bluuebunny/crossref_metadata_2025 huggingface dataset:
Interim Method for Determination of Volatile Organic Compounds in Hazardous Wastes
Authors: Gurka Donald F , Warner J Scott , Silvon Larry E , Bishop Thomas A , Mckown Mary M
Published: February 2020

An analytical protocol is presented for the determination of volatile organic compounds in hazardous wastes that are amenable to the purge-and-trap method. The protocol features a tetraethylene glycol dimethyl ether (tetraglyme) extraction of the liquid or solid waste, addition of an aliquot of the tetraglyme waste to water, and purging of the tetraglyme-water mixture with subsequent gas chromatographic/ mass spectrometric (GC/MS) analysis. The size of the tetraglyme aliquot is determined by gas chromatographic screening of a hexadecane waste extract. Quality assurance/quality control procedures are included within the analytical protocol. Spike extraction recoveries of industrial wastes obtained by following this protocol are given.
Automated Sample Cleanup for Pesticide Multiresidue Analysis. Part II—Design and Evaluation of Column Chromatography Module
Authors: Gretch Fred M , Rosen Joseph D
Published: February 2020

An automated, continuous flow system is described for Florisil column chromatography of pesticide residues from food extracts. Evaluation of the system using 5 common organochlorine and organophosphorus pesticides in 2 crop matrices demonstrates essentially no difference in recovery or precision between automated and currently used manual analyses. The automated procedure uses only 20% of the solvents and adsorbents used in the manual procedure and is 3 times faster.
Decomposition of 4,4'-(Diazoamino)-bis(5-methoxy-2-methylbenezenesulfonic Acid) in Solutions ofFD&C Red No. 40
Authors: Richfield-Fratz Naomi
Published: February 2020

4,4'-(Diazoamino)-bis(5-methoxy-2-methylbenzenesuIfonic acid), when present as a reaction by-product in FD&C Red No. 40, is shown to decompose rapidly in aqueous solutions of the color additive. The decomposition is halted by the addition of sodium borate buffer. Quantitationly liquid chromatography shows that decomposition is nonlinear with time and follows approximate first order kinetics.
Quantitative Amino Acid Analysis of Feedstuff Hydrolysates by Reverse Phase Liquid Chromatography and Conventional Ion-Exchange Chromatography
Authors: Elkin Robert G
Published: February 2020

Corn, soybean meal, and isolated soybean protein samples were acidhydrolyzed and analyzed for amino acid content by reverse phase liquid chromatography (LC) and by conventional ion-exchange chromatography (IEC) using an amino acid analyzer. The former method employed pre-column derivatization with orthophthalaldehyde (OPTA)/ethanethiol and fluorescence detection. In the LC procedure, glycine and threonine were not resolved, and proline and cyst(e)ine were not detected. In general, amino acid values obtained by LC and IEC compared closely within and across feedstuffs, and both agreed well with published amino acid composition data. The notable exceptions were aspartic acid, glutamic acid, and alanine. Results of this study suggest that reverse phase LC with pre-column OPTA derivatization can be applied to accurately measure primary amino acids in individual feedstuffs.
Extraction of Organic Acids by Ion-Pair Formation with Tri-n-Octylamine. Part V. Simultaneous Determination of Synthetic Dyes, Benzoic Acid, Sorbic Acid, and Saccharin in Soft Drinks and Lemonade Syrups
Authors: Puttemans Marc L , Dryon Louis , Massart Désiré L
Published: February 2020

Synthetic dyes, benzoic acid, sorbic acid, and saccharin are extracted simultaneously from soft drinks with 0.01M tri-n-octylamine at pH = 5.5 and are back-extracted to an aqueous phase with 0.1M sodium perchlorate. The perchlorate solution is injected directly into the reverse phase liquid chromatographic system which permits the separation of all the substances investigated. Forty-six commercial samples of soft drinks and 11 lemonade syrups were analyzed. All samples conformed to the legal prescriptions.
Separation and Analysis of Pilocarpine, Isopilocarpine, and Pilocarpic Acid by Reverse Phase Liquid Chromatography: Collaborative Study
Authors: Van Ackeren John L , Venable Richard M , Wainer Irving W
Published: February 2020

A method for separating and determining pilocarpine and 2 degradation products was developed and subjected to collaborative study. Pilocarpine, isopilocarpine, and pilocarpic acid were isolated on a reverse phase liquid chromatographic phenyl bonded column and detected by UV spectrophotometry at 220 nm. Nine collaborators received commercial samples labeled to contain 2,1, and 0.5% pilocarpine and a 2% practice sample. The collaborative results for pilocarpine were excellent; coefficients of variation ranged from 3.20 to 4.10%. The method was adopted official first action for determination of the active component, pilocarpine, in the presence of isopilocarpine and pilocarpic acid. Although quantitative results for the degradation products were not as good, the method is suitable as a limits test for these substances.
X-Ray Powder Diffraction Data for Selected Drugs: Furosemide, Hydrochlorothiazide, Naproxen, Naproxen Sodium, Propranolol Hydrochloride, and the Halopheniramine Maleates
Authors: De Camp Wilson H
Published: February 2020

X-ray powder diffraction data for 9 commonly used drug substances are reported. The data for furosemide, hydrochlorothiazide, propranolol hydrochloride, dexchlorpheniramine maleate, and brompheniramine maleate have been indexed by reference to published crystal structure data. The racemic modifications of propranolol hydrochloride and brompheniramine maleate are shown to exist as racemic compounds rather than racemic mixtures.
Determination of Chlorinated Methylthiobenzenes and Their Sulfoxides and Sulfones in Fish
Authors: Gardner Albert M , Abramovitch Akiva
Published: February 2020

