bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Microbial Assay Systems for Determining Antibiotic Residues in Soils
Authors: Katz Jack M , Katz Stanley E
Published: February 2020

Procedures tor the assay or bacitracin, chlortetracycline, erythromycin, oxytetracycline, and tylosin residues in soils are presented. Except for tylosin, 1 μg antibiotic/g soil could be detected and measured. Recoveries of bacitracin (43.0-83.9%) averaged 60.3% and were unaffected by clay, sand, or silt content. Recoveries of chlortetracycline (40.0-116.0%) averaged 63.9% with no apparent relationship between recoveries and soil composition. Recoveries of oxytetracycline (30.8-100.0%) averaged 64.5% and were affected by silt and clay content. There was an inverse relationship between recoveries of tylosin and clay and silt content. Recoveries ranged from 6.5% in a soil containing 23.7% silt and 16.3% clay to 74.1% in a soil containing 96.3% sand. Recoveries of erythromycin were similarly related to clay and silt content, with recoveries averaging 36.3% in soil containing 40% silt and clay and 76.0% in soil containing 96.3% sand. Penicillin could not be recovered from soils because of its instability. Streptomycin was irreversibly adsorbed and could not be extracted from any soil studied.
Rapid Method for Extraction and Reverse Phase Liquid Chromatographic Determination of Paraquat Residues in Water
Authors: Ahmad Ijaz
Published: February 2020

A simple and fast analytical method is described for the quantitative determination of low levels of paraquat residues in water. The method involves extraction and concentration of paraquat in water by using a C18 Sep-Pak cartridge followed by reverse phase high performance liquid chromatographic determination with ultraviolet detection at 257 nm. Recoveries of paraquat from spiked samples were above 93% with a coefficient of variation of 6.1%. The method can be used for water samples with paraquat concentrations as low as 0.05 ppm.
Simultaneous Determination of Protein (Nitrogen), Phosphorus, and Calcium in Animal Feedstuffs by Multichannel Flow-Injection Analysis
Authors: Staden Jacobus F Van
Published: February 2020

A 3-channel flow-injection procedure was developed, which enables the simultaneous determination of protein, phosphorus, and calcium in a wide range of animal feeds from a single digestion. Samples are digested with a block digestor, diluted, and analyzed at a rate of 82 samples/h. Protein (nitrogen) as ammonia is determined colorimetrically by the indophenol method. Phosphorus and calcium are determined by measuring the absorbances of the molybdenum blue and calcium-cresolphthalein complexes at 660 and 580 nm, respectively. Protein is determined in the range from 0 to 75%, phosphorus in the range from 0 to 6%, and calcium in the range from 0 to 6%. The results obtained do not differ significantly from those obtained by proven manual methods, and considerable time, space, and reagents are saved.
Comparative Analysis of Meat Samples Prepared with Food Chopper and Bowl Cutter
Authors: Pettinati Julio D , Ackerman Stanley A , Jenkins Ronald K , Happich Muriel L , Phillips John G
Published: February 2020

Analyses of meat samples after preparation with either a bowl cutter or by the official procedure with a food chopper were compared for homogeneity of comminution and for differences in fat, moisture, and protein content. Cutting time in the bowl cutter was limited to minimize temperature rise in samples. Beef chuck, pork shoulder, and beef shank, cheek, and tongue were used in the study. Variances of replicate analysis data for the 5 meat types were pooled for either cutter or chopper treatment and for each analyzed component. Sample portions cut and mixed by using the bowl cutter were more homogeneous than those ground with a food chopper. Comparative accuracy was indicated by fat and moisture means: 5 were in good agreement and 5 differed significantly; 3 of 5 paired protein means differed significantly but were within 0.3% protein. Results on precision and accuracy as well as the simplicity and convenience of the bowl cutter procedure favor its use as an alternative to a food chopper for preparing meat samples for analysis.
High Performance Liquid Chromatographic Analysis of Rotenone Formulations: Collaborative Study
Authors: Bushway Rodney J ,   Collaborators:, Bennett M J , Betker W R , Bolduc R , Burns A , Carlstrom A A , Cuan E , Doherty P J , Freedlander R S , Fugere J B , Gentry G M , Hanks A R , Hodgins W E , Jung P D , King W , Launer J E , Meinen V J , Minyard J P , Polli R L , Porterfield D , Schwamb L , Skelly N E , Stringham R W , Wood G A
Published: February 2020

A collaborative study was conducted on a high performance liquid chromatographic (HPLC) method for determining rotenone in formulations. One liquid and 4 dust samples, containing other rotenoids and pesticides, with rotenone guarantees ranging from 0.75% to 20% were analyzed by 16 laboratories. Peak height measurements were used by 14 laboratories while 8 laboratories used integrator area measurements. Samples were extracted on a rotary shaker for 1% h with dioxane. An aliquot was analyzed using reverse phase HPLC and UV detection at 280 nm. Coefficients of variation ranged from 2.47 to 3.19% for peak height determinations and from 2.56 to 6.00% for peak area determinations. One collaborator analyzed the samples by the official infrared method for a comparison. The HPLC method has been adopted official first action.
Multiresidue Method for Determination of Pesticides in Kiwif ruit, Apples, and Berryfruits
Authors: Holland P T , Mcghie T K
Published: February 2020

A rapid multiresidue procedure for fruits, based on methanol extraction, is presented. Water and highly water-soluble co-extractives are removed by partitioning the pesticides into toluene. Carbon-cellulose-Florisil cleanup is performed before gas chromatography on OV-225 with electron capture detection. A wide range of pesticides can be determined to 0.1 mg/kg without concentrating the extract. Gas chromatography of the crude toluene partition using SE-30 and an alkali flame ionization detector provides confirmatory data and allows detection of some carbamates. Dichlorvos, dimethoate, and acephate are determined directly in the methanol extract by flame photometric detection. High recoveries were obtained for 4 organochlorine insecticides, 13 organophosphorus insecticides, 2 synthetic pyrethroids, two JV-methyl carbamates, and 10 fungicides. The method is economical of solvents, glassware, and time, and is recommended for routine surveillance of residue levels on fruit.
High Performance Liquid Chromatographic and Colorimetric Determination of Synthetic Dyes in Gelatin-Containing Sweets, Following Polyamide Adsorption and Ion-Pair Extraction with Tri-n-octylamine
Authors: Puttemans Marc L , Dryon Louis , Massart Désiŕe L
Published: February 2020

Dyes are determined in gelatin-containing sweets. The gelatin must be eliminated first because it interferes with the normal ion-pair extraction of dyes with tri-n-octylamine to chloroform. Techniques such as precipitation of gelatin with organic solvents, and add and enzymatic digestion of gelatin are shown to be unsuccessful because the remaining ;elatin still influences the extraction scheme. Posicive results are obtained when dyes are adsorbed on polyamide, gelatin is washed away, and dyes are desorbed with a methanol-ammonia mixture. Dyes are identified by thin layer chromatography and high performance liquid chromatography (HPLC), and quantitated by HPLC or colorimetry.
Electrothermal Atomic Absorption Spectroscopic Determination of Chromium in Plant Tissues
Authors: Cary Earle E , Rutzke Michael
Published: February 2020

This method involves sample digestion in nitric, perchloric, and sulfuric acids. Chromium is concentrated by coprecipitation with ferric hydroxide. Redissolved iron is removed by liquid-liquid extraction, remaining silica is dissolved with hydrofluoric acid, and chromium is determined by electrothermal atomic absorption spectrometry. The sensitivity and detection limits for chromium approach those given by the manufacturers of the various instruments. Recovery studies and analysis of standard materials show that this method is reliable.
Determination of Lead in Bonemeal by Differential Pulse Anodic Stripping Voltammetry Using a Hydrochloric Acid Solubilization
Authors: Satzger R Duane , Kuennen Roy W , Fricke Fred L
Published: February 2020

