bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rubidium Sulfate Flame Detector: Modification of Flame Ionization Detectors, Parameter Characteristics, and Regions of Response of the Flame for Phosphorus Compounds
Authors: Deloach Hiroko K , Hemphill Delbert D 
Published: February 2020

Abstract
To obtain a reliable alkali-flame detector with a rubidium sulfate source, commercial detection systems were modified. Improvements were made in Barber-Colman Model 5121 FID and Varian Aerograph Model 1200 FID systems to decrease operational difficulties and detection inadequacies. Equipped with a rubidium sulfate alkali source and an adjustable platinum anode, the modified Barber- Colman FID was used to study the phosphorus response of various regions in the flame. Flame configuration, affected by flow rates of gases, influences not only the absolute response level but also the response profile as a function of the anode height. Consequently, the region of maximum response was altered markedly by the flame configuration. The region of the flame with maximum ion population is located within the area immediately surrounding the outside of the flame rather than in the flame.
Characterization of Heroin: A Preliminary Study
Authors: Pro M J , Brunelle R L 
Published: February 2020

Abstract
Heroin samples from 100 actual cases were examined by multiple analytical techniques. After preliminary examination by microscopy and chemical analysis indicated similarity of questioned and known specimens, as many as 22 chemical elements were measured by neutron activation analysis and atomic absorption. Since illicit heroin is crudely produced, the qualitative elemental analysis is significant; however, more important for characterization purposes is the quantitative determination of the elements found because the concentration ranges for each element are extremely large.
Determination of Total Arsenic in Total Diet Samples
Authors: Hundley Harvey K , Underwood Joseph C 
Published: February 2020

Abstract
A simple, sensitive, and reproducible procedure has been investigated for the determination of total arsenic in composite food samples. Samples are dry ashed in the presence of magnesium oxide and magnesium nitrate, and arsenic is evolved from an acid solution as its hydride. The arsine is reacted with silver diethyldithiocarbamate to give a red complex that is measured photometrically. The absorbance of this complex is proportional to arsenic over a wide range of concentrations (1–20 μg arsenic). The method presented is sensitive to 0.05 ppm (1 μg/20 g product).
Detection of Adulteration in Fruit Juices by Qualitative Determination of Carbohydrates by Gas-Liquid Chromatography
Authors: Fitelsox J 
Published: February 2020

Abstract
Sugars and sorbitol in fruit juices can be separated readily by a simple GLC procedure. All fruits show a major fructose peak, followed by 2 smaller glucose peaks. Cherry, plum, apple, and pear also contain sorbitol, which appears between the 2 glucose peaks. None of the small berry fruits contains any sorbitol. The larger fruits, such as apple and pear, also have sucrose, which may occur only as traces in the small fruits. Authentic fruits, as well as many commercial samples, have been examined and the characteristic profiles of the various groups verified. Fruits from various countries, as well as different varieties, exhibit identical patterns. Several commercial concentrates that were judged to be adulterated on the basis of abnormal sugar patterns were also tested by other methods; results confirmed the presence of foreign material. Collaborative studies on 4 samples were conducted and all 9 collaborators reported correct results. The method is recommended for adoption as official first action.
Quantitative Determination of Sugars in Fruits by GLC Separation of TMS Derivatives
Authors: Klixe David A , Fernandez-flores Enrique , Johnson Arthur R 
Published: February 2020

Abstract
A rapid quantitative method for the determination of sugars in fruits is described. Sugars are converted into trimethylsiJyl derivatives after separating interfering organic acids by precipitation as lead salts. Fructose, glucose, sucrose, and sorbitol are measured by using ∝-D-glucoheptose as a n internal standard. Twenty-eight authentic fruit samples were analyzed. Recovery studies were made anil results compared with those obtained by using the AOAC Munson-Walker general method for reducing sugars.
An Evaluation of Five Methods for the Quantitative Determination of Cyclopropenoid Fatty Acids
Authors: Coleman Eugene C 
Published: February 2020

