bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas-Solid Chromatographic Determination of Volatile Denaturants in Ethanol Solution
Authors: Martin Glenn E , Figert Donald M
Published: February 2020

A gas-solid chromatographic determination of volatile denaturants in non-beverage alcohol samples was studied by 10 collaborators representing 6 laboratories. The mean values obtained by 10 collaborators for a concentration of 2.00% each in ethanol solution were: acetone 2.14, ethyl acetate 1.95, ethylene glycol monomethyJ ether 1.90, toluene 1.89, methanol 2.08, chloroform 1.89, n-butanol 1.95, ethylene glycol monoethyl ether 1.88, methyl isobutyl ketone 1.83, isopropanol 2.18, sec.-butanol 2.01, and benzene 2.03. The mean values obtained by the 10 collaborators for a concentration of 4.00% each were: 4.08, 3.94, 3.91, 3.94, 4.07, 4.04, 4.01, 3.99, 3.99, 4.12, 4.05, and 4.06%, respectively. Likewise, at a concentration of 8.00%, each of the results by these same collaborators were: 7.89, 7.94, 8.07, 8.03, 8.04, 8.19, 7.98, 7.97, 8.10, 7.99, 8.10, and 8.07%, respectively. As a general rule, as the precision improved so did the accuracy.
Gas-Liquid Chromatographic Determination of Residues of Chlorpyriphos and Leptophos, Including their Major Metabolites, in Vegetable Tissue
Authors: Braun Heinz E
Published: February 2020

A method is described for the determination of residual chlorpyriphos (O, O-diethyl 0-3,5,6- trichloro- 2 - pyridyl phosphorothioate) and leptophos (O-(4-bromo-2,5-dichlorophenyl) O-methyl phosphonothioate), and their respective oxygen analogs and hydrolytic metabolites, in field-treated vegetables. Samples are extracted by blending with acetonitrile followed by liquid-liquid partitioning between benzene and aqueous sodium carbonate to separate the parent compounds and oxygen analogs from the hydrolytic metabolites. Both fractions are individually cleaned up on silica gel which also serves to fractionate the parent compounds from their oxygen analogs as the result of oncolumn hydrolysis of the oxygen analogs. Chlorpyriphos and leptophos are determined by flame photometric gas-liquid chromatography (GLC); the residual and derived hydrolysis products are derivatized with trimethylsilyl acetamide and determined by electron capture GLC. Overall recoveries from fortified samples averaged 95% for the parent compounds and 85% for the oxygen analogs and hydrolytic metabolites. Detection limits approximated 0.005 ppm for chlorpyriphos and leptophos, 0.002 ppm for the oxygen analogs, and 0.001 ppm for the hydrolytic metabolites.
Collaborative Study of the Microanalytical Oxygen Flask Sulfur Determination with Dimethylsulfonazo III as Indicator
Authors: Scroggins Laverne H
Published: February 2020

The volumetric, microchemical oxygen flask sulfur determination using dimethylsulfonazo III as the sulfate indicator and standard barium perchlorate as the titrant was tested by 21 collaborators. The samples studied were sulfanilamide, benzyl-isothiourea hydrochloride, cystine, potassium sulfate, and potassium sulfate with a phosphate additive. Only 5 collaborators reported good results for the potassium sulfate when it was contaminated with phosphate. Overall statistical evaluation of the data for the 4 pure compounds gave satisfactory values—average standard deviation 0.10, overall average deviation of the mean from theoretical value 0.16, and average bias 0.10. However, a statistical analysis of the reproducibility among analysts showed 10 of the 21 laboratories had an overall average deviation of the mean from the theoretical value greater than 0.20. A critical factor was the necessity for vigorous, efficient stirring during the titration to overcome indicator lag-time by hastening the fading of the pseudo-end point color. Thus, many collaborators reported the titration to be slow and tedious. It is recommended that the study of the microanalytical oxygen flask sulfur determination be continued.
Rapid Screening Method, Including Automated Colorimetry, for Low Residue Levels of Linuron and/or Chlorpropham in Vegetables
Authors: Friestad HÅkon O
Published: February 2020

Linuron and/or chlorpropham are extracted from crop material with acetonitrile and the extracts are given preliminary cleanup with a slightly modified Mills-Onley-Caither method. The herbicides are hydrolyzed to aromatic amines which, after automatic diazotization and coupling, are determined by colorimetry. The use of manual rapid and efficient cleanup and hydrolysis steps have made it possible to establish lower limits of detection of about 0.01 mg/kg, equivalent to those commonly obtainable by GLC, for the 4 crops tested. Recoveries from carrots and potatoes, when corrected for predetermined consistent procedural losses, averaged 95% with satisfactory precision.
Collaborative Study of the Microanalytical Determination of Bromine and Chlorine by Oxygen Flask Combustion
Authors: Lalancette Roger A , Steyermark Al
Published: February 2020

Twenty collaborators studied a specific method for bromine and chlorine, using oxygen flask combustion followed by mercurimetric titration. The method was previously adopted as official first action for iodine in organic compounds. Eighty-four determinations were performed on p-bromoacetanilide for which the statistical evaluation of the data gave x = 37.30%, x—theory = —0.03%, s = 0.13, and sm = 0.18. With the exception of one collaborator (x—theory = —0.55%), all obtained acceptable accuracy and precision and only his accuracy was not acceptable. Statistical evaluation of the data for 85 determinations on p-chloroacetanilide gave x = 20.86%, x—theory = −0.04%, s = 0.11, and sm = 0.11. All collaborators obtained acceptable accuracy and precision. The official first action method for iodine has been adopted as official first action for bromine and chlorine as an alternative to the Carius method.
Ion Exchange Determination of Strontium-89 and Strontium-90 in Milk: Collaborative Study
Authors: Baratta Edmond J
Published: February 2020

