bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Organic Acids in Vanilla Extracts by GLC Separation of Tnmethylsilylated Derivatives
Authors: Fitelson J , Bowden George L
Published: February 2020

A method for the analysis of organic acids in vanilla extracts has been developed. The lead salts of the organic acids are separated, trimethylsilylated derivatives are formed directly from the lead salts, and the trimethylsilylated de rivatives are separated by GLC. Typical vanilla chromatograms show about 20 acid peaks, with 8 major ones. The main vanilla acid shows up as the largest peak, identified as 7. Malic acid occurs naturally in vanilla and is measured by Peak 2. Tahiti extracts are distinguished from other extracts by the smaller Peak 2, and the ratio of Peak 7 to Peak 2 can be used to identify these extracts. To measure the peak heights on a standard basis, known quantities of glutaric acid are added to the vanilla extract sample; this internal standard appears between vanilla acid Peaks 1 and 2. Gross deficiency in vanilla solids in the extract is detected by low peak heights; additions of foreign acids are readily shown by abnormal peak heights or by foreign peaks. This method was studied by ten collaborators and the unknowns were identified correctly. The proposed method provides more information in a shorter time than any method or combination of methods now available. However, since each GLC instrument has different responses to the same set of empirical conditions given in the method, each analyst must test authentic extracts and establish the characteristics to be used for the basis of comparison. The method is recommended for adoption as official, first action.
Collaborative Study of a Colorimetric Method for Paraquat in Formulations
Authors: Carlstrom A A
Published: February 2020

A colorimetric method described by Yuen, Bagness, and Myles in 1967 was collaboratively studied with paraquat formulations containing 2 lb/gal. (about 20% cation). Paraquat is determined in a diluted solution by measuring the absorbance, at 600 mμ, of the blue free radical produced by reduction with alkaline sodium dithionite, and its absorbance is compared to a reference standard curve. Standard deviation estimation of random error was 0.22 for paraquat dimethylsulfate formulations and 0.26 for paraquat dichloride. Standard deviation estimates of systematic error were 0.20 and 0.62, respectively. The method is recommended for adoption as official, first action.
Colorimetric Determination of Ronidazole in Feeds
Authors: Szalkowski C R , Kanora J
Published: February 2020

Ronidazole, (l-melhyl-5-nitroimidazoI- 2-yl)mcthyl carbamate, is extracted from finished poultry feeds with methanol and chromatographcd on an AL2O3-FIorex column. The eluate is concentrated and dissolved in CCI4 and the ronidazole is extracted with. H2O. The purified ronidazole is hydrolyzcd in NaOH solution in the presence of copper and p-aminobenzoic acid; the resulting diazonium compound is then coupled with naphthylethylenediamine to form a colored complex, which is measured spectrophotometrically at 550 mµ. No significant interference was found from finished feeds, domestic and foreign, or from 48 common feed additives. Recovery experiments on 36 laboratory-prepared feed samples at levels ranging from 0.0015 to 0.030% ronidazole averaged 100.8% with a standard deviation of 2.4.
Comparison of FAO and AOAC Methods for Dairy Products
Authors: Taylor James R
Published: February 2020

Studies were made of proposed FAO methods for phosphorus in cheese and processed cheese products, citric acid in processed cheese products, and a polarographic method for sucrose in sweetened condensed milk. The FAO methods give precise and accurate results. Collaborative studies are recommended.
Thin Layer Densitometric Determination of Rotenone and Deguelin
Authors: Delfel Norman E , Tallent William H
Published: February 2020

Rutenone and deguelin are separated by chromatography on silver nitrate-impregnated silica gel G with chloroform acetone: acetic acid (196:3:1) solvent system. Glass plates, 20 × 20 cm, are coated with a special spreader producing a 0.25 mm layer and a 1.00 mm band at the upper end. Since additional solvent is required to saturate the thicker band, such plates give resolutions comparable to plates twice as long. Developed plates are treated with nitric acid vapor, then ammonia vapor, to produce dark spots for the rotenoids. Plates are scanned with a commercial densitometer, and the quantity of rotenoids is calculated from peak area in the resultant curve. Kecoveries of rotenone and deguelin added to extracts of Tephrosia vogelii, Lonchocarpus nicou, and Derris elliptica averaged 104.1 and 99.4%, respectively. The standard deviation of the method applied to plant extracts was 7.9% for rotenone and 8.3% for deguelin. The amounts of rotenone in the L. nicou samples were comparable to those determined by the AOAC crystallization and infrared methods.
A New Approach to the Raney Catalyst Powder Method for Total Nitrogen in Fertilizers
Authors: Brabson J A , Woodis T C
Published: February 2020

Further study of the Raney catalyst powder method for the determination of nitrogen in fertilizers established conditions in which the commercial alloy containing 50% Ni and 50% Al was a more efficient reductant for nitrates than an experimental alloy that contained 10% Co. Errors in measurement were decreased, accuracy was increased, and time was saved by adding all the sulfuric acid and part of the potassium sulfate as a single dilute solution and heating the mixture immediately to promote the reduction. Changes in the amounts of reagents, including use of the contents of a Kcl-Pak without the polyethylene envelope, resulted in smoother and more effective Kjeldahl digestions. The method is “rugged” and is equally applicable to the refractory compound nicotinic acid, mixtures of nitrates and organic materials, and the simplest inorganic fertilizers. The time required for an analysis can be further shortened by using “Autopettes” for dispensing the standard acid and a “Titralyzer” for back titrations.
Diethylnitrosamine and Other N-Nitrosamines in Foods
Authors: Sen N P , Smith Dorothy C , Schwinghamer L , Marleau J J
Published: February 2020