Abstract
An evaluation of 5 methods for determining 5% or less cyclopropenoid fatty acids was made in terms of accuracy, precision, and sensitivity. GLC of the methyl mercaptan derivatives of cyclopropenoid fatty acids and titration with hydrobromic acid in toluene were found to be unsuitable. GLC of the silver nitratemethanol derivatives (quantitation by an internal standard) and titration with hydrobromic acid in acetic acid were equally precise, and the former required less sample; however, both methods gave low recoveries. GLC of silver nitrate-methanol derivatives (quantitation by peak area normalization) and a hydrobromic acid-benzene back-titration method gave good recoveries. The Halphen test was found to be the best general method when calibrated with a cyclopropenoid fatty acid standard analyzed by the silver nitrate-methanol GLC method (quantitation by peak area normalization) or the hydrobromic acid-benzene back-titration method.
Gas Chromatographic Determination of cis- and trans-Diethylstilbestrol in Feed Premix
Authors: Rutherford B S 
Published: February 2020

Abstract
A method for the determination of the relative amounts of cis- and trans-diethylstilbestrol isomers in feed premix is presented. Trimethylsilyl derivatives are formed and analyzed by gas chromatography. The 2 peaks obtained have been characterized by comparison with NMR data and by mass spectrometry.
Assay of Ormetoprim in Feeds
Authors: Osadca M , Ritter E De 
Published: February 2020

Abstract
A method is described for assay of ormetoprim in feeds at levels down to 0.001%, which involves extraction by blending with alkali and chloroform after brief enzyme digestion, cleanup of the extract by solvent transfers, a carefully timed oxidation with permanganate, destruction of excess permanganate with bisulfite, acidification, and transfer to chloroform for fluorescence reading in a spectrofluorometer. Recoveries of ormetoprim added to feeds are excellent, the fluorescence response is linear over the working range, and blank values on unmedicated feeds are low. A collaborative study was made with 4 samples of broiler starter ration containing graded levels of ormetoprim at normal feeding levels and at lower and higher levels. The recoveries were good and the potency ratios were close to theoretical values, but in view of the small number of collaborators reporting, it is recommended that study of the method be continued.
Immunochemical Quantitation of Soybean Protein in Raw and Cooked Meat Products
Authors: Kamm L 
Published: February 2020

Abstract
The method described in this paper for the quantitative measurement of soybean protein in meat products is based on the specificity of immunological techniques, as demonstrated by other investigators. The major improvements claimed are higher sensitivity (0.1% or 0.5 μg glycini11)? economy in volume of antisera per determination (0.1 ml), selective measurement of the “heat-stable” fraction, and suitability for routine analysis.
Note on a Rapid Paper Chromatographic Method for the Estimation of Added Monosodium Glutamate in Food
Authors: Bailey Brian W , Swift Herbert L 
Published: February 2020

Abstract
Ascending paper chromatography is proposed as a method for the estimation of monosodiumglutamate. Free glutamate was determinedin a variety of Chinese foods. Glutamateconcentrations of 0.4 to 1.5% by weight as themonosodium salt are reported. The use ofcommon inexpensive equipment combinedwith ease of manipulation makes the methodideally suited to routine laboratory operation.
A Re-examination of the By-product Obtained During the Preparation of DDA and Unequivocal Differentiation of DDE and DDNU
Authors: Stavric B , Neville G A 
Published: February 2020

Abstract
As the result of unexpected chemical behavior encountered in a study with the DDT-metabolites 1,1-bis(p-chlorophenyl)ethylene (DDNU) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the characterization of these 2 compounds was re-examined and found to be at variance with data found in the chemical literature. DDNU and DDE have now been more fully differentiated and characterized by NMR and IR spectroscopy, and the principal IR bands of each have been assigned and discussed.
A Method for the Analysis of Fish, Animal, and Poultry Tissue for Chlorinated Pesticide Residues
Authors: Porter Mildred L , Porter Mildred L , Young Susan J V , Burke Jerry A 
Published: February 2020

Abstract
A method for extracting residues of chlorinated pesticides from fish, meat, and poultry tissue by blending with petroleum ether is described. The usual petroleum ether-acetonitrile partitioning and Florisil column chromatographic procedures are used for cleanup. A modification of the widely used petroleum ether-acetonitrile partitioning resulted in an improved cleanup with an insignificant loss in pesticide recovery. Levels of metabolically incorporated chlorinated pesticide residues extracted from fish, meat, and poultry tissue by the petroleum ether method were equivalent to residue quantities extracted by Soxhlet with chloroform-methanol (1 + 1). Recoveries of representative chlorinated pesticides added to samples of various tissues at levels of 0.1-2.0 ppm ranged from 90 to 102%.
Determination of Trifluralin in Formulations by Gas Chromatography
Authors: Hambleton Larry G 
Published: February 2020