Eleven collaborators performed a second collaborative study of an ion exchange method for determining strontium-89 and -90. For milk containing 29.0 and 197 pCi/L of strontium- 89, the results at 2 levels were: average 31.0, 199.6; range 26-36, 164-290; standard deviation 2.9, 7.2; and per cent error 10.0, 3.4. For milk containing 32.4 and 151.2 pCi/L of strontium-90, the results were: average 32.5, 149.9; range 27.2-38.0, 125.3-170.3, standard deviation 0.32, 4.17; and per cent error 0.9, 2.8. The method has been adopted as official first action.
Collaborative Study of the Gas Chromatographic Determination of Six Thiocarbamate Herbicides in Formulations
Authors: Barney James E
Published: February 2020

Eptam, Ordram, Ro-Neet, Sutan, Tillam, and Vernam thiocarbamate herbicides are determined in emulsifiable and granular formulations by gas chromatography on an OV-1, SE-30, or OV-17 column with a flame ionization detector. Another thiocarbamate is used as an internal standard. The method was tested collaboratively by 19 laboratories, 18 of which tested the method on all 6 thiocarbamates. The coefficient of variation for 12 formulations was 3.10%. A significant amount of systematic error was detected, particularly in the analysis of emulsifiable formulations. The method has been adopted as official first action, and it is recommended that additional studies be conducted.
Quantitative Determination of Polysorbate 60 in Shortening: Collaborative Study
Authors: Smullin Charles F
Published: February 2020

Six samples of shortening, containing from 0.38 to 1.02% polysorbate 60, were submitted to 7 collaborators. The shortening is saponified and, after acidification, the acids are removed. The aqueous polyol solution is desalted and the polyoxyethylated polyols are precipitated as a highly insoluble heteropoly acid complex, using barium hydroxide as the precipitant. The polysorbate 60 content is calculated from the weight of the precipitate, using a gravimetric factor. Average recoveries from the collaborative samples ranged from 97.7 to 103.2%, with standard deviations from 0.019 to 0.061. The method has been adopted as official first action.
Evaluation of Malonate Dulcitol Lysine Iron Agar for Presumptive Identification of Salmonellae
Authors: Stroup John R
Published: February 2020

Malonate dulcitol lysine iron agar (MDLI) was evaluated, using 173 Salmonella subgenus I (19 serotypes) from 129 samples and 140 Salmonella subgenus III (Arizona hinshatcii) from 17 samples. Sixty-four stock cultures were tested including 3 Salmonella subgenus II, 5 Salmonella subgenus IV, and 5 Edwardsiella tarda. Three hundred thirty-five non-Salmonellae from 81 samples were also studied. Only the Edwardsiella cultures and 1 other non- Salmonellae gave aberrant results in MDLI. Five of the known Salmonella serotypes tested and 2 serotypes isolated from samples gave atypical results. If MDLI is used to differentiate the subgenera, and lysine iron agar is used to confirm lysine decarboxylase for subgenera II, III, and IV, as well as act as a source of cells for "O" group serology, then the results of this study indicate that 305 (97.4%) of the 313 Salmonellae isolated from samples gave typical reactions within 30 hr. Biochemical and serological tests should be used to confirm cultures that give positive reactions.
Gas-Liquid Chromatographic Quantitative Determination of Vanillin and Ethyl Vanillin in Foods
Authors: Schlack Janis E , Dicecco Joseph J
Published: February 2020

A gas-liquid chromatographic method for vanillin and ethyl vanillin in foods has been devised. Vanillin and ethyl vanillin are extracted into methylene chloride, and the extract is purified, concentrated, and then chromatographed on an EGSS-X column. Recovery of vanillin and ethyl vanillin averaged 99.54 and 98.05%, respectively.
Gas-Liquid Chromatographic Determination of Choline in Low and High Potency Multiple Vitamin Tablets and Liver Preparations
Authors: Garavelli Caesar B
Published: February 2020

A procedure is described for the quantitative determination of 0.020—6.0 mg choline in low and high potency reference multiple vitamin tablets and standard liver preparations. The trimethylamine quantitatively produced in a sealed tube by treatment with aqueous 5 0% alkali is simultaneously extracted with 0.200—0.500 ml of an isobutanol-ethanol (1+1) mixture and determined by gas-liquid chromatography. An average recovery of 100 ± 3 % was obtained.
Scale-up of AOAC Method III for Quantitation and Isolation of Aflatoxins in Nuts and Nut Products for Chemical and Biological Confirmation
Authors: Diprossimo Vincent P
Published: February 2020

The official AOAC Method III for aflatoxins in peanuts and peanut products (Best Foods or BF method) has been adapted to a larger sample size (500 g), approaching the sample handling capacity of the 1 kg official AOAC Method I (FDA Contaminants Branch or CB method). The modified procedure (NY method) was used in place of the 1 kg CB method for obtaining quantitative assay results and for isolation of pure aflatoxin B1 for derivatization and bioassay. Two samples of naturally contaminated unshelled pistachio nuts and 4 peanut product samples were analyzed using the modified NY method and the results were compared with quantitative assays using official methods. Results were in excellent agreement with the official methods. The thin layer chromatographically pure aflatoxin B1 recovered using the modified procedure on various products was 39 to 57% of that calculated to be present in the samples, a favorable recovery compared to the 1 kg CB method (usually about 50%). All derivatizations carried out were successful (3 samples) and all biological confirmations were successful (2 samples were tested by the chick embryo bioassay for aflatoxin B1 toxicity).
Automatic Potentiometric Titration of Sodium Sulfate in Certifiable Water-Soluble Colors
Authors: Bailey John E , Graichen Charles
Published: February 2020

