bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Chromatographic Determination of Primary and Secondary Amines as Pentafluorobenzamide Derivatives
Authors: Ripley Brian D , French Bruce J , Edgington Lloyd V 
Published: February 2020

Abstract
An analytical method is described for the determination of mono- and dialkylamines in foodstuffs. Amines are derivatized to their pentafluorobenzamides which may be separated by gas chromatography (GC) and determined using an N-P detector. Analysis of the derivatives by GC-mass spectrometry indicated they were all mono-substituted. The amines were isolated from foodstuffs by alkaline distillation of ≥75% sample volume. The distribution of dimethylamine (DMA) in distillate volumes indicated 2 maxima from barley and malt, which could represent 2 or more sources of DMA. DMA concentrations of 6.6-8.8 ppm in barley, 11 ppm in malt, and 1.2 ppm in beer are higher than previously reported.
Determination of Geotrichum Mold in Comminuted Fruits and Vegetables: Collaborative Study
Authors: Cichowicz Stanley M , Bandler Ruth ,   Collaborators:, Bandler R , Dzidowski G , Floyd D , Kaminski J , McNerney F , Trauba R 
Published: February 2020

Abstract
The official AOAC method for determination of Geotrichum mold in canned fruits and vegetables (44.079) requires a series of 3 sieves, Nos. 8, 16, and 230, to separate the packing liquid from the product and the mold from the packing liquid. Although this method has been successful for whole or coarsely chopped products (e.g., green beans, potatoes, carrots, and beets), finely divided products such as fruit purees and tomato products tend to clog the sieves. A method was developed in which the product is centrifuged, diluted by volume, stained with crystal violet, and counted with the sieving steps eliminated. The proposed method was adopted official first action.
New Method for Differentiating Members of the Bacillus cereus Group: Collaborative Study
Authors: Harmon Stanley M ,   Collaborators:, Bryant R , Campbell D , Chieu J , English L , Graham J , Lancette G , Latt T , McLaughlin P , Pratt M , Noah C , Nygaard G , Radle D , Staben D , Stern N , Varney G 
Published: February 2020

Abstract
A collaborative study was conducted of a new method for differentiating members of the Bacillus cereus group. Using the new method, each of 14 collaborators identified 8 Bacillus cultures, which represented 3 biotypes of the B. cereus group. Each culture was tested for motility, hemolytic activity on trypticase- soy-sheep blood agar, and rhizoid growth on nutrient agar; carbol-fuchsin stain was used to determine the presence of protein toxin crystals. Cultures were identified as B. cereus (biotype 1), B. cereus var. mycoides (biotype 2), or B. thuringiensis (biotype 3). All collaborators correctly identified the unknown cultures and classified them correctly as to biotype. There were no statistically significant differences in the identification rates among the different laboratories. Additional tests by one participant on 5 strains of Bacillus anthracis showed that the new method is also adequate for differentiating B. anthracis from typically reacting strains of B. cereus. The method has been adopted interim official first action.
Confirmatory Method for N-Nitrosodimethylamine and N-Nitrosopyrrolidine in Food by Multiple Ion Analysis with Gas Chromatography-Low Resolution Mass Spectrometry Before and After Ultraviolet Photolysis
Authors: Kimoto W I , Fiddler Walter 
Published: February 2020

Abstract
A confirmatory procedure is described for determining N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) in bacon, beer, and malt by gas chromatography-low resolution quadrupole mass spectrometry (GC-MS). The presence of 3 monitored ions, m/z 30, 42, and 74 for NDMA, and m/z 30,42, and 100 for NPYR, before and disappearance after photolysis under UV light at 365 nm without quantitation of peak areas was considered confirmatory evidence for their presence. The extracts, obtained by mineral oil distillation methods' for bacon and malt, and dry column methods for bacon and beer, underwent cleanup procedures before capillary GC-MS analysis. Less than 100 ng nitrosamine in the total extract, or approximately 2 ng NDMA or 3 ng NPYR injected into the GC-MS instrument, can be confirmed by this method. This technique should also be applicable for other volatile nitrosamines.
Determination of Tocopherols (Vitamin E) by Reduction of Cupric Ion
Authors: Contreras-Guzmán Emilio S , Strong Frederick C 
Published: February 2020

