bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple Derivatization Procedure for Gas-Liquid Chromatographic Analysis of Diflubenzuron in Pond Water and for Analysis of Its Trifluoromethyl Analog Penfluron in Boll Weevils
Authors: DeMilo Albert B , Terry Paul H , Rains Diane M 
Published: February 2020

Abstract
A simple and convenient gas-liquid chromatographic procedure involving electron capture detection is described for determining diflubenzuron (N- [[(4-chlorophenyl) amino] carbonyl] - 2,6-difluorobenzamide) in pond water and for determining the uptake of penfluron (trifluoromethyl analog of diflubenzuron) by boll weevils sexually sterilized by this compound. Both compounds were quantitatively converted to their respective N-(trifluoroacetyl) anilines by treatment with trifluoroacetic anhydride and pyridine in benzene at 50–60 °C. In boll weevil analyses, the procedure was quantitative for penfluron at concentrations involving microgram quantities (10–35 ≧g/weevil) without the necessity of a cleanup step. However, at submicrogram quantities, background interference necessitated a thin layer chromatographic cleanup prior to derivatization. This modification enabled the determination of 100 ng/ weevil. Analysis for diflubenzuron in natural pond water gave excellent results. For example, diflubenzuron at 2, 0.2, and 0.02 ppm in pond water was recovered at 95, 82, and 98%, respectively. A mechanism describing the reaction is proposed.
High Pressure Liquid Chromatographic Method for Probenecid in Flavored Oral Suspensions Containing Ampicillin: Collaborative Studies
Authors: Vollmer Paul J , Alexander Thomas G , Haneke Carol 
Published: February 2020

Abstract
A high pressure liquid chromatographic method for determining probenecid in oral suspensions of amoxicillin was applied to the determination of probenecid in oral suspensions of ampicillin. Three preparations containing various known amounts of probenecid in synthetic mixtures of ampicillin oral suspensions were analyzed by 5 chemists in an intralaborastory study, with satisfactory results. Blind duplicates of 3 prepared oral suspensions were sent to 12 collaborators, who were instructed to analyze the samples in a fixed random order. The standards showed a satisfactory linear response. Average recoveries of probenecid in the interlaboratory study for the 6 mixtures ranged from 95.2 to 99.1%, and the coefficients of variation ranged from 1.63 to 4.9%.
Gas-Liquid Chromatographic Determination of T-2 Toxin and Diacetoxyscirpenol in Corn and Mixed Feeds
Authors: Romer Thomas R , Boling Tamara M , Macdonald John L 
Published: February 2020

Abstract
A gas-liquid chromatographic method has been developed for the simultaneous determination of the T-2 toxin and diacetoxyscirpenol (DAS) in corn and mixed feeds. The analytes are extracted with aqueous methanol. Ammonium sulfate is used to denature and precipitate proteinaceous compounds and to salt out low polar compounds. The analytes are selectively concentrated into chloroform, which is washed with aqueous potassium hydroxide to remove acidic compounds. Residual interferences are removed by silica gel column chromatography. Heptafluorobutrylimidazole (HFBI) is added to form esters of the analytes. The HFB-esters are separated on an SE-30 glass column and measured with a 63Ni electron capture detector, using methoxychlor as an internal standard. The method has been applied to corn, livestock feeds, and pet food. The limit of detection is 100 ng T-2 toxin and 25 ng DAS/g. Average recoveries of 105 and 97% and coefficients of variation of 17 and 10% were obtained for T-2 toxin and DAS, respectively.
High Pressure Liquid Chromatography with Ultraviolet Absorbance or Fluorescence Detection of Carbaryl in Potato and Corn
Authors: Lawrence James F , Leduc Raymonde 
Published: February 2020

