bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Liquid Chromatographic Determination of Riboflavin in Milk and Dairy Products
Authors: Ashoor Samy H , Knox Michael J , Olsen, Jacquelyn R , Deger Dru Ann 
Published: February 2020

Abstract
Reported here is a simple liquid chromatographic (LC) method for the i determination of riboflavin in milk (liquid, evaporated, and dry), yogurt, ' and cheese. The method involves passing liquid samples or filtrates of semisolid and solid samples through a Clg cartridge. Retained riboflavin is then eluted with an aliquot of 50% methanol in 0.02M acetate buffer of pH 4. A volume of the eluate is injected into the LC system | consisting of a CJ8 column, a solvent of water-methanol-acetic acid (65 + 35 + 0.1, v/v) with a flow rate of 1 mL/min, and a UV detector set at 270 nm. The method is precise and accurate and compares i favorably with the present AOAC method. Moreover, it involves fewer sample preparation steps and has a total analysis time of less than 1 h.
Simplified Cleanup and Liquid Chromatographic Determination of Oxamyl Residues in Potato Tubers
Authors: Mcgarvey Brian D , Chiba Mikio , Olthof Theo H A 
Published: February 2020

Abstract
A simple and efficient method is presented for the extraction, cleanup, and liquid chromatographic (LC) determination of oxamyl residues in potato tubers. Samples are extracted with methanol, partitioned into dichloromethane, and cleaned up using Sep-Pak Florisil cartridges. LC determination is performed using a Zorbax PSM 60 size exclusion ; column with an acetonitrile-water (1 + 9) mobile phase and UV detection at 254 nm. Recovery of oxamyl from spiked control tubers averaged 94.1 and 85.9% at fortification levels of 0.4 and 0.08 \μg oxamyl/g tuber, respectively. The minimum detectable concentration of oxamyl by this method is 0.01 μg/g
Determination of Total and Free Water in Triple Superphosphate Fertilizers by Using Thermal Analysis
Authors: Kostyrko Krystyna , Skoczylas Malgorzata , Klee Andrzej 
Published: February 2020

Abstract
Thermal analysis methods were used to study dehydration of triple superphosphate. A redrying procedure followed by Q-derivatographic analysis (under quasiisobaric and quasiisothermal conditions) as well as differential scanning calorimetry (DSC) was applied. Attempts were made to establish the correct drying-oven temperature for determination of water content, i.e., the temperature at which free or total water is removed from the fertilizer. Thermal decomposition of monocalcium orthophosphate monohydrate, the major component of triple superphosphate, was studied and a model was advanced for the reactions that occur during decomposition of this salt. The free water was completely released when superphosphate was heated at a constant temperature of 85°C. The total water was entirely released at 160°C. At 150°C, the process of removing the water of crystallization from the orthophosphate was disturbed by other concomitant dehydration processes which result in irreversible decomposition of this salt. The results obtained indicate that the thermal methods of analysis used are complementary.
Oxidation and Hydrolysis Determination of Sulfur Amino Acids in Food and Feed Ingredients: Collaborative Study
Authors: Macdonald John L , Krueger Mark W , Keller John H 
Published: February 2020

Abstract
Samples of 6 food and feed ingredients and a purified protein, plactoglobulin, were analyzed by 7 laboratories to determine the concentrations of cysteine as cysteic acid and methionine as methionine sulfone. Samples were oxidized by reaction with performic acid before hydrolysis with 6N HC1. The free amino acids were then separated and measured by ion-exchange chromatography on dedicated amino acid analyzers. Each laboratory was provided with a detailed method as well as sealed vials containing solutions of standards. For the determination of cysteine as cysteic acid, the coefficients of variation between laboratories for duplicate samples ranged from 7.13 to 10.8% for the 6 ingredients. For the determination of methionine as methionine sulfone, the coefficients of variation between laboratories for duplicate samples ranged from 1.18 to 12.8% for the 6 ingredients. Cysteine and methionine recoveries were determined by analysis of β-Iactoglobulin and were based on expected levels of each amino acid from amino acid sequence data. The mean recovery of cysteine was 95% with a range of 91-101%. The mean recovery of methionine was 101% with a range of 98-106%. This method has been adopted official first action.
Extraction of Light Filth from Unground Marjoram: Collaborative Study
Authors: Dent Russell G , Glaze Larry 
Published: February 2020