Dimethyl-, diethyl-, di-n-propyl, and other nitrosamines in foods are determined semiquantitatively as follows: (a) initial extraction of the nitrosamines from foods into suitable solvents, (b) isolation of the nitrosamines from other interfering materials by steam distillation and ion exchange cleanup, (c) detection and semiquantitative estimation by TLC, and (d) final identification by GLC analysis of the separated compounds. The detection limit for dimethylnitrosamine in foods was 0.15 ppm and for diethyl- and di-re-propylnitrosamines, 50 ppb. The method has been successfully applied to wheat flour, fish, cheese, and spinach samples.
Forensic Aspects of Cystolith Hairs of Cannabis and Other Plants
Authors: Nakamura George R
Published: February 2020

Cystolith hairs, important criteria for the identification of marihuana leaf fragments, occur among several dicotyledonous families, notably the Moraceae, Boraginaceae, Loasaceae, Ulmaceae, and Caimabinaceae. Since cystoliths also develop in many forms, most species can be differentiated from Cannabis only by a very close morphological examination. The Duquenois-Levine test was found useful in confirmation, since none of 82 species, many of which had hairs similar to those found on Cannabis, yielded a positive test.
Collaborative Study on the Determination of Aflatoxins in Cottonseed Products
Authors: Pons Walter A
Published: February 2020

Twelve laboratories collaboratively studied a method for estimating aflatoxins in cottonseed products, using both visual and fluorodensilometric estimation of aflatoxins on TLC plates. Average recovery of total aflatoxins (B1 + B2) added to five products was 85% by visual and 90% by densitometric estimation; average coefficients of variation were 18 and 12%, respectively. Within- and between-laboratory precision was essentially equivalent for both types of measurement, with no significant systematic errors among the laboratories. There was a high degree of correlation between visual and densitometric estimation of aflatoxins.
Reaction of Aflatoxin B1 with Acetic Acid-Thionyl Chloride
Authors: Wiley Mabry , Waiss Anthony C , Bennett Nancy
Published: February 2020

The two main products of the reaction of acetic aeid-thionyl chloride with aflatoxin B1, used as a confirmatory test for aflatoxin B1, were identified as the α- and β-isomers of l-acetyl-2-hydro-6-methoxydifurocoumarone
Collaborative Study of the Determination of Ethanol in Wine by Chemical Oxidation
Authors: Caputi Arthur , Wright Dawson
Published: February 2020

A collaborative study was conducted on a chemical or dichromate oxidation procedure for etlianol in wine. The method is based on the steam distillation of ethanol from a 1 ml wine sample into an acidified solution of potassium dichromate, followed by heating 20 min at 60°C to complete the oxidation of the ethanol to acetic acid. The unreacted dichromate is determined by titration with a standard ferrous ammonium sulfate solution, using o-phenanthroline as an indicator. Eleven collaborators participated in the study, of whom seven were familiar with the method and four were not. Eight samples with alcohol content ranging from 11.8 to 23.5% by volume were analyzed. The standard deviations of the reported answers on the identical samples varied from 0.024 to 0.063% in the range of 11.8–20% ethanol and rose to 0,161% in the sample which contained 23.3% ethanol by volume. This reproducibility is better than has been reported with other commonly used methods, and it is recommended that the method be adopted as official first action.
Analysis of Tritium in Water: A Collaborative Study
Authors: Sodd Vincent J , Scholz Kenneth L
Published: February 2020

A liquid scintillation procedure using 1,4-dioxane, naphthalene, PPO, and POPOP as the scintillator was evaluated in a collaborative study of the determination of tritium in water. The tritium counting efficiencies for seven collaborating laboratories using this technique and commercially available liquid scintillation spectrometers ranged from 8.3 to 26.5%. The minimum detectable activity by the method, based on 99% confidence limits, 100 min counting time, and backgrounds from 9 to 67 cpm, ranged from 0.2 to 0.5 pCi/ml. Statistical results showed no evidence for systematic error. The coefficient of variation varies from 3.4 to 7.3% over the concentration range 2.91–115.8 pCi/ml. It is recommended that the method be adopted as official first action.
Determination of Pentachlorophenol in Blood, Urine, Tissue, and Clothing
Authors: Barth W F , Curley August , Thrasher C L , Sedlak V A , Armstrong Robert
Published: February 2020

An epidemic with two deaths occurred in a nursery in St. Louis after the use of pentachlorophenol as a mildew preventive with the laundry detergent. Samples of blood, urine, tissue, and clothing from the nursery were extracted with ethyl ether. The ether solution was extracted with 5% sodium hydroxide; the basic solution was acidified and then extracted with benzene. The benzene solution was analyzed by electron capture gas chromatography, using a 3% diethylene glycol succinate column with 2% sirupy phosphoric acid on 60-80 mesh Chromosorb G. Pentachlorophenol was found in the samples in sufficient quantity to account for the epidemic. The presence of pentachlorophenol was confirmed by gas chromatogrifplryrmass spectroscopy and by thin layer analysis.
Determination of Mesurol and Five of Its Metabolites in Apples, Pears, and Corn by Gas Chromatography
Authors: Bowman M C , Beroza Morton
Published: February 2020

