bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Detection of Chlorinated Insecticides in the Presence of Polychlorinated Biphenyls
Authors: Dolan J W , Hall R C , Todd T M 
Published: February 2020

Abstract
A gas chromatographic method for selectively detecting chlorinated insecticides in the presence of polychlorinated hiphenyls is reported. A Coulson electrolytic conductivity detector was modified to allow precise control of furnace temperature and hydrogen reaction gas flow. A furnace temperature of 600°C and a hydrogen flow of 1-2 ml/min were most advantageous for selective detection of chlorinated insecticides in the presence of polychlorinated hiphenyls.
Wet Sieve Analysis of Limestone
Authors: Rexroad Paul R 
Published: February 2020

Abstract
A study of wet sieving vs. dry sieving was made on 47 limestone samples. Fifteen samples showed absolute differences of 5% or more on a U.S. No. 40 sieve when the dry samples were not crushed to break agglomerates. Three samples differed by more than 15%. Crushing “with a hard rubber roller on a hard rubber mat” reduced the absolute difference by 2.9 to 10.3% on the 15 samples. The wet sieving technique has been accepted as an alternative technique for crushing of agglomerates.
Determination of Esters in Alcoholic Beverages
Authors: Coe G R , Baldwin S , Andreasen A A 
Published: February 2020

Abstract
Results are presented on a collaborative study comparing 2 methods for the determination of esters in distilled alcoholic beverages. A previously described colorimetric method was compared with the present official AOAC saponification method, 9.050–9.052. Statistical evaluation of the data shows that the 2 methods are comparable in accuracy and precision. The colorimetric method has been adopted as official first action as an alternative to 9.050–9.052 for the determination of esters in distilled alcoholic beverages.
Collaborative Study of the Determination of Total Lipids in Fish Meal
Authors: Knobl George M , Miller Harry 
Published: February 2020

Abstract
A semimicro method for determining total lipids in fish meal, using a compact extraction apparatus, was subjected to collaborative study. Four fish meals were analyzed for total lipids by 8 collaborators. Per cent lipid content of meals prepared from Canadian herring, Peruvian anchovetta, Atlantic menhaden I, and Atlantic menhaden II were 14.69±0.37, 15.98±0.28, 14.66±0.45, and 10.86±0.26, respectively. In our laboratory, the new extraction technique was also compared with a blender technique. In general, the variation in lipid content within a laboratory, using the extractor, was less than the variation found in our laboratory, using the blender. The semimicro method for the determination of total lipids in fish meal has been adopted as official first action. It is recommended that another collaborative study be conducted, using both the blender and the extractor.
Comparison of Gas Chromatographic Calibration Methods for Analysis of Menadione and Menadione Sodium Bisulfite Content of Pharmaceutical Products
Authors: Shepparid A J , Hubbard W D , Prosser A R 
Published: February 2020

Abstract
A comparative study was made of 2 GLC calibration methods for determining the menadione and menadione sodium bisulfite content of pharmaceuticals. One method utilizes an external standard and the second method makes use of butylated hydroxyanisole as an internal standard. Measurements were made on 8 pure solutions of known concentration of menadione and on 5 pharmaceuticals containing menadione or menadione sodium bisulfite. No significant difference was found between the results obtained by the 2 methods.
Collaborative Study of the Determination of Available Manganese in Fertilizer
Authors: Thorpe Virginia A 
Published: February 2020

Abstract
A collaborative study was conducted to show that the H2SO4-HNO3 digestion in the atomic absorption method for manganese in fertilizer more nearly reflects the available divalent manganese than the HC1 digestion now in use. A method to determine water-soluble forms of manganese was included in the study. Modifications of the HC1 digestion used for total manganese content including available and unavailable forms of manganese (Mn(II) and Mn(IV)) and the H2SO4-HNO3 digestion used for total divalent forms of available manganese were adopted as official first action; the water extraction method was adopted as official first action for water-soluble forms of divalent manganese.
Microbiological Assay of Monensin in Chicken Rations
Authors: Breunig H Latham , Kline Richard M , Bikin H 
Published: February 2020