Abstract
Ihe present method for filth in unground marjoram is conducted in 2 parts. The first of these, which is for heavy filth and sand, requires the spice to be boiled with petroleum ether, then floated off with chloroform and, if needed, carbon tetrachloride. The second part, which is for light filth, is dependent on completion of the heavy filth section. After the spice is air-dried, the light filth is extracted with heptane and water. The proposed method was developed to make light filth independent of heavy filth analysis, improve filth recoveries, and reduce microscopic examination time. The light filth is extracted by ethanol defatting followed by a combination 15-60% ethanol/mineral oil extraction in a Wildman trap flask. Tween 80-NaEDTA solution is added to the trapping system to reduce the rising of excess plant material to the trap interface. The official method (AOAC 13th edition sees 44.142,44.120(b)) produced an average of 8 extraction papers per test portion and microscopic examination took an average of 88 min per test portion. The official method gave average recoveries of 14% for rodent hairs and 26% for insect fragments with 2 spike levels of 15 and 30 for each filth element. Recoveries of the 2 levels of each spike were not significantly different (P &gt; 0.05). The proposed method gave average recoveries of 73% for rodent hairs and 70% for insect fragments. The proposed method has been adopted official first action to replace AOAC 13th edition sees 44.142 and 44.120(b) for unground marjoram only
Quality Assurance in the Pesticide Product Laboratory
Authors: Hill Dean F 
Published: February 2020

Abstract
Although the overall quality assurance concepts and goals for pesticide formulation analysis are similar to those required of an environmental or trace level analysis laboratory, some important distinctions exist, particularly for quality control. Generally, target levels (label values) are known and pesticide identification can be assumed, thus minimizing the need for verification of pesticide identity and for detailed confirmation of quantitative results reasonably close to the label value. Exceptions are cross-contaminant screening and by-product analysis. Quality control efforts in the formulation laboratory are concentrated on those samples falling outside the established acceptance criteria. The use of official (AOAC/Collaborative International Pesticides Analytical Council (CIPAC)) methodology, replicate determinations, second analyst confirmation, and alternative methodology (if necessary) is stressed. Specific attention must also be paid to the quality and preparation of analytical reference standards.
Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Meats: Validation Study for Swine and Beef Fats
Authors: Ault James A , Spurgeon Timothy E , Gillard Douglas S , Mallinson Edward T 
Published: February 2020

Abstract
A validation of a previously studied method for determining organochlorine residues in poultry fat was conducted to extend the usefulness of the method to beef and swine fats. The validation samples consisted of 16 materials all analyzed in duplicate. Fortification levels ranged from 0.02 to 1.2 ppm for a-BHC, lindane, cis- and Irans-chlordane, octachlor epoxide, o,p'- and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 101 % with a range of 7 9 - 113%, not including toxaphene. The ranges of coefficients of variation wtreCV. = 0-23.37% and CVX = 3.74-26.19%. The results were comparable to the previous collaborative study of the same method for poultry fat. The extended method has been adopted official first action
Multiresidue Method for Determination of Eight Neutral β-Lactam Penicillins in Milk by Fluorescence-Liquid Chromatography
Authors: Munns Robert K , Shimoda Wilbert , Roybal Jose E , Vieira Cassandra 
Published: February 2020

Abstract
A method of determining total penicillins begins with an enzymatic hydrolysis of the (J-Iactam ring to form their respective penicilloate product. Acetonitrile precipitates much of the casein and protein, which are then separated from the liquid by centrifugation. The lipids are removed from the aqueous fraction with methylene chloride. Mercuric chloride is added, which reacts with the penicilloate to liberate the side chain that has a terminal aldehyde. These penilloaldehyde products are extracted with methylene chloride and are subsequently reacted with dansyl hydrazine. The resulting fluorolabeled side chains are separated by liquid chromatography on a C18 column with acetonitrile- water as mobile phase. The fluorescence is measured by the mercury line at 254 nm excitation wavelength and a 500 nm filter on the emission side. The overall average recoveries from milk spiked at 25, 50, and 100 ppb are benzyl penicillin 79.4%; phenoxymethyl penicillin 59.7%; phenethicillin 75.9%; nafcillin 87.7%; methacillin 47.5%; oxacillin 57.6%; cloxicillin 37.3%; and dicloxicillin 26.4%.
Detection of Tricresyl Phosphates and Determination of Tri-o-Cresyl Phosphate in Edible Oils
Authors: Krishnamurthy Mahishi N , Rajalakshmi S , Kapur Om Prakash 
Published: February 2020