Abstract
This research details the principal characteristics of a new chemical reaction for the determination of tocopherols (vitamin E). The proposed technique is based on the reduction of Cu(II) to Cud) by the tocopherols. The reduced ion is then available to form a complex with 2,2'-biquinoline (cuproine) and with 2,9-dimethyl - 4,7-diphenyl-l,10-phenanthroline (bathocuproine), which have maximum absorbances at 545 and 478 nm, respectively. One mole of tocopherol reduces 2 moles of copper. When urea is used as a catalyst in the reaction, α-tocopherol and γ-tocopherol react completely in 10 s; δ-tocopherol reacts in 90 s. The reaction is not affected by exposure to light. The method was compared with 2 other methods: reduction of Fe(III) to Fe(II) and complexation with 2,2'-bipyridine (conventional Emmerie- Engel method), and reduction of the free radical l,l'-diphenyl-2-picrylhydrazyl (DPPH) to the corresponding hydrazine. Absorptivities of the complexes Cu(cuproine)+2, Cu(bathocuproine)+2, Fe-(bipyridine)++, and DPPH, in terms of concentration of tocopherol were: 30.89,61.87,39.91, and 48.86 Lg-1 cm-1, respectively.
Interfacing an ICAP System to Food and Drug Administration's Large Computer Facility
Authors: Capar Stephen G , Dusold Laurence R 
Published: February 2020

Abstract
An inductively coupled argon plasma (ICAP) emission spectrometer is capable of simultaneously determining the concentrations of many elements. The Jarrell-Ash ICAP systems at FDA have dedicated minicomputers which control the analysis via terminal commands. The standard ICAP terminal interface has been changed to enable logging of ICAP data onto a magnetic tape data cartridge. This tape is subsequently processed through the programming language APL into a large computer system. The transfer of data into the large computer system enables additional statistical processing, report writing, archival storage, and magnetic reel tape generation for transferring processed data to computer systems of other agencies. Three of FDA's ICAP systems use these data processing procedures. The ICAP terminals have been upgraded or replaced from current loop 110-300 baud to RS-232-C 1200 baud and equipped with magnetic tape data cartridge units. Separate graphics display terminals with magnetic tape data cartridge units are used to read the data into the large computer system at 1200 or 4800 baud.
Data System and Software for a Fourier Transform Infrared Spectrometer
Authors: Philbrick John W , Herr Wayne F 
Published: February 2020

Abstract
The computer described has as its primary purpose the control of an FTIR spectrometer. This task requires enough power to handle the rather high peak load of this instrument. Software has been written to flexibly shift the system resources to meet this task, and to make these resources available to the spectroscopist for other jobs as required. Clearly these jobs include the routines of collecting, transforming, storing, and displaying the spectra of interest. The capabilities described go beyond that, to include the ability to handle an automatic sample changer, to vary the measurements made on samples within that sample changer as required, and to annotate the resulting plots with much of the routine bookkeeping data required in an analytical laboratory. This system has the ability to multitask — to perform up to 3 tasks at a time, or to pipeline — to automatically pass data from one region to another. Both of these provide enhanced productivity. The system supports high level language, for the user's own analyses. It has facilities for library searching, to help identify the unknown samples. Finally, it has text processing, to allow the user to prepare reports and papers in a modern way. In short, the line between an instrument computer and a laboratory computer has been blurred by the growth of the capabilities of the former.
Selection of Enzyme Sources for Improved Sensitivity in Enzymatic Determination of Organophosphorus Pesticides
Authors: Bhaskar Sana Udaya , Nanda Kumar Nanguneri V 
Published: February 2020

Abstract
The Michaelis-Menten constant (Km) for cholinesterases from different liver sources, the inhibitor concentration for 50% inhibition (I50), and the lower limit of estimation were determined for 3 organophosphorus pesticides and their oxygen analogs. Maximum sensitivity in organophosphorus pesticide determinations can be achieved by choosing the enzyme source which has a higher Km value. An inverse relationship is suggested between Km and the lower limit of estimation.
Screening Procedure for Detection of Volatile AT-Nitrosamines in Cooked Bacon by One-Trap Mineral Oil Vacuum Distillation and Thermal Energy Analyzer
Authors: Greenfield Earl L , Vasco G A , Legette L , Malanoski Anthony 
Published: February 2020

Abstract
A rapid screening procedure for the detection of volatile N-nitrosamines in fried bacon has been developed for the regulatory monitoring of bacon. This procedure uses vacuum mineral oil distillation of an alkaline sample. The distillate is collected in a prewet trap immersed in liquid nitrogen. After thawing, the distillate is transferred to a separator. The trap is rinsed with methylene chloride which is then used to extract the nitrosamines. The methylene chloride is dried with Na2S04 and concentrated. A gas-liquid chromatograph coupled to a thermal energy analyzer is used to identify and quantitate the nitrosamines. Recoveries of 7 volatile N-nitrosamines added to 25 g fried bacon at the 10 ppb level (μg/kg) ranged from 78 to 92%.
Simple Paper Chromatographic Method for Rapid Detection of Chromate(VI) in Fresh Water
Authors: Rajendrababu Satram , Nanda Kumar Nanguneri V 
Published: February 2020

Abstract
A simple concentration method for detection of potassium (di)chromate directly in fresh water is described. Interference from acidity, alkalinity, or the presence of salt is eliminated by neutralization with phosphate buffer. A simple and sensitive method for potassium chromate or dichromate(VI) separation and detection by paper chromatography is also described. Succinate dehydrogenase inhibition with 2-(4-iodophenyl)-3-(4-nitrophenyl)-5- phenyltetrazolium chloride (INT)-phenazonium methosulfate (PMS)-sodium succinate mixture as the chromogenic reagent is the detection technique. An acetone-water-EDTA solvent system allows enzymatic detection of potassium (di)chromate in fresh water with the least cleanup effort: 2 μg can be detected by a spot test or 5 μg may be chromatographically detected directly from fresh water.
Modified Nuclear Magnetic Resonance Assay of Gentamicins
Authors: Reuter Nicholas P , Haneke A Carol , Lewis Evelyn , Alexander Thomas G , Mazzola Eugene , Aszalos Adorjan 
Published: February 2020

Abstract
An NMR spectrometric method was designed to assay the fractional “C” composition of gentamicin preparations. The gentamicin C1 and C2 contents of the samples are calculated from the N-methyl and C-methyl integration ratios of the corresponding functional groups of the gentamicin structures. Gentamicin C1a content is obtained by subtraction of (C1 + C2)% from 100%. This new NMR assay is applicable to 90 MHz NMR instruments and is more accurate and less time consuming than the presently used official assay described in the Code of Federal Regulations.
Determination of Radium-228 in Foods and Water
Authors: Baratta Edmond J , Lumsden Ella M 
Published: February 2020

Abstract
A procedure was developed for the rapid determination of 228Ra by measuring its decay product 228Ac. The method is applicable to a variety of types of samples such as food and water. Food samples can be prepared by dry- or wet-ashing techniques. The 228Ac is precipitated with lanthanum carrier, dissolved, purified by solvent extraction, and finally decontaminated on anion and cation exchange resins. The 228Ac is counted in a thin-window, low-level gas flow beta counter. It may be necessary to count the sample several times to follow the 6 h half-life of 228Ac so that its purity is ensured. The method is sensitive to 1 pCi/sample of food ash and to 1 pCi/L of water.
Nutritional Adequacy and Safety of Infant Formulas
Authors: Frattali Victor P 
Published: February 2020

Abstract
The Infant Formula Act contains specific requirements for minimum and, in some cases, maximum levels for a list of nutrients that may be revised as warranted by the development of new scientific information. Formulas are required to be manufactured in accordance with quality control procedures to ensure that the safety and nutritional potency of a formula is built into the manufacturing process. A formula that does not provide the minimum level for any required nutrient shall be deemed to be adulterated and may be subject to removal from the market. A manufacturer is required to promptly notify the Secretary of the Department of Health and Human Services of instances whereby a formula does not meet the nutrient requirements, is otherwise adulterated or misbranded, and, as such, presents a risk to human health. There are other provisions in the Act, but these establish that, for infant formulas, nutritional safety is clearly recognized as an integral part of food safety.
Gas-Liquid Chromatographic Screening Method for Determination of Methyl Mercury in Tuna and Swordfish
Authors: James Theron 
Published: February 2020