A method has been developed for the automatic potentiometric titration of sulfate in water-soluble colors, which has the advantage of requiring little sample preparation and attention. A platinum indicating electrode is used with a coated silver reference electrode. The colors are dissolved in 75% alcohol. The sulfate is titrated with lead nitrate solution, using a Hiranuma recording automatic titrator. The method is applicable to the determination of sulfate in all sulfonated certifiable water-soluble colors except External D&C Green No. 1. It is not applicable to the determination of sulfate in the certifiable water-soluble fluorescein colors, namely, FD&C Red No. 3, D&C Orange No. 11, D&C Red No. 22, D&C Red No. 28, and D&C Yellow No. 8. The method is also not applicable to D&C Red No. 19. The
Determination of Uncombined Intermediates in FD&C Yellow No. 6 by High-Pressure Liquid Chromatography
Authors: Singh Manjeet
Published: February 2020

A high-pressure liquid chromatographic method is presented for the isolation and determination of uncombined intermediates in FD&C Yellow No. 6 (sunset yellow FCF, CI. No. 15895). Samples of FD&C Yellow No. 6 containing 0.1-0.4% sulfanilic acid, 0.1-0.4% 6-hydroxy-2-naphthalenesulfonic acid, and 0.3— 1.0% 6,6'-oxybis(2-naphthalenesulfonic acid) were prepared and analyzed using this method. Recoveries ranged between 94 and 101%. Twenty-two samples of FD&C Yellow No. 6 were analyzed by the conventional column elution chromatographic method as well as by the high-pressure liquid chromatographic method. Good agreement was obtained between the 2 methods.
Fluorometric Determination of Selenium in Foods
Authors: Ihnat Milan
Published: February 2020

A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.
Atomic Absorption Spectroscopic Determination of Cadmium in Fungicide Formulations
Authors: Jung Paul D , Clarke David
Published: February 2020

A rapid and accurate method for the determination of cadmium in fungicidal materials using the secondary absorption at 326.1 nm has been developed. Analyses of several fungicide formulations containing cadmium, as well as synthetically prepared samples, are reported and discussed. The range of recovery of cadmium from synthetic samples was 100—105%.
Total Sugars as Invert in Animal Feed Products: Collaborative Study
Authors: Moore Howard P , Berg Dorothy
Published: February 2020

An expressed need for a method of analyzing for total sugars as invert in animal feed products led to a modification of the volumetric sugar method. Twenty collaborators, analyzing 3 pairs of samples of molasses products, plus a known concentration of sucrose and a sample of dried whey, produced results with standard deviations ranging from 1.25 to 1.86 and coefficients of variation ranging from 3.6 to 5.1. The average recovery of the known sucrose solution was 98 % with a standard deviation of 1.22 and a coefficient of variation of 2.9. The method has been adopted as official first action to replace sec. 7.058.
Gas-Liquid Chromatographic Determination of 3-Trifluormethyl-4-nitrophenol Residues in Fish
Authors: Allen John L , Sills Joe B
Published: February 2020

A procedure for the determination of 3-trifluormethyl-4-nitrophenol (TFM) in fish tissues is described. Homogenized tissues are extracted with hexane-ethyl ether; the extract is cleaned up by partitioning the TFM from the extracting solvent into 0.1N NaOH, acidifying the aqueous solution, and partitioning again with hexaneethyl ether. The TFM is methylated with diazomethane and analyzed by gas-liquid chromatography, using electron capture detection. Recoveries ranged from 75 to 100% from fish muscles that were spiked with 0.01—2.00 μg TFM/g.
Collaborative Study of the Rat Hemoglobin Repletion Test for Bioavailability of Iron
Authors: Fritz James C , Pla Gwendolyn W , Harrison Bertha N , Clark Geneva A
Published: February 2020

A collaborative study of the hemoglobin repletion test was conducted with male weanling rats. The rats were depleted for 4 weeks on a low-iron casein based diet. They were then divided into 13 comparable groups of at least 8 animals each. One group continued on the basal diet. Three groups were given different levels of each of 4 samples. Sample 1 was FeS04.7H20, used as the reference standard. Samples 2 and 3 were from the same lot of electrolytically reduced iron separated into fractions of different particle size by nitrogen elutriation, and were 7—10 and 27—40 /tm, respectively. Sample 4 was a mixture of several lots of food grade ferric orthophosphate. After 2 weeks on the test diets, individual blood samples were drawn for hemoglobin determinations. The data were analyzed by the parallel lines technique, and relative biological values, vs. FeS04 = 100, together with 95% confidence limits were calculated. The relative biological values were as follows: reduced iron, 7—10 /mi = 63.5 ± 10.9; reduced iron, 27— 40 /im = 3 7 . 9 ± 1 2 . 2 ; ferric orthophosphate = 44.5±4.8. This revised method for measuring bioavailability of iron has been adopted as official first action to replace the original method, 39.A15-39.A17.
Manual Microbiological Turbidimetric Analysis of Chlortetracycline in Feeds
Authors: Ragheb Hussein S , Cummings Anne M
Published: February 2020