Abstract
The microbiological plate assay method for monensin in chicken rations reported earlier was submitted in a slightly modified form to 10 collaborating laboratories, along with randomized and coded samples. Other factors in the experiment design were ration types (4 at 2 potency levels) and feed forms (2—meal and pellets). Mean recoveries on 4 ration types were 90.5–96.3% of label over all laboratories and feed forms, while mean recoveries on the 2 feed forms were 96.7% for meal and 89.7% of label for pellets over all laboratories and ration types. The mean recoveries in the 10 laboratories ranged from 78.6 to 119.9% of label, with a median of 93.8%. Only one laboratory was an outlier. There were no significant interactions. The laboratories were uniform with respect to within-laboratory variation. Relative standard deviations of the assay within the laboratories ranged from 3.5 to 12.5% with a median of 6.85%. The microbiological assay method for monensin has been adopted as official first action.
Collaborative Study of a Method for Determining Lead in Plant and Animal Products
Authors: Hoover William L 
Published: February 2020

Abstract
A method for the determination of lead in food products was collaboratively studied. The method involves co-precipitation of lead with strontium sulfate, conversion to carbonate, dissolution in nitric acid, and determination by atomic absorption spectrophotometry. Eight collaborating laboratories reported analytical results for 24 test samples. Results indicated that the systematic error was essentially the same as the random error at the 99% level. Acceptable coefficients of variation were observed. The method has been adopted as official first action.
Synthesis of Chlorobiphenyls Labeled with Deuterium and Chlorine-36
Authors: Hutzinger O , Pothier C , Safe S 
Published: February 2020

Abstract
Four di-, tetra-, and hexachlorobiphenyls labeled with deuterium (&gt;98%) in specific positions have been prepared by selective hydrogenolysis of iodine from chloroiodobiphenyls with lithium aluminum deuteride. 3,3’,4,4’- Tetrachlorobiphenyl (4,4’-36Cl) and 2,2’,4,4’,- 5,5’-hexachlorobiphenyl (4,4’-36Cl) were made by the decomposition of the corresponding chlorobiphenyl diazonium fluoroborates in dimethyl sulfoxide in the presence of ferric chloride-36Cl. The 2 synthetic routes described are models for the preparation of many related compounds because a variety of amino compounds, which are starting materials in the reactions described, are readily available.
Rapid Screening Method for the Determination of Organochlorine Pesticide Residues in Wheat by Electron Capture Gas Chromatography
Authors: Levi Iser , Mazur P B , Nowicki T W 
Published: February 2020

Abstract
A rapid screening method, employing a gas chromatographic technique with electron capture detection, has been developed for t h e analysis of organochlorine pesticide residues in hard red spring wheat. Ground wheat is extracted by ball-milling with an ethyl etherhexane (3 + 97) extractant. After filtration, the extract is cleaned up on a partially deactivated Florisil column, using a single eluting system, ethyl ether-hexane (1 + 99). The eluate i s concentrated before gas chromatographic analysis. Sixteen organochlorine pesticide chemicals were recovered in excess of 80% from wheat samples fortified at 0.010 and 0.200 ppm. Organochlorine pesticide residues were recovered by the rapid method from 18 samples with field-incurred residues as efficiently as by t he Bertuzzi et al. method. Organochlorine pesticide residues were also recovered by t h e rapid method from 4 samples with field-incurred residues and from 2 wheat samples, spiked at 0.500 ppm as efficiently as by the total extraction method of Mumma et al. The rapid method offers a savings in time and solvents over.the Bertuzzi et al. method for the determination of organochlorine pesticide residues in wheat.
A Systematic Approach to Ink Identification
Authors: Brunelle Richard L , Pro Maynard J 
Published: February 2020

Abstract
A systematic approach to identification of writing inks is presented. This approach uses a multiple technique method for analysis of the inks to develop a large number of identifiable points for comparison. Well established methods are used for the analysis of inks, such as thin layer chromatography, spectrophotometry, and gas-liquid chromatography, in addition to traditional methods for comparison which use ultraviolet and infrared light. The inks are identified by comparing the results of the questioned inks with results obtained from a complete library of writing inks maintained by this laboratory. By using the described approach, most inks can be identified with a high degree of certainty.
Collaborative Study of a Joint AOAC-OICC Method for the Determination of Ash in Cacao Products
Authors: Iverson John L 
Published: February 2020

