bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thin Layer Chromatographic Determination of Aflatoxin B1 in Corn Silage
Authors: Häggblom Per E , Casper Howard H 
Published: February 2020

Abstract
A procedure is described for the purification and quantitation of aflatoxin B1 in corn silage. The toxin is extracted and partially purified using parts of the AOAC minicolumn detection method. The extract is further cleaned up on a 2-step minicolumn and is then analyzed by using thin layer chromatography. Essentially all interferences are removed when the procedure is applied to moldy and non-moldy corn silage. The estimated limit of detection is 5 μg aflatoxin B1/kg corn silage, and 73±8% of the added aflatoxin B1 (20 and 85 μg/kg) was recovered. No aflatoxin B1 was detected in 270 samples collected from 19 silage piles in late fall 1976 and early spring 1977. This procedure also removes interferences associated with moldy corn and mixed feeds.
Automated Fluorometric Determination of Vitamin A in Milk
Authors: Thompson James N , Madère René 
Published: February 2020

Abstract
A previously published fluorometric method for vitamin A in milk, involving saponification in centrifuge tubes and extraction with hexane, was automated using conventional automated equipment including a filter fluorometer. The extraction and separation steps were affected by the presence of fat, so standards were prepared in milk. The peaks obtained with samples were 95% of steady state values. The coefficients of variation for 10 replicate analyses were 1.9% for unfortified milk and 1.3% for fortified milk. In tests on 19 different milk samples, the results of the automated and manual fluorometric methods differed by less than 10%; a colorimetric method using SbCl3 gave more erratic results and was more lengthy and laborious.
Survey of Cured Meat Products for Volatile N-Nitrosamines: Comparison of Two Analytical Methods
Authors: Havery Donald C , Fazio Thomas , Howard John W 
Published: February 2020

Abstract
A survey has been completed of 106 cured meat samples for 14 volatile N-nitrosamines. N-Nitrosopyrrolidine has been confirmed in fried bacon at levels ranging from 5 to 75 ppb. Unconfirmed trace levels of N-nitrosodimethylamine have been observed in a variety of cured meat products. The comparison of the multi-detection gas-liquid chromatographic (GLC)- mass spectrometric method with the mineral oil distillation-thermal energy analyzer (TEA) method for the determination of volatile N-nitrosamines in foods shows good agreement between the analytical methods, especially at the 10 ppb level, and excellent agreement between the GLC and TEA analyses of an identical sample extract.
High Pressure Liquid Chromatographic Determination of Imazalil Residues in Gtrus Fruit
Authors: Norman Shirley M , Fouse David C 
Published: February 2020

Abstract
A high pressure reverse phase liquid chromatographic method is described for determining the fungicide imazalil (1-[2,4-dichlorophenyl) -2- (2-propenyloxy)ethyl] -1H-imidazole) residues in whole citrus fruit, peel, and pulp. Imazalil is extracted from the fruit with ethyl acetate, partitioned into acid and back into ethyl acetate for cleanup, and detected by ultraviolet absorbance at 202 nm. Recovery from whole ground fruit of known amounts of imazalil applied to the surface of intact fruit averaged 84% 24 hr after application and 80% after the fruit had been stored 4 weeks at 15°C.
High Pressure Liquid Chromatographic Determination of Major Organic Acids in Cranberry Juice
Authors: Coppola Elia D , Conrad Edward C , Cotter Richard 
Published: February 2020

Abstract
A reverse phase high pressure liquid chromatographic method is presented for the simultaneous separation and determination of quinic, malic, and citric acids in single strength, undiluted cranberry juice. After a 1:10 dilution and cleanup through a disposable column, major organic acids in cranberry juice are separated on a Bondapak/C18 column and quantitated by using a differential refractometer. Twenty-seven samples of different single strength cranberry juice were analyzed using this method; the mean content of quinic, malic, and citric acids were 1.32 (std dev. 0.150), 0.92 (std dev. 0.079), and 1.08% (std dev. 0.111), respectively. Mean percent recoveries of each acid were quinic 95.4 (std dev. 6.8), malic 96.6 (std dev. 5.8), and citric 94.0% (std dev. 4.8).
Potentiometric Method for Determining Triphenyltin Compounds in Formulations: Collaborative Study
Authors: Litan René , Basters John , Martijn Albertus , Van Der Molen Thomas , Pasma Piet , Rabenort Barend , Smink Jaap 
Published: February 2020