The turbidimetric log-probability plots of chlortetracycline HCl (CTC-HCl) showed the same dosage-response slope for Staphylococcus aureus, Streptococcus faecalis, and Bacillus cereus. The slope was different for Klebsiella pneumoniae and Salmonella gallinarum. In Penassay broth at pH 7.0, S. aureus appeared to be the most suitable organism for turbidimetric assay of CTC-HCl in feeds. The useful range was between 0.04-0.14 μg CTC-HCl. Two commercial unmedicated feeds (A and B) were each fortified at finished feed levels by addition of premixes containing CTC-HCl alone or in combination with penicillin and sulfamethazine. CTC-HCl recovery from feed A was 97.5— 107.2% turbidimetrically and 99.5-123.2% by the AOAC method, 38.179-38.182. Comparable results for feed B were 87.1-93.3% (turbidimetric) and 99.4-108.3% (AOAC). For both feeds, the overall coefficient of variation was higher (9.5-23.9%) for the manual turbidimetric assay than for the plate assay (5.5— 6.0%). Comparison of the 2 methods for analysis of premix samples showed essentially the same CTC-HCl recovery and comparable precision. The main advantage of the manual turbidimetric method over the plate assay is that results can be obtained within the same day of analysis.
Hexachlorophene in Cosmetics by Partition Chromatography and Ultraviolet Spectrophotometry
Authors: Wilson Clifton H
Published: February 2020

Five samples at 3 levels of hexachlorophene concentration were analyzed by 6 collaborators. Results show recoveries of 79—103% for samples containing from 1 to 10 mg hexachlorophene. The standard deviation varied from 0.039 to 0.33 and the coefficient of variance ranged from 1.55 to 9.77%. The method has been adopted as official first action.
Collaborative Study of a Chromatographic Method for Determination of Patulin in Apple Juice
Authors: Scott Peter M
Published: February 2020

Collaborators in 20 laboratories studied a method for the determination of patulin in apple juice. The collaborators mixed patulin solutions with the apple juice to obtain 9 spiked samples (of which 2 were blanks) and 1 practice sample. After column chromatography of the apple juice extract, patulin was estimated visually by thin layer chromatography, using 3-methyl-2-benzothiazolinone hydrazone.HCl as the spray reagent. Mean recoveries of patulin ranged from 69.8 to 98.3% for 3 contamination levels. The method has been adopted as official first action for the determination of patulin in apple juice.
Spectrophotometric Assay of Karathane Technical and Karathane Formulations
Authors: Black Ronald F , Kurtz C P , Baum Harry
Published: February 2020

A spectrophotometry procedure for the determination of total dinitrooctylphenols and dinitrooctylphenyl crotonates in Karathane Technical (dinocap) and Karathane formulations has been collaboratively studied. The sample is dissolved in petroleum ether; the total mono- and dinitrooctylphenols are then selectively extracted with aqueous sodium hydroxide solution and examined photometrically at 410 nm. The dinitrooctylphenyl crotonates are hydrolyzed in aqueous pyridine solution and measured photometrically at 442 nm. Five collaborators analyzed Karathane Technical, Karathane LC, and Karathane WD in duplicate on each of 2 days. Statistical analysis indicates that between- laboratory precision, s, of the dinitrooctylphenyl crotonate determination, excluding outliers, was 2.05, 0.71, and 0.79% absolute at the 76, 38, and 18% assay levels, respectively. The precision of the dinitrooctylphenol determination on the same sample series was s = 0.071% at the 2.3% concentration level, 0.18% at the 1.88% level, and 0.457% at the 2.20% level, respectively. It is recommended that another collaborative study be conducted with an increased number of collaborators, incorporating changes in the procedure suggested by the collaborators.
Collaborative Study of the Extraction of Light Filth from Canned Whole Shrimp
Authors: Dent Russell G
Published: February 2020

The method developed utilizes a washing technique for shrimp larger than 1", followed by an acid digestion with mineral oil as the flotation liquid. In the case of the smaller shrimp, the washing step is eliminated. A Corning percolator is used for trapping; the percolator is drained in 2—3 stages. Average recoveries from 6 collaborators were 73.6% for rodent hairs (20 added) and 91.9% for fly setae (20 added). The proposed method has been adopted as official first action.
Detection of Synthetic Vanillin in Vanilla Extracts by Isotopic Analysis
Authors: Bricout Jacques , Fontes Jean-Charles , Merlivat Liliane
Published: February 2020

The isotopic composition of vanillin was investigated in order to distinguish synthetic wood lignin vanillin and natural vanilla-extracted vanillin. Natural vanillin is enriched in deuterium and carbon-13 as compared to synthetic vanillin. This enrichment probably results from differences in the synthetic pathways of this compound. In particular, carbon isotope fractionation is associated with photosynthesis; this fractionation lowers the 13C/12C ratio by about 20 0/00, relative to atmospheric carbon dioxide, for the Calvin cycle in photosynthetic carbon dioxide fixation, which occurs in trees. The fractionation factor is even lower, about 13 0/00, for the orchid Vanilla planifolia Andrews in which the Crassulacean acid metabolic pathway probably operates.
Structure of Alkaline Hydrolysis Products of Neostigmine Methylsulfate and Neostigmine Bromide
Authors: Kling Rita E
Published: February 2020

The nuclear magnetic resonance spectra of the alkaline hydrolysis products of neostigmine bromide and neostigmine methylsulfate confirm that the products are m-hydroxyphenyltrimethylammonium salts and not 3-dimethylaminophenol as mentioned in early literature. Ultraviolet, infrared, and elemental analysis data are also presented in the quaternary structure confirmation of the alkaline hydrolysis product of neostigmine bromide.
Determination of Propoxyphene Hydrochloride, Aspirin, Phenacetin, and Caffeine in Combination
Authors: Cunningham Catherine G , Barkan Susan
Published: February 2020