Abstract
A joint AOAC-OICC method for determining ash in cacao products, combining the best features of AOAC method 13.003 and OICC method 4a-E/1952 and with an ashing temperature of 600°C, has been developed. The results from an international collaborative study with 12 collaborators were in good agreement. The preferred method is pre-ashing of the sample under infrared lamps, followed by overnight ashing, thus eliminating reweighing at intervals to arrive at constant weight. The method for determining ash in cacao products has been adopted as official first action.
Organic Acids in Vanilla by Gas-Liquid Chromatography: Interpretation of Analytical Data
Authors: Schoen Kurt L 
Published: February 2020

Abstract
A method for interpreting data obtained by using AOAC method 19.046–19.048 for the gasliquid chromatographic determination of vanilla acids is given. Total adjusted peak heights of unknown extracts and authentic extracts are compared. The total organic acid content of the unknown extracts is expressed as a percentage of the total organic acid content of the authentic extract. Thus variations in operator techniques and gas-liquid chromatographic conditions are eliminated and a more accurate quantitative judgment regarding the vanilla bean content of the unknown sample can be made. Data on authentic and unknown vanilla extracts are given.
Wet Oxidation Method for the Determination of Submicrogram Quantities of Mercury in Cereal Grains
Authors: Malaiyandi M , Barrette J P 
Published: February 2020

Abstract
A simple and rapid wet-digestion procedure is described in which flour samples containing bound and unbound mercury are decomposed, using a sulfuric-nitric acid mixture in the presence of small amounts of vanadium pentoxide. Fortification studies with 3 organomercuric compounds on mixed cereal flour indicate average recoveries in excess of 96% in the 20–500 ppb range. This wet digestion method is compared with the Klein procedure to illustrate the advantages and significance of the vanadium pentoxide oxidation.
Collaborative Study of an On-Column Periodate Reaction Method for the Analysis of Phenylpropanolamine Hydrochloride in Elixirs
Authors: Clark Charles C 
Published: February 2020

Abstract
Twelve laboratories collaboratively studied a method for the quantitative UV determination of phenylpropanolamine HC1 in elixirs. The phenylpropanolamine is separated from water-soluble impurities and strong acids by elution from a weakly basic Celite column. Further cleanup is accomplished by retention of the phenylpropanolamine on a weakly acidic column while the weak acids, weak bases, and organic-soluble neutrals are eluted. Phenylpropanolamine is eluted from the column after neutralization with NH3 and is converted to benzaldehyde via an on-column periodate reaction. The samples collaboratively studied consisted of 2 commercial and 2 synthetic elixirs. Recoveries of the synthetic elixirs averaged 100.1 and 101.8% for mixtures containing 5.05 and 12.52 mg/5 ml phenylpropanolamine HC1, respectively. The means and standard deviations for the commercial preparations were 4.75 ±0.12 and 12.34±0.16 mg/5 ml. The method has been adopted as official first action.
Gas Chromatographic Determination of Triarimol in Formulations and Technical Material
Authors: Frank Richard , Decker Oliver D , Day Edgar W 
Published: February 2020

Abstract
The triarimol content in formulations and technical materials is determined by flame ionization gas-liquid chromatography after the sample is dissolved in or extracted with chloroform. Pesticides commonly occurring with triarimol do not interfere in this method. Replicate injections of emulsifiable concentrate and wettable powder samples showed good precision.
Gas-Solid Chromatographic Determination of Oxygen, Nitrogen, Carbon Dioxide, Ethylene, and Nitrous Oxide at Ambient Temperature
Authors: Finkelson Martin J 
Published: February 2020

Abstract
A gas-solid chromatographic method is described for the separation and determination of 5 medicinal gases at ambient temperature, using 2 gas chromatographic columns, Porapak Q and Molecular Sieve 13X, operated in series with a 6-port thermal conductivity detector and I recorder. An electronic digital integrator is used for calculating peak areas. Data on retention time, linearity, reproducibility of injection, and comparison with absorption methods are presented. Analytical results for oxygen, nitrogen, carbon dioxide, ethylene, and nitrous oxide are attainable within 1.0% without the use of an internal standard.
Determination of Oxalic Acid in Foods
Authors: Franco Vincent , Krinitz Benjamin 
Published: February 2020