A safe, rapid method is described for the determination of lead in bonemeal. This method uses a hydrochloric acid solubilization performed under pressure followed by determination by differential pulse anodic stripping voltammetry. This provides an alternative to a nitric-perchloric acid wet ash. Data obtained using both methods are compared. The mean recovery of a standard Pb spike was 99.2 ± 1%. The concentration of Pb in bonemeal ranged from 1.0 to 15.6 μg/g.
Dilution Errors in Aflatoxin Determinations Caused by Compounds Extracted from Peanuts
Authors: Dickens James W , Whitaker Thomas B
Published: February 2020

Several methods have been developed to analyze peanuts for aflatoxin by using thin layer chromatography (TLC). These methods depend on solvent extraction of aflatoxin from a sample of the product. Unfortunately, solvent solutions used to extract aflatoxin from peanuts also extract measurable quantities of other compounds such as oils, fats, sugars, and protein. The volume of these extracted compounds causes error in measuring the proportion of the solvent solution analyzed for aflatoxin. Also, because the cleanup procedures for some methods are inadequate, the volume of some of these extracted compounds also causes error in measuring the proportion of the extracted aflatoxin placed on TLC plates. These 2 errors cause underestimation of aflatoxin concentrations by approximately 11,14, and 57c for the CB method, the modified version of the BF method generally used for raw peanuts, and a water slurry method, respectively. The correction specified bytheCB method for fats in the extraction solvent reduces the approximate error for the CB method from 11 to 1%.
Determination of Styrene Migration from Food-Contact Polymers into Margarine, Using Azeotropic Distillation and Headspace Gas Chromatography
Authors: Varner Sandra L , Breder Charles V , Fazio Thomas
Published: February 2020

Migration studies were conducted to determine the quantity of styrene that migrates from polymers into fatty foods, specifically margarine. Azeotropic distillation was used to isolate styrene from the margarine. Headspace gas chromatography with a Chromosorb 104 column and a flame ionization detector was used for quantitation. The quantitation limit for the method was about 25 ppb (wt/wt) styrene in margarine. On the average, greater than 90% of the styrene was recovered. Several commercial margarines were examined. The method and results of the migration studies are presented. There was no detectable migration of styrene into margarine.
Application of Tenax Trapping to Analysis of Gas Phase Organic Compounds in Ultra-Low Tar Cigarette Smoke
Authors: Higgins Cecil E , Griest Wayne H , Olerich Gerry
Published: February 2020

A method well suited to the analysis of gas phase organic compounds in ultra-low tar delivery cigarette smoke has been developed. The cigarette is smoked directly through a filter and a Tenax trap arranged in series. The components collected on Tenax are analyzed by thermal-desorption programmed-temperature gas chromatography. Components are then quantitated by the use of external standards. The smoke from high tar delivery cigarettes also can be analyzed by thermal desorption gas chromatography of portions of well mixed solid dilutions of the trapping Tenax. Deliveries of 34 gas phase components were determined for 4 ultra-low tar cigarettes having tar deliveries ranging from <0.01 to 3 mg tar/cigarette, and 24 components for 5 cigarettes delivering 7 to 45 mg tar/cigarette.
Screening of Fresh Water Fish Extracts for Enzyme-Inducing Substances by an Aryl Hydrocarbon Hydroxylase Induction Bioassay Technique
Authors: Casterline James L , Bradlaw June A , Puma Bartholomew J , Ku Yuoh
Published: February 2020

A sensitive biological test to detect the presence of certain contaminants, such as highly toxic halogenated dioxins, dibenzofurans, and biphenyls in foods, was applied to extracts of fresh water fish that had been prepared by a food extraction-cleanup procedure developed by the Food and Drug Administration for pesticides and industrial chemicals. Aryl hydrocarbon hydroxylase (AHH) activity in a rat hepatoma cell line was used as the biological detection system for residues that induce enzyme activity. The induction of AHH activity by the extracts was compared with a standard AHH-induction curve for the most active compound known, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and results were computed as TCDD equivalents. Several dilutions of fish extracts were used to produce AHH-induction curves from which an optimal dose-response range was determined and used to estimate TCDD equivalents. Cleaned-up extracts of fish obtained from different water bodies in the United States were examined for AHH activity. The samples which had low levels of polyhalogenated contaminants produced low biological activity, while a higher activity was obtained from fish that contained higher levels of polyhalogenated contaminants. The results suggest that the fish extracts can be screened for AHH inducers before chemical analysis.
Identification of Trout and Salmon Bloods by Simple Immunological Technique and by Electrofocusing Patterns of Red Cell Enzyme Superoxide Dismutase
Authors: Sutton John G , Goodwin Janet , Horscroft Gillian , Stockdale Russell E , Frake Allan
Published: February 2020