Mesurol and five of its metabolites were determined in apples, pears, and whole corn plants. The crop was chopped with buffer to prevent hydrolysis of some of the metabolites and then extracted with acetone. The extracts were separated by liquid chromatography on silica gel into sulfide, sulfoxide, and sulfone fractions, and each fraction was further subdivided into carbamate and phenolic fractions by liquid chromatography on alumina. After the carbamates were hydrolyzed to their respective phenols (because the carbamates decomposed partially during GLC), the phenols in each fraction were determined by GLC with a sulfur-sensing flame photometric detector. No significant interference from crop extracts occurred. Recoveries ranged from 68 to 106% and generally were 80% or better; sensitivities were about 0.01 ppm. A procedure for determining the conjugated phenols liberated by acid hydrolysis is also described.
Collaborative Study Comparing Gas-Liquid Chromatographic and Chemical Methods for Quantitatively Determining Vitamin E Content of Pharmaceutical Products
Authors: Sheppard A J , Hubbard W D , Prosser A R
Published: February 2020

A collaborative study was conducted to compare the USP XVII (Emmerie-Engel) method and three GLC methods for quantitatively determining a-tocopherol, a-tocopheryl acetate, and a-tocopheryl succinate in pharmaceutical products. Nine collaborating laboratories analyzed seven pharmaceuticals encompassing tablets, capsules, and liquids. The mean coefficients of variation were: USP method, 28.6%; GLC method A, 10.2%; GLC method B, 10.8%; GLC method C, 18.0%. GLC method A was the method of choice of those evaluated. The vitamin E analogs are extracted with n-hexane from ground tablets and capsules; liquid preparations are diluted with n-hexane or injected directly onto the GLC column. The compounds are chromatographed on an 8′ × 4 mm id glass column paeked with 5% SE-30 on 100-120 mesh silanized Gas Chrom P, operated between 270-285°C, and the carrier gas flow rate adjusted so that ∝-tocopheryl acetate appears within 23-27 min. Acetic anhydride-pyridine reaction is utilized to determine whether ∝-tocopherol or ∝-tocopheryl succinate is present in a sample, since these two analogs have similar retention times. It is recommended that GLC method A be adopted as official first action.
Detection and Identification of Salmonella from Dry Milk: Report of a Collaborative Study
Authors: Poelma P L , Wilson C R , Romero A , Padron A
Published: February 2020

A method for the detection and identification of Salmonella from dry milk was subjected to collaborative study. A 100 g sample is reconstituted in 1 L distilled water with 2 ml 1% aqueous brilliant green dye, incubated, subcultured in selenite cystine broth and tetrathionate broth, incubated, and streaked on selective plates of brilliant green agar, Salmonella-Shigella agar, and bismuth sulfite agar. After incubation, suspicious colonies can be further identified by biochemical and serological tests. Samples of nonfat dry milk and dry whole milk, some inoculated with Salmonella binza, Salmonella tvorthington, and Citrobacter, were examined by 30 collaborators. Results from 23 of 28 collaborators were in agreement; the method will detect and identify Salmonella from positive nonfat dry milk and dry whole milk. The method is recommended for adoption as official first action.
Gas Chromatographic Determination of Residues of Dimethoate and Its Oxygen Analog in Field-Sprayed Kale
Authors: Storherr R W , Watts Randall R
Published: February 2020

Significant residues of the oxygen analog of dimethoate were found when both 1.0 and 0.5 lb of active dimethoate/acre were sprayed on field-grown kale. At the 14 day sampling period, the residue ratio of dimethoate oxygen analog to dimethoate was 4:1 as determined by GLC, using a glass column packed with 2% diethylene glycol succinate (stabilized) on Gas Chrom Q and a potassium chloride thermionic detector.
Gas Chromatography of Organophosphorus Pesticides: Retention Times and Response Data on Three Columns
Authors: Watts Randall R , Storherr R W
Published: February 2020

GLC systems with potassium chloride thermionic detection are described for analysis of over 60 organophosphorus pesticides and alteration products. Each compound was chromatographed on three GLC columns: 10% DC-200, QF-1/DC-200 mixed, and 2% stabilized diethylene glycol succinate liquid phases on 80–100 mesh Gas Chrom Q support. Retention times and response data are shown for all the pesticides chromatographed on each of the three columns.
Charcoal Column Cleanup Method for Many Organophosphorus Pesticide Residues in Crop Extracts
Authors: Watts Randall R , Storherr R W , Pardue John R , Osgood Theodore
Published: February 2020

In the charcoal column cleanup method for organophosphorus pesticide residues in crops, the pesticides arc extracted from the crops with ethyl acetate and a 10–20 g aliquot is placed directly on the charcoal adsorbent column for cleanup. The Kuderna-Danish concentrated eluate is analyzed by GLC, using the potassium chloride thermionic detector. Analytical results are presented for pesticide field-treated crops and for crop extracts fortified with a total of 60 parent organophosphorus pesticides and alteration products. Recoveries averaged 90% or better in most cases.
Analysis of a Single Crop Extract for Substituted Urea Herbicides and Metabolites, Chlorinated Insecticides, and Amitrole
Authors: Onley John H , Yip George
Published: February 2020