Abstract
A gas chromatographic method has been developed that is rapid and specific for trifluralin in formulations. The sample is extracted with acetone, an internal standard is added, and the solution is diluted to volume and injected into a gas chromatograph equipped with a flame ionization detector. Three typical trifluralin formulations were analyzed by both the gas chromatographic method and an ultraviolet method. The gas chromatographic method gave an average recovery of 101.2%.
Evaluation of Two Extraction Procedures for Pesticide Residues Resulting from Foliar Application and Root Absorption
Authors: Burke Jerry A , Porter Mildred L , Young Susan J V 
Published: February 2020

Abstract
The acetonitrile extraction procedure of Mills et al. and the 35% water-acetonitrile extraction procedure of Bertuzzi et al. were evaluated for the determination in fresh and dehydrated samples of 4 organochlorine pesticide residues resulting from foliar application or root absorption. Extraction of 2 organophosphorus pesticide residues from fresh samples was also studied. Extraction efficiencies were hased on the amount of pesticide residue removed by exhaustive Soxhlet extraction with chloroform-methanol (1 + 1). Residues resulting from foliar application of aldrin (dieldrin), diazinon, endosulfan (isomers I and II and endosulfan sulfate), methoxychlor, parathion, and TDE to green vegetables were determined after acetonitrile extraction; results ranged from 92 to 104% of the amounts determined after exhaustive extraction. Only one-half to two-thirds of dieldrin absorbed from the soil into potato tubers could be detected after acetonitrile extraction. Acetonitrile alone was not satisfactory for extracting dehydrated samples. When dehydrated samples containing residues resulting from foliar application were extracted with 35% water-acetonitrile, results were comparable to those by exhaustive extraction. However, the water-acetonitrile extraction was also ineffective for root-absorbed residues in the dehydrated samples. Analysis of samples after storage indicated that organochlorine pesticide residues on fresh vegetables undergo little or no change during frozen storage.
Fate of S-[(2-Methoxy-5-oxo-Δ2-1,3,4-thiadiazolin-4-yl) methyl]-O,O-dimethyl Phosphorodithioate (Supracide) in Field-Grown Agricultural Crops and Soil
Authors: Eberle D O , Hörmann W D 
Published: February 2020

Abstract
Analytical methods are presented for routine determination of residues of unchanged Supracide (GS 13005; S-[(2-methoxy-5-oxo-Δ2-1,3,4-thiadiazolin-4-yl)methyl]-O,O-dimethyl phosphorodithioate), its oxygen analog (GS 13007), and 2-methoxy-5-oxo-Δ2-1,3,4-thiadiazolin (GS 12956) in different agricultural crops and soil. The unchanged insecticide is determined by gas chromatography, using both sodium thermionic and electrolytic conductivity detectors with a limit of detectability of 0.01 ppm. GS 13007 is detected on thin layer chromatographic plates by fly head cholinesterase inhibition and GS 12956 by silver nitrate with a detection limit of 0.01 ppm each. Average degradation curves from field trials are calculated statistically, and the penetration of GS 13005 into the meat and core of apples has been studied in field and laboratory experiments.
Determination of Ethylene Thiourea Residues in Foods, Using Thin Layer and Gas Chromatography
Authors: Onley John H , Yip George 
Published: February 2020

Abstract
Thin layer and gas chromatographic methods have been developed for the determination of ethylene thiourea in fruits, vegetables, and milk. The food sample is extracted with an ethanol-chloroform mixture and partially cleaned up on a cellulose column. For TLC determination, an aliquot (5–25 g) is further cleaned up on an aluminum oxide column. The remainder of the sample is treated with a methanolic solution of 1-bromobutane and the resultant derivative is isolated and measured by GLC, using a thermionic detector. Recoveries at fortification levels of 0.02 to 10 ppm exceeded 80%.
Mass Spectra of Fifteen Chlorinated Aromatic Fungicides
Authors: Hutzinger O , Jamieson W D , Safe S 
Published: February 2020

Abstract
Fragmentation patterns on electron impact of 15 chlorinated aromatic fungicides were investigated. In most cases strong molecular ions were obtained and the peak clusters due to the 35Cl and 37Cl isotopes and the number of chlorine atoms in the molecule were highly characteristic. Many of the polychlorinated fungicides give ions (e.g., C6Cl4, C6Cl3, C6Cl2, C6Cl, and C6 (CN)2) whose structures can be best represented as acyclic polyunsaturated moieties.
Estimating Bacterial Populations in Raw and Simulated Maple Sap by a Modified Resazurin Test
Authors: Kissinger J C 
Published: February 2020