Abstract
Tricresyl phosphate (TCP) in contaminated edible oils was extracted using acetonitrile and detected by thin layer chromatography as well as gas chromatography (GC). The chromatoplate was developed with isooctane-ethyl acetate (90 + 10) and visualized by spraying with 2,6- dichloroquinone chloroimide. TCP gives a characteristic blue-violet spot when heated at 100°C for 15 min. The method is direct and sensitive and can be used to detect as low as 2.5 p.g TCP or TOCP (tri-o-cresyl phosphate). GC was carried out using 10% OV-101 as the stationary phase and flame ionization detection for confirmation and quantitation of TOCP in oils.
Microwave Oven Drying Determination of Total Solids in Processed Tomato Products: Collaborative Study
Authors: Chin Henry B , Kimball John R , Hung Joyce , Allen Bradford 
Published: February 2020

Abstract
Fourteen laboratories analyzed 7 samples of tomato products with total solids content ranging from 6.5 to 40.2%. Samples were analyzed directly with the exception of samples with solids contents greater than 15%, which were diluted with water (1 + 1 for up to 30% solids and 1 + 3 for greater than 30% solids). The 2-4 g samples were dried at 100% power for 4 min. The results of the collaborative study showed good repeatability and reproducibility: 5„ = 0.16 (CV = 0.46%) and S, = 0.36 (CV = 1.06%) for the higher solids samples and S„ = 0.37 (CV = 3.76%) and Sx = 0.14 (CV = 1.41%) for samples with total solids up to 15%. Results were compared with those obtained using vacuum oven drying. No difference was seen in the results by the 2 methods at the 95% level of confidence. The microwave oven drying method has been adopted official first action as an alternative to the vacuum oven drying method for total solids.
Multiresidue Method for Quantitative Determination of Organophosphorus Pesticides in Foods
Authors: Blaha John J , Jackson Patricia J 
Published: February 2020

Abstract
A multiresidue method for the quantitative determination of organophosphorus pesticides in foods from the Food and Drug Administration's Total Diet Study is described. The organophosphorus pesticides are separated on the basis of polarity and determined in both fatty and nonfatty foods with a minimum of interferences. The foods analyzed included raw and cooked individual foods as well as combination dishes, water, and whiskey. Recoveries of 17 organophosphorus pesticides in 41 foods ranged from about 80 to 118%.
Hydrolysate Preparation for Analysis of Amino Acids in Sorghum Grains: Effect of Oxidative Pretreatment
Authors: Elkin Robert G , Griffith Joseph E 
Published: February 2020

Abstract
Sorghum samples were either untreated or oxidized with performic acid (PA) before hydrolysis, and their amino acid contents were determined by cation exchange chromatography using an amino acid analyzer. HC1 was used to destroy excess PA. Oxidative pretreatment of the samples resulted in increased yields of Cys (as cysteic acid), Met (as Met dioxide), and His, destroyed Tyr and Phe, and resulted in the appearance of an extraneous peak which most likely consisted of halogenation by-products (HBP) of Tyr and Phe. The destruction of Tyr and Phe occurred despite the presence of phenol, a halogen scavenger, in both the PA and hydrolysis reagents. The higher His values observed in all oxidized samples most likely resulted from the co-elution of His with Tyr and Phe HBP. It was concluded that the complete (except Trp) amino acid content of a feedstuff cannot be accurately determined from only one oxidized hydrolysate preparation by using this particular procedure.
Screening and Quantitation of Ochratoxin A in Corn, Peanuts, Beans, Rice, and Cassava
Authors: Soares Lucia M Valente , Rodriguez-Amaya Delia R 
Published: February 2020

Abstract
To answer the need for simple, economical, rapid methods for mycotoxins, a procedure for screening and quantitation of ochratoxin A was developed. A methanol-aqueous KC1 extraction is used, followed by cleanup with clarifying agents and partition into chloroform. Part of the chloroform extract is used for screening and the other part for quantitation by thin layer chromatography (TLC). The screening procedure takes 40 min, using a silica gel/aluminum oxide minicolumn developed for this purpose. The limits of detection are 80 and 10 |xg/ kg, respectively, for minicolumn screening and TLC quantitation. Ammonium sulfate is efficient in cleaning samples of corn and cassava; cupric sulfate is better with peanuts, beans, and rice. Tests were conducted on triplicate spiked samples of yellow corn meal, raw peanuts, dried black beans, polished rice, and cassava flour at different levels (400, 200, 80, 40, and 10 p-g/kg). Recoveries ranged from 86 to 160% and the coefficients of variation ranged from 0 to 26%.
Determination of Monensin Sodium Residues in Beef Liver Tissue by Liquid Chromatography of a Fluorescent Derivative
Authors: Martinez Elizabeth E , Shimoda Wilbert 
Published: February 2020

Abstract
Monensin sodium does not have an ultraviolet (UV) absorbance above 220 nm, and therefore cannot be detected by liquid chromatography (LC) with a UV detector. A method was developed in which monensin residues are extracted from beef liver tissue, acetylated, partitioned, and reacted with 9-anthryldiazomethane to form a fluorescent derivative for quantitation by LC. The reliable level of sensitivity is 50 ppb, but 15 pjib can be detected. Recoveries ranged between 71 and 96% with an average of 83.5%.
Permethrin and Its Two Metabolite Residues in Seven Agricultural Crops
Authors: George Donald A 
Published: February 2020

Abstract
Metabolite residues of permethrin are not reported in the literature for most agricultural crops. This paper reports residues of permethrin and its 2 metabolites (dichlorovinyl acid and metaphenoxybenzyl alcohol) in 7 different agricultural crops (Chinese cabbage, spinach, asparagus, raspberries, green peas, turnip roots, and turnip greens). Permethrin residues declined approximately 85% within 7 days after treatment in all crops. In most cases, the acid metabolite residues peaked at 3 days, and declined after that. Translocation of residues into turnip roots was very slight; the average was less than 0.05 ppm for permethrin and alcohol metabolite residues and none was detected for the acid metabolite residue. Permethrin residues in the turnip greens averaged approximately 2 ppm for the 0.112 kg ai/ha treatment, and 6 ppm for the 0.224 kg ai/ha treatment.
Determination of Gibberellic Acid Residues on Fruits by Synchronous Scanning Derivative Spectrofluorometry
Authors: Blanco C Cruces , Sánchez F García 
Published: February 2020

Abstract
A synchronous derivative spectrofluorometric method is described for the determination of the plant growth regulator, gibberellic acid (GA3). The method is based on the formation of a fluorogen in concentrated sulfuric acid. The reaction is carried out at 85% sulfuric acid and in aqueous medium. The common fluorometric method with a linear dynamic range of 137-400 ppb, and a detection limit of 48 ppb is described. The synchronous first and second derivative method has linear dynamic ranges between 7.6-40 ppb and 12-40 ppb, with detection limits of 3.5 and 6.7 ppb, respectively. The influence of reaction variables and of other plant growth regulators present, and the application to residues on oranges, lemons, and grapes, are also described.
Evaluation of Monier-Williams and Committee Methods for Bisulfite Determination as Used by the Potato Processing Industry
Authors: Moylan John G , Bowes F William , Pappin Walter J 
Published: February 2020

Abstract
The Monier-Williams and the iodometric Committee methods were evaluated for the determination of bisulfite in potato products. Both methods showed critical problems in accuracy and precision at concentrations below 60 ppm. Sensitivity levels of 25 ppm are possible with the Monier-Williams method. However, accuracy problems reflected by the coefficients of variation (Monier-Williams, 47.4%; Committee, 78.2%) as well as variability in recoveries and blank values for both methods produce qualitative rather than quantitative analytical data at low SO2 concentrations
Determination of Biuret in Urea and Mixed Fertilizers by Cupric Ion Selective Electrode
Authors: Corominas Luis F , Navarro Roberto A , Rojas Pedro , Cruz José L 
Published: February 2020