An established method for chlorinated insecticides has been modified and extended to include substituted urea herbicides, some urea metabolites, and amitrole. Starting with an acetonitrile sample extract, chlorinated insecticides are removed by petroleum ether extraction for the usual cleanup and determination. The aqueous acetonitrile phase is next extracted with methylene chloride and carbon tetrachloride to isolate the urea compounds (chloroxuron, diuron, fenuron, fluometuron, linuron, metobromuron, monuron and neburon) and some of their metabolites. This combined extract is chromatographed on a MgO-cellulose-Florisil column from which two eluatcs are obtained: one contains the substituted urea herbicides, aniline metabolites, and one compound with the urea moiety and the second contains four compounds with the urea moiety. Both eluates are analyzed by thin layer chromatography. Finally, the aqueous acetonitrile extract is passed through a column of Amberlite IR-120 resin. Amitrole (3-AT), which is absorbed on the resin, is removed with NH4OH and determined by a colorimetric procedure. Recoveries of all compounds from samples fortified at 0.05–5 ppm ranged between 70 and 106%. Apparent limit of sensitivity was 0.05 ppm for both the substituted urea herbicides and their metabolites and for amitrole. Recoveries for the chlorinated insecticides at 0.005 ppm ranged between 76 and 104%.
Alkalimetric Quimociac Method for Phosphorus in Fertilizers: Collaborative Study
Authors: Caudill Paul R
Published: February 2020

The alkalimetric variation of the quimociac method was shown by collaborative testing to be accurate and precise for determining total phosphorus, citrate-insoluble phosphorus, or available phosphorus by the direct method. The method is recommended for adoption as official first action.
Sampling Bulk Fertilizers in Railroad Cars and Piles
Authors: Gehrke Charles W , Baker Winfred L , Krause Gary F , Russell C H
Published: February 2020

The AOAC official samplers (stream sampler, compartmental triers, and Missouri “D” tube) secured samples of ammoniated granular fertilizers at all locations in railroad cars and warehouse piles that were well within the AAFCO tolerances. Dry blended fertilizers in lots of this size could not be sampled as outlined in this study. Recommendations are made for the sampling of fluid fertilizers (in absence of free ammonia).
Aflatoxins: Improved Resolution by Thin Layer Chromatography
Authors: Stubblefield R D , Shannon G M , Shotwell O L
Published: February 2020

Water was added to solvent systems for TLC of aflatoxins to achieve more reproducible results in laboratories where temperature and relative humidity vary. Resolution of the toxins also improved. Increments of water were added to solvent systems composed of acetone-chloroform (10 + 90, 12 + 88, and 15 + 85, v/v). As the water concentration was increased, separation of aflatoxins B2 and G1 improved. These two toxins are usually the most difficult to resolve in these solvent systems. Separations were the best with wateracetone-chloroform (1.5 + 12 + 88, v/v/v). Water added to methanol-chloroform (3 + 97, v/v) improved resolution of this solvent system but not enough for quantitative analysis, or at times, qualitative analysis. The solvent system water-methanol-ether (1 + 3 + 96, v/v/v) separated aflatoxins as well as water-acetone-chloroform (1.5 + 12 + 88, v/v/v).
Microbiological Assay of Erythromycin Thiocyanate in Feeds
Authors: Perdue H S , Gordon J A , Mannebach J
Published: February 2020

A modified procedure has been developed for extracting low levels (5-20 g/ton) of erythromycin thiocyanate from feeds. In the new method, erythromycin thiocyanate is extracted from the feed with acetone, the acetone is evaporated, and the extract is washed with n-hexane (5 parts) followed by methanol (1 part). The n-hexane and methanol washings are combined and partitioned with phosphate buffer prior to assay using Sarcina lutea ATCC 9341. Recovery averaged 106 ± 10%.
Microbiological Assay of Streptomycin in Feeds
Authors: Mayernik John J
Published: February 2020

Studies of the microbial assay of streptomycin were conducted to evaluate (1) four methods of preparing compensating standard curves and (2) a n IRC-50 resin separation method to overcome the interference of feed components in low level feeds. Compensating curves were prepared from extracts of blank feed, from extracts of feed in which streptomycin was adsorbed by IRC-50 in a batch method and also in a column method, and from extracts of feed by the method of standard addition. Recoveries of streptomycin using the extract of blank feed and extract of feed by the method of standard addition were promising (83–96%), whereas recoveries using IRC-50 resin-inactivated extract were low (47–62%). The IRC-50 resin separation method was found to be satisfactory in principle, but the interference of the feed components was not resolved. Further studies are planned on the compensation methods and the resin separation method.
Modified Resazurin Test for Estimating Bacterial Population in Maple Sap
Authors: Kissinger J C
Published: February 2020

The resazurin test for bacterial counts in milk has been modified for estimating the bacterial cells in maple sap. This simple test provides an approximate bacterial cell count in 2–3 hr.
Characterization of the Steam Nonvolatile Residue of Bergamot Oil and Some Other Essential Oils
Authors: Cieri Ugo R
Published: February 2020

A method is presented for identifying and estimating the coumarins and furocoumarins present in bergamot oil and four other essential oils. Solutions of the nonvolatile residue of the oils are spotted on silica gel thin layer plates and developed in hexane-ethyl acetate (75+25) for 4 hr. The separated compounds are identified by their Rf values and characteristic fluorescence under short wave UV light; the spots are marked, scraped from the plate, and extracted with chloroform. The centrifuged extracts are scanned in a recording spectrophotometer from 400 to 240 mμ. Bergaptene, citroptene, bergamottin, and 7-methoxy-5-geranoxycoumarin were also individually estimated. Bergaptol, isopimpinellin, and xanthotoxin could be estimated only roughly because of low absorbance readings or lack of standards. A procedure to isolate and purify bergamottin from bergamot oil and 7-methoxy-5-geranoxycoumarin from lime oil, to serve as reference standards, is also included.
Effect of Dilution on Mold Counts of Tomato Catsup
Authors: Schulze Arnold E , Eisenberg William V , Douglas Ruth G , Parran Hamilton M
Published: February 2020