Abstract
Five laboratories collaboratively studied 2 procedures for the quantitative determination of triphenyltin compounds in technical material and in formulations. Both procedures include an extraction step and a potentiometric titration but differ in how byproducts are removed. The first is based on cleanup with sodium tartrate and in the second one alkaline alumina is used for purification. The performance, however, is different. The reproducibility and the repeatability are significantly better with the alumina method than with the tartrate method. The average (systematic) difference between the 2 methods was —2.3%. The method based on alkaline alumina cleanup has been adopted as an interim CIPAC method.
Substitution of n-Heptane for Ethyl Ether in USP Assay for Chlorpromazine Hydrochloride in Tablets, Injections, and Sirups
Authors: Kirchhoefer Ross D , Myrick James W 
Published: February 2020

Abstract
Peroxide levels above 0.0001% in the ethyl ether used in the USP XIX assay for chlorpromazine hydrochloride in tablets, sirups, and injections produce a distorted spectrophotometric curve in the 350-220 nm region. The use of peroxide-free ethyl ether or n-heptane avoids this problem. Recoveries of 91–100% are obtained with either of these reagents.
Gas-Liquid Chromatographic Determination of Sodium Bisulfite in Complex Matrices
Authors: Czarnecki John J , Koehler Walter R , Cooper Aaron D 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) headspace technique is described for determining sodium bisulfite in a dermatological cream. The sample is dispersed in an aqueous medium and acidified to convert sulfite to volatile sulfur dioxide which partitions into the headspace. An aliquot of the headspace vapor is analyzed by GLC using the sulfur-selective flame photometric detector. Advantages of the method include the facility of sample preparation, the specificity and sensitivity resulting from the combined use of the headspace technique and the flame photometric detector, and the applicability of the method to various types of sample matrices. Recoveries ranged from 95 to 102% for spiked samples containing 200—2000 ppm sodium bisulfite. For the sample size and experimental conditions used in this application, the detection limit is 0.02 mg sodium bisulfite.
Gas-Liquid Chromatographic Determination of Maleic Hydrazide in Tobacco and Tobacco Smoke
Authors: Haeberer Alfred F , Chortyk Orestes T 
Published: February 2020

Abstract
A method is presented for the determination of the plant growth regulator maleic hydrazide (MH; l,2-dihydro-3,6-pyridazinedione) in tobacco and tobacco smoke. Residues are converted to the bis(trimethylsilyl) derivative before analysis by gas-liquid chromatography. The method has been applied to cigarettes and condensed smoke and has been used to determine the per cent transfer of MH into cigarette smoke. Free MH residues could be determined directly on the tobacco samples, whereas total MH values were obtainable only after acid hydrolysis. In spite of large MH residues in tobacco, only 0.2% of the MH was transferred into smoke.
Gas-Solid Chromatographic-Mass Spectrometric Confirmation of Low Levels of Acrylonitrile After Distillation from Food-Simulating Solvents
Authors: McNeal Timothy , Brumley William C , Breder Charles , Sphon James A 
Published: February 2020

Abstract
Acrylonitrile (AN) in aqueous food-simulating solvents is concentrated by adding methanol and distilling the AN-methanol azeotrope. AN in heptane is partitioned into water and azeotropically distilled with methanol. This procedure concentrates approximately 30% of the An in 0.5 ml methanolic solution. The concentrate obtained is analyzed by gas-solid chromatography (GSC) and the presence of AN is confirmed by GSC-mass spectrometry, using multiple ion monitoring of ions at m/z 53, 52, 51, and 26. Levels as low as 0.01 ppm AN in the original food-simulating solvents can be confirmed. The migration of AN into 8% ethanol and 3% acetic acid contained in styrene-acrylonitrile bottles has been confirmed by using this method.
Gas-Solid Chromatographic Determination of Moisture in Lyophilized Pharmaceutical Products
Authors: Lyman Gary W , Johnson Raymond N 
Published: February 2020

