bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Dry Column Method for Determination of N-Nitrosopyrrolidine in Fried Bacon
Authors: Pensabene John W , Miller Arthur J , Greenfield Earl L , Fiddler Walter
Published: February 2020

A rapid method has been developed for the determination of N-nitrosopyrrolidine (NPYR) in fried bacon at less than the 1 ppb level. Ground fried bacon is mixed with anhydrous sodium sulfate and Celite by using a glass mortar and pestle. This dry mixture is then added to a chromatographic column containing a layer of acid-Celite. The column is washed with pentane-dichloromethane, and the nitrosamines are eluted with pure dichloromethane. The eluate is concentrated, and the nitrosamines are quantitated by using a gas chromatograph interfaced with a thermal energy analyzer. Recovery of the nitrosamine internal standard, N-nitrosoazetidine, added at the 10 ppb level, was over 90%. The results obtained by this method are in good agreement with the mineral oil distillation procedure currently used in the FSIS monitoring program. Because 25 samples can be analyzed per day per person, this simple screening procedure offers advantages over other methods.
Comparison of Nitrite and Nitrate Determinations in Vegetables: Suitability for Accurate and Automated Measurements
Authors: Lox Frans , Okabe Akitsugu
Published: February 2020

A method is reported for improved accuracy for nitrate and nitrite determinations in aqueous solutions, especially plant extracts. The sampling procedure can be adapted for automated determinations: At least 6 aliquots with increasing volume of nitratecontaining solutions are subjected to the reducing agent under stabilized conditions to obtain nitrite, treated with one of 2 different diazotization reagents, and measured colorimetrically. The slope of the curve, absorbance vs sampled volume, is determined by linear regression; this slope is directly dependent on the nitrate (nitrite) content. Original nitrite is determined by omitting the reducing step. Low nitrate levels (<0.1 μg/mL) can be determined directly with the sulfanilamide-N-(l-naphthyl)ethylenediamine dihydrochloride diazotization procedure or indirectly by constant nitrate addition, with the sulfanilic acid-1-naphthylamine hydrochloride diazotization mixture (Griess reagent). The latter procedure can be used to measure concentrations up to20μg/mL.
Wax in Wool by Wide-Line Proton Magnetic Resonance: Rapid Non-Destructive Method
Authors: O'Keefe John H , Sharry Leo F
Published: February 2020

A wide-line proton magnetic resonance technique (PMR), in which hydrogen response is used as the measure of wax in dried greasy wool, is a viable and preferred alternative to the commonly used Soxhlet procedure in which extracted weight is measured. The validity of the PMR method depends on wax hydrogen composition (inter- and intra-breed) being constant, and on background contribution from non-wax hydrogen (in suint, wool fiber, and vegetable matter) being small and constant. The experimentation reported in this paper shows that both requirements are met. The PMR method for wax is precise (better than 0.1% at mid-range); rapid (200 samples per 8 h day); sensitive (better than 15 mg); and yields a linear calibration graph over the entire range (0-100%) for a 5 g sample. A comparison of the methods shows that the linear regression line for wax by Soxhlet (y) against wax by PMR (x) is given by y = 1.0257 (SE 0.2277) + 0.9894 (SE 0.0142)x, with r2 = 0.99, and n = 20.
Colorimetric Determination of 3-Amino-l,2,4-Triazole in Grain or Meal
Authors: Galoux Michel , Van Damme Jean-C , Bernes Albert
Published: February 2020

This colorimetric method for the determination of 3-amino-l,2,4-triazole in grain or meal is a modification of the Storherr and Burke method. The herbicide is extracted from grain with methanol, and purified by adsorption-desorption on resin. The extract is cleaned by digestion with sulfuric acid and clarified with charcoal. The colored complex formed by coupling with N-(1-naphthyl)ethylenediammonium dichloride is measured spectrophotometrically at 455 nm. The limit of detection is 0.05 ppm.
Gas-Liquid Chromatographic Determination of Residues of Oxadiazon and Its Metabolites in Green and Dry Hops and Hop Foliage
Authors: George Donