cleanup step in the TLC method, ELISA detected a progressive decrease in recovery from 150.5 to 105.3% (before correction for the presence of other aflatoxins) or from 93.5 to 65.4% (after correction for other aflatoxins) of B1 added to the samples. The ELISA data support the conclusion obtained from previous studies that cleanup treatments were not necessary in the ELISA. When large amounts of other aflatoxins are present, an understanding of the cross-reactivity of antibody with other aflatoxins in the ELISA is essential for final interpretation of the data.
Liquid Chromatographic Determination of Aflatoxins in Feedstuffs Containing Citrus Pulp
Authors: Paulsch Walter E , Sizoo Eric A , Van Egmond Hans P 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was developed for the determination of aflatoxins in feedstuffs containing citrus pulp. The feedstuff sample is extracted with chloroform, followed by Sep-Pak Florisil cartridge cleanup and Sep-Pak C18 cartridge cleanup. The final eluate (water-acetone, 85 + 15, v/v) is submitted to reverse-phase liquid chromatography with water-methanol-acetonitrile (130 + 70 + 40, v/v/v) as mobile phase and postcolumn derivatization with iodine. Citrus components are removed from the extract efficiently. The limit of detection for aflatoxin B1 is&lt; 1 μg/kg. Other aflatoxins can also be detected and measured. Recoveries of aflatoxins B1 B2, G,1 and G2 for dairy rations spiked at 13, 5, 10, and 4 μg/kg were 87, 86, 81, and 82%, respectively. Corresponding coefficients of variation were 3.1, 3.6, 5.2, and 3.8%, respectively.
UV Spectrophotometric Determination of Hydralazine Hydrochloride in Tablets:
Collaborative Study
Authors: Mopper Barry 
Published: February 2020

Abstract
A UV spectrophotometric method for the determination of hydralazine hydrochloride in tablets was collaboratively studied by 5 laboratories. The method is based on conversion of hydralazine to a tetrazolo [5,l-a]phthalazine derivative which shows an absorption maximum at about 274 nm. Each collaborator received blind duplicate samples of 2 commercial powdered composites from 10 and 100 mg tablets, and 1 synthetic tablet formulation. Each collaborator also received a set of 10 tablets for determination of content uniformity. The pooled mean recovery of hydralazine hydrochloride from the synthetic formulation was 101.2 ± 0.94%. The mean assay values for 10 and 100 mg tablets were 95.6 ± 0.98 and 101.0 ± 0.73% of the declared amounts, respectively, with corresponding CV values of 1.02 and 0.73%. The pooled mean for individual tablet assay was 99.8 ± 3.26% of the declared value, with a CV of 3.29%. The method has been adopted official first action
Dimetridazole Residues in Pork Tissue. II. Application of Liquid Chromatographic Method to
Monitor Elimination of Drug and its Major Metabolite
Authors: Carignan Germain , Macintosh Agnes I , Skakum William , Sved Stephen 
Published: February 2020

Abstract
A study was conducted to monitor the elimination of dimetridazole (DMZ) and its major metabolite 2-hydroxymethyl-l-methyl-5-nitroimidazole (HMMNI) in swine plasma and tissue, using a liquid chromatographic method with electrochemical detector sensitive to 0.5 ppb. The study consisted of 2 experiments. In the preliminary experiment, one young female piglet was fed medicated ration containing 125 ppm dimetridazole (DMZ) for 2 weeks, followed by a withdrawal period using regular ration for 5 days. Another, control, piglet was given regular diet throughout. Plasma concentrations of DMZ and its most important residue, HMMNI, were measured daily at 2 h after the morning feeding and, on days 8 and 15, several times during the day. The 2 h concentrations after 3 days loading ranged from 47 to 77 ppb for DMZ and 424 to 1081 ppb for HMMNI. A daily cycle in the plasma levels was seen for both substances. Upon withdrawal of medication, elimination of drug and metabolite was biexponential with a terminal half-life of 6.7 h. In the second experiment, 5 piglets were medicated as above and slaughtered 2, 6, 12,25, and 49 h after withdrawal of the medication; the concentration of DMZ and HMMNI was measured in plasma, muscle, kidney, and liver. DMZ in the plasma amounted to 22 and 1.8 ppb at 2 and 6 h, while HMMNI declined from 535 ppb at 2 h to 0.75 ppb at 25 h. Most values for both substances found in muscle were close to those in the plasma; in kidney they amounted to 9-17% of the plasma levels. Very little HMMNI and no DMZ was found in the liver at 2 h. No drug or metabolite could be detected at 49 h in any of the tissues studied
Determination of Polysorbates in Foods by Colorimetry with Confirmation by Infrared Spectrophotometry, Thin-Layer Chromatography, and Gas Chromatography
Authors: Kato Haruyasu , Nagai Yuji , Yamamoto Katsuhiko , Sakabe Yoshio 
Published: February 2020