A procedure was developed to determine chlorinated methylthiobenzenes and their respective sulfur oxidation products in fish. Perch samples fortified at the 0.1 ppm level with 2,4,5-trichloromethylthiobenzene, pentachloromethylthiobenzene, and their sulfoxides and sulfones were extracted and cleaned up using an adaptation of the official AOAC method for multiple residues of organochlorine pesticides. The Florisil column cleanup was modified; 200 raL 6% petroleum etherethyl ether eluted the methylthiobenzenes, 200 mL 50% PE-EE eluted the sulfones, and 200 mL EE eluted the sulfoxides. Recoveries determined by electron capture (ECD) gas chromatography (GC) were 75- 101% for the methylthiobenzenes and their sulfones and 63-93% for the sulfoxides. Co-extracted materials in the Florisil eluates that interfered with the ECD/GC quantitation were removed by partitioning the sulfoxides and sulfones into sulfuric acid and by thin layer chromatography on silica gel, using methylene chloride-hexane (50 + 50) as the developing solvent. Seven fish samples containing residues of chlorinated benzenes or polychlorinated biphenyls (PCBs) were examined for chlorinated methylthiobenzenes, methylthio-PCBs, and their oxidation products by matching GC retention times obtained with the EC detector and a flame photometric detector operated in the sulfur mode. These analytes were not found in the fish samples above a detection level equivalent to 0.02 ppm 2,4,5-trichloromethylthiobenzene.
Chemical Derivatization Analysis of Pesticide Residues. IX. Analysis of Phenol and 21 Chlorinated Phenols in Natural Waters by Formation of Pentafluorobenzyl Ether Derivatives
Authors: Lee Hing-Biu , Weng Li-Da , Chau Alfred S Y
Published: February 2020

A sensitive, isomer-specific method is described for the simultaneous and quantitative analysis of 22 phenols (phenol, 18 chlorophenols, and 3 chloroalkylphenols) in natural waters. The sample was acidified to pH ≤2, extracted with dichloromethane, evaporated, and dissolved in acetone. The phenol extract was then reacted with pentafluorobenzyl bromide (PFBBr) to give the PFB ether derivatives. After silica gel column cleanup, the ethers were chromatographed on a 12 m OV-1 fused silica capillary column attached to an electron capture detector (ECD). The detection limit was 0.1 ppb for 1 L samples. Recoveries of phenols from pH 2 water samples fortified at 10, 1, and 0.1 ppb were a80% in most cases except for phenol which was only 30 to 35% recovered. Coefficients of variation were between 2 and 10% for all phenols. However, phenol recovery was quantitative when the sample volume was reduced to 100 mL. Because ECD sensitivities to the 22 phenol PFB ethers were similar, this method is most suitable for simultaneous screening of nonchlorinated and monochlorinated phenols as well as other higher chlorophenols at trace levels.
Determination of Xanthomegnin in Grains and Animal Feeds by Liquid Chromatography with Electrochemical Detection
Authors: Carman Allen S , Kuan Shia S , Francis Octave J , Ware George M , Luedtke Alan E
Published: February 2020

A sensitive, highly selective liquid chromatographic (LC) method is described which uses electrochemical (EC) reduction of the analyte in the determinative step. The method is capable of determining xanthomegnin in mixed animal feeds and grains at levels ranging from 15 to 1200 ng/g. The method can detect as little as 0.5 ng xanthomegnin injected on the LC column. Xanthomegnin is extracted with chloroform and 0.1M phosphoric acid. An aliquot of the crude extract is purified by silica gel column chromatography using a Sep-Pak silica gel cartridge. A novel feature of the method is that xanthomegnin is "backed off' the column by reversing the flow of the eluant through the column. LC is then used to separate xanthomegnin from other interfering substances. Xanthomegnin is detectd by EC reduction at −0.16 V. Recoveries of xanthomegnin added to samples at levels ranging from 15 to 1200 ng/g averaged 79% with a coefficient of variation of 7.9%. Results also demonstrate that this LC system can separate the related metabolites viomellein and rubrosulphin from each other and from xanthomegnin and that the same EC detection system can be used to detect these metabolites.
Capillary Gas Chromatographic Determination of T-2 Toxin, HT-2 Toxin, and Diacetoxyscirpenol in Cereal Grains
Authors: Cohen Huguette , Lapointe Michel
Published: February 2020

A capillary gas chromatographic (GC) method using an electron capture detector is described for determining T-2 and HT-2 toxins and diacetoxyscirpenol (DAS) in cereal grains at levels as low as 100 ppb for T-2 and DAS and 50 ppb for HT-2. Samples are extracted with methanol-water according to the Scott method, and further purified on a silica gel cartridge and a cyano column. Heptafluorobutyrylimidazole (HFBI) is added to form the esters of the analytes. Ester(s) of T-2, HT-2 and DAS are separated on a 30 m × 0.32 mm DB-5 fused silica column and measured with a "Ni electron capture detector. Samples were confimed by gas chromatography/mass spectrometry using electron impact ionization and single ion monitoring at the molecular mass of 501.11 m/z for T-2, 665.08 m/z for HT-2, and 502.12 m/z for DAS at 10 000 resolving power. The method was applied to wheat, oats, and barley. Average recoveries ranged from a low of 65% for T- 2 in barley to a high of 99% for DAS in oats.
Liquid Chromatographic Determination of Ammoniacal and Urea Nitrogen in Fertilizer
Authors: Mizobuchi Munehiko , Kitada Yoshimi , Tamase Kikuo , Sasaki Michiko , Ueda Yasuyuki
Published: February 2020