Species identification of animal bloods is readily achieved by immunological tests. Differentiation among fish species on this basis is more difficult although considerable success has been achieved on the basis of both inter- and intra-specific differences in their serum proteins. This report describes a method for the identification of the different species of fish within the Salmonidae family and some coarse fish families on the basis of an immunological test and electrofocusing patterns of the enzyme superoxide dismutase from the red cell. The immunological technique relies on the development of a specific anti-trout (Salmonidae) serum which is used initially to differentiate the blood of a Salmonidae from other freshwater fish. Further discrimination, within the Salmonidae, is made on the basis of the different polymorphic forms of the enzyme superoxide dismutase separated in a pH 2.5 to 8 gradient. Using this technique, it is possible to differentiate among salmon, sea/brown trout, char, cheetah trout, and a number of varieties of rainbow trout.
High Pressure Liquid Chromatographic Determination of Sulfisoxazole in Dosage Forms: Collaborative Study
Authors: Roos Robert W ,   Collaborators:, Alexander L R , Falcone N , Lepore J , Mack G D , Marzilli J , Muzeni R , Papas A N
Published: February 2020

A reverse phase high pressure liquid chromatographic method for the determination of sulfisoxazole in tablets, solution, and ointment dosage forms was collaboratively studied by 7 laboratories. The method uses a C18 column, an acetonitrile-acetic acid-water mobile phase, sulfadimethoxime as the internal standard, and photometric detection at 254 nm. Collaborators were supplied samples of 2 commercial tablets, 1 synthetic tablet powder, 1 commercial and 1 synthetic ophthalmic solution, and 1 commercial ophthalmic ointment. Mean recoveries of sulfisoxazole from the synthetic tablet powder and ophthalmic solution were 99.9 and 100.0%, respectively. Mean coefficients of variation for all samples analyzed were less than 2%. The method was adopted interim official first action.
Comparison of AOAC and Atomic Absorption Spectrophotometry Methods for Determining Sodium in Fertilizers: Collaborative Study
Authors: Corominas Luis F , Navarro Roberto A , Rojas Pedro ,   Collaborators:, Aihara M , Baker N I F , Baumgartner B , Case V W , Cherwin M G , Erickson E , Huber E J , Hunter G B , Jasper D , Johnson F J , Lartigue L , Mobley R J , Navarro R A , Reimann L , Rojas P , Roll E F , Sabapathy T R , Sensmeier R K , Smith J L , Ware W C , Williams J L , Wood T M , Woodis T C
Published: February 2020

A collaborative study was carried out to compare AOAC method 2.147-2.150 for determining sodium in fertilizers with the atomic absorption spectrophotometric (AAS) method. Twelve synthetic NPK samples, 6 pairs of blind duplicates (0.06-8.5% Na), were sent to 22 collaborators; a total of 13 sets of results were received and evaluated by the modified matched pairs technique. The AAS method showed better performance in samples with low sodium content and high potassium content. The AAS method has been adopted official first action for determining sodium in fertilizers.
Survey of Infant Foods for Clostridium botulinum Spores
Authors: Guilfoyle Dennis E , Yager James F
Published: February 2020

A total of 236 samples of infant foods, including honey, dry cereal, nonfat dry milk, evaporated milk, canned formula, and canned baby food, were collected in the New York City area and tested for the presence of Clostridium botulinum spores. Methods for recovery of spores were validated using foods spiked with 4 spores/mL or g. None of the products contained C. botulinum spores, indicating that their incidence in these commercial foods is not widespread. This limited study did not identify any food types that could be suspected of being involved in the transmission of infant botulism.
Ion-Pair Reverse Phase Liquid Chromatographic Determination of Sodium Acifluorfen in Feed
Authors: Roy Timothy A , Meeks J Ralph , Mackerer Carl R
Published: February 2020