Abstract
Carbaryl (1 - naphthyl -N - methylcarbamate) was extracted from corn and potato with acetone. The acetone extract was partitioned into methylene chloride-hexane and concentrated for cleanup on a 5 % water-deactivated Florisil column. The fraction containing the carbamate was subjected to high pressure liquid chromatographic (HPLC) analysis on a 25 cm LiChrosorb Si60 (5 &gt;m) column (2.2 mm id) by various means. First, the pesticide was analyzed directly with ultraviolet (UV) absorption detection at 254 nm and a mobile phase of trimethylpentane- isopropanol (96+4). After this, a fluorescent derivative was prepared, using dansyl chloride (5-dimethyIaminonaphthalene- 1-sulfonyl chloride), and analyzed by HPLC, using trimethylpentane-dioxane ( 9 5 + 5 ) as the mobile phase, with both UV absorption (254 nm) and fluorescence (excitation 365 nm, emission &gt;400 nm) detection. The response/ng for the dansyl derivative with fluorescence detection was 1.3 times greater than that for UV detection and 8 times more sensitive than direct UV detection of the carbamate. About 10 ppb carbaryl could be detected after derivatization in the foods studied; for direct analysis, 30—50 ppb could be detected at a 2:1 signal:noise ratio. Recoveries at 0.1 ppm averaged 9 0% by direct analysis compared with 7 8% after derivatization.
Bioavailability, in vitro Solubility, and Physical and Chemical Properties of Elemental Iron Powders
Authors: Motzok Ilary , Verma Ramesh S , Chen Shy-Show , Hasper Jaroslava , Hancock Ronald G V , Ross Henry U 
Published: February 2020

Abstract
The relative biological value (RBV) for rats of the iron from 7 elemental iron powders (produced by electrolysis, reduction with hydrogen (H2), carbon monoxide (CO), and desiccated ammonia (NH3), and carbonyl process) were compared with the in vitro solubility of the iron powders in 0.2% HC1 (w/v, ca 0.05/V) for periods of 5 to 90 min. The values obtained for per cent solubility in 10 min were within the fiducial limits of the individual RBVs of 6 iron samples; the exception was one preparation of carbonyl iron whose solubility, but not RBV, was as high as that of electrolytic iron. These data indicate that dissolution rates were good predictors of bioavailability of some types of elemental iron powders. There was good agreement between specific surface areas and particle size distributions of discrete fractions containing fine particles of comparable sizes (7—10 μm) of electrolytic, H2- and CO-reduced iron, and whole preparations of carbonyl iron, but these measurements were not satisfactory criteria for predicting bioavailability. SLOWPOKE neutron activation analysis of the iron powders showed that the carbonyl iron samples contained the lowest concentrations of elements producing short- and long-lived radioisotopes (24Na, 27Mg, 49Ca, 38Cl, 28A1, 66Cu, 56Mn, 52V, 101Mo, 51Cr, 122Sb, and 60Co) with the exception that the Mo content of one preparation was ca 2 times higher than in the other iron samples. Electrolytic iron contained higher levels of Na, Ca, Al, Cu, Mn, V, Sb, and Co than carbonyl iron. H2-, CO-, and NH3-reduced iron samples contained the highest levels of impurities, notably Na, Mg, Ca, CI, Al, Cu, Mn, V, and Cr.
Semi automated Method for Determining Ferrous Sulfate in Pharmaceuticals: Collaborative Study
Authors: Mccullen Percy A 
Published: February 2020

Abstract
A semiautomated colorimetric method is described for determining ferrous sulfate in tablets, capsules, and elixirs. The method involves the formation of an orange-red complex between 1,10-phenanthroline and ferrous ion. Collaborators were supplied with 3 solid composites and one liquid sample. Two of the solid composites were prepared from commercial tablets of different dosage and one from commercial timed-release capsules; the fourth sample was an elixir. The results of the automated analyses for ferrous sulfate agreed well with those of the applicable USP method. No interference was found from ferric iron or from the red and green coloring used on coated tablets. The method has been adopted as official first action.
Liquid Chromatographic Determination of Lasalocid in Premixes
Authors: Hagel Robert B 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method has been developed to determine lasalocid in premixes. The method is simple and rapid, requiring an extraction of the drug and separation of insoluble material before HPLC. Elution times are typically &lt;10 min per sample. The average recoveries for lasalocid at the 16.5 and 50% levels were 100.2±2 and 100.0±2%, respectively. The precision of the method (coefficient of variation = 0.02) compares favorably with that of the approved bioassay (coefficient of variation = 0.06).
Colorimetric Determination of Arprinocid in Feed
Authors: Fink David W , Martin Kobert P , Pivnichny James V , Shim Jung-Sook K 
Published: February 2020