Mold counts of samples from 34 catsup factories in the United States were made by two methods: a direct count and a 1 + 1 dilution. An average mold count on undiluted catsup of 44% (which is in a significant range) was reduced to an average of 35.5% on dilution. From factories with special comminuting equipment, a few samples showed greater reduction in mold count on dilution than samples produced with the conventional pulper and finisher; samples processed with an Urschel Comitrol in the FDA pilot plant showed less reduction.
Collaborative Study of a Colorimetric Determination of Nitrate in Tobacco
Authors: Rosene C James
Published: February 2020

A colorimetric method for determining water-soluble nitrate in tobacco was studied by 14 laboratories on eight Burley and two cigar filler tobacco samples with nitrate levels of 0.5–2.4%. In the method, ground tobacco is extracted with water and filtered, and an aliquot is then treated with 2,4-xylenol in sulfuric acid; then the resulting 6-nitro-2,4-xylenol is removed by distillation and measured spectrophotometrically at 450 µm. Results show that, althoughthe precision standard deviation among laboratories is generally acceptable, the systematic error standard deviation is unacceptably high. This study will be continued.
Extraction and GLC Determination of Mixed Sulfonamides in Feeds
Authors: Fravolini Arnaldo , Begliomini Alfredo
Published: February 2020

Seven sulfonamides added to feed samples were extracted with DMF and hydrolyzed to the amines with sulfuric acid. After alkalization, the extracts were analyzed by GLC, using a Carbowax 20M column. Recoveries averaged between 94 and 104%. The described method is rapid and requires a minimum of manipulations.
Nonaqueous Polarographic Analysis of Nitroglycerin
Authors: Woodson Albert L , Alber Larry L
Published: February 2020

The DC and AC polarographic response of nitroglycerin in the nonaqueous medium of acetonitrile-0.1M tetrabutylammonium perchlorate is presented. DC polarographic results are shown to be superior with respect to sensitivity limits and linearity of the response (wave height) vs. concentration profile. DC polarography is applied successfully to the analysis of two types of commercial formulations containing nitroglycerin. The results are compared with other methods for the determination of nitroglycerin, e.g., infrared, the phenoldisulisulfonic acid procedure for organic nitrates, and a column chromatographic procedure.
Atomic Absorption Analysis of Copper and Lead in Meat and Meat Products
Authors: Dalton Edward F , Malanoski Anthony J
Published: February 2020

Atomic absorption spectrophotometric determination of lead and copper in meat products is described. Organic material is destroyed by dry ashing at 500°C. Copper and lead levels ranged from 1–5 and 1–10 ppm, respectively.
Chemical Composition of Florida Orange Juice Concentrates
Authors: Floyd Kermit M , Harrell Jimmy E
Published: February 2020

Authentic samples of Florida orange juice concentrates were analyzed for soluble solids, acidity, amino acids, polyphenolics, f-malic acid, and betaine. Samples were collected from various processing plants during January through May 1968. Authentic data and a statistical study are presented.
Determination of 2-Nitropropanol Residues in Cottonseed
Authors: Devine James M , Fletcher Barbara , Zweig Gunter
Published: February 2020

2-Nitropropanol, a metabolite of Lanstan, can be extracted from cottonseed with ethyl acetate and analyzed by electron capture GLC. The average recovery for fortification levels ranging from 0.05 to 0.2 p pm was 84.7 ± 11.1%. Lanstan does not interfere with this method because it elutes with the solvent under the GLC conditions used for analysis.
Elemental Analyses of Plant Leaf Tissue by Several Laboratorie
Authors: Jones J Benton
Published: February 2020

Eighteen laboratories reported the analyses of seven plant tissue referee samples for the elements N, P, K, Ca, Mg, Al, B, Cu, Fe, Mn, Na, and Zn. Agreement among the laboratories was good for the elements N, P, Mn, Mg, K, and Ca. Poor agreement was obtained for the elements B and Cu with only fair agreement for Na, Al, Zn, and Fe. The results from this exchange of samples were not too different from those obtained by others in similar studies. Although the probable sources for the variances were not investigated, failure to specify drying and ashing technique, as well as the lack of plant tissue standards from a reliable source, may have contributed to discrepant analyses in some laboratories. Also, analysts need to carefully evaluate calibration and operating techniques, particularly when emission spectrographs are used to perform plant tissue analyses. Exchange of plant tissue referee samples between laboratories can be of assistance to the analyst when plant tissue standards are not available.
Improved Method for the Analysis of Total Nitrogen and TCA-Precipitable Nitrogen in Tuberculin and Johnin Biologies
Authors: Czech Fred P , Sunseri Alfred P
Published: February 2020

Tuberculin is routinely tested for safety, potency, etc., including chemical tests for total and TCA-precipitable nitrogen content. The last two tests have large methodological errors. Methods obtaining greater accuracy and precision are presented and compared to present procedures; they are recommended as substitutes for existing methods.
Compounds Identified in Whisky, Wine, and Beer: A Tabulation
Authors: Kahn J H
Published: February 2020

