bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Colorimetric Method for the Determination of Nitarsone in Feeds
Authors: George G M , Morrison J L
Published: February 2020

An improved procedure for the determination of nitarsone in poultry feeds has been developed. The drug is extracted from feed with 50% dimethylsulfoxide; interferences are removed by column chromatography of the extract on alumina. The drug is eluted from the column with 4% NaOH and assayed colorimetrically with the Bratton-Marshall reaction after reduction of the nitro group with aqueous 4% titanous chloride. The average recovery of nitarsone from laboratory-medicated feed was 97.0% of theoretical with an average coefficient of variation of 3.4%. The method was applicable to both fresh feeds and feeds stored for periods up to 6 months. This method was subjected to a collaborative study for the determination of nitarsone in medicated feeds. The average recovery from 6 collaborators was 103.5% with an average coefficient of variation of 12.7%. Most of the collaborators reported satisfactory results and therefore this method is recommended for adoption as official first action.
Collaborative Study of the Determination of Dimetridazole in Feeds by UV Spectroscopy
Authors: Morrison J L
Published: February 2020

A collaborative study of a previously reported method for the analysis of dimetridazole in feeds has been conducted. The drug is extracted from the feed with methanol, cleaned up by column chromatography on alumina, and measured spectrophotometrically at its ultraviolet wavelength maximum. Nine collaborators participated in this study. The average coefficient of variation was 5.7% for feeds containing 0.015–0.016% dimetridazole and 8.9% for feeds containing 0.05–0.06% dimetridazole. The recovery for these groups was 99 and 97%, respectively. The method is recommended for adoption as official first action.
Collaborative Study on the Determination of Propylene Glycol, Glycerine, and Triethylene Glycol in Tobacco
Authors: Giles J A
Published: February 2020

Propylene glycol, glycerine, and triethylene glycol were extracted from 10.0 g tobacco by shaking 1 hr with methanol. All three polyols were determined simultaneously by GLC of the supernatant extract, using a 42 × 3/16″ column of 1 + 1 Diatoport S-Chromosorb 101 coated with 5% Carbowax 20M-terephthalic acid. The column temperature was programmed at 90−240°C; anethole was used as the internal standard. The method was studied collaboratively by 11 laboratories. Systematic errors have been reduced to acceptable levels except in samples containing very low or high concentrations of a given humectant.
Determination of Cadmium in Total Diet Samples by Anodic Stripping Voltammetry
Authors: Hundley Harvey K , Warren Edward C
Published: February 2020

Anodic stripping analysis was investigated for the determination of cadmium in food samples and was found to be as reliable as atomic absorption for the determinative step. A hanging mercury drop is utilized to form an amalgam during controlled potential reduction. The amalgam is then stripped from the electrode by controlled electrolysis with a linearly varying potential. The recorded current measured during the stripping step was a direct linear function of the bulk concentration of cadmium. The minimum sensitivity, 0.01 ppm or 0.03 μg/ml in the final solution, is limited by the reagent blank.
Gas Chromatographic Determination of Pyrrolidonecarboxylic Acid
Authors: Lee C Y
Published: February 2020

An analytical method is described for analysis of 2-pyrroIidone-5-carboxylic acid (PCA) in foods. PCA was extracted with ethyl acetate, using a modified Widmark extraction apparatus, and then silylated with trimethylchlorosilane and hexamethyldisilazane in the presence of pyridine. The trimethylsilylated PCA derivative was separated by gas-liquid chromatography on a 6′ × 1/4″ °d stainless steel column of 3% SE-30 on Gas Chrom Q and detected with a flame ionization detector. Recovery of PCA was 94-108%. This procedure is a relatively simple and rapid analytical method as compared to the conventional methods.
Rapid Method for Extraction of Light Filth from Corn Meal, Rye, Pumpernickel, and Buckwheat Flour
Authors: Miller Mary T
Published: February 2020

A rapid method for the separation of light filth from a variety of high bran flours consists of a defatting procedure in a Soxhlet extractor, followed by separation of the filth elements with mineral oil in a HCl-ethyl alcohol medium. The proposed method gives clean papers and good recoveries and has no critically timed steps.
Thin Layer Chromatographic Determination of Sodium Monofluoroacetate
Authors: Perry Vernon A
Published: February 2020