Abstract
A modified resazurin test was used to estimate bacterial populations growing in natural and simulated maple saps. Comparable results were obtained from both substrates, with a slight decrease in dye reduction time noted when the natural sap substrate was used. Simulated sap could provide a readily available substitute for natural sap in collaborative testing.
Determination of Formaldehyde in Maple Sirup: Variation of the Blank
Authors: Underwood J C 
Published: February 2020

Abstract
The amount of formaldehyde in 23 samples of commercial maple sirup from various parts of the maple-producing areas of the United States ranged from 0.36 to 1.85 ppm with an average of 0.75 ppm. These sirups were made from sap of maple trees not treated with a paraformaldehyde germicidal pellet. This “blank” was lower than the 0.95 value used in the official method for HCHO (31.184-31.189), but the few high values would present a problem for maple sirup producers who must keep residual HCHO in maple sirup below 2 ppm. The distillate of sirup which isolates the formaldehyde yielded 3 carbonyl compound peaks by GLC, one of which corresponded to HCHO. Work is being done to determine if the others may be interfering compounds.
Non-Vanillin Vanilla Volatiles in Vanilla Extract
Authors: Potter Richard H 
Published: February 2020

Abstract
The flavors of vanilla extract may be made stronger by the artful addition of volatile chemicals. This method detects these additions by gas chromatography at levels down to 10 ppm. The volatiles are extracted with isopentane, which is then concentrated to 0.2-0.5 ml, at which point vanillin is precepitated before chromatography. Authentic samples are run at the same time as samples; curves of both are compared. Adulteration will appear as foreign peaks. Hexadecane is used as an internal standard so that the curves may be correlated. The test is qualitative; no attempt is made to identify adulterations. Coded samples of authentic extract and adulterated extract were sent to 7 collaborators, all of whom correctly identified the adulterated samples.
Chromatographic Separation of Free Amino Acids in Table Sirups
Authors: Johnson Arthur Russell , Corliss Richard L , Fernandez-Flores Enrique 
Published: February 2020

Abstract
Qualitative chromatographic methods for the separation of free amino acids in table sirups are presented to aid in the development of chemical indices of composition which may be useful in establishing the identity of sirups and detecting their adulteration. Free amino acids in 2 table sirups were isolated on ion exchange columns and eluted with dilute ammonia. The concentrated amino acid mixture in the eluate was spotted directly on silica gel G plates for TLC analysis, or the amino acids were converted to their N-trifluoroacetyl n-butyl esters for GLC analysis. As many as 16 amino acids were qualitatively separated and identified and a potential for quantitative analysis was demonstrated.
Spectrophotometric Determination of Roxarsone in Animal Feeds
Authors: George G M , Morrison J L 
Published: February 2020

Abstract
Roxarsone is administered in the feed as a growth stimulant for chickens, turkeys, and swine. The drug is extracted with 2% dibasic potassium phosphate solution, the extract is centrifuged, the centrifugate is adjusted to the isoelectric point of proteins with hydrochloric acid, and the precipitated proteins are removed by centrifugation. Interferences are removed by treating the solution with activated charcoal at pH 12, which leaves a solution of roxarsone of intense color that can be measured spectrophotometrically at 410 nm. This method was subjected to a collaborative study. The average recovery from 13 collaborators was 99.25% with an average coefficient of variation of 6.91%. It is concluded that satisfactory results were reported and is therefore recommended that this method be adopted as official first action.
Method for Analysis and Chemical Confirmation of Sterigmatocystin
Authors: Stack Michael , Rodricks J V 
Published: February 2020

Abstract
A method is described for the analysis of grain samples for the presence and quantitative estimation of sterigmatocystin. Initial extraction with acetonitrile-water (9 + 1) containing KCl is followed by partition of the extract first against hexane and then against CHCl3, and, if needed, silica gel column chromatography. This sequence provides an extract in which the sterigmatocystin can be estimated by fluorescence intensity comparison on TLC plates against a pure sterigmatocystin standard. Visualization of the sterigmatocystin on the TLC plates is enhanced by an AlCl3 spray reagent. After preparative TLC, the identity of sterigmatocystin is confirmed by formation of an acetate derivative and of a derivative formed by treating the suspected extract with aqueous acid.
Confirmation of Chlorophenoxy Acid Herbicide Residues by Transesterification
Authors: Yip George 
Published: February 2020