Ammoniacal nitrogen in fertilizer is converted to an ammonium-fluorophor derivative and determined by liquid chromatography (LC) on a LiChrosorb RP-18 column and subsequent measurement of fluorophotometric intensity. Urea is converted to ammonia with the aid of urease and then determined similarly. Detection limit of the method is 0.2 μg nitrogen in 2.2 mL. When 5.0 g fertilizer is diluted to 500 mL and then diluted 50-fold with deionized, distilled water, the detection limit equals 1 % ammoniacal or urea nitrogen in commercial fertilizer.
Evaluation of Laboratory Performance of the AOAC Method for PSP Toxin in Shellfish
Authors: Adams Willard N , Furfari Santo A
Published: February 2020

Laboratory performance of the official AOAC method for paralytic shellfish poison (PSP) toxin in shellfish was evaluated. Two series of naturally toxic shellfish split samples were distributed (15 in 1979 and 19 in 1982) to state shellfish-monitoring laboratories which participate in the National Shellfish Sanitation Program. The laboratories performed bioassays on duplicate 100 g portions of each 220 g split sample. Bioassays were consistent among the laboratories and compared favorably with those of previous studies.
Paper Chromatographic Method for Identification and Semiquantitative Determination of
Pyridine and α-Picoline in Denatured Spirit, French Polish, and their Derived Preparations
Authors: Mali Bhagwat D , Ambade Kartik A
Published: February 2020

A paper chromatographic method is described for determination of pyridine and a-picoline in ordinary denatured spirit, french polish, and their derived illicit liquors. The method is based on conversion of the pyridine bases to their salts (sulfate or hydrochloride). The salt residue is subjected to 2-dimensional paper chromatography on filter paper, using methanol-butanol-acetic acid-ethyl acetate (20 + 10 + 1 + 10) as developing solvents, and is sprayed uniformly with sodium rhodizonate followed by barium chloride (for sulfate salts), or ammmoniacal silver nitrate followed by fluorescein (for hydrochloride salts). Pyridine bases in alcoholic samples containing resinous/volatile matter are estimated in the filtrate obtained after their treatment with alum at pH 5-6. The amount of pyridine and a-picoline is calculated from calibration graphs obtained by plotting the square of the spot diameter against pyridine and a-picoline concentrations. The method allowed detection and estimation of pyridine bases in denatured alcoholic samples at a concentration as low as 60 mg/L. Average recovery of added pyridine bases was 99.4% by this method.
Gas Chromatographic Determination of Oxalic Acid in Foods
Authors: Ohkawa Hironori
Published: February 2020

A new quantitative gas chromatographic (GC) method has been developed for the determination of oxalic acid in foods. Solid sample is extracted with water (soluble oxalic acid) or 2N hydrochloric acid (total oxalic acid) at room temperature. An aliquot of sample extract is evaporated to dryness, and the oxalic acid in the residue is methylated with 7% hydrochloric acid-methanol. The reaction mixture is extracted with chloroform, and dimethyl oxalate is quantitated by GC. Recovery of oxalic acid added to liquid samples averaged 100.6%; recoveries from extracts of solid samples were 96.2-99.5 and 97.2-100.1% for water and hydrochloric acid extractions, respectively. Results are shown for determination of oxalic acid in spinach and beverages. The technique is simple, rapid, and accurate, and small samples may be used. The limit of determination is 20 μg.
Performance Characteristics of Methods of Analysis Used for Regulatory Purposes.
I. Drug Dosage Forms. C. Automated Methods
Authors: Horwitz William , Albert Richard
Published: February 2020

For analysis of drug dosage forms, precision measures of AOAC approved automated methods, usually containing a spectrophotometric or fluorometric measurement step, were recalculated on a consistent statistical basis, using a computer program "FDACHEMIST." Ten collaborative studies of 14 compounds in 38 materials, consisting of various dosage forms, usually in 10 replications by an average of 7 laboratories, with a total of 2461 determinations, were reviewed. The average relative standard deviations within-laboratory (RSD0) and among-laboratories (RSDX) were 1.1 and 1.9%, respectively, and the ratio of RSD„/RSDX was 0.57, with an average outlier rate of 0.57% of the reported values. The line of best fit for RSDX plotted against — log concentration increases slightly with decreasing concentration, extending from an RSDX of about 1.6% at 100% concentration to an RSDX of 2.2% at 0.1% concentration, a change in RSDX of about 0.2% for a 10-fold decrease in concentration, independent of analyte and matrix.
The FDA Surveillance Index for Pesticides: Establishing Food Monitoring Priorities Based on Potential Health Risk
Authors: Reed Donald V
Published: February 2020

Through an approach called the Surveillance Index (SI), the U.S. Food and Drug Administration (FDA) is systematically evaluating the potential health risk of pesticides that may be present as residues in foods. The SI is being used as a primary tool in the establishment of monitoring priorities. Each pesticide is classified and assigned to one of 5 levels of potential risk. The SI documents that are prepared for individual pesticides (a) summarize the information used to assess potential dietary exposure and health risk, (b) provide the rationale for the assigned classification, and (c) identify needs and actions necessary to accomplish appropriate monitoring of the food supply. Reasons are described for the development of the SI, the content of the SI Documents, and the use of the SI in planning and redirecting FDA pesticide monitoring activities.
Disappearance of Organochlorine Residues from Abdominal and Egg Fats of Chickens, Ontario, Canada, 1969-1982
Authors: Frank Richard , Rasper Jarka , Braun Heinz E , Ashton Gordon
Published: February 2020