A microanalytical method for the detection and quantitative estimation of the rodenticide sodium monofluoracetate from animal tissue has been developed. This procedure uses thin layer chromatography, requires little or no special cleanup, and will detect as little as 0.1 Mg monofluoroacetate as the ammonium salt.
Analytical Methods for the Fungicide ∝,∝-bis(p-Chlorophenyl)-3-Pyridinemethanol
Authors: Day E W , Decker O D , Koons J R , Holzer F J
Published: February 2020

Methods are described for the identification and determination of parinol in formulations, soils, and plant tissues. Gas chromatography on a column of 1.5% OV-17 at 230°C is the most generally applicable technique. Flame ionization detection is employed for macro amounts of parinol and electron affinity for trace quantities. However, an intensely red halochromic salt formed when parinol is dissolved in H2SO4 is the basis for a highly sensitive and selective spectrophotometric procedure. The absorbance maximum at 520 nm obeys Beer’s Law in the 0.5-5.0 μg/ml range. Comparisons of these 2 methods are made for macro quantities of parinol. An alternative residue procedure is suggested which utilizes thin layer chromatography with visualization after H2SO4 spray. Residue data in soils and fruits are reported.
Rapid Qualitative Screening Method for the Detection of Micro Amounts of Cyanide Residues in Wines and Spirits
Authors: Bates Brian L
Published: February 2020

The proposed method for the qualitative screening and detection of prussic acid in wine lees spirits and wines at and below 0.1 ppm is very sensitive and can be performed rapidly using apparatus that is readily available commercially. The method eliminates the concentration step of the modified Hubach method and the test papers can be prepared more quickly and with less manipulation than the FeS04- NaOH test papers of the Hubach method; they are also more sensitive and require no additional color development after removal from the ground-glass flanges as in the Hubach method. The condenser specified for the test is very efficient in preventing alcohol vapors from interfering with the test. A small column of lead dioxide effectively eliminated interference by sulfur dioxide. For samples containing ≥0.1 ppm hydrogen cyanide, as indicated by the intensity of the blue spot, an alternative quantitative method can be used for an accurate assay of the amount present. This test can be applied to other beverages and samples besides wine lees spirits and wines.
Availability Of Iron
Authors: Pla Gwendolyn W , Fritz James C
Published: February 2020

The high incidence of iron deficiency anemia in the United States and elsewhere is caused by insufficient iron intake, plus poor utilization of many dietary sources of iron. There is need to select assimilable sources of iron for fortification of foods; animal studies show that many of the iron compounds used for cereal enrichment are poorly utilized. A method to measure availability of iron is proposed and is currently being studied collaboratively. Preliminary data indicate that in vitro solubility tests are not satisfactory to evaluate availability of iron supplements.
Comparative Analysis of Variance of the Kjeldahl Nitrogen and a Neutron Activation Nitrogen Technique
Authors: Doty W H , Munson A W , Wood D E , Schneider E L
Published: February 2020

A comparative study of the variance components of a neutron activation nitrogen analysis and the Kjeldahl nitrogen analysis was conducted. A total of 448 individual assays were made by each method on 56 samples covering 17 types of feeds and ingredients. The coefficient of variation of the neutron activation data was 1.07. The coefficient of variation of the Kjeldahl data was 0.58. The statistical treatment showed no operator variance in the highly automated neutron activation technique. The total within-laboratory variance was divided evenly between day and error variance in the neutron activation procedure. In the Kjeldahl technique, the greatest portion of the within-laboratory variance was seen in the error (differences/duplicate determination) component.
Effect of Weight Loss of Solvent Extractives During Oven Drying Upon Crude Fat Determinations in Selected Materials
Authors: Gillingham J T , Colby D A
Published: February 2020

Selected stock feeds were analyzed for crude fat by the direct (AOAC 22.033) and the indirect (AOAC 22.034) methods. The direct method invariably yielded lower values (about 2% crude fat), due to instability of solvent extractives at 100°C during drying. The difference between the methods was greatest for silages (about 4.5% crude fat) and it was shown to be due to volatilization of organic acids during drying of the solvent extractive. The authors claim that the indirect method is the better approach to valid crude fat determinations. Vacuum drying (22.003) of oil seeds and silage preparatory to extraction was found to effect a weight loss, exclusive of moisture, either by volatilization or decomposition of heat-labile compounds. Titratable organic acids in silages decreased as a result of vacuum drying. It is claimed that preliminary drying of stock feeds, especially silage, should be accomplished by drying over H2SO4 (22.007) or by freeze-dry ing.
Determination of Water-Insoluble Nitrogen in Mixed Fertilizers
Authors: Katz Stanley E , Fassbender Carol A , Greenstein Merril
Published: February 2020