Abstract
An analytical method has been developed for the determination of arprinocid (9-(2-chloro- fluorophenylmethyl) -9ff-purin-6-amine) in feed, based upon measurement of the absorbance of the diazo chromophore formed from product of zinc reduction of the drug in acidic solution. The analyte is extracted from the feed into chloroform in the presence of a pH 7 phosphate buffer and isolated by adsorption chromatography on alumina, followed by partitioning between hexane and 0.15M HC1. The reduction product in the aqueous phase is then treated for colorimetric measurement. This procedure has been applied to determining 0.0010-0.0080% arprinocid in feed with precision of &lt;5% relative standard deviation near the middle of this concentration range. Of 32 feed additives examined, only zoalene and sulfamethazine were serious interferences. study and discussion of several factors, e.g., reaction time, pH, and amount of zinc metal, that affect the analytical reactions are also included.
Determination of Neomycin Residues in Eggs and Stability of Residues After Cooking
Authors: Katz Stanley E , Levine Priscilla R 
Published: February 2020

Abstract
The procedure for neomycin residues used a surfactant to improve extraction, a centrifuge step to eliminate solids that interfere with the diffusion of the antibiotic, and a heat treatment to destroy interfering lysozyme activity. The use of Bacillus stearothermophilus and a 65°C incubation yielded a rapid assay with a sensitivity of 0.2 μg neomycin activity/g egg. Frying eggs caused little or no loss of activity, poaching resulted in 25% loss, and soft boiling and hard boiling caused little or no loss of applied activity. Neomycin residues in eggs were quite stable to normal egg preparation procedures.
Control of Hormone Treatment in Animals and Residues in Meat—Regulatory Aspects and Approaches in Methodology
Authors: Karg Heinrich , Vogt Karl 
Published: February 2020

Abstract
Although the benefit of using anabolic hormones for fattening purposes under specific situations in animal husbandry (for instance, veal production) has been acknowledged in European countries, the regulatory consequences were quite different from those in the United States. With the exception of the United Kingdom, there were no approvals to use estrogens for other than distinct veterinary purposes. Hence the methodological approaches were rather to control the illegal treatments and imports. One measure is the uterus weight bioassay. Furthermore morphological parameters (prostate test) and estrogen determinations by thin layer chromatography in urine (also from the bladder) were proposed for detection of treated animals. Radioimmunoassays are in development and considered sensitive enough for residue studies in carcasses, perhaps applicable in combination with high pressure liquid chromatography. The re-evaluation of the regulatory situation is in progress in France and Germany and under consideration in the United Kingdom. Guidelines may be the recommendations of the FAO/WHO Symposium 1975 in Rome on anabolic agents in animal production indicating the variety of risks due to different compounds in question and preference to those with low oral activity and defined bio-degradation.
Use of Radioimmunoassay for Monitoring Hormonal Residues in Edible Animal Products
Authors: Hoffmann Bernd 
Published: February 2020

Abstract
Radioimmunoassay (RIA) is valuable for sensitive and specific routine measurements of hormones in body fluids. The method is also applicable to determine tissue levels of hormones which, according to tracer studies and depending on the compound, are scattered in the lower ng and pg/g range. For practical assay application it must be decided whether the parent compound or a major metabolite should be measured. Both toxicological and practical regulatory aspects have to be considered, but in any case knowledge of the metabolic profile of the compounds is necessary, especially since the specificity of the RIA group analysis is limited. When applying extraction and purification steps, differences between compounds and between tissues have to be considered; generally more difficulties are encountered than with plasma. Validation of the method should first demonstrate no unspccific interference with the antigen-antibody reaction; then the other reliability criteria have to be established. So far RIAs for the quantitation of estrogens, testosterone, progesterone, and trienbolone—a synthetic androgen—in various bovine tissue samples have been developed. The lower limit of sensitivity ranges between 10 and 70 pg/g. Quantitation of physiological levels of testosterone and progesterone is possible, but there are still some problems with estrogens.
Reverse Phase High Pressure Liquid Chromatographic Determination of Aflatoxins in Foods
Authors: Beebe Roberta M 
Published: February 2020

Abstract
A method for determining aflatoxins by high pressure liquid chromatography (HPLC) with fluorescence detection after CB extraction and cleanup has been applied to various foods. Recoveries at 1—15 ppb levels from green coffee and peanut butter were 72-85 and 74—104%, respectively. Precision of the method has been tested for peanut butter. Other products to which the method has been successfully applied include tree nuts, seeds, grains, chocolate-covered peanut butter candy, and roasted, salted-in- shell peanuts. High levels of aflatoxins found in several samples of nuts by this method have been verified by the official thin layer chromatographic (TLC) method. The advantages of this HPLC method are speed, precision, sensitivity, selectivity, and immediate chemical confirmation of aflatoxins B1 and G1. None of the products analyzed required special cleanup procedures. Preparative-scale HPLC was used to isolate purified B1 for toxicity testing.
Microcrystalline Identification Test of Some Amphetamines and Hydrochlorothiazide: Collaborative Study
Authors: Auerbach Leonora 
Published: February 2020