Abstract
A method is presented for the detection of polysorbates (PSs) in 8 kinds of processed foods by colorimetric and thin-layer chromatographic (TLC) techniques. The PSs are extracted from processed foods with a mixture of methylene chloride and ethanol by using an Extrelut column. The extract is further purified by using a silica gel column. The PS extract is complexed with cobalt-thiocyanate (Cothiocyanate) reagent and is determined spectrophotometrically at 620 nm. The recoveries and coefficients of variation for 8 kinds of processed foods fortified with 0.1% PS 80 were 67.9-94.6% and 4.0- 11.3%, respectively. The detection limit of TLC corresponded to 50 mg PS 80/kg. PS identity was confirmed by infrared spectrophotometry of PS extract, and gas chromatography of fatty acids and thin layer chromatography of POE-sorbitan residues after saponification.
Determination of Aspartame in Beverages Using an Alcohol Oxidase Enzyme Electrode
Authors: Smith Vicki J , Green Richard A , Hopkins Thomas R 
Published: February 2020

Abstract
A new method for the determination of the artificial sweetener aspartame is described. α-Chymotrypsin is used to cleave the methyl ester group of aspartame, producing methanol hydrolytically. The methanol is detected using an electrode which is constructed by physically trapping yeast alcohol oxidase enzyme at the tip of a dissolved oxygen electrode. The decrease in oxygen concentration, which occurs as methanol is enzymatically oxidized to formaldehyde, is measured amperometrically. Aspartame levels in diet soft drinks as determined by the proposed method and by liquid chromatography are in excellent agreement. The relative standard deviation of the measurements is 0.83%. The methanol present in diet cola as a result of aspartame degradation can also be measured by using the electrode without α-chymotrypsin.
Development of Serological Ovine Field Test (SOFT) by Modified Agar-Gel Immunodiffusion
Authors: Cutrufelli Mark E , Mageau Richard P , Schwab Bernard , Johnston Ralph W 
Published: February 2020

Abstract
A serological ovine field test (SOFT) has been developed for detection of lamb or sheep tissue in a wide variety of raw meat products. The test is an adaptation of previously developed field screening immunodiffusion tests for beef, poultry, and pork detection. The SOFT test was demonstrated to be specific, sensitive, and accurate in the analysis of 104 samples.
Colorimetric Determination of Tetracycline Derivatives in Pharmaceutical Preparations
Authors: Saha Utpal 
Published: February 2020

Abstract
A quick colorimetric method is reported for the determination of tetracycline derivatives such as oxytetracycline hydrochloride (OTCH), chlortetracycline hydrochloride (CTCH), methacycline hydrochloride (MCH), and doxycycline hydrochloride (DCH). The method involves complexation of the above derivatives with cupric chloride in alkaline medium. The yellowish green copper complexes of OTCH, CTCH, MCH, and DCH show maximum absorbance at 395, 410, 400, and 400 nm, respectively. The color intensity obeys Beer's law in the concentration range of 0-20 μg/mL.
Liquid Chromatographic Determination of Seven Antioxidants in Dry Foods
Authors: Page B Denis , Charbonneau Claudette F 
Published: February 2020