A procedure was developed for the determination of water-insoluble nitrogen which did not require alteration of the sample by grinding. Samples of the fertilizer were washed in a column with the equivalent of 100 inches of water. The residual nitrogen was then determined by conventional Kjeldahl procedures. The procedure was as reproducible as the present official method but was applicable to all types of sources of water-insoluble nitrogen. Since grinding was eliminated, particle sizesolubility relationships and coatings were not affected.
Evaluation of Methods to Establish the Natural Origin of Adrenal Cortex Injections
Authors: Cunningham C G
Published: February 2020

Usual bioassay methods fail to establish animal origin of the product. Chemical assay and one-dimensional TLC are satisfactory for detecting adulteration when a single steroid (i.e., hydrocortisone) is substituted in an abnormally high ratio to the total steroids. The problem is more difficult when the adulteration is a sophisticated mixture of steroids in their normal ratios. Two-dimensional TLC of the adrenal cortex injection offers the best evidence of adulteration. The presence or absence of nonsteroidic substances naturally present in animal glands is demonstrable in the chromatograms. A standard of identity of adrenal cortex extract is needed to establish the purity and potency of the injection and its natural origin.
Collaborative Study of a Gas Chromatographic Determination of Ethchlorvynol in Drugs
Authors: Davidson Arthur W
Published: February 2020

Ten laboratories studied a GLC method for ethchlorvynol in drugs. l,3-Dichloro-2-propanol is the internal standard and Carbowax 20M is the liquid phase. Recoveries on solutions containing 11.068, 9.000, 46.209, and 54.301 mg/ml were 99.6 ± 2.9%, 100.0 ± 1.3%, 99.7 ± 1.9%, and 100.1 ± 2.9%, respectively. The method is recommended for adoption as official first action.
Methods for Some Alkaloids, Barbiturates, and Combinations. II. Collaborative Study of an Ion Exchange Method for Ephedrine Sulfate or Amphetamine Sulfate Alone or Combined with Barbiturates and Antihistamines
Authors: Smith Donald J
Published: February 2020

Sympathomimetic amines and antihistamines are retained on a column of sulfonated polystyrene cation exchange resin by the positive charge located in the cationic center of the molecule. These basic compounds are eluted from the column with appropriate concentrations of HCl and determined by UV absorption. An anion exchange column assists in removing interfering colored matter. The barbiturates pass through both columns with the original solvent and are measured by UV absorption in a buffered solution. Recoveries for the 8 drug ingredients in 3 combinations range from 98.9±1.7% for ephedrine sulfate to 95.4±3.8% for amphetamine sulfate on 3 practice samples per collaborator, and 99.5±2.0% for ephedrine sulfate to 96.7 ±3.3% for amphetamine sulfate on 6 unknown samples per collaborator. The method is recommended for adoption as official first action.
Spectrophotometric Determination of Phosphatase Activity in Milk Utilizing a New Alkaline Phosphatase Assay System
Authors: Kleyn D H , Yen W
Published: February 2020

The new method is based on the use of phenolphthalein monophosphate as a substrate, for the determination of residual alkaline phosphatase. Upon hydrolysis, phenolphthalein is released to yield a red solution. A visual test, in which the color developed in a milk sample is compared with the color of a standard prepared with the same milk, was collaboratively studied and subsequently adopted as official first action for skim milk, milk, and light cream. In the present study the release of phenolphthalein was quantitated through the utilization of dialysis, followed by subsequent measurement of absorbance of the dialysate in a spectrophotometer at 550 nm or by visual comparison of the dialysate with prepared color standards.
Oxygen Combustion Method for Determination of Bromide Residues in Foods
Authors: Dow Matthew L
Published: February 2020

Samples of wheat, flour, dried milk, or pecans are ashed in a modified Schoniger oxygen flask and bromide is determined by titration with standardized sodium thiosulfate solution or by direct spectrophotometry. A collaborative study indicated about 90% recovery at the 100 ppm bromine level. Standard deviations from 3.7 to 35.3 ppm and from 2.8 to 21.8 ppm were obtained for the titration and spectrophotometric determination, respectively.
Determination of Crotoxyphos in Milk and in the Body Tissues of Cattle and Pigs
Authors: Oehler D D , Claborn H V
Published: February 2020