Abstract
A method for determining biuret in urea and mixed fertilizers by using a cupric ion selective electrode (CISE) has been developed to take advantage of the simplicity of the apparatus. The method is based on the same principle as the atomic absorption spectrophotometric (AAS) method, 2.091-2.093: formation of a biuret-copper complex, elimination of excess copper, and determination of complexed copper. However, some changes were needed to eliminate starch and alcohol interferences. The method was tested for ruggedness and then compared with the AAS method for 4 fertilizer samples. Averages and variances were equivalent at the 99% confidence level according to t- and F-tests. A collaborative study is recommended to compare behavior of both methods in different laboratories.
Determination of Iodine Values of Lipids by Bromide Ion Selective Electrode
Authors: Abdel-Moety Ezzat M , Ahmad Abdel-Kader S , El-Din Mohie Sharaf 
Published: February 2020

Abstract
A semimicro method for determination of iodine values of lipids is described. An accurately weighed smear of sample (10-20 mg) on a strip of ashless filter paper, 14 × 40 mm, is brominated with bromine vapors for about 5 min. Excess bromine adsorbed on the filter paper is allowed to sublime. Bromine absorbed by the sample is directly related to the degree of unsaturation. Paper with brominated sample is subjected to oxygen flask combustion in the presence of 2 mL 1M sodium hydroxide solution and 10 mL water as absorbing liquid. Bromide formed, which is equivalent to unsaturation, is determined by bromide ion selective electrode. Bromide ions can be also determined by gravimetry or by indirect argentometric titration. The results were statistically analyzed. The iodine values of some fatty acids and oils, determined by this technique, are in accord with those of some officially approved methods.
Liquid Chromatographic Determination of Zoalene and Its Metabolites in Chicken Tissues with Electrochemical Detection
Authors: Parks Owen W , Doerr Robert C 
Published: February 2020

Abstract
A procedure is described for the quantitation of Zoalene (3,5-dinitro-o-toluamide) and its 2 major monoamino metabolites in chicken tissues. The method includes blender extraction of tissue with chloroformethyl acetate (1 + 1), adsorption of the drug and metabolites on neutral alumina, and subsequent elution of the residues with pH 3.5 formate buffer-methanol (6.5 + 3.5). Recovered residues were separated on a 5 μ C18 column with the alumina eluting solvent as the LC mobile phase. The parent drug and metabolites were detected and quantitated with an electrochemical detector in the reductive mode with a minimum level of reliable measurement of 0.1 ppm. Overall mean recoveries greater than 85% were obtained with Zoalene and its 2 monoamino metabolites in breast, thigh, and liver tissues fortified with 0.25-2.00 ppm. The results on tissues from chickens fed a diet containing 0.0125% Zoalene are presented.
Practical Screening Procedure for Sulfathiazole in Honey
Authors: Schwartz Daniel P , Sherma Joseph 
Published: February 2020

Abstract
A simple, inexpensive procedure is described for rapidly screening small samples of honey for sulfathiazole (ST), a drug formerly used but not approved in the United States for the prophylactic treatment of American foulbrood disease of bees. The method uses 2 plastic tubes arranged in tandem. The upper tube contains a bed of alumina, which removes some interfering pigments. The lower tube contains a very small bed of anion exchange resin in the HSO4- form, which traps the ST. The drug is eventually eluted and detected using the Bratton-Marshall diazotization-coupling reagents. Honey containing 0.1 ppm ST can be readily detected. An optional dye concentration step permits the detection of as little as 25 ppb ST.
Polarographic Determination of Antihistamines by Complexation with Cd(II)
Authors: Temizer Aytekin , Özaltin Nuran 
Published: February 2020

Abstract
The polarographic behavior of the complexes formed by Cd(II) ion with ethanolamine derivative antihistamines such as diphenhydramine hydrochloride, dimenhydrinate, and chlorphenoxamine hydrochloride was studied. Antihistamines form spontaneous complexes with Cd(II) ion in the presence of KNO3. In addition, pH 8.00 borate buffer was added to increase the differential pulse polarogram peak height, and tetraalkyl ammonium salts were added to increase the linear range. The method of determination developed has been applied to commercial tablet, capsule, elixir, and injection forms of ethanolamine derivative drugs and has been compared with official methods.
Outliers in Collaborative Studies: Coping with Uncertainty
Authors: Albert Richard H 
Published: February 2020

Abstract
An overview is given of the options available in detecting and dealing with outliers in collaborative studies. The fundamental points of agreement and disagreement are highlighted. The common sense approach of just looking at the data is emphasized. The importance is stressed of making a harmonized choice of outlier treatments, even though such a choice may not be optimal for all circumstances.