Abstract
Two methods for the determination of oxalic acid were collaboratively studied. In both methods, the oxalic acid in spiked and unspiked spinach is precipitated as calcium oxalate from a buffered (pH 4.0–4.5) solution. The precipitate is separated from the solution by centrifuging 15 min at 1700 rpm. The oxalic acid is determined either by titrating the oxalate in the precipitate with potassium permanganate or measuring the calcium in the precipitate by atomic absorption and calculating it as oxalic acid. Mean recoveries of oxalic acid added at the 175 mg/100 g level were 99.5 and 100.5% for the titration and atomic absorption methods, respectively. Mean recoveries at the higher levels were 99.4% (315 mg oxalic acid added/100 g) and 97.8% (350 mg/100 g), respectively.
Gas-Liquid Chromatographic Determination of Phenothiazine in Medicated Feeds
Authors: Colvin Billy M , Prudom Albert E , Whitlock Larry L , Hanks Alan R 
Published: February 2020

Abstract
A simple and rapid method is described for the determination of phenothiazine in feeds. Phenothiazine is extracted with chloroform containing chlorobenzilate as an internal standard. The extract is injected into a gas chromatograph and peak height ratios are used for quantitation. The analysis of commercial samples shows that the method compares well with the more commonly employed colorimetric AOAC method, and good precision, with recoveries ranging from 96.0 to 99.9%, is obtained in the analysis of prepared samples.
Infrared Identification and Potentiometric Determination of Glycine in Dietetic Beverages
Authors: Coppola Elia D , Hanna J Gordon 
Published: February 2020

Abstract
Infrared identification and nonaqueous potentiometric and visual titration of glycine in diet drinks is described for samples containing as little as 0.2% glycine. Sodium benzoate and saccharin do not interfere in the glycine determination. An average recovery of 99.3±1.00% was obtained for added glycine for a series of 7 determinations.
Collaborative Study of the Multicomponent Method for Polycyclic Aromatic Hydrocarbons in Foods
Authors: Fazio Thomas , White Richard H , Howard John W 
Published: February 2020

Abstract
A collaborative study was conducted on the multicomponent method for polycyclic aromatic hydrocarbons in foods. Samples of smoked ham fortified with benzo(a)pyrene, benzo(e)pyrene, benz(a)anthracene, and benzo(g,h,i)perylene were analyzed by 12 collaborators. Average per cent recovery at the 10 ppb (μg/kg) level for the 4 compounds ranged from 70 to 90%. The within-laboratory standard deviation indicates that the precision of the method is not significantly different for any one of the hydrocarbons. The method has been adopted as official first action.
Reverse Phase Thin Layer Chromatography of Some Aroclors, Halowaxes, and Pesticides
Authors: Stalling David L , Huckins James N 
Published: February 2020

Abstract
The components of Aroclors® 1232, 1248, 1254, and 1260; Halowaxes® 1099, 1013, and 1014; and several chlorinated pesticides are resolved by reverse phase thin layer chromatography (RPTLC), which permits component separation by partition between a nonpolar stationary phase and a polar mobile phase. Rf values of resulting spots were calculated for 2 of 4 new solvent systems (mobile phases). RPTLC patterns were reproducible and characteristic of each material examined. The spots were recovered from the plates and characterized by gas-liquid chromatography (GLC) and/or GLC-mass spectrometry. In some cases, single GLC peaks of Aroclor standards were resolved into more than one component by RPTLC, whereas some RPTLC spots of Halowaxes were resolved into as many as 4 GLC peaks. The analysis of environmental residues of chlorinated compounds was facilitated by this technique.
Comparison of Gravimetric and Volumetric Sodium Tetraphenylboron Methods for Determining K2O in Fertilizers
Authors: Melton James R , Hoover William L , Howard Peggy A 
Published: February 2020

Abstract
The official final action volumetric sodium tetraphenylboron method for determining potassium in fertilizers, 2.090–2.092, is compared with a gravimetric modification of the method. The modified method, which is less time consuming than the official method, is described. Seven Magruder check samples were analyzed by both methods and results compare favorably. Advantages and disadvantages of both methods are discussed.
Rapid, Sensitive Method for Determination of Mercury in a Variety of Biological Samples
Authors: Deitz Frank D , Sell Jerry L , Bristol Douglas 
Published: February 2020