Ion-pair reverse phase liquid chromatography (LC) and UV detection at 280 nm have been used to determine sodium acifluorfen (sodium-5-[2-chloro- 4-(trifluoromethyl)-phenoxy]-2-nitrobenzoate), an experimental diphenyl ether herbicide, in dog feed. Sodium-5-(2,4-dichlorophenoxy)-2-nitrobenzoate is used as the internal standard. The feed is homogenized in 0.01N HC1, followed by ethyl acetate extraction, and centrifugation. The organic layer is removed and evaporated and the residue is reconstituted in methanol and filtered before LC analysis (mobile phase methanol-water (58 + 42), 0.005M in letrabutylammonium phosphate and 0.045M in (NH4)2HPO4, at pH 7.4). The ion-pair technique offers a high degree of control over the retention characteristics of the herbicide and internal standard. The use of the internal standard permits precise and accurate quantitation and substantially reduces analysis time compared with the external standard method.
Comparison of Gas Chromatographic/Mass Spectrometric and Liquid Chromatographic/Mass Spectrometric Methods for Confirmation of Coumaphos and Its Oxygen Analog in Eggs and Milk
Authors: White Kevin D , Min Zhao , Brumley William C , Krause Richard T , Sphon James A
Published: February 2020

A comparison of a liquid chromatographic (LC)/mass spectrometric (MS) procedure for confirming coumaphos, an organophosphate insecticide, and its oxygen analog in milk and eggs with a capillary gas chromatographic (GO/MS method is presented. For the confirmation of coumaphos and its oxygen analog, multiple ion detection of both positive and negative ions from the chemical ionization mass spectra was used. Samples of milk and eggs fortified with the 2 compounds at the 0.1,0.01, and 0.005 ppm levels were analyzed. The major finding is the relatively greater efficiency of the LC/MS interface compared with the GC/MS capillary injector.
Liquid Chromatography, Microfluorometry, and Dye-Titration Determination of Vitamin C in Fresh Fruit and Vegetables
Authors: Wills Ron B H , Wimalasirl Pushparany , Greenfield Heather
Published: February 2020

The vitamin C content of several fresh fruit and vegetables was determined by a liquid chromatographic (LC) method which gave simultaneous separate values for ascorbic acid and dehydroascorbic acid (DHA) and by the official AOAC methods of microfluorometry and dye-titration. The levels of ascorbic acid obtained by LC and dye-titration were in good agreement, except for a few colored products where it was difficult to determine the end point of the titration. The combined values for ascorbic acid and DHA obtained by LC and microfluorometry were in agreement for most produce, but for about one-third of the samples, the values obtained by microfluorometry were significantly higher.
Liquid Chromatographic Assay for Dalapon Grasskiller Products: Collaborative Study
Authors: Stevens Timothy S , Wedelstaedt Cathy ,   Collaborators:, Bennett B , Grorud R , Harris T , Hodgins E , King S W , Lonn P D
Published: February 2020

As a replacement for the present mercury reagent titration assay for dalapon grasskiller products, a liquid chromatographic method has been developed and collaboratively studied. The method separates the active ingredient, 2,2-dichloropropionic acid, from its related products by paired ion chromatography with UV detection at 214 nm. Statistical analysis of the data indicates that a single assay from one laboratory should not differ by more than 2.2% from the average assay of many laboratories, at the 95% confidence level, for products containing about 75% 2,2-dichloropropionic acid equivalent as the magnesium and/or sodium salt. The method has been adopted official first action.
Determination of Authenticity of Sake by Carbon Isotope Ratio Analysis
Authors: Martin Glenn E , Burggraff James M , Alfonso Felipe C , Figert Donald M
Published: February 2020

Sake samples are fractionally distilled so that the resultant ethanol concentration of the distillate is approximately 95%. Determination of 14C by liquid scintillation counting on the ethanol fraction differentiates alcohol produced by fermentation from synthetic ethanol produced from fossil fuel sources. 13C/12C stable isotope ratio analysis (SIRA) is capable of detecting alcohol from a cane or corn source in sake samples. This analysis also shows the addition of corn or cane sugar before or after fermentation of the sake.
Rapid Direct Determination of Lead in Evaporated Milk by Anodic Stripping Voltammetry Without Sample Pretreatment
Authors: Zink Eric W , Moffitt Robert A , Matson Wayne R
Published: February 2020