The title compounds are isolated by partition chromatography, using a new procedure combining the classical assay for aspirin-phenacetincaflfeine with the previously reported method for propoxyphene, in which the active principle is eluted as the sulfamate ion pair. All 4 components are determined spectrophotometrically. Results are given for standard and commercial preparations.
Determination of Steroid Phosphates in Formulations of Creams, Ointments, and Solutions by Blue Tetrazolium Reduction
Authors: Van Dame Halver C
Published: February 2020

A collaborative study has been completed on a method for the determination of steroid phosphates in creams, ointments, and solutions. The steroid is almost completely separated from interfering materials such as oils, fats, and waxes found in pharmaceuticals by using a hydrolysis step in which the steroid phosphate is hydrolyzed to the alcohol by an alkaline phosphatase enzyme. After the interfering materials are removed, the steroid is quantitatively measured by the blue tetrazolium reaction. Results from 10 collaborators for 3 samples each of dexamethasone phosphate cream, dexamethasone ophthalmic ointment, and dexamethasone phosphate solution for injection were 100.0, 98.1, and 101.2% recovery, respectively; the corresponding coefficients of variation were 3.31, 3.08, and 2.57. The method has been adopted as official first action.
Determination of Prednisolone Sodium Phosphate by Ion-Pair Extraction
Authors: Kaplan Gilbert B , Levine Joseph
Published: February 2020

Prednisolone sodium phosphate cannot be extracted as such from aqueous solutions because of its polar characteristics. It can be extracted as its ion pair, using a relatively high molecular weight aliphatic amine as counter ion. Liquid formulations of prednisolone sodium phosphate are rapidly assayed by incorporating the sample as immobile phase in a partition chromatographic column. Prewash with suitable organic solvents removes extractable adjuvants; the phosphate ester is eluted with a solution of trihexylamine hydrochloride in methylene chloride. The ester is extracted from the eluate with sodium hydroxide solution, and measured by ultraviolet spectrophotometry.
Collaborative Study of an Ion Exchange Method for the Chromatographic Separation of Mixtures Containing Expectorants, Sympathomimetic Amines, Antihistamines, or Phenothiazine in Pharmaceuticals
Authors: Smith Donald J
Published: February 2020

An ion exchange chromatographic method has been applied to the determination of 9 drugs in various dosage forms, alone or in combination: chlorpheniramine maleate, codeine phosphate, dextromethorphan. HBr, glyceryl guaiacolate, phenylephrine. HCI, phenylpropanolamine . HCI, potassium guaiacolsulfonate, promethazine. HO, and pyrilamine maleate. Nitrogenous bases are separated from the excipients by retention on a sulfonated polystyrene resin column. These basic compounds are eluted from the column with the appropriate concentration of HCI and are determined by ultraviolet (UV) absorption. The organic acids are retained on the quaternary ammonium anion resin. The acidic compounds are eluted from the columns with the appropriate concentration of HQ and determined by UV absorption. Average recoveries and standard deviations for the 9 drug ingredients in 3 simulated combinations ranged from a low of 93.2±4.03% (phenylpropanolamine . HCI) to a high of 98.8±4.8% (codeine phosphate), for 6 unknown samples per collaborator. Comparable values were reported for 2 commercial sirups collaboratively studied. The method has been adopted as official first action for the following compounds: (a) promethazine . HCI, phenylephrine. HCI or phenylpropanolamine. HCI (except in tablets or powders), and potassium guaiacolsulfonate; (b) promethazine. HCI codeine phosphate, and potassium guaiacolsulfonate; (c) phenylephrine. HCI or phenylpropanolamine. HQ (except in tablets or powders), dextromethorphan.HBr (except in sirups), potassium guaiacolsulfonate, and pyrilamine maleate; and (d) phenylephrine. HCI or phenylpropanolamine. HCI (except in tablets or powders), dextromethorphan. HBr (except in sirups), glyceryl guaiacolate, and pyrilamine maleate.
Colorimetric Determination of Ethinyl Estradiol in Oral Contraceptive Formulations
Authors: Wu John Y P
Published: February 2020

Ethinyl estradiol in oral contraceptive formulations is separated from the sample on a chromatographic column prior to color formation with methanol-sulfuric acid reagent directly in the chloroform-isooctane eluate. Collaborative results on 3 commercial tablet samples averaged 93.93, 98.69, and 98.50% of label claim. The standard deviations and coefficients of variation were 2.61, 2.39, and 2.82, and 2.77, 2.43, and 2.86%, respectively. The method has been adopted as official first action.
Sodium Contamination by Filter Paper
Authors: Ali Mohammad W , Kalra Yash P
Published: February 2020

During the analysis of small samples of peats, the concentration of sodium in the blank solutions was observed to be high in relation to that found in the sample solutions. Sodium contamination by filter paper was suspected and confirmed. For accurate measurement of low sodium concentrations in peat samples, the filter paper should be washed with dilute hydrochloric acid before the acid solution of the ash is filtered.
Collaborative Study of Two Analytical Methods for the Analysis of Formothion Formulations
Authors: Sauer Horst H , Bosshardt Hans P
Published: February 2020