Abstract
A gas-solid chromatographic procedure is described for the analysis of low levels of moisture in individual lyophilized vials of pharmaceutical products. Dry ethanol, which contains methanol as the internal standard, is injected through the septum of the vial to dissolve the lyophilized contents. An aliquot of this solution is then withdrawn and injected onto a Porapak QS column at 110°C where the components are separated and detected using thermal conductivity detection. A solvent blank correction allows quantitation of the water in the individual vial. The method is conveniently applied to samples containing as little as 50 μ g water/vial, and as many as 25 vials can be assayed/day. A simple technique is also described for removing water from the ethanol solvent to &lt; 1 0 0 ppm, using a molecular sieve.
Rapid Florisil Cleanup Method for Analysis of Chlorinated Pesticide Residues
Authors: Stimac Robert M 
Published: February 2020

Abstract
A modification of the current Florisil chromatographic cleanup procedure for pesticide residue analysis is presented. By prewashing the Florisil column with a specified quantity of ethyl ether, many chlorinated pesticides, including dieldrin and endrin, can be eluted in one step. The demonstrated cleanup efficiency of the proposed method eliminates the need for further cleanup, since the concentrated eluate is suitable for gas chromatographic analysis. Recovery of 13 chlorinated pesticides in typical products of corn wet milling ranged from 85 to 115%.
Mechanized System for Liquid Chromatographic Determination of 4-Nitrophenol and Some Other Phenolic Pesticide Metabolites in Urine
Authors: Ott Daniel E 
Published: February 2020

Abstract
Protecting the health of workers who are exposed to pesticides is of concern. One helpful approach is to periodically analyze the urine of such workers for metabolites of those pesticides encountered in the working environment. Therefore, an analytical system for several urinary pesticide metabolites, which incorporates a high degree of mechanization, has been developed. Urine samples (ca 8 ml) are placed in a sampler module. An acid hydrolysis step, a steam distillation step, and a combined liquid chromatographic separation and UV absorption determinative step are performed automatically, except for the need for an operator to turn a loop valve injector for the liquid chroma tograph at an exact time after the start of sampling each sample. At the slowest rate, a sample is analyzed every 24 min with a lower limit of detectability from 1 to 2 ppm added 4-nitrophenol in urine. Acid hydrolysis is included to cleave urinary conjugates of the analyte(s) of metabolic origin; steam distillation provides considerable cleanup. The method, with minor adjustment of chromatographic conditions, also responds to &lt;5 ppm each of the other phenols derivable from the below-named (and some other) pesticides. Alternative conditions permit detection of &lt;1 ppm 1-naphthol. Exact limits lower than the numerical values stated have not been determined. The method has the capability for assessing human exposure primarily to parathion, paraoxon, methyl parathion, and EPN, but also to carbaryl, Landrin, 2-phenyIphenol, bromophos, bromophos-ethyl, iodofenphos, 2,4,5-trichlorophenol, 2,4,5-trichlorophenoxyacetic acid, fenoprop, trichloronat, and fenchlorphos. The applicability of the method was demonstrated by fortifying urine with phenolic standards corresponding to the phenolic moieties as metabolically produced from these pesticides or to the phenolic parent pesticide.
Collaborative Study of the Gas-Liquid Chromatographic Determination of Malathion in Formulations and Technical Materials
Authors: Wayne Richard S 
Published: February 2020

Abstract
A gas-liquid chromatographic method was studied collaboratively for determining malathion in wettable powders, an emulsifiable concentrate, a dust, and the technical grade product. Flame ionization detection, m-diphenoxybenzene as the internal standard, and a column containing 5% SP-2401 or OV-210 on 100-120 mesh Gas-Chrom Q or Supelcoport were used for the determination. Agreement between replicates in individual laboratories was excellent. Agreement between laboratories was satisfactory. The method offers improved specificity and ease of operation when compared to the official first action methods. The method has been adopted as official first action.
Detection of Salmonella in Onion and Garlic Powders: Collaborative Study
Authors: Andrews Wallace H , Wagner Dean , Roetting Mary Jo 
Published: February 2020

Abstract
The relative efficiency of trypticase soy broth with added 0.5% K2SO3 and lactose broth as pre-enrichment media for recovering Salmonella from onion powder and garlic powder was collaboratively studied. For each spice, 13 collaborators each received 5 duplicate samples; 4 of the 5 replicate samples were inoculated with 1 of 4 levels of S. thompson ranging, at initiation of analysis, from &lt;3 to 93 organisms/g onion powder and &lt;3 to 43 organisms/g garlic powder. Salmonella growth was inhibited in each of these spices as evidenced by a rapid decline of most probable number values in samples determined immediately after and 7 days following inoculation. Collaborative results of cultural analyses demonstrated superiority of the modified trypticase soy broth for recovering Salmonella in each of the 2 spices. The improved method of detecting Salmonella in onion and garlic powders has been adopted as official first action.
Semiautomated Method for the Analysis of Formulations of Chlorpheniramine Maleate and Brompheniramine Maleate
Authors: Cox Don C , Kirchhoefer Ross D 
Published: February 2020