Abdominal fats were collected from 8-week old broilers slaughtered at provincially inspected abattoirs across Ontario between 1969 and 1982. Domestically produced hen eggs were collected from either egg grading stations or producers over the same period. Composite samples were analyzed for organochlorine insecticides and industrial chemicals. Between 1979 and 1982, organophosphorus insecticides were routinely included in these analyses. ΣDDT and PCB residues declined rapidly between 1969 and 1982 in extractable lipids of both abdominal and egg fats, while dieldrin declined less markedly over the same period. Declines in residues followed first order logarithmic regression equations. Chlordane and heptachlor epoxide were rarely observed above the detection limit of 1 μg/kg in egg fat; however, the incidence of these residues in abdominal fat increased after 1973 following the removal of aldrin, dieldrin, and heptachlor in 1969 and the subsequent increased use of chlordane for soil insect control until 1977. Lindane residues were rarely observed above the detection limit. In 1979, when the detection limit was reduced, both a-BHC and lindane were identified, but at levels below 1 μg/kg. Endosulfan, methoxychlor, and fenthion were identified on one or 2 occasions over the 13-year period.
Long-Term Preservation of Egg and Tissue Homogenates for Determination of Organochlorine Compounds: Freezing Versus Freeze-Drying
Authors: Norstrom Ross J , Won Henry T
Published: February 2020

Storage of wet egg homogenates at temperatures from —18° to — 28°C was more suitable for long-term preservation than freeze-drying. Changes in residue levels of heptachlor epoxide, oxychlordane, dieldrin, hexachlorobenzene, p,p'-DDE, mirex, and PCBs were not significant over a 3-year period in fresh herring gull egg homogenates stored at —18° to -28°C. Compounds with gas chromatographic retention times shorter than hexachlorobenzene vaporized during freeze-drying at a rate proportional to their volatility. Evaporative losses of components with vapor pressures less than hexachlorobenzene did not occur in naturally contaminated herring gull eggs after storage at room temperature for up to 1 year. Higher losses of all compounds, up to 25% for p,p'-DDE, occurred in freeze-dried whole-body herring gull homogenates. Easily dehydrochlorinated compounds were rapidly degraded in freeze-dried chicken egg homogenate at room temperature: The half-life of p,p'- DDT and p,p'-DDD was about 20 days, and that of α and γ-hexachlorocyclohexane was <16 days. About one-third of oxychlordane in herring gull eggs was lost in 1 year under these conditions, but none was lost after freeze-drying when the homogenate was stored at -18° to -28°C.
Improved Method for Extraction of Light Filth from 90% Rye Bran Crisp Bread
Authors: Haynos Richard R
Published: February 2020

A new technique has been developed for the analysis of light filth in a high bran rye product. Compared with the official AOAC method, 44.063, the plates were much easier and less time-consuming to read microscopically (about 8 min compared with about 34 min for the AOAC method). Average recoveries for insect fragments and mouse hairs were 93.4 and 90.8%, respectively, with coefficients of variation (32 samples) of 7.7 and 7.9%, respectively. Average recoveries by the AOAC method were 87.5% for insect fragments and 62.5% for mouse hairs, with coefficients of variation (6 samples) of 7.9 and 14.1%, respectively. A ruggedness test for 7 variables in the extraction indicated that 2 variables caused significant changes in the results.
Screening Tests for Sulfa Drugs and/or Dinitrobenzamide Coccidiostats and Their Monoamino
Metabolites in Chicken Livers
Authors: Parks Owen W
Published: February 2020

Two procedures were developed for the simultaneous determination of 0.1 ppm sulfaquinoxaline and sulfadimethoxine, 1.0 ppm Zoalene and nitromide, and/or 0.1 ppm of their reduced coccidiostat metabolities from the same sample of chicken liver. Both methods include blender extraction of 5 g liver with chloroform-ethyl acetate (1 + 1), adsorption of the drugs and metabolites on neutral alumina, and subsequent elution with 0.2M carbonate buffer (pH 11.0). In Method A, all parent drugs and coccidiostat metabolites were partitioned into dichloromethane, following the addition of a small amount of tetrabutylammonium hydroxide (TBAH). The presence of the dinitrobenzamides was confirmed by the formation of a color with TBAH, which occurs when the solvent is concentrated (Zoalene = green; nitromide = red). Sulfa drugs and coccidiostat metabolites were detected by the Bratton- Marshall reaction after thin layer chromatographic (TLC) separation. Method B separates the individual classes by selective extraction techniques. The coccidiostats and their metabolites were extracted from the buffer eluate by ethyl acetate-dichloromethane (3 + 1) before ion pairing: sulfa drugs were extracted with dichloromethane after ion pairing with TBAH. The detection techniques were similar to those described for Method A.
Sensitive Determination of Ethopabate Residues in Chicken Tissues by Liquid Chromatography
with Fluorometric Detection
Authors: Nagata Tomoko , Saeki Masanobu , Nakazawa Hiroyuki , Fujita Masahiko , Takabatake Eigo
Published: February 2020

A liquid chromatographic (LC) method is described for determination of ethopabate residues in chicken tissues. The drug is extracted from tissues with acetonitrile, and the extract is concentrated to 2-3 mL. This aqueous solution is rinsed with ethyl acetate and cleaned up by Florisil column chromatography. LC analysis is carried out on a Zorbax ODS column, and ethopabate is quantitated by using a fluorometric detector set at 306 nm (excitation) and 350 nm (emission). Recoveries of ethopabate added to chicken tissues at levels of 0.01 and 0.05 ppm were 87.8 and 92.7%, respectively. The detection limit was 100 pg for ethopabate standard, and 0.5 ppb in chicken tissues.
Normal Phase Liquid Chromatographic Determination of Nanogram Quantities of Ivermectin in
Cattle Blood or Plasma
Authors: Schnitzerling Herbert J , Nolan James
Published: February 2020

A method has been developed for determining ivermectin in 5 mL samples of cattle blood by a 2-step process: cleanup solvent extraction followed by direct injection onto a normal phase liquid chromatography (LC) system with UV detection. Recovery was 77-80% ±5.5% standard deviation. Endogenous interference that may be present caused the lower limit of detection to be set at 4-5 ng/mL. The method was used to show that in blood the distribution of ivermectin favors plasma in a fixed proportion over cellular material, and further to provide a time-course profile of ivermectin in the whole blood of injected cattle. In whole blood, ivermectin concentration peaked between 3 and 5 days and dissipated slowly with a half-life of 3 days.
Atomic Absorption Spectrophotometric Determination of Liver Copper: Collaborative Study
Authors: Osheim David L , Ross Frank P
Published: February 2020

Eleven collaborating laboratories conducted replicate analyses on 4 blind duplicate pairs of bovine liver samples that either had naturally acquired copper levels or were spiked with one of 3 copper levels. A National Bureau of Standards Bovine Liver sample (SRM 1577, 193 ± 10 mg copper/kg) and a 1000 mg copper/L standard were also submitted to the collaborators. The method requires the tissue to be digested with concentrated HN03 at 60°C, diluted to volume with water, and analyzed by atomic absorption spectrophotometry. The intralaboratory coefficients of variation (CV„) ranged from 5.6 to 19%; the interlaboratory CVX values ranged from 7.1 to 21%. The lower limit of detection was estimated to be 1 mg copper/kg tissue. The method has been adopted official first action.
Improved Polarographic Method for Determination of Glyphosate Herbicide in Crops, Soil,
and Water
Authors: Friestad Hakon O , Bronstad Jan O
Published: February 2020

A prior method for determination of glyphosate in water samples has been modified to accommodate samples of crops and soils. Differential pulse polarography as the determinative step enables analysis in an aqueous medium, which is important during extraction of this compound. Residues are cleaned up and concentrated by ion exchange on a strong basic resin in OH- form. The method is rapid, is applicable to a relatively broad selection of sample types, and gives recoveries consistently better than 60% with good precision. The main shortcoming of the method is that the limit of detection of 0.5-1.0 ppm may sometimes be inadequate. The metabolite, aminomethyl phosphonic acid, is not detected.
Liquid Chromatographic Determination of Primidone in Tablets: Collaborative Study
Authors: Roberts Stanley E
Published: February 2020

Six laboratories collaboratively studied a liquid chromatographic (LC) method for the quantitative determination of primidone in tablets. Two lots each of commercially prepared 50 and 250 mg tablets and 2 authentic mixtures, at 50 and 250 mg levels, were sent to each collaborator. Samples were dissolved in the mobile phase, filtered, and injected into the chromatograph. Average recoveries for the 8 samples ranged from 97.5 to 101.2%, and coefficients of variation ranged from 0.53 to 3.01%. The LC method has been adopted interim official first action.
Analysis of USP Epinephrine Injections for Potency, Impurities, Degradation Products, and d-Enantiomer by Liquid Chromatography, Using Ultraviolet and Electrochemical Detectors
Authors: Kirchhoefer Ross D , Sullivan Gerard M , Allgire James F
Published: February 2020

A liquid chromatographic (LC) method was adapted for the determination of epinephrine and related impurities in intravenous and cardiac injections; ultraviolet (UV) and electrochemical detectors (EC) were used in series. Epinephrine was determined and related impurities, i.e., adrenalone, epinephrine sulfonic acid, and norepinephrine, were detected directly in a small portion of the injection solution. Diastereoisomers of the epinephrine enantiomers were prepared by derivatization and determined by LC with a UV detector. The recovery of epinephrine added to epinephrine injection was 100%. The recovery of d-enantiomer from ad, I mixture was 100%. Impurities at levels < 1% were easily detected. The LC method with UV detection is faster and more convenient than the USP XX method. In addition, impurities can be detected in the same portion of sample. The procedure is stability- indicating.
Simple Automated Wet Digestion of Animal Tissues for Determination of Seven Elements by Atomic Absorption Spectroscopy
Authors: Salisbury Craig D , Chan Wayne
Published: February 2020

A simple, automated wet digestion procedure was developed for the quantitative determination by atomic absorption spectroscopy (AAS) of arsenic, cadmium, copper, mercury, lead, selenium, and zinc in animal tissue. A commercial digestion block system with automated temperature programming was used. Recoveries of all elements from spiked bovine liver and kidney samples exceed 95%. The analytical results obtained for samples of NBS Bovine Liver (No. 1577a) agree well with certified values. The procedure is safe and requires minimum analyst time.
Analysis of Phenols by Chemical Derivatization. IV. Rapid and Sensitive Method for Analysis of 21 Chlorophenols by Improved Chloroacetylation Procedures
Authors: Lee Hing-Biu , Hong-You Robert L , Chau Alfred S Y
Published: February 2020