The 2 methods collaboratively studied were a gas-liquid chromatographic (GLC) method, using either a flame photometric or a flame ionization detector, a column packed with 3% OV-225 on 80-100 mesh Chromosorb W (HP), and an internal standard; and a paper chromatographic (PC/C) method in which the chromatographed spot is combusted and the formothion content is determined colorimetrically as phosphorus. Four samples of formothion, 50% technical solution, 25 and 33% emulsifiable concentrates, and 70% ultralow volume formulation, were studied. Collaborative results for the GLC method (5 collaborators for 3 samples and 7 collaborators for 1 sample) were satisfactory, with standard deviations ranging from 0.57 to 1.42. PC/C values (3 collaborators) were higher but still satisfactory, with standard deviations ranging from 1.50 to 5.22. Both methods have been adopted as full CIPAC methods, with the GLC method as the reference method. The GLC method has been adopted as official first action by the AOAC.
Automated Method for Determining Direct Available P2O5 in Fertilizers
Authors: Wall Larry L , Gehrke Charles W
Published: February 2020

In the automated method for the analysis of direct available and total P205 in fertilizers, a heating bath is used to destroy ammonium citrate and colored material and for hydrolysis of non-orthophosphates. The heating bath was maintained at 98°C and contained a 40' time delay coil, providing 15 min digestion. Improvements on the method for the automated digestion of citrate extracts of fertilizer included decreasing the reagent and sample flow rates by factors of 2 to 5. All of the citrate in those samples containing the highest levels of citrate was not destroyed; however, the slight effect of the remaining citrate could be eliminated by changing the concentration of the molybdovanadate reagent. No difficulty was encountered with the hydrolysis of non-orthophosphates. With this analytical system, steady state conditions were reached at a sampling rate of 40 samples/hr and with a 4 : 1 sample-to-wash ratio. Repeated analyses were made on 9 samples, and the accuracy and precision of results obtained by the automated method compared very well with data by the official AOAC gravimetric method.
Further Survey of Cured Meat Products for Volatile N-Nitrosamines
Authors: Panalaks Thavil , Iyengar Jagannath R , Donaldson Barbara A , Miles Walter F , Sen Nrisinha P
Published: February 2020

Eighty samples of various kinds of cured meat products were analyzed for volatile nitrosamines. Nitrosopyrrolidine (NPy) was determined by using thin layer chromatography and simple dialkylnitrosamines were measured by using a gas-liquid chromatographic (GLC) method with a Coulson electrolytic conductivity detector (pyrolytic mode). Seventeen samples contained 13–105 ppb NPy; 29 samples contained 2–35 ppb dimethylnitrosamine (DMN) ; 9 samples contained 2-25 ppb diethylnitrosamine (DEN). In a few cases the identities of NPy, DMN, and DEN were confirmed by GLC-mass spectrometry.
Comparison of Two Analytical Methods for Penicillin Residues in Milk
Authors: Katz Stanley E , Fassbender Carol A , Hackett Arthur J , Mitchell Ralph G
Published: February 2020

Two microbiological assay procedures for penicillin residues were compared for the analysis of milk from a lactating cow treated experimentally for mastitis. There was very little difference between procedures when penicillin levels were above 1 unit/ml; below 1 unit/ml the centrifuge procedure gave consistently higher concentrations than those found by using an FDA-suggested procedure in which the milk was assayed directly without centrifugation. The ratio of results between the centrifuge and FDA-suggested procedures ranged from 1.10 to 1.67 for levels below 1 unit /ml. When the centrifuge procedure was used, residues were found 12–36 hr longer than could be detected with the FDA-suggested methodology.
Collaborative Study of Methods for the Determination and Chemical Confirmation of Aflatoxin M1 in Dairy Products
Authors: Stubblefield Robert D , Shannon Gail M
Published: February 2020

An international collaborative study involving 19 collaborators was conducted to test methods for the determination and chemical confirmation of aflatoxin M1 in dairy products. For the quantitative method, collaborators assayed samples of liquid and powdered milk, cheese, and butter containing low levels of M1. Statistical results indicated that sensitivity and precision of this method were comparable to other AOAC methods for aflatoxin M1. Impurities were present in blue cheese extracts that tended to interfere with thin layer chromatography. Analysis of liquid milk samples from different areas revealed that some milk extracts may require column chromatography. For the chemical confirmatory method, collaborators prepared acetate and hemiacetal derivatives of M1 in extracts of liquid milk and colby cheese. A sensitivity limit of 30 ng M1 was apparent for the method, and most collaborators easily identified the derivatives. As a result of this collaboration, both methods have been adopted as official first action methods.
Analysis of Penicillic Acid by Gas-Liquid Chromatography
Authors: Thorpe Charles W , Johnson Robert L
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for the analysis of the mycotoxin penicillic acid in corn, dried beans, and apple juice. The samples are extracted with ethyl acetate and the penicillic acid is isolated by liquidliquid extraction, followed by elution from a 3 g silica gel column with hexane-ethyl acetate. Penicillic acid is determined by GLC of the trifluoroacetate derivative, using a 6' column containing OV-101 and an electron capture detector. Penicillic acid can be detected at the 4 μg/kg level with recoveries of added penicillic acid greater than 80%. Confirmation may be obtained by gas chromatography-mass spectrometry. Analysis of 20 commercial corn samples originating from several Midwest counties with potential mold problems showed that penicillic acid was present in 7 samples at levels ranging from 5 to 230 μg/kg. Penicillic acid was found in 5 of 20 commercial samples of dried beans at levels of from 11 to 179 μg/kg.
Collaborative Study of AOAC Methods I and III for the Determination of Aflatoxins in Peanut Butter
Authors: Stack Michael E
Published: February 2020