Abstract
The liquid chromatographic determinative step of the official method for propyl gallate, trihydroxybutyrophenone, tert-butylhydroquinone, nordihydroguaiaretic acid, butylated hydroxyanisole (BHA), 3,5-di-tert-butyl-4-hydroxymethylphenol, and butylated hydroxy toluene (BHT) in fats and oils has been applied to their determination in a number of dry foods. A representative sample (10 g) is homogenized first with hexane (25 mL), then with 5 mL added water, and finally with 75 mL added acetonitrile. The hexane and acetonitrile are decanted, filtered, and separated; the hexane and rehydrated food are reextracted with 2 additional portions of acetonitrile, and the combined acetonitrile extracts are concentrated and diluted to 10 mL. An aliquot is analyzed as described in the official method, using a 150 X 4.6 mm 5 μm C-18 column. The need for rehydration to maximize the recovery of BHA and other antioxidants from marketplace dry food samples such as potato flakes, dry coffee whiteners, and dessert topping mixes was demonstrated. Rehydration was not required for cheese snacks, breakfast cereals, cake mixes, and some other foods. The need for rehydration should be determined by analyzing other foods with and without the addition of water. Potato and corn chips, popcorn and cheese snacks, breakfast cereals, dry beverage mixes, rice, potato flakes, french fried potatoes, and cake mixes were spiked with the above antioxidants at 10-50 ppm. Overall recoveries ranged from 64.3 to 105.6% and repeatabilities ranged from 0.7 to 10.8%. A total of 109 samples of the above foods were analyzed, and 64% contained detectable (&gt; 1-2 ppm) antioxidants, mainly BHA and BHT.
Comparison of the Ion Exclusion Chromatographic Method with the Monier-Williams Method for Determination of Total Sulfite in Foods
Authors: Kim Hie-Joon 
Published: February 2020

Abstract
Experimental data comparing the alkali extraction/ion exclusion chromatographic method with the Monier-Williams method for determination of total sulfite are presented in (a) enzymatic and nonenzymatic browning systems, (b) vegetables containing naturally occurring sulfite, and (c) a carbohydrate-type food additive, erythorbic acid. Excellent agreement, with a linear correlation coefficient of 0.99, was observed in fresh potato samples homogenized with sulfite and allowed to react for different time intervals (enzymatic browning system). A good overall correlation was observed in dehydrated, sulfited apple samples heated for different times (nonenzymatic browning system); however, as heating time increased, higher results were obtained by the Monier-Williams method than by the alkali extraction/ion exclusion chromatographic method. The results of determining sulfite in the alkali trapping solution following acid distillation or acid treatment without heat suggested that this deviation was due to a fraction of sulfite bound to the browning reaction products in such a way that it was released by acid distillation but not by alkali extraction or acid treatment without heat. Similar behavior was demonstrated in cabbage with naturally occurring sulfite, which was released by acid distillation but not by alkali extraction or acid treatment without heat. The ion exclusion chromatographic method could overcome interference by the volatile caramelization reaction products in the Monier-Williams determination of erythorbic acid.
Dry Rehydratable Films for Enumeration of Coliforms and Aerobic Bacteria in Dairy Products: Collaborative Study
Authors: Curiale Michael S , Fahey Paul , Fox Terrance L , Mcallister J Sue 
Published: February 2020

Abstract
A collaborative study was conducted to compare proposed dry-film plating methods, using aerobic count plates and coliform count plates, to standard agar plating methods for quantifying aerobic bacteria and coliforms in dairy products. In this study, 5 food products (chocolate milk, pasteurized cheese, nonfat dry milk, evaporated milk, and vanilla ice cream), selected as representative dairy products, were analyzed by 11 collaborating laboratories. The results indicate that the dry-film plating methods are equivalent to or better than the agar plating methods. The aerobic count and coliform count dry-film plating methods have been adopted official first action.
Determination of Sterigmatocystin in Barley by Acetylation and Liquid Chromatography
Authors: Abramson David , Thorsteinson Tom 
Published: February 2020