A quantitative, rapid, sensitive, and isomer-specific method for the analysis of chlorophenols in natural water by in situ chloroacetylation is presented. Without pre-extraction, phenols in water are chloroacetylated by chloroacetic anhydride in the presence of K2CO3. Because of differences in reaction kinetics and stability, various chloroacetates were removed from the reaction mixture at different intervals. If analysis of other classes of neutral organic compounds is also required, a more elaborate procedure involving solvent extraction of organic compounds and back-extraction of phenols into K2CO3 solution followed by chloroacetylation is proposed. When a 12 m OV-1 fused silica capillary column was used, 22 phenol chloroacetates were easily resolved in a single run. Using distilled and natural water samples, this method has been validated and shown to be applicable over a concentration range of 0.1 to 100 μg/L of the phenols studied.
Irace Level Detection of Chlorinated Paraffins in Biological and Environmental Samples, Using
Gas Chromatography/Mass Spectrometry with Negative-Ion Chemical Ionization
Authors: Schmid Peter P , Muller Markus D
Published: February 2020

A method is described for detection of chlorinated paraffins (CPs) in biological and environmental samples. Sample preparation includes sulfuric acid treatment followed by adsorption chromatography on ilumina, which yields the CPs in one fraction that is almost free of interfering material. Using gas chromatography/mass spectrometry j with negative-ion chemical ionization, the limit of detection is 5 ng (corresponding to the lower ppb range). CP levels of 30 ppm, 200 ppb, ' and 5 ppb were found in sewage sludge, human fat, and sediment, respectively.
Purge and TVap Method for Determination of Ethylene Dibromide in Table-Ready Foods
Authors: Heikes David L
Published: February 2020

An improved method has been developed for the determination of ethylene dibromide (EDB, 1,2-dibromoethane) in a variety of tableready foods. Samples are mixed with water and sparged with nitrogen for 1 h with stirring in a water bath at 100°C. The EDB collected on the adsorbent Tenax TA is eluted with hexane and determined by gas chromatography (GC) with electron capture (EC) and confirmed with Hall electrolytic conductivity (HECD) detection using a second GC column. The highest levels of EDB were also confirmed by full scan GC/mass spectrometry (GC/MS). Twenty-five table-ready foods from the Food and Drug Administration's Total Diet Study that were analyzed by this method exhibited levels up to 70 ppb (pecans). Recoveries from fortified samples ranged from 91 to 104%. Values from this procedure were compared to those obtained by a modified Rains and Holder codistillation method. In all 25 samples this purge and trap procedure showed equivalent or superior recoveries and detected levels of EDB.
Liquid Chromatographic Determination of Hypoxanthine Content in Fish Tissue
Authors: Burns Garth B , Ke Paul J
Published: February 2020

A liquid chromatography (LC) method for determining the hypoxanthine content in fish tissues has been developed. Hypoxanthine is extracted with 0.6M perchloric acid, and determined by LC on a reverse phase microparticulate column with UV absorbance detection. The mobile phase is 0.01M potassium phosphate buffer (pH 4.5). The percent relative standard deviation for measurements by the recommended method was less than 7% with a detection limit of 10 ng. Recoveries of hypoxanthine added to various fish tissues were better than 90%. The operational errors, interferences, and recoveries for spiked samples have been investigated and compare favorably with an established xanthine oxidase enzyme method. The described LC method is simple, rapid, and specific for measuring hypoxanthine content in various fish tissues. Some post-mortem studies have indicated the method may also be used for the determination of adenosine monophosphate, inosine monophosphate, and inosine.
Isotopic Composition of Carbon in Vinegars
Authors: Krueger Dana A , Krueger Harold W
Published: February 2020

Measurements of δ13C and 14C-activity were performed on vinegars from various known sources. Natural vinegar can be distinguished from petrochemical acetic acid by 14C-analysis: Natural vinegar currently gives values of > 112% of modern activity; petrochemical acetic acid yields values of 0% of modern activity. Apple cider vinegar can be distinguished from corn-derived vinegar by δ13C-analysis: Cider vinegar gives δ13C-values near — 26%o; corn-derived vinegars yield δ13C-values near - 10% δ13C-Analysis also can be applied, with some restrictions, to wine vinegars. These techniques are applied to a series of retail vinegars.
Effect of pH on Absorbance of Azo Dye Formed by Reaction Between Nitrite and Sulfanilamide/
N-(l-Naphthyl)ethylenediamine in Residual Nitrite Methods for Foods
Authors: Davis Carl E , Leffler Richard , Anderson John B , Soderberg David L , Meredith Filmore I
Published: February 2020

Current methods used for determining residual nitrite concentration in foods involve forming an azo dye that is measured spectrophotometrically. Conventional procedures do not specify control of pH for the final colored solution. Because many indicator dyes are pH-dependent, absorbance of the azo dye may vary not only because of nitrite concentration differences, but also because of pH variation. Thus, erroneous results could arise from a standard curve developed at one pH and used for a test sample at a different pH. This would cause an inaccurate concentration conversion from the standard curve. In this study, absorbances at λmax wavelengths were recorded at 28 pH values (range 1.0-4.5) for each of 5 nitrite concentrations. A mathematical equation was fitted to these data and its plot gives a 3-dimensional response surface showing the relationships between pH, nitrite concentration, and absorbance. A modification for the spectrophotometric measurement of nitrite is proposed.
Vitamin A and Vitamin E Content of Infant Formulas Produced in the United States
Authors: Landen William O , Hines Don M , Hamill Thomas W , Martin James I , Young Ednar , Eitenmiller Ronald R , Soliman Abdel-Gawad M
Published: February 2020