A collaborative study was designed and carried out to test the accuracy and precision, at low levels of contamination, of AOAC methods I, 26.015-26.020, and III, 26.026-26.030, for the determination of anatoxins in peanut butter. Ten test samples and 1 practice sample of each peanut butter were analyzed by each method. Two test samples were naturally contaminated with about 2 μg aflatoxin B1/kg. The 8 spiked samples (duplicate samples for each level) had 0, 2, 4, and 8 μg B1 added/kg and B2 was added at one-fourth the B1 level. The 7 collaborators were instructed to analyze the samples according to methods I and III except for minor modifications necessary to handle the low level of aflatoxins in the sample extracts and to quantitate the aflatoxin content both visually and densitometrically. The results of this study indicate that the analysts were able to determine the aflatoxins in the 2–10 μg/kg range with either method although method I gave better accuracy and precision and had less interferences than method III.
Review of Gas-Liquid Chromatography of Marihuana
Authors: Parker James M , Stembal Brian L
Published: February 2020

Gas-liquid chromatographic (GLC) methods used in the separation, identification, and quantification of Cannabis components are reviewed. Glass columns packed with 3% OV-17 offer better separation of tetrahydrocannabinol isomers and greater sensitivity. GLC identification of new Cannabis constituents, preparation of trimethylsilyl ether derivatives of known cannabinoids, and preparation of pure standards from Cannabis samples are discussed along with problems in cannabinoid quantification. Use of a 6' × ¼" glass column packed with 3% OV-17 on 100–120 mesh Gas-Chrom Q is suggested for GLC separation of Cannabis components.
Fluorometric Determination and Thin Layer Chromatographic Identification of Diethylstilbestrol in Beef Liver
Authors: Ponder Carl
Published: February 2020

Diethylstilbestrol (DES) and its monoglucuronide conjugate (DES-G) are extracted from homogenized beef liver by blending with acetonitrile containing triethylamine sulfate. An alkaline solution saturated with sodium chloride extracts DES and DES-G from the acetonitrile. The alkaline extract is acidified with sulfuric acid, triethylamine is added, and DES and DESG are extracted with 1-heptanol. DES is cleaved from DES-G by refluxing the 1-heptanol extract after adding ammonium chloride and monobasic ammonium phosphate. Solvent partitioning is used to isolate the DES, which is irradiated in a buffer solution with ultraviolet light to form the phenanthrenedione derivative. The dione is converted to the phenanthrenediol derivative in an acidified bisulfite solution. The diol derivative is isolated by solvent partitioning and determined fluorometrically in methanol. Thin layer chromatography is used for confirmation of DES. Recovery on 5 samples spiked with DES-G equivalent to 1, 2, and 4 ppb DES ranged from 82.5 to 104%.
Thin Layer Chromatographic Determination of Subsidiary Dyes in D&C Red No. 19 and D&C Red No. 37
Authors: Bell Sandra
Published: February 2020

A thin layer chromatographic method is presented by which triethylrhodamine and other lower ethylated subsidiary colors are separated from D&C Red No. 19 and D&C Red No. 37. After removal from the plate, subsidiary dyes are extracted from silica gel C adsorbent and quantitated spectrophotometrically. Recoveries of 1, 2, and 5% of added triethylrhodamine ranged from 89 to 1 0 3% for D&C Red No. 19 and from 85 to 1 0 2% for D&C Red No. 37.
Atomic Absorption Determination of Lead in Apples
Authors: Markus John R
Published: February 2020

Two studies have been conducted on the analysis of apples for lead by atomic absorption spectrophotometry using the official first action method, 25.B01–25.B05. Sixteen laboratories participated in each study. Recoveries ranged from 92.6 to 110% (101.6% average) in the first study. A second study, in which procedural modifications were made, showed recoveries ranging from 91.2 to 109.7%, with an average of 100.0%. Coefficients of variation for the first and second studies were 5.19 and 4.94%, respectively. On the basis of the second study, procedural modifications have been incorporated into the 12th Edition of Official Methods of Analysis.
Multiresidue Analysis of Fourteen Organophosphorus Pesticides in Natural Waters
Authors: Ripley Brian D , Wilkinson Robert J , Chau Alfred S Y
Published: February 2020

A method is described for the determination of 14 organophosphorus pesticides in natural waters at less than μg/L (ppb) concentrations. Two extraction methods are described: the vortex stirring method for water that forms light emulsions and the separatory funnel method for water that forms heavy emulsions during extraction. Extraction recoveries were 95– 110% for all compounds except crufornate (115%). Two concentration methods are also described with recoveries of 95–116%. Compounds were determined by isothermal gas chromatography using a flame photometric detector that is quantitatively sensitive to phosphorus. The sensitivity of the method for most of the 14 compounds was 0.01 ppb, using 1 L water. Retention times of all compounds were constant during isothermal analysis. Possible losses due to storage were also examined.
Preparation, Gas Chromatographic Behavior, and Spectroscopic Properties of Hydroxylated Chlorobiphenyls
Authors: Hutzinger Otto , Safe Steve , Zitko Vladimir
Published: February 2020

Some useful methods for the preparation of chlorobiphenylols have been investigated. Twenty monohydroxy and dihydroxy derivatives of chlorobiphenyls are described; 10 are new compounds and several are known metabolic products from animals or microorganisms. The relationship between structure of the chlorobiphenylols and gas chromatographic retention time as well as electron capture detector response, including those of derivatives, has been examined. The ultraviolet, fluorescence, and mass spectra of these hydroxylated derivatives have also been examined with a view towards analysis and structure elucidation of metabolites.
Liquid Chromatographic Method for Determination of Patulin in Apple Juice
Authors: Ware George M , Thorpe Charles W , Pohland Albert E
Published: February 2020

The apple juice sample is extracted with ethyl acetate and the extract is cleaned up by elution from a silica gel column with ethyl acetate-benzene. Patulin is determined by use of a liquid chromatograph, a 25 cm Zorbax-Sil column, and a 254 nm ultraviolet detector. This method has a lower detection limit of 11 μg/L with recoveries of patulin added to apple juice >85%. Gas chromatographic-mass spectrometric analysis of the acetate derivative is used for confirmation. Patulin was detected at levels ranging from 44 to 309 μg/kg in 8 of 13 commercial samples of apple juice.
Gas-Liquid Chromatography of Trichlorfon in Soluble Powder Formulations
Authors: Bowman Phil B , Dame Peter W
Published: February 2020

A procedure is described for the determination of trichlorfon in a soluble powder formulation by gas-liquid chromatography. Silylation prevents on-column degradation of trichlorfon to dichlorvos. The procedure provides quantitative recovery from the formulation as demonstrated by a spiking study. A relative standard deviation of less than 2% was obtained for 6 replicate assays of a single lot of formulation. The mass spectral fragmentations of trichlorfon and trichlorfon-trimethylsilyl ether are described.
Automated System for the Gas-Liquid Chromatographic Determination of Acetaldehyde, Ethyl Acetate, and Fusel Oils in Alcoholic Beverages
Authors: Burgett Charles A
Published: February 2020

An automated gas-liquid chromatographic (GLC) system, including automatic sampling, calculation, and reporting, was applied to the analysis of 7 samples representing 4 types of alcoholic beverages. Using a GLC column packed with glycerol-1,2,6-hexanetriol on Gas-Chrom R and a flame ionization detector, the following compounds were separated and quantitatively measured: acetaldehyde, ethyl acetate, propanol, isobutanol, active amyl alcohol, and isoamyl alcohol. Acetal is resolved from the other compounds.
Collaborative Study of a Potentiometric Titration Method for Determining Sodium Chloride in Foods
Authors: Brammell Wallace S
Published: February 2020

The official final action potentiometric titration method for sodium chloride in canned vegetable products was modified to provide a general quantitative method for foods. The product is dispersed with water and acidified, and soluble chlorides are titrated potentiometrically with silver nitrate. The method is applicable to levels of ≥0.03% sodium chloride. As in all methods involving precipitation of chlorides with silver nitrate, bromide and iodide interfere but not significantly at the levels found in most foods. Interference by protein, amino acids, and phosphate, hydroxyl, carbonate, sulfate, and fluoride ions is prevented by acidifying the sample. In the collaborative study, 10 collaborators successfully analyzed 12 different foods (beef broth, soy sauce, salted whole eggs, margarine, prepared mustard, baby food (carrots), bread, TV dinner, parmesan cheese, canned salmon, ham, and peanut butter), obtaining coefficients of variation ranging from 0.49 to 5.99%, an indication of the precision of the method. Potentiometric titration of chloride in ashed and nonashed samples gave close agreement for sodium chloride content, showing that protein and other organic matter present do not interfere, that ashing is not necessary, and that dispersion or blending with water is adequate for sample preparation. With the proposed method, the sodium chloride content of a food sample can be determined with precision and accuracy in 2—6 min. The method has been adopted as interim official first action.
Thin Layer Chromatographic Identification of Crimidine in Animal Stomach Contents in Experimentally Induced Castrix Poisoning
Authors: Hoskam Elisabeth G , Beek Huug Van
Published: February 2020

Crimidine (2-chloro-4-dimethylamino-6-methylpyrimidine), the active ingredient of the rodenticide Castrix, is extracted from animal stomach or gizzard contents with chloroform in an alkaline medium. The extract is used for thin layer chromatography on a silica gel or polyamid sheet containing a fluorescent indicator; water-30% ammonia (100+2) or water-methanol-30% ammonia (80+20+2) is the mobile solvent. After drying, crimidine appears under ultraviolet light as a dark spot on a fluorescent background. Amounts of 5 μg crimidine are clearly visible; the purple-red dye present in Castrix kernels remains on the baseline.
Zirconium Dioxide, A New Catalyst, in the Kjeldahl Method for Total Nitrogen Determination
Authors: Glowa William
Published: February 2020

The standard Kjeldahl method for the determination of total nitrogen in fertilizers, feeds, foods, and beverages has been modified to eliminate the use of mercuric oxide, which is poisonous to the environment. A new mixed catalyst, consisting of 0.60 g cupric sulfate and 0.20 g zirconium dioxide in combination or 0.70 g zirconium dioxide alone, is recommended to replace the 0.70 g or more of mercuric oxide used in all official macro Kjeldahl methods.
Extraction and Analysis of Aroclor 1254 Components in Blood
Authors: Welborn Michael E , Borchard Ronald E , Hansen Larry G , Metcalf Robert L
Published: February 2020

Extraction, cleanup, and quantitation methods for polychlorinated biphenyls (PCBs) are discussed with reference to the analysis of individual chromatographic peaks as well as total PCBs. Extraction of blood samples with hexane-saturated acetonitrile maintains the integrity of the biologically modified PCB profile and permits accurate description of pharmacokinetic parameters. Individual components are quantitated by measuring peak heights in varying concentrations of Aroclor so that residues can be reported relative to the parent mixture. Absolute quantitation of component peaks can be accomplished by using these relative values and the percentage composition of the Aroclor.