Abstract
A previously described procedure for the identification of methamphetamine, dl-deoxyephedrine, dextroamphetamine, and amphetamine and a new procedure for hydrochlorothiazide identification have been subjected to collaborative study. The method for the amphetamines depends upon their volatilization from a strongly basic solution into a hanging drop containing gold chloride and the formation of characteristic crystals. The hydrochlorothiazide method is direct: the I2-KI solution is added to an alkaline solution of hydrochlorothiazide to cause the deposition of characteristic crystals. Of the 40 unknown drug dosage form powders supplied to 10 collaborators, 39 were correctly identified. The results indicate that the amphetamine procedure is capable of distinguishing between methampetamine and dl-deoxyephedrine. The age of the gold chloride reagent is important in these tests. The official final action tests for dl-deoxyephedrine and methampetamine were modified and Table 36:04 has been revised to reflect these changes. The hydrochlorothiazide test has been adopted as official first action and added to Table 36:05.
Efficient Concentration Procedure for Recovery of Nanogram Amounts of Hexachlorocyclohexane Isomers
Authors: Malaiyandi Murugan 
Published: February 2020

Abstract
Attempts to concentrate hexane solutions containing ca 1-50 pg/ml α-, β-, γ-, and δ-isomers of hexachlorocyclohexane (HCH) in Kuderna- Danish (K-D) evaporators gave inconsistent recoveries, ranging from 45.0 to 98.1%. This disadvantage has been overcome by adding a built-in distillation trap below the Vigreauxbubble condensing system of the Snyder column. Using the K-D evaporator with the modified Snyder column for concentrating 5 replicate solutions with 6 different concentrations of mixtures of HCH, mean % recoveries (standard deviation) of 92.4 (±5.5), 100.4 (±6.0) , 99.0 (±7.2) , and 79.7 (±9.7) were obtained for the α-, β-, γ-, and δ-isomers, respectively, indicating excellent performance efficiency of the system. A low F-ratio was obtained from statistical analysis of recovery data for the 4 isomers, denoting insignificant differences between concentrations for each isomer. Furthermore, the method has been evaluated by analyzing hexane samples fortified with isomeric mixtures of HCH by an independent analyst. For 3 different levels of fortification, mean recoveries (%) were 87.9, 94.9, 90.1, and 72.4 for the α-, β-, γ-, and δ-isomers, respectively.
Selective Colorimetric Determination of Linuron in Soils in the Presence of Metabolites
Authors: Friestad Håkon O 
Published: February 2020

Abstract
Intact residues of linuron in soils are determined by dichloromethane extraction, cleanup of the extract by partition between dimethyl sulfoxide and petroleum ether, acid hydrolysis in closed test tubes, and automated colorimetry of the resulting 3,4-dichloroaniline. Low blank values for soil types of widely varying characteristics make untreated controls superfluous. The detectability limit is approximately 0.1 mg/kg. Recovery is 88—106% and the standard deviation in the 0.5—1.0 mg/kg range is less than 0.1 mg/kg. Metabolites will not influence the analysis unless they are present in considerably higher amounts than the parent compound.
Gas-Liquid Chromatographic Method for Determining Fentin in Fentin-Maneb Preparations: CIPAC Interlaboratory Study
Authors: Basters John , Martijn Albertus , Van Der Molen Thomas , Pasma Piet , Rabenort Barend , Van Rossum Bram , Smink Jaap 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) method is described for determining fentin acetate and fentin hydroxide in formulations in the presence of maneb. Triphenyltin acetate or hydroxide is converted to butyltriphenyltin by the Grignard reaction; the product is determined by GLC, using flame ionization or thermal conductivity detection, a column containing 5% SE-30 on Chromosorb W (HP) or Gas-Chrom Q, and docosane as the internal standard. Fifteen laboratories tested the method on 6 samples. The estimated repeatabilities expressed as coefficients of variation, ranged from 0.8 to 1.4% and the estimated reproducibilities from 1.3 to 1.7%.
Determination of Ethylene Dibromide in Fortified Soils by Molecular Emission Cavity Analysis Using a Modified Extraction Process
Authors: Abdel-Kader Mohammed H K , Peach Michael E , Stiles David A 
Published: February 2020