Abstract
A rapid screening method has been developed for determining methyl mercury in tuna and swordfish. Fish tissue is blended with acidic KBr solution to release methyl mercury, which is then extracted into methylene chloride. After cleanup by partitioning with cysteine, the methyl mercury is extracted into toluene and determined by gas-liquid chromatography. The proposed method compares favorably with the official AOAC atomic absorption method.
Determination of Gentamicin Sulf ate C1a, C2, and C1 Components by Ion Pair Liquid Chromatography with Electrochemical Detection
Authors: Getek Timothy A , Haneke A Carol , Selzer George B 
Published: February 2020

Abstract
The 3 major components of gentamicin sulfate (C1a, C2, and C1) were separated by a liquid chromatographic method using a reverse phase C18 bonded silica gel column and an aqueous ion pair solvent system consisting of 0.015M pentanesulfonic acid sodium salt, 0.2M sodium sulfate, and 0.1% acetic acid. Individual C components as well as several unknown minor constituents were detected by an electrochemical flow cell with a glassy carbon working electrode set at a potential of +1.3 ± 0.1 V vs Ag/Agd. The analytical response was linear over a concentration range of 16-30 μg. A plot of peak areas vs concentration of C fractions yielded a correlation coefficient of 0.999 or better for the Cla, C2, and C1 components of gentamicin sulfate.
Rapid Extraction and Gas-Liquid Chromatographic Determination of Benzoic and Sorbic Acids in Beverages
Authors: Coelho Ricardo G , Nelson David L 
Published: February 2020

Abstract
A rapid method for extraction and quantitative determination of sorbic and benzoic acids in carbonated drinks and fruit juices is described. Acidified sample aliquots are transferred onto an Extrelut column. Acid preservatives are then eluted from the column with a mixture of ethyl ether-petroleum ether. Content of preservatives in the concentrated ethereal extract is readily determined by temperature-programmed gas-liquid chromatography without the need to prepare derivatives.
Sources of Variance in the Bioassay of Protein Value
Authors: Elliott James G , Mcclure Foster D 
Published: February 2020

Abstract
A factorial design was used to simultaneously evaluate the relative effect of 8 experimental factors and their interactions on the weanling rat bioassay of protein value: (1) source of protein: ANRC casein, lactalbumin, high-protein wheat flour; (2) protein level of the diet: 5 and 10%; (3) dietary fat level: 10 and 20% corn oil; (4) animal: ARS-Sprague-Dawley, from Taconic Farms; (5) age of animal: 21 and 28 days; (6) acclimation time: 2 and 4 days; (7) replication: 2 complete replications in time; and (8) duration of the test: food consumption and body weights were measured at 3, 7,10,14,17, 21, 24, and 28 days after starting the test diet and converted to the ratio of grams of weight gained per gram of protein consumed for each weigh day. The official AOAC method for determining the protein efficiency ratio was followed with minor modifications. All 8 factors and many of their possible interactions appeared to significantly influence the measured ratios. When the ratios were adjusted by reference to the corresponding value for casein as a control, fat level, rat source, rat age, and acclimation time were no longer significant sources of variation. Plots of measured ratios and their coefficients of variation against time suggest that the optimum assay time varies with the protein but that the assay time should not be less than 21 days. The generally used 28-day assay time seems to offer no increase in precision over 21 days.
Radiometric Microbiological Assay of Vitamin B6: Assay Simplification and Sensitivity Study
Authors: Guilarte Tomas R 
Published: February 2020

Abstract
Modification of a previously developed radiometric microbiological assay for vitamin B6 reduces assay complexity and time. Reduction of enzymatic treatment from 24 to 3 h essentially eliminates one day's time for the analysis of plasma samples. Use of lyophilized Kloeckera brevis cultures eliminates routine subculturing of the test organism, with no significant effect on test results. Modifications in test vial size and total volume in test vials have increased assay sensitivity to a level of 0.25 ng pyridoxine (PN), pyridoxal (PL), or pyridoxamine (PM) per vial level and decreased the amount of medium and labeled substrate (i.e., L-[l-14C]valine), thus reducing assay cost.
Gas Chromatographic Determination of Fumigant Residues in Stored Grains, Using Isooctane Partitioning and Dual Column Packings
Authors: Daft James L 
Published: February 2020