Components which have been identified in alcoholic beverages by this laboratory and by other workers are listed with the pertinent references.
Note on Detection and Quantitative Analysis of Cyclohexylamine
Authors: Gunner S W , O’Brien R C
Published: February 2020

CIIA is reacted with picryl chloride to form a stable crystalline N-trinitrophenyl derivative. This procedure eliminates CHA loss during sample work-up and, using GLC, permits detection in the subnanogram range with an electron capture detector. Quantitative analysis is achieved using 3,3,5-trimethylcyclohexylamine as internal standard and is illustrated by the analysis of CHA in cyclamate at a level of 1 ppm.
Survey of Chlorinated Insecticide Residue Analyses in Soils
Authors: Woolson E A , Kearney P C
Published: February 2020

Kecovery methods of 12 laboratories were compared for the extraction and detection of 11 chlorinated hydrocarbon insecticides in three soil types. Nine laboratories averaged 78% recovery (range 60–106%) with an average error of the mean of 21% and average coefficient of variation of 45%. Highest recoveries were obtained from wet samples extracted with hexane-acetone by Soxhlet extraction. Variability increased as concentration decreased below 1.00 p pm insecticide.
Head Space Gas Procedure for Screening Food Samples for Dithiocarbamate Pesticide Residues
Authors: Mcleod H A , Mccully K A
Published: February 2020

screening procedure has been developed for dithiocarbamate residues in foods. The CS2 evolved from an H2SO4-sample mixture at 60°C for 30 min was determined by GLC; recoveries of ferbam, thiram, and ziram added to apples, strawberries, lettuce, celery, cabbage, cucumber, and carrots ranged from 80 to 114% at 3.5 ppm and from 86 to 112% at 7 ppm. Recoveries of maneb, nabam, and zineb were not satisfactory. When an HCl-stannous chloride reagent was substituted for the H2SO4 reagent, recoveries of the ethylenebisdithiocarbamates were considerably improved. Maneb and ziram recoveries ranged from 70 to 95% in all samples; ferbam, thiram, and ziram, from 84 to 100%; and nabam, from 44 to 83%. The difference between duplicate recovery values, using the latter reagent, ranged from 0 to 11.2% units; 87% of these values were less than 10%.
Rapid GLC Method for Determining Residues of Fenthion, Disulfoton, and Phorate in Corn, Milk, Grass, and Feces
Authors: Bowman M C , Beroza Morton
Published: February 2020

Residues of fenthion, disulfoton, and phorate may each consist of the parent insecticide and five metabolites formed by oxidation of the thionophosphate and sulfide groups in each molecule. The analysis of these residues has been simplified and speeded by oxidizing the insecticide and its metabolites to the oxygen analog sulfone with m-chloroperbenzoic acid. After removal of the acid on an alumina column, the compound is determined by GLC with a flame photometric detector. Sensitivity (twice noise) is at least 0.001 ppm. When equal amounts of the six compounds were added to corn, milk, grass, and feces at levels of 0.2 to 5.0 ppm, the recoveries were 95–96% for fenthion and 74–82% for disulfoton and phorate. In analyses of field-treated samples, recoveries were 89–92% of those obtained by previous procedures, which are much more time-consuming.
Estimation of Aflatoxin in Corn by “Dockage” Assay
Authors: Johnson Robert M , Greenaway Walter T , Dolan William P
Published: February 2020

A method of analyzing corn for aflatoxin was developed by assaying only the broken corn, foreign material, and chaff (dockage). Only 1 out of 21 commercial ground corn samples to which corn containing aflatoxin was added gave positive results for aflatoxin. On the other hand, all “Dockage” portions sieved from these same samples gave positive results. The procedure consists of streaking corn extracts on preparative coated sheets for cleanup, separation, and identification. If quantitative results are desired, fluorescent areas are collected and spotted on TLC plates for identification under UV light.
Validation of a Modified Version of Actero™ Salmonella Enrichment Media for Rapid Detection of Salmonella spp. in Environmental and Food Samples
Authors: Boumail Afia , Eyraud Alex , Akassou Mounia , Geffroy Mélanie , Sicard Jean-Félix , Tremblay Renaud , Olishevskyy Sergiy
Published: February 2020

Background

Actero™ Salmonella Enrichment Media1 (Actero™ Salmonella) is a culture broth developed to recover Salmonella spp. from foods and environmental surfaces. Performance of Actero™ Salmonella broth has already been assessed and validated (AOAC Performance Tested MethodSM 041403) for the detection of Salmonella spp. in various foods, feeds and environmental samples.

Objective

This study aimed to validate the performance of a modified version of Actero™ Salmonella broth by incorporating one of the two liquid supplements into the powdered formula.

Methods

Inclusivity, exclusivity, stability, and lot-to-lot studies were carried out. Raw ground beef, chicken carcass rinse, dry pet food and stainless steel samples were enriched for 14–20 h at 35–39°C and analyzed using real-time PCR assay as well as by direct plating.

Results

The Probability of Detection assay confirmed the equivalent performance of the alternative methods as compared to the reference methods. All Salmonella strains, except Salmonella II : 57: z29:-, were able to grow in Actero™ Salmonella broth. One-half of the non-target strains did not grow in Actero™ Salmonella broth, whereas the atypical for Salmonella growth was observed for other non-target microorganisms subsequently plated onto selective and differential agars. Lot-to-lot consistency was demonstrated for three consecutively manufactured lots of the broth. The liquid broth was proven to be stable at 4°C for up to 9 weeks of storage.