Vitamin A (vitamin A palmitate) and vitamin E (a-tocopheryl acetate) levels were determined in 77 samples of fortified infant formulas manufactured by 4 firms in the United States from 1981 to 1983 and were compared by formulation base (soy, milk) and manufacturing firm. For vitamin A and vitamin E, the mean values (IU/100 kcal) were 454 ± 95 (range 248-614) and 2.0 ± 0.7 (range 1.1-5.0), respectively. No significant differences (a = 0.05) were found in levels (IU/100 kcal) of vitamin A and vitamin E between milk- and soy-based formulas. When the mean vitamin A and vitamin E levels of formulas produced by the various firms were compared on an IU/100 kcal or percent of label declaration basis, significant differences (a = 0.05) were found among firms. Mean vitamin A levels for the various products compared to label declarations ranged from 126% of declared for the ready-to-use formulas to 139% of declared for the powders. Mean vitamin E levels ranged from 97% of declared for ready-to-use formulas to 118% of declared for concentrates. Except for one sample that contained 248 IU vitamin A/100 kcal, the formulas met the requirements of the 1980 Infant Formula Act.
Atomic Absorption Spectrophotometric Determination of Cobalt in Foods
Authors: Barbera Reyes , Farre Rosaura , Montoro Rosa
Published: February 2020

A method is described for the determination of cobalt in foods. After wet digestion, iron in the sample is removed by liquid-liquid extraction, and cobalt is isolated and extracted. Final determination is done by flame atomic absorption spectrophotometry. Analysis of NBS reference materials by this procedure gives results in close agreement with certified values. The limit of quantitation is 4.3 ng/mL. Recovery studies and analysis of standard materials show that this method is reliable.
Determination of Reserpine in Commercial Tablets by Liquid Chromatography with Fluorescence Detection
Authors: Cieri Ugo R
Published: February 2020

A procedure is presented for the determination of reserpine in commercial tablets by liquid chromatography (LC). The sample is extracted with methanol if only reserpine is present. If the sample contains other ingredients, CHCl3 is used for extraction from aqueous suspension; the CHCl3 is subsequently completely evaporated in the presence of methanol. For LC, a normal phase column, methanol as the eluting solvent, and a fluorometric detector are used. A recovery study indicated that no measurable degradation of reserpine occurs during evaporation of the CHCl3 extract. Several commercial tablets containing reserpine alone or in combination with other ingredients were analyzed by the proposed method, and the results were compared with those obtained by the current official USP methods for reserpine.
Detection of Parasites in Fish Muscle by Candling Technique
Authors: Valdimarsson Grimur , Einarsson Hjalti , King Frederick J
Published: February 2020

This study determined optimum conditions for detecting codworms in skinned cod fillets by using candling tables under commercial conditions. The best balance of factors was sought for obtaining maximum lighting conditions, reducing operator fatigue, retaining natural fillet color, and having a high contrast between parasites and fish flesh. Based on the results obtained, a recommended procedure has been adopted by AOAC.
Liquid Chromatographic Determination of Aminocarb in Technical and Formulated Products: Collaborative Study
Authors: Slahck Stephen C
Published: February 2020

An LC method for determination of aminocarb (Matacil™) in aminocarb technical and formulated products has been developed and subjected to a collaborative study with 10 participating collaborators. Formulations are extracted with tetrahydrofuran-buffer (60 + 40) and analyzed by reverse phase chromatography, with n-butyrophenone as internal standard. Collaborators were furnished with standards and samples of technical and 180 oil flowable products for analysis. Coefficients of variation obtained on these samples were 0.72 and 1.7%, respectively. The method has been adopted official first action.
Simultaneous Liquid Chromatographic Determination of Rotenone and Pyrethrins in Formulations
Authors: Bushway Rodney J , Johnson Harold , Scott Donald W
Published: February 2020

This paper describes a reverse phase liquid chromatographic (LC) method to simultaneously determine rotenone and pyrethrins in pesticide formulations. The mixed standards along with the formulations were accurately weighed to contain approximately 200 (μg rotenone and 150 (μg pyrethrins/mL. Stabilized tetrahydrofuran was used to dissolve all substances. An aliquot was injected into the LC system equipped with a Zorbax ODS column, and chromatographed with a mobile phase of acetonitrile-water (70 + 30). Rotenone and the pyrethrins were monitored at 240 nm and 0.4 AUFS. Retention times for rotenone, pyrethrin II, and pyrethrin I were approximately 7, 11.5, and 25.5 min, respectively. For 3 different formulations analyzed 6 times each, the percent coefficients of variation were all < 3. This method is also applicable to products containing either rotenone or pyrethrins. No significant interferences were observed from the inactive ingredients of the formulations at the concentrations added.
Determination of Polychlorinated Dibenzo-p-Dioxins in Technical Pentachlorophenol
Authors: Singh Joginder , Miles Walter , Barrette Jean P
Published: February 2020

Thirty-four technical pentachlorophenol samples from 4 different manufacturers were analyzed for the presence of hexa-, hepta-, and octachlorodioxins. A double column procedure for extraction and cleanup was used for processing the samples, followed by gas chromatographymassspectrometry for qualitative and quantitative determinations. All runs were performed isothermally on a packed glass column of 3% Dexsil 400. Octachloronaphthalene was used as an internal standard for quantitative estimations. The amounts of chlorodioxins found ranged from 1 to 38.5 ppm hexachlorodioxin, 119 to 562 ppm heptachlorodioxin, and 361 to 1723 ppm octachlorodioxin. Interfering polychlorinated diphenyl ethers and polychlorinated dibenzofurans were also observed in these samples.
Improved Cleanup for Gas Chromatographic Determination of Propiconazole Residues in Soil, Wheat Grain, Straw, and Leaves
Authors: Bai Quing-Yun , Liu Chang Wu
Published: February 2020

A simple and sensitive method is described for determination of propiconazole, a new type of broad-spectrum systemic fungicide, in soil, wheat grain, straw, and leaves. Pesticide residues in or on grain and green plant materials are extracted with methanol (or a mixture of methanol and water (4 + 1), for soil), partitioned into methylene chloride, and cleaned up on an alumina column for grain and soil or an activated charcoal column for green plant materials. The amount of residue is quantitatively measured by gas chromatography using an alkali flame ionization detector in the nitrogen-sensitive mode. Recoveries from soil, grain, and green plant materials fortified at 0.1-5 mg/ kg are better than 80%. The practical detection limits of this method are 0.01 mg/kg in grain and soil and 0.02 mg/kg in green plant materials.
Liquid Chromatographic Analysis of Dehydroacetic Acid and Its Application to Wines
Authors: Welling Paul L M , Van Duyvenbode Marianne C , Kaandorp Ben H
Published: February 2020

A simple liquid chromatographic procedure is described for determination of the preservative dehydroacetic acid (DHA) in wine. No cleanup procedure is necessary; the sample is injected onto an NH2 column without further pretreatment. The mobile phase is a 9 + 1 mixture of acetonitrile-sodium acetate buffer adjusted to pH 4 with acetic acid. Total run time is less than 10 min. Dehydroacetic acid is determined by using the absorbance at 307 nm; the detection limit is estimated to be 0.2 ppm. The method may also be suitable for detecting DHA in a variety of foodstuffs in low concentrations
Liquid Chromatographic Determination of Carbadox Residues in Animal Feed
Authors: Roybal Jose E , Munns Robert K , Shimoda Wilbert
Published: February 2020

A liquid chromatographic (LC) method for determining residues of carbadox in the 0.01-10 ppm range in swine feed is described. Carbadox is extracted from ground feed with 25% acidified methanol- CHCl3, removed from emulsion-forming coextractables via an alumina column, separated from highly colored pigments by acid-base liquid- , liquid partitioning, and finally isolated from interferences on a second | alumina column. Isocratic reverse phase LC at 305 nm is used for quantitation. The average overall recovery at the 0.1,0.5, and 1.0 ppm J spike levels was 83.0% with a standard deviation of 2.04% and a coefficient of variation of 2.46 %.
Assessment of Protein Quality Methodology for Infant Formulas
Authors: Mitchell Geraldine Vaughan , Jenkins Mamie Young
Published: February 2020

Rat bioassay was used to assess the protein quality of powdered infant formulas and to evaluate the feasibility of using modified casein diets (containing the same source and level of fat and carbohydrate contributed by the infant formulas) as reference standards. Modification of the casein diet to match the milk-based formulas caused a significant reduction in weekly protein efficiency ratios (PER) and net protein ratios (NPR) at the third and fourth weeks. Modification of the casein diet to simulate the soy-based formulas had no significant effect on NPR values; PER values were more varied. When PER and NPR values of the powdered milk-based formulas were expressed relative to the unmodified reference standard, the relative values were lower than when each matched reference was used. With few exceptions, the relative weekly PER values of the soy-based formulas were similar regardless of the standard used. The relative NPR values of the formulas had a pattern similar to the relative PER values. The data indicate that protein quality evaluation of infant formulas using rat bioassay warrants the use of matched casein reference diets for each type of formula.
Corrected Relative Net Protein Ratio (CRNPR) Method Based on Differences in Rat and Human Requirements for Sulfur Amino Acids
Authors: Sarwar Ghulam , Peace, Robert W , Botting Herbert G
Published: February 2020

The requirement for sulfur amino acids was calculated for growing rats fed 8% protein diets. The r a t and human requirements for sulfur amino acids were compared and a correction factor was developed to reflect the differences. This correction factor was used to determine corrected relative net protein ratio (CRNPR) values for a number of potential meat extenders and their mixtures with beef. The methionine + cystine requirement of growing rats was estimated to be 4% of protein for 8% protein diets. The methionine + cystine requirement of rats was about 50% higher than that of humans (2.65% of protein). Based on this comparison (rat/human), a correction factor of 1.5 was developed to correct RNPR values of those protein products that were deficient in sulfur amino acids for r a t growth. The CRNPR values of beef, casein, soybean protein products, pea concentrate, and peanut meal were 100,100, 91-97, 75, and 73, respectively. Mixtures (50:50 protein basis) of beef with casein, soybean concentrate, soybean isolate, pea concentrate, peanut meal, rapeseed concentrate, rapeseed isolate, sunflower isolate, or wheat gluten were equal to beef in CRNPR values. The CRNPR method is a good predictor of protein quality for humans of those protein products that are deficient in sulfur amino acids.
Extraction of Light Filth from Whole Peppermint Leaves: Collaborative Study
Authors: Boese Jack , Nakashima Marvin , Glaze Larry E
Published: February 2020

Results are reported for a collaborative study of a method for the extraction of light filth from whole peppermint leaves. A 5 g sample is defatted with isopropanol in a simple reflux appartus. Rat hairs, insect fragments, and whole insects are isolated by wet sieving on a No. 230 sieve, a deaerating boil in 40% isopropanol solution, flotation with Tween 80-Na4edta (1 + 1) and mineral oil-heptane (85 + 15), and trappings in a Wildman trap flask. Average recoveries obtained by 6 collaborators for 3 spike levels of rat hairs (5,10,15) were 83.3, 87.5, and 82.2%, respectively. For whole insects (5,10,15) recoveries averaged 85.0, 80.0 and 77.2% respectively; for insect fragments (20, 30, 50) recoveries averaged 79.6, 88.3, and 84.8%, respectively. The average recoveries for the 3 levels of each analyte were not significantly different. The method has been adopted official first action.