The method presented describes the direct determination of lead in evaporated milk in which the milk ashing step prior to analysis is eliminated. Digital instrument readout units are μg Pb /mL milk. Total analysis time after instrument calibration is less than 3 min per sample. Range of the method is 0.05-1.0 ppm lead in milk, and precision of the method expressed by relative standard deviation of duplicate pairs ranged from 30% at 0.1 μg/mL to 3% at 1.0 μg/mL of lead in milk. The method compares favorably with the AOAC official first action anodic stripping voltammetric method (25.074). In addition, the method appears to work equally well for skim evaporated milk, sweetened condensed milk, and nonfat powdered dry milk when the latter two are reconstituted with water according to product label instructions. Recovery and interference studies are presented.
Spectrophotometric Determination of Hydralazine Hydrochloride Tablets Using Ninhydrin
Authors: Dutt Manesh C , Ng Tju-Lik , Long Lian-Tun
Published: February 2020

A method is described for the assay of hydralazine HC1 in tablets, based on the colored product formed by the reaction between hydralazine and ninhydrin. The reaction is conducted at room temperature in a pH 3 buffer solution and the colored product is measured spectrophotometrically at the absorption maximum at 442 nm. Under the stipulated conditions, this reaction is highly specific for hydralazine and is not affected by other drugs which may be used in combination with hydralazine. Results of infrared and mass spectrometric studies suggested that the colored product is a hydrazone. Ultraviolet spectrophotometry also showed that dilute solutions of hydralazine degrade rapidly in the presence of alcohols.
Five-Year Study of Mycotoxins in Virginia Wheat and Dent Corn
Authors: Shotwell Odette L , Hesseltine Clifford W
Published: February 2020

Every year during the 5-year period 1976-1980, approximately 100 samples each of corn and wheat from trucks delivering the grains at elevators in Virginia were collected by personnel of the Federal Grain Inspection Service and shipped to NRRC. Samples were analyzed as soon as possible for aflatoxin, zearalenone, and ochratoxin A. The 3 mycotoxins were not detected in any wheat sample. Zearalenone and ochratoxin A were not found in any corn sample; however, aflatoxin was detected in at least 25% of the corn samples from every crop year. In 1976-1980, the incidence of aflatoxin at levels of 20 ng/g or more (the Food and Drug Administration guideline) ranged from 18 to 61%; aflatoxin incidence above 100 ng/g was 5-29%. The average aflatoxin levels in corn samples collected in the 5 years varied from 21 to 137 ng/g. Moisture content of the samples was not determined, so aflatoxin levels given may be higher than they were at harvest. However, there are obviously differences from year to year. In freshly harvested corn samples collected by fieldmen of the Statistical Reporting Service in yield surveys in 1978 and 1979, aflatoxin incidence above the FDA guideline was 10 and 13%, and above 100 ng/g was 4 and 7%. The average aflatoxin level in all samples collected in 1978 was 13 ng/g and in 1979, 36 ng/g. Some aflatoxin can be expected yearly in Virginia corn, but the incidence and levels vary from year to year.
Automated Sample Cleanup for Pesticide Multiresidue Determination. I. Evaluation of Solvent Partitioning Module
Authors: Gretch Fred M , Rosen Joseph D
Published: February 2020

An automated continuous flow procedure is described that improves the cost effectiveness and precision of AOAC methodology for multiresidue pesticide determinations in nonfatty foods. Individual modules capable of performing automated solvent partitioning and automated column chromatography were constructed and integrated into a continuous flow system. Data are presented comparing the recoveries and precision for the determination of 8 pesticides (aldrin, dieldrin, p,p’ - DDT, ethion, heptachlor epoxide, lindane, parathion, and ronnel) partitioned from 2 food crops (spinach and tomatoes) by both the manual and automated procedures.