Conclusions and Highlights

The incorporation of one of the two specific supplements into a powdered formula of Actero™ Salmonella broth made it more convenient to use without compromising the performance and accuracy.
New SI and precision measurements: an interview with Tianchu Li
Authors: Wang Jin
Published: February 2020

On 13–16 November 2018, the 26th General Conference of Weights and Measures (CGPM) was held in Paris. The conference adopted Resolution A on ‘Revision of the International System of Units (SI).’ According to Resolution A: four of the SI basic units, namely kilograms, amps, kelvin and mole, are defined by the Planck constant h, the basic charge constant e, the Boltzmann constant k and the Avogadro constant NA, respectively. This establishes the basic quantities and units in SI on a series of constants. The new SI was officially launched on 20 May 2019. This is the most significant change and a milestone in the history of metrology since the Metre Convention was signed in 20 May 1875. Professor Tianchu Li, an academician of the Chinese Academy of Engineering, has been working on time and frequency standards for 37 years. In this interview, Prof. Li reviews the quantization and constant evolutions of the second and meter, and introduces the redefinitions of ampere, kelvin, kilogram and mole, and their significance for precision measurements.
Yogurt, cultured fermented milk, and health: a systematic review
Authors: Savaiano Dennis A , Hutkins Robert W
Published: February 2020

Consumption of yogurt and other fermented products is associated with improved health outcomes. Although dairy consumption is included in most dietary guidelines, there have been few specific recommendations for yogurt and cultured dairy products. A qualitative systematic review was conducted to determine the effect of consumption of fermented milk products on gastrointestinal and cardiovascular health, cancer risk, weight management, diabetes and metabolic health, and bone density using PRISMA guidelines. English language papers in PubMed were searched, with no date restrictions. In total, 1057 abstracts were screened, of which 602 were excluded owing to lack of appropriate controls, potential biases, and experimental design issues. The remaining 455 papers were independently reviewed by both authors and 108 studies were included in the final review. The authors met regularly to concur, through consensus, on relevance, methods, findings, quality, and conclusions. The included studies were published between 1979 and 2017. From the 108 included studies, 76 reported a favorable outcome of fermented milks on health and 67 of these were considered to be positive or neutral quality according to the Academy of Nutrition and Dietetics’ Quality Criteria Checklist. Of the 32 remaining studies, the study outcomes were either not significant (28) or unfavorable (4), and most studies (18) were of neutral quality. A causal relationship exists between lactose digestion and tolerance and yogurt consumption, and consistent associations exist between fermented milk consumption and reduced risk of breast and colorectal cancer and type 2 diabetes, improved weight maintenance, and improved cardiovascular, bone, and gastrointestinal health. Further, an association exists between prostate cancer occurrence and dairy product consumption in general, with no difference between fermented and unfermented products. This article argues that yogurt and other fermented milk products provide favorable health outcomes beyond the milk from which these products are made and that consumption of these products should be encouraged as part of national dietary guidelines.

Systematic review registration:  PROSPERO registration no. CRD42017068953.
Clinical applications of exosome membrane proteins
Authors: Hu Qian , Su Hang , Li Juan , Lyon Christopher , Tang Wenfu , Wan Meihua , Hu Tony Ye
Published: February 2020

Extracellular vesicles (EVs) are small membranous particles that can mediate cell-to-cell communication and which are divided into at least three categories according to their subcellular origin and size: exosomes, microvesicles, and apoptotic bodies. Exosomes are the smallest (30–150 nm) of these EVs, and play an important role in EV-mediated cell-to-cell interactions, by transferring proteins, nucleic acids and, lipids from their parental cells to adjacent or distant cells to alter their phenotypes. Most exosome studies in the past two decades have focused on their nucleic acid composition and their transfer of mRNAs and microRNAs to neighboring cells. However, exosomes also carry specific membrane proteins that can identify the physiological and pathological states of their parental cells or indicate their preferential target cells or tissues. Exosome membrane protein expression can also be directly employed or modified to allow exosomes to serve as drug delivery systems and therapeutic platforms, including in targeted therapy approaches. This review will briefly summarize information on exosome membrane proteins components and their role in exosome–cell interactions, including proteins associated with specific cell-interactions and diseases, and the potential for using exosome membrane proteins in therapeutic targeting approaches.
Opening the Trojan horse: phylogeny of Astyanax, two new genera and resurrection of Psalidodon (Teleostei: Characidae)
Authors: Terán Guillermo E , Benitez Mauricio F , Mirande J Marcos
Published: February 2020