A new procedure was devised for the extraction, cleanup, and determination of residues of crotoxyphos in milk and in the body tissues of cattle and pigs. The tissue samples were extracted with hexane or hexane-acetone and partitioned into acetonitrile. After cleanup of the extracts and milk on a Florisil column, crotoxyphos was detected with flame photometric gas chromatography. Recoveries ranged from 80 to 98%.
Rapid Sample Preparation for Gas-Liquid Chromatography of Pesticide Residues by Ball-Grinding Extraction, Freeze-out, and Semimicro Column Cleanup
Authors: Grussendorf O W , Mcginnis A J , Solomon J
Published: February 2020

A rapid method for analysis of organochlorine and organophosphate pesticide residues is described. The samples are ground and extracted in one step, using only n-hexane, even for moist materials. Most of the lipids and waxes are removed from the extract by freezeout from acetone solution; pigments and any residual lipids and waxes are removed by a final cleanup on a Florisil column. The semimicro approach is stressed and a number of samples can be processed simultaneously, thus saving time, space, and materials. The procedure is simple, only small volumes of solvent are employed, and good recoveries are obtained. The purity of final extracts is high, thereby avoiding contamination of the GLC column and permitting production of clean, sharp chromatograms. A number of special small, simple metal and glass devices are essential. Specifications for their construction and use are fully described.
Note on Determination of Traces of Silver in Pond Water by Quenching of Fluorescence
Authors: White Merrie N , Lisk Donald J
Published: February 2020

Two new spray reagents for the cholinesterase inhibition method for insecticide analysis are described, namely, the acetate and butyrate esters of N-methyl indoxyl. The fluorescent hydrolysis products have greater fluorescence stability than with indoxyl acetate and are less subject to degradation to nonfluorescent colored substances. Subnanogram amounts of paraoxon were detected on TLC plates.
Note on Improved Spray Reagents for TLC Fluorogenic Detection of Cholinesterase Inhibitors
Authors: Schutzmann R L
Published: February 2020

Two new spray reagents for the cholinesterase inhibition method for insecticide analysis are described, namely, the acetate and butyrate esters of N-methyl indoxyl. The fluorescent hydrolysis products have greater fluorescence stability than with indoxyl acetate and are less subject to degradation to nonfluorescent colored substances. Subnanogram amounts of paraoxon were detected on TLC plates.
Note on a Rapid Determination of Aflatoxins in Peanuts and Peanut Products
Authors: Liem D H , Beljaars P R
Published: February 2020

A simple and rapid extraction procedure, based on a direct extraction introduced by Pons and a single liquid-liquid extraction proposed by Waltking, is described for peanuts and peanut products. Methanol is used as the extracting solvent. TLC, using the system described by Engstrom, yielded satisfactory results. The method is suitable for aflatoxin Bi levels of 8 μg/kg (or higher) in peanut butter and roasted peanut products. Aflatoxin B1 levels down to 3 μg/kg can be detected in raw peanuts and peanut shavings.
Fatty Acid Composition of Cod Liver Oil Determined by Urea Fractionation and Modified Programmed Temperature Gas Chromatography
Authors: Iverson John L
Published: February 2020

Esters of fatty acids in marine oils, with similar GLC retention times, are concentrated in separate fractions by this proposed urea fractionation procedure. Esters which are present at the ppm level and are normally hidden under major peaks can then be detected. By modified programmed temperature gas chromatographic techniques, it is possible to detect trace amounts of the short and long chain fatty acids. Accurate identifications are assured by the correlation of fatty acid structure with the preferential order in which they form complexes and retention times before and after hydrogenation. Cod liver oil was found to contain 130 fatty acids. Most of the esters present in trace amounts are predominately C20 to C34 acids which have not been previously reported.
Sterochemical Composition of d- and l-Amphetamine Mixtures by Thermal Analysis of the Bepzoyl Derivatives
Authors: Ment William M , Marino Victor S
Published: February 2020

A procedure for the thermal analysis of the benzoyl derivative of amphetamine is presented, which enables rapid determination of the stereochemical composition of d- and l-amphetamine mixtures with ±5% accuracy and requires as little as 5 mg amphetamine salt. Identification of the predominant isomer and confirmation of the isomeric ratio estimation are made by the addition to the sample derivative of an equal amount of standard amphetamine benzoyl derivative of opposite isomeric composition in order to form the amphetamine racemate, which is then analyzed by a second melting range measurement. Melting ranges are determined with the aid of a microscope equipped with a Kofler hot stage.
Carbaryl Insecticide: Analysis of Formulations by Colorimetry
Authors: Mcdermott W H , Duvall A H
Published: February 2020

The p-nitrobenzenediazonium fluoborate analytical method for 1-naphthol has been used as a basis of a colorimetric method for determining carbaryl insecticide in formulations. In a solution of KOH in methanol, the carbaryl is saponified to 1-naphthol, which is then determined colorimetrically. This method has been shown to be specific for measuring carbaryl content in mixed formulations in admixture with 13 different pesticides.
Automation of Methods for Meat and Meat Products. I. Determination of Protein
Authors: Mcneal Jon E , Karasz Albert , George Elmer
Published: February 2020

An automated method for the analysis of protein in meat was studied. The investigation included selection of proper standards, development of a method for presolubilizing meat samples for presentation to the AutoAnalyzer, and the construction of AutoAnalyzer manifolds to give protein results comparable to those obtained by the official AOAC Kjeldahl method. The method was found to be applicable to meat and meat products ranging from 5 to 25% protein.
Collaborative Study of Copper, Sodium, and Potassium in Feeds by Atomic Absorption Spectrophotometry and Sodium and Potassium by Flame Emission Spectrophotometry
Authors: Heckman Mary
Published: February 2020

Twelve laboratories collaborated in a study of the analysis of feeds for copper, sodium, and potassium by atomic absorption spectrophotometry and for sodium and potassium by flame emission spectrophotometry. Solutions of feed samples containing known additions of the elements under study were analyzed. Results indicate that the atomic absorption method is suitable for copper. Further study is required for sodium and potassium.
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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Design of a Simply Constructed Streaker for Thin Layer Chromatography
Authors: Freeman H P
Published: February 2020

An efficient large capacity TLC streaker of simple design is described. This streaker is easy to operate and can be made inexpensively from standard laboratory equipment.
Estimating Bacterial Populations in Raw and Simulated Maple Sap by a Modified Resazurin Test
Authors: Kissinger J C
Published: February 2020

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

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

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

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

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

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

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

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

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

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

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

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.
Collaborative Study of a Method for the Analysis of Cocoa Beans for Aflatoxins
Authors: Scott P M , Przybylski W
Published: February 2020

Results from 10 collaborating laboratories were used to evaluate a method for the determination of aflatoxins in cocoa beans. Two types of raw cocoa beans, one from Trinidad and one from Ghana, were intentionally contaminated with aflatoxins at levels of 8 to 35 μg/kg. Mean recoveries of all aflatoxins from all samples ranged from 57 to 104%; mean recoveries of aflatoxin B1 from Ghana cocoa beans were 83 to 97%. The method has been adopted as official first action.
Polarographic Determination of Piperazine in Animal Feeds
Authors: McLean J D , Daniels O L
Published: February 2020

A simple and rapid polarographic method has been developed for the analysis of piperazine in animal feeds. A polarographically reducible condensation product of piperazine dihydrochloride is formed in the presence of excess formaldehyde in pH 5 buffer solution; the diffusion current of the product is measured at —0.98 v vs. a saturated calomel reference electrode.
Collaborative Study of the Determination of Propylene Glycol, Glycerol, and Triethylene Glycol in Tobacco
Authors: Williams John F
Published: February 2020

Collaborative study was carried out on a method for determination of propylene glycol, glycerol, and triethylene glycol in tobacco. The method involves gas chromatography of the methanolic extract of tobacco on a 42 × 3/16″ column packed with 5% Carbo wax 20M-terephthalic acid on 60-80 mesh 1:1 Diatoport S-Chromosorb 101 mixed support. 1,3-Butylene glycol is used as an internal standard. The oven temperature is programmed from 90 to 240°C at 15°/min. Results for propylene glycol and glycerol gave coefficients of variation <10%. Results for triethylene glycol in cut tobacco at mean concentration levels of 0.95 and 1.30% gave coefficients of variation of 9.24 and 6.93%, respectively. At a mean concentration level of 0.54% triethylene glycol, the coefficient of variation was 20.8%. The method has been adopted as official first action.
Volume Determinations of Oil- and Dry-Roasted Nut Products
Authors: Werren John C , Allhands Frank H , Blomquist V H
Published: February 2020

Six laboratories studied a method for determining the volume of oil- and dry-roasted nut products. Five different samples consisting of 10 units each were examined and the mean volumes were determined. Satisfactory precision was obtained. The method has been adopted as official first action.