Abstract
The determination of chlorpheniramine maleate and brompheniramine maleate in tablets, capsules, injections, and elixirs has been automated. The active ingredient is dissolved in dilute HCl. The dilute acid solution is sampled, made basic with dilute NaOH, and extracted with isooctane. The isooctane phase is resampled and the drug is re-extracted into dilute HCl. The absorbance of the acidic aqueous layer is monitored at 265 nm. The method is an automated version of the general USP XIX assay for salts of organic nitrogenous bases. The results from the semiautomated procedure agree well with the USP XIX and NF XIV official methods. Recoveries were 100% from an authentic tablet material. The system is linear from 0 to 300% of declared potency. The procedure is free from common excipient and dye interferences. Precision data are included for both the automated and official methods.
Survey of Some Market Basket Commodities for Polynuclear Aromatic Hydrocarbon Content
Authors: Joe Frank L , Roseboro Emma L , Fazio Thomas 
Published: February 2020

Abstract
The Food and Drug Administration multicomponent regulatory procedure for determining polynuclear aromatic hydrocarbons in foods was recently used to survey 24 foodstuffs for the presence of these compounds. The procedure has a reliable limit of quantitation of 2 ppb. The potent carcinogen benzo (a) pyrene was detected in only one of the 24 products analyzed, at a level of 3 ppb. Pyrene and/or fluoranthene were found in 19 of the 24 samples examined, at levels ranging from less than 1 ppb to about 75 ppb. A comparison of the recent survey data to that obtained approximately 10 years ago reveals that the types and levels of polynuclear aromatic hydrocarbons found are essentially unchanged.
Determination of Chlorinated Pesticide Residues in Foods. III. Simultaneous Analysis of Chlorinated Pesticide and Phthalate Ester Residues by Using AgNO3-Coated Florisil Column Chromatography for Cleanup of Various Samples
Authors: Suzuki Takashi , Ishikawa Kiyoshi , Sato Nobutoshi , Sakai Kei-Ichi 
Published: February 2020

Abstract
A simplified method suitable for simultaneous analysis of chlorinated pesticide and phthalate ester residues in various foods was developed. Chemical residues were quantitatively extracted from fatty and vegetable samples with acetonitrile as follows: Chemical standard in 0.5 mL ethanol solution was added to 10 g homogenized sample. After 3 hr, pork and beef were extracted 3 times with 20 mL portions of acetonitrile. The acetonitrile layers were diluted with water and extracted with n-hexane. Rice samples were combined with 10 mL water, 5 mL acetonitrile, and 1 mL ethanol and extracted 3 times with 20 mL portions of n-hexane. The re-hexane concentrate from each sample was submitted to AgNO3-coated Florisil column chromatography. The AgNO3 coating adequately adsorbed interfering coextractives. Extracts of fish and vegetable samples were separated into 2 fractions by the above column chromatography. Supplemental cleanup procedures were also developed to accurately determine phthalate esters eluted in the second fraction. Satisfactory gas chromatograms were obtained for most samples.
Sampling Variances of Bulk-Blended Dry Fertilizers
Authors: Pettygrove G Stuart , Schneider Paul S 
Published: February 2020

Abstract
Probe and stream samples were collected from 50 loads of dry bulk-blended fertilizer at 21 blending plants in central Iowa. The variances in N, P2O5, and K2O content attributable to sample collection were much larger than those used to compute the fertilizer Investigational Allowances recommended by the American Association of Plant Food Control Officials. Manufacturing conditions in this study were not controlled and could have inflated the sample collection variance, but no relationship was observed between the variance and a number of manufacturing parameters, including nutrient level and particle size mismatch of blending ingredients. Therefore, it seems that the sample collection variance used to compute the Investigational Allowance underestimates the inherent variability that occurs in sampling of physically blended fertilizers. Probe samples tended to be lower in N and P2O5 content and higher in K2O content than were stream samples. The use of materials poorly matched in particle size, coupled with slow blender discharge, tended to result in larger differences between probe and stream samples.
Confirmation of Organothiophosphorus Insecticide Residues in Fruit and Vegetables by Oxidative Derivatization
Authors: Singh Joginder , Cochrane William P 
Published: February 2020