Abstract
The estimation of sterigmatocystin by fluorescence liquid chromatographic analysis of the acetate derivative has eliminated the background interference normally encountered in analysis of underivatized sterigmatocystin in barley. Barley samples are extracted with acetonitrile-water; the extract is then washed with hexane, transferred to chloroform, and eluted from a silica gel column with cyclohexane- ethyl acetate. The extract is heated with pyridine and acetic anhydride for 3 h to give a stable derivative. Reverse-phase liquid chromatography, using a methanol-water mobile phase gradient and fluorescence detection, is the method of determination. Recoveries from barley samples spiked with 20,110,190, and 765 μg sterigmatocystin/ kg were 31, 69, 75, and 96%, with coefficients of variation between 2.8 and 5.4%. Sterigmatocystin is confirmed by comparing retention times in underivatized extracts of samples and standards, using methanol-water (3 + 2) mobile phase and ultraviolet detection.
Extraction of Light Filth from Spirulina Powders and Tablets: Collaborative Study
Authors: Nakashima Marvin J 
Published: February 2020

Abstract
Results are reported for a collaborative study of a method for the extraction of light filth from spirulina (a blue-green alga) powder and tablets. A 50 g portion of either powder or tablets is dispersed in water, and then boiled with dilute HCl solution. Hairs and insect fragments are isolated by wet sieving on a No. 230 sieve, flotation with mineral oil, and washings of the mineral oil in a percolator. Average recoveries by 12 collaborators for tablets and powders were 70.6 and 70.2%, respectively, for 10 rat hair spikes and 68.3 and 84.4%, respectively, for 20 insect fragment spikes. The method has been approved interim official first action.
Determination of Sulfites in Foods by Simultaneous Nitrogen Purging and Differential Pulse Polarography
Authors: Holak Walter , Specchio John 
Published: February 2020

Abstract
An improved technique has been developed for determination of sulfites in food by differential pulse polarography. A Teflon™ sleeve is fitted to the dropping mercury electrode capillary so that SO2 is purged from the sample and simultaneously detected at peak potential. Bound sulfite in the sample is released at room temperature by addition of base in the absence of oxygen. For some foods, the prepared sample was passed through a Sep-Pak C-18 cartridge to remove naturally occurring sulfur compounds so that only added sulfite is measured. The level of detection was approximately 1 μg S02/g. Results agreed with those obtained by the optimized Monier- Williams method for a variety of foods.
Liquid Chromatographic Determination of Ketoprofen and Its Related Compounds in Raw Materials, Capsules, and Enteric Coated Tablets
Authors: Beaulieu Beaulieu , Lefrancois J , Ong H , Lovering Edward G 
Published: February 2020

Abstract
A liquid chromatographic method for the determination of ketoprofen and 6 known related compounds has been developed. The lower limit of quantitation of the related compounds in the drug is 0.05% or less for all compounds, and the precision of the drug assay method is about 1.5%. The highest levels of impurities found in 3 drug raw material samples and 4 solid oral dosage formulations were 1.37 and 0.43%, respectively.
Simultaneous Determination of Oxytetracycline, Tetracycline, and Chlortetracycline in Milk by Liquid Chromatography
Authors: Thomas Michael H 
Published: February 2020

Abstract
A simple, rapid procedure is described for the simultaneous quantification of 3 tetracycline drugs in bovine milk. Samples are prepared by dilution with an EDTA/phosphate buffer solution and filtration through a molecular weight cutoff filter. Analytes are concentrated on-column using a reverse-phase gradient elution system of oxalic acid, acetonitrile, and methanol. The limits of quantitation are approximately 15-50 ng/mL and the limits of detection are 10-20 ng/ mL, depending on the compound. For oxytetracycline, over the range 50-1200 ng/mL, the average recovery and intralaboratory coefficient of variation were 97% and 4.1%, respectively. Over the same range, these parameters were, respectively, 97% and 5.0% for tetracycline, and 89% and 6.4% for chlortetracycline. The applicability of this procedure is demonstrated by separation and detection of incurred tetracycline residues in milk from treated animals.