Abstract
A gas chromatographic (GO procedure for determining fumigants in grains was developed. Fumigants were leached from grain samples with the official AOAC method using acetone-water (5 + 1). They were then partitioned from the leachate with isooctane, yielding a dry, stable extract that was analyzed by GC. Fortified sample recoveries ranged from 90 to 100%. Two GC columns were used, 20% OV-101 and 20% OV-225/20% OV-17 (2 + 1). These columns gave dissimilar retention profiles and baseline resolution for the 7 fumigants investigated: chloroform, ethylene dichloride, carbon tetrachloride, trichloroethylene, chloropicrin, ethylene dibromide, and tetrachloroethylene. Further tests showed that grain samples could be screened for fumigant residues by direct injection of the acetone-water leachates obtained using the AOAC method.
High Pressure Liquid Chromatographic Determination of Monensin in Feed Premixes
Authors: Macy Thomas D , Loh Andrew 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method has been developed to determine monensin in feed premixes. The method is simple and rapid. Monensin is extracted with methanol-water and determined in the extracting solution by HPLC. Average recovery for monensin from a 13.2% premix sample was 103% (coefficient of variation (CV), 2.6%) by HPLC and compares with the value of 100% (CV, 3.4%) obtained by the turbidimetric bioassay method.
Rapid Gas-Liquid Chromatographic Method for Determination of Sulfathiazole in Swine Feed
Authors: Munns Robert K , Roybal Jose E 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) method for determining residues of sulfathiazole (STZ) in swine feed has been developed. Feed is extracted first with acetone and then with ammonia-acetone. STZ is isolated from other feed extractives on a Sephadex LH-20 column with methanol-toluene. The sulfa residues are methylated with diazomethane, and the eluate is evaporated to dryness. A solution containing an internal standard of methyl sulfasymazine is used to dilute the sample before injection onto an OV-25 GLC column. The precision of the method was determined by assaying 10 sets of feed spiked at 0.5,1,2, and 5 ppm STZ. The mean recoveries and coefficients of variation were 90.2 (5.90), 89.5 (4.67), 87.4 (5.62), and 87.7% (4.29), respectively. The critical steps of the method, including the stability of STZ, were also determined.
Hot Leaching of Ceramic and Enameled Cookware: Collaborative Study
Authors: Gould John H , Butler Stephen W , Boyer Kenneth W , Steele2 Edward A ,   Collaborators:, Adams P B , Boone G H , Brandenburger H , Calloway G F , LCarr R , Carroll D M , Clarkson S , Colon M A , Cubbon R C P , Eppler R A , Feldman J , Kato T , Keren D , Klein K , Krauth A , LaBrie M , Langhorne L , McLaren M G , Nuijt M F , Parish H D , Patel S C , Poplawski T , Power J L , Root D E , Rivera R , Toal J , Trencansky J C , Wered R 
Published: February 2020

Abstract
A hot leach method published by the World Health Organization for determining Pb and Cd in ceramic and enameled ware was collaboratively studied in 14 laboratories. The method consisted of heating a solution of 4% acetic acid at the boil for 2 h in 6 samples of specially glazed ceramic ware and 6 samples of special enameled ware. The acid was allowed to cool and stand in contact with the ware for an additional 22 h. At the end of the 2 h heating period and again at the end of the 24 h period, the leach solution was assayed by atomic absorption spectrophotometry for Pb and Cd. Ruggedness testing before the collaborative study revealed that: (1) the quantity of metal released increased as the average leach temperature approached the boiling point, (2) the quantity of Pb and Cd released from enameled ware increased linearly with time during 7 h of boiling, (3) the concentration of acid could be varied from 2 to 6% with no apparent effect on the amount of metal released, and (4) the room temperature (RT) contact period lasting from 22 to 120 h (after the 2 h heating period) did not increase the amount of metal released. The quantities of Pb and Cd measured by the collaborators at the end of 2 h of heating and after 24 h of total contact were essentially identical. The amounts of Pb and Cd were not related to the quantity of acid solution required to restore the leach solution volume to its initial value after boiling. The collaborative results showed that the period of standing at RT is not necessary and probably can be eliminated from the method. The modified method, which requires analysis of the leach solution immediately after the 2 h heating period, has been adopted interim official first action by AOAC.