Abstract
A method is described for the determination of small quantities of ethylene dibromide (EDB) in soils. The EDB is distilled from an aqueous slurry of the fortified soil into a cooled mixture of acetone-isooctane, which is then decomposed in a Schoniger flask. The resultant hydrogen bromide is injected into an indium-lined cavity of a molecular emission cavity analysis instrument and is quantitated from the intensity of the InBr emission (λmax = 376 nm). The detection limit of EDB is less than 0.5 ppm. Recovery of EDB added to soils at 0.5—10 ppm was greater than 96%.
Minicolumn Detection Method Applied to Almonds: Collaborative Study
Authors: Stanley George I , Diprossimo Vincent P , Koontz Anna C 
Published: February 2020

Abstract
The minicolumn screening method for aflatoxins was collaboratively tested on naturally contaminated almonds. The nuts were extracted, and the extract was cleaned up and applied to a Velasco-type minicolumn. This permits the detection of total anatoxins (B1, B2, G1, G2) as a fluorescent band on the Florisil layer of the column. The results of 20 collaborators are presented. Samples containing 0, 2, 5, 10, and 25 ng aflatoxin/g were analyzed. Ninety-six per cent of the samples containing 5—25 ng total aflatoxins/g and 83% of the negative samples were correctly identified. The method has been adopted as official first action for detection of total aflatoxin levels of ≥5 ng/g.
Instability of PR Toxin in Blue Cheese
Authors: Scott Peter M , Kanhere Shriniwas R 
Published: February 2020

Abstract
PR toxin was unstable in solvent extracts of blue cheese and in strongly acidic solutions. However, it was appreciably stable over a 2.5 hr period in moderately acidic methanol-water extracts (pH 2—3) of blue cheese. Using this extraction mixture, it was determined that PR toxin was not stable in blue cheese itself. PR toxin reacted with model neutral and basic amino acids and the formation of PR imine from PR toxin in the presence of blue cheese was demonstrated. While PR imine added to blue cheese could be recovered on analysis after 5 min, over a 2—5 day period it too was unstable in the cheese.
Gas-Liquid Chromatographic Determination of Nicotine Contained on Cambridge Filter Pads: Collaborative Study
Authors: Wagner John R , Thaggard Neil A 
Published: February 2020

Abstract
Nicotine was extracted from Cambridge filter pads with 10 mL 2-propanol containing 1 mg anethole/mL as the internal standard. Five standards ranging from 0.25 to 1.25 mg nicotine/ mL were injected into a 6 ft × 1/8 in. column packed with 2% KOH and 10% Carbowax 20M on 45—60 mesh diatomaceous earth to standardize the procedure. The injection port and detector were operated at 200—250°C, the column was operated at 165°C, and the helium flow was adjusted to ca 40 mL/min. Data were taken with systems giving resolutions of 1 count/mv-sec. Results from 16 laboratories gave standard deviations ranging from 0.02 to 0.06 mg nicotine/mL. Suggested improvements were incorporated into a second study, and 13 laboratories analyzed 5 paired samples; standard deviations ranged from 0.02 to 0.03 mg nicotine/mL. The method has been adopted as official first action.
Colorimetric Determination of Carvone in Volatile Oils in the Presence of Menthone and Pulegone
Authors: Karawya Mohamed S , Hifnawy Mohamed S , El-Hawary Seham S 
Published: February 2020

Abstract
Carvone, menthone, and pulegone in volatile oils are determined by measuring at 370 nm the color obtained by their reaction with 3,5-dinitrobenzoic acid (DNBA) or m-dinitrobenzene (DNB). The DNBA method is sensitive to 50—1500 μg carvone or pulegone/10 mL and to 500-1500 μg menthone/10 mL. The DNB method is as sensitive to carvone and menthone as is the DNBA method, but it is less sensitive to pulegone (300—1500 μg/10 mL). Either carvone or pulegone in the presence of menthone can be determined by using the DNBA method at concentrations less than 500 μg menthone/10 mL. Carvone can also be estimated by the DNB method without pulegone and menthone interference when these constituents are present at levels less than 300 and 500 μg/10 mL, respectively. Other ketonic constituents, piperitone, methyl heptenone, and ionone, did not respond to the color reaction except at concentrations above 750 μg/10 mL. The method was successfully used for the estimation of carvone in oils of Mentha viridis, M. crispa, caraway, and dill.