The freshwater fish genus Astyanax is one of the most diverse among the Characidae. The genus is defined by a combination of character states that are widely distributed in Characidae. In addition, the genus has the broadest geographical distribution in the family, being found in a great variety of environments of the Neotropical region. Although phylogenetic relationships were treated only partially, many authors agree that the genus is not monophyletic. In this contribution, we study the phylogenetic relationships of Astyanax in the context of the family Characidae, by combining morphological and molecular data. A total of 520 morphological characters, nine molecular markers and 608 taxa are analysed, of which 98 belong to Astyanax. According to our results, Astyanax is not monophyletic. We recovered species attributed to Astyanax in different subfamilies: Gymnocharacinae (including the type species), Stevardiinae and Tetragonopterinae. Among the species recovered in Gymnocharacinae, most (including the type species, the resurrected Psalidodon, and the new genus Andromakhe gen. nov.) were recovered in Gymnocharacini, while the remaining ones were recovered in Probolodini (transferred to Deuterodon or the new genus Makunaima gen. nov.).
A total-evidence approach resolves phylogenetic placement of ‘Cafius’ gigas,a unique recently extinct rove beetle from Lord Howe Island
Authors: Jensen Arn Rytter , Jenkins Shaw Josh , Żyła Dagmara , Solodovnikov Alexey
Published: February 2020

Cafius gigas Lea, 1929 (Coleoptera: Staphylinidae) was a large rove beetle endemic to Lord Howe Island (LHI) resembling Cafius and the LHI flightless endemic Hesperus dolichoderes (Lea, 1925). Like several other LHI endemics, C. gigas became extinct due to human-introduced rats. It is a legacy species valuable for understanding the LHI biota in terms of evolutionary biology and historical biogeography. Whether C. gigas was a member of Cafius Curtis, 1829, restricted to oceanic shores and prone to trans-oceanic dispersal, or related to H. dolichoderes, would have different implications. We subjected C. gigas to a total-evidence phylogenetic analyses of morphological and molecular data using model-based and parsimony methods. As a result, it is transferred to Hesperus Fauvel, 1874 with the new combination Hesperus gigas (Lea, 1929) comb. nov. Our analysis indicates that the montane leaf litter inhabitant H. gigas evolved neither in situ nor from a seashore Cafius-ancestor, or from an ancestor shared by two other LHI endemic congeners, Hesperus pacificus Olliff, 1887 and H. dolichoderes. It also suggests that all three Hesperus species that currently occur on LHI could have evolved on various seamounts at various times before reaching LHI.
KIT and PDGFRa mutational patterns in Sardinian patients with gastrointestinal stromal tumors
Authors: Palomba Grazia , Paliogiannis Panagiotis , Sini Maria C. , Colombino Maria , Casula Milena , Manca Antonella , Pisano Marina , Sotgiu Giovanni , Doneddu Valentina , Palmieri Giuseppe , Cossu Antonio
Published: February 2020

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal malignancy of the gastrointestinal tract. We provide in the present article the molecular characterization of a series of primary GISTs in a cohort of Sardinian patients (Italy), with the aim to describe the patterns of KIT and PDGFRa mutations and the corresponding clinical features. Ninety-nine Sardinian patients with histologically-proven diagnosis of GIST were included in the study. Medical records and pathology reports were used to assess the demographic and clinical features of the patients and the disease at the time of the diagnosis. Formalin-fixed, paraffin-embedded tissue samples were retrieved for each case, and mutation analysis of the KIT and PDGFRa genes was performed. KIT and PDGFRa mutations were detected in 81.8% and 5% of the cases, respectively. The most common KIT mutation was W557_K558del in exon 11, while D842V in exon 18 was the most common PDGFRa genetic alteration; V561D was the only PDGFRa mutation found in exon 12. The global “wild-type” cases, with no mutations in either the KIT or PDGFRa genes, were 13 (13.1%). The mean survival of those patients was approximately 46.9 (±43.9) months. Globally, 86.9% of Sardinian patients with GIST had a KIT or PDGFRa mutation; the former were more frequent in comparison with other Italian cohorts, while PDGFRa mutations were rare. No statistical differences in survival between mutated and wild-type cases, and between KIT and PDGFRa mutated cases were detected in our study.
ALTERED BLOOD AND AQUEOUS HUMOR LEVELS OF ASPROSIN, 4-HYDROXYNONENAL, AND 8-HYDROXY-DEOXYGUANOSINE IN PATIENTS WITH DIABETES MELLITUS AND CATARACT WITH AND WITHOUT DIABETIC RETINOPATHY
Authors: Oruc Yavuz , Celik Fatih , Ozgur Gokhan , Beyazyildiz Emrullah , Ugur Kader , Yardim Meltem , Sahin Ibrahim , Akkoc Ramazan Fazil , Aydin Suleyman
Published: February 2020

Purpose:

Diabetic retinopathy (DRP) is the formation of edema and small vessels in the retina due to high blood glucose levels. Asprosin is a hormone that stimulates the release of glucose from the liver into the circulation. Considering the relationship between oxidative stress and DRP, our study aimed to determine the levels of the oxidative stress markers 4-hydroxynonenal (4-HNE) and 8-hydroxy-2′-deoxyguanosine (8-OHdG), as well as asprosin, in the blood and aqueous humor (Aq) of patients with and without DRP.

Methods:

Thirty patients with single-eye DRP and cataract (DRP + C), 30 patients with diabetes mellitus and cataract without DRP (DM + C), and 30 healthy control (CON) participants were enrolled into this retrospective study. Except for healthy controls, Aq and blood samples were taken from these patients during their cataract operation. Asprosin, 4-HNE, and 8-OHdG concentrations were analyzed using enzyme-linked immunosorbent assays.

Results:

In patients with DRP, the levels of asprosin, 4-HNE, and 8-OHdG were significantly higher in both Aq and blood samples compared with the group of patients without DRP.

Conclusion:

These findings suggest that the measurement of asprosin, 4-HNE, and 8-OHdG levels may support clinicians in determining the risk of DRP development.