Abstract
Oxidative derivatization of 10 organothiophosphorus insecticides at nanogram levels, with neutralized sodium hypochlorite (NaOCl) produced their respective P = O oxygen analogs, as shown by GC/MS and FT-IR analysis. In addition, phorate resulted in phorate oxon sulfoxide while methidathion gave a mixture of oxidation products. Four macro-scale oxidation products of methidathion were isolated by thin layer chromatography and 3 were identified, namely, methidaoxon, bis(2-methoxy-Δ2-1,3,4-thiadiazolin-5-on-4-yl) sulfide, and the corresponding disulfide, by comparison of their infrared and mass spectra with those of authentic samples. The relative response to sulfide and disulfide products of the flame photometric detector in both the P- and S-modes is discussed. This derivatization is applied to the confirmation of chlorpyrifos, ethion, phorate, DMPA (Zytron), leptophos, and methidathion in celery, potatoes, lettuce, tomatoes, and apples at 0.25–0.5 ppm fortification levels.
Investigation and Simplification of the Sweep Co-Distillation Cleanup of Pesticide Residues in Animal Fats
Authors: Heath Andrew B , Black Robert R 
Published: February 2020

Abstract
The sweep co-distillation technique of Storherr et al. was investigated and simplified. Six organochlorine pesticides in animal fats were cleaned up under various distillation conditions as follows: No solvent was used, or solvent injection rates were 1 mL/min or 2 mL/3 min. Distillation tubes of 6.7 and 9.0 mm id diameter were compared. Distillation temperatures were varied from 150 to 300°C The complex condenser of Storherr et al. was compared with a simpler pipet condenser. A U-tube condenser which allows direct introduction onto a Florisil column for secondary cleanup was evaluated. The following modifications to the sweep co-distillation technique resulted: no solvent introduction, distillation temperature 230°C, nitrogen flow rate 600 mL/min, 6.7 mm id distillation tubes with simplified packing, and incorporation of the U-tube condenser. The new technique gave recoveries comparable to those of Storherr et al., but it is faster than most bisolvent partition methods and no large volumes of solvent are required.
Liquid Chromatographic Determination of Desoxycorticosterone Acetate in Oil Injections
Authors: Smith Edward 
Published: February 2020

Abstract
To determine desoxycorticosterone acetate in oil injections, reverse phase partition chromatography on silanized, purified siliceous earth was used to separate the corticosteroid ester from the bulk of the oil vehicle. The latter was retained on the column while the steroid and the sterol and triterpenoid fractions of the oil were eluted. An internal standard was added to this eluate, which was then subjected to reverse phase high performance liquid chromatography (HPLC). The desoxycorticosterone acetate was quantitatively separated in the HPLC procedure from any free desoxycorticosterone, preservatives, and minor components of the oil. The suitability of the HPLC procedure was verified with a number of C18 packing materials, both pellicular and microparticular. The desoxycorticosterone acetate was adequately resolved from the internal standard, progesterone, with most C18 packing materials evaluated. The proposed procedure provides a suitable stability-indicating assay for desoxycorticosterone acetate in oil injections.
Mass Spectrometric 13C/12C Determinations to Distinguish Honey and C3 Plant Sirups From C4 Plant Sirups (Sugar Cane and Corn) In Candied Pineapple and Papaya
Authors: Doner Landis W , Chia David , White Jonathan W 
Published: February 2020

Abstract
Stable carbon isotope ratio analysis was applied to concentrated extracts of authentic honey-processed pineapple and papaya samples and imported candied samples alleged to have been processed with honey. The 9 imported samples had δ13C values ranging from –11.1 to –15.0%0, while pineapple and papaya samples known to be processed with honey had values of –25.0 and –25.2%0, respectively. The results show that the imported samples were processed with sugar sirups derived from plants using the Hatch-Slack (C4) photosynthetic cycle, such as sugar cane and corn, rather than with honey which is derived from Calvin (C3) floral sources.