Abstract
A simple, rapid method for the routine determination of mercury at levels as low as 2 ng (2 ppb) in a wide variety of biological samples is described. Vanadium pentoxide-catalyzed wet digestion at 140°C is used for complete oxidation of organic tissue. Mercury is determined by flameless atomic absorption spectrophotometry, utilizing a syringe technique to transfer mercury-containing vapor to the absorption cell. Replicate analyses of samples on different days showed good precision and accuracy. Coefficients of variation for determinations within a day’s run ranged from 2 to 17% at mercury concentrations of 30 to 40 ppb. Results obtained by this method agreed very closely with those obtained by neutron activation analyses of the same samples. On a routine basis, 2 analysts can analyze 30–40 samples/day.
Collaborative Study of a Gas-Liquid Chromatographic Determination of d-trans-Allethrin
Authors: Meinen Vernon J , Kassera Dean C 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) method for the quantitative determination of d-trans-allethrin in technical materials and formulations was collaboratively studied. The samples are diluted with acetone and analyzed by GLC, using a flame ionization detector and a 5% OV-1 GLC column. A statistical evaluation of the matched pair technical samples shows an overall coefficient of variation of 0.34% and a coefficient of random error of 0.49%. An evaluation of the F-factor reveals no indication of systematic error contributions. A statistical evaluation of the results for 2 d-trans-allethrin formulations showed coefficients of variation of 4.98 and 1.98. An examination of the t-values revealed a small contribution to systematic error. The somewhat high results of sample C are believed to be a result of lower quality GLC resolution. The addition of a requirement for minimum GLC column performance to the method should increase the overall quality of the GLC resolution. The method has been adopted as official first action.
Free Acid in Esters of 2,4-Dichlorophenoxyacetic Acid and 2,4,5-Trichlorophenoxyacetic Acid and Their Formulations
Authors: Hammond Howard 
Published: February 2020

Abstract
The free acid content of 2,4-D and 2,4,5-T esters and formulations is determined by titration to pH 7.0, using a pH meter. Average recoveries and standard deviations for 9 collaborators, analyzing 4 samples containing different amounts of the esters, were 0.2067± 0.0201 and 0.3778±0.0245 for 2,4-D ester and 0.6208±0.0555 and 1.4622±0.1356 for 2,4,5-T ester. The method has been adopted as official first action.
Collaborative Study of the Determination of Ammonia as an Index of Decomposition in Crabmeat
Authors: Steinbrecher Kurt 
Published: February 2020

Abstract
A colorimetric method for determining the ammonia content in crabmeat in various stages of decomposition was studied collaboratively. The method involves the color reaction between ammonia, thymol, and alkaline bromine water. The mean values for organoleptic Class 1, Class 2, and Class 3 of decomposition were found to be 281, 568, and 1376 μg NH3/g crabmeat, respectively. By statistical analysis these means were found to be significantly different from each other, and were found to arise from different populations. Useful cut-off points can be selected to separate the classes. The method has been adopted as official first action.
Collaborative Study of an Enzymatic Digestion Method for the Isolation of Light Filth from Fresh Pork Sausage
Authors: Gecan John S , Alioto Philip 
Published: February 2020

Abstract
An alternative method has been developed for the isolation of light filth from fresh pork sausage. The method involves particle size reduction, enzymatic digestion, wet sieving, deaerating, and floating with n-heptane-mineral oil from cooled 40% isopropanol. Collaborative study of the method showed the extraction papers and the recovery of light filth elements to be comparable to or better than those obtained for 40.B07. The method has been adopted as official first action as an alternative to 40.B07.
Thin Layer Chromatographic Test for Mammalian Urine on Wheat
Authors: Thrasher Joel J 
Published: February 2020

Abstract
Follow-up experimental work of the 1971 preliminary method study revealed the need for a change in sample size, an improved extract cleanup technique, and the identification of a urine-specific metabolite. A modified method collaboratively tested in 1972 is capable of handling a larger sample in the Soxhlet extractor. The extract is cleaned of interfering substances by chromatography with an appropriate solvent prior to 2-dimensional TLC. The indicator metabolites, urea, allantoin, and indican, are detected by sequential sprays. The collaborative study resulted in 90% correct positive determinations with no false positives. The minimum detection level is approximately 2 μl urine/9 g wheat. The method has been adopted as official first action.