Abstract
Low level residues of 5 chlorophenoxy acids (MCP, 2,4-D, 2,4,5-TP, 2,4,5-T, and 2,4-DB) can be easily confirmed by a transesterification reaction in which the methyl esters are converted to the propyl esters. An aliquot of the methyl ester is heated 5 min with n-propanol and sulfuric acid. Water is added and the organic phase is analyzed by either electron capture or microcoulo metric gas chromatography. A fruit sample fortified with 0.02 ppm 2,4,5-T illustrates the usefulness of the procedure.
Recovery of Organophosphorus Compounds Using the AOAC Multiresidue Method
Authors: Pardue John R 
Published: February 2020

Abstract
Sixty organophosphorus compounds were studied by using the official AOAC method for pesticide residue analysis. Recoveries of 13 compounds averaged between 80 and 110%; 9 additional compounds were partially recovered; and the remainder of the compounds was not recovered. All studies were conducted on standard compounds without the presence of crop material.
Effects of Solvent Composition on the Column Partition Chromatography of Amines: Computer-Generated Distribution Maps
Authors: Doyle Thomas D 
Published: February 2020

Abstract
A theory of effects of solvent composition on the partition of amines is discussed, for both free amines and ion-pairs. A computer program is described which outputs distribution maps showing the effects of solvent, pH, and ion-pairing. These plots automatically select conditions for the column partition chromatographic separation of amine mixtures.
Combined Gas Chromatography-Mass Spectrometry of Multiple Chlorinated Pesticide Residues in Foods
Authors: Bellman Sander W , Barry Thomas L 
Published: February 2020

Abstract
A system for the identification of multiple chlorinated pesticide residues in foods by combined gas chromatography-mass spectrometry (GLC-MS) is described. Its use is shown in the identification of p,p′-DDE in cheese, of the α-isomer of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) in cocoa beans, and of the α-, β-, γ-, and δ-isomers of HCH in frog legs. This technique is used to demonstrate the absence of polychlorinated biphenyls as an interference in the quantitation of p,p′-DDT and p,p′-DDE in fresh and smoked chubs.
Esterase Specificity and Sensitivity to Organophosphorus and Carbamate Pesticides: Factors Affecting Determination by Thin Layer Chromatography
Authors: Mendoza Celso E , Shields J B 
Published: February 2020

Abstract
Beef liver esterase was much more sensitive to organophosphorus pesticides than pig liver esterase, whereas the opposite was true for carbamates. Marked difference in specificity was noted for the inhibition of beef and pig esterases due to malathion and parathion. Inhibition of beef and pig liver esterases attributed to ethion was due to conversion of ethion to a product under the lights in the laboratory. However, inhibition of beef esterase attributed to parathion was due to conversion of parathion to paraoxon by the beef extract. Although bee head esterase was most sensitive to organophosphorus and carbamate pesticides, it had disadvantages over pig or beef liver esterase. The bee esterase was approximately 8 or 33 times less active than the same amount of beef or pig liver esterase. The bee brei (100 ml) was sufficient to spray 40 thin layer plates only, whereas the pig and beef liver extracts (1 L each) were sufficient to spray 10,000 and 2,500 plates, respectively. The technique was also used to detect pesticides in the presence of pea and carrot extractives. Advantages of the thin layer chromatographic-enzyme inhibition technique are discussed.
Fate of Aflatoxin During Roasting and Storage of Contaminated Peanut Products
Authors: Waltking Arthur E 
Published: February 2020

Abstract
A study of the effects of the pilot plant roasting of contaminated peanuts showed an average loss, after roasting, of 40–50% of the B1 and G1 aflatoxins and 20-40% of the B2 and G2 aflatoxins originally present. Portions of both the raw and roasted products (peanut butters prepared with commercially rejected peanuts) were stored in both paper bags and air-tight glass jars and periodically reassayed for aflatoxin. No significant change in aflatoxin content was found after 3 months of storage at 75 °F regardless of the container. However, significant reduction of aflatoxins was observed in other aflatoxin-contaminated peanut products which had been stored at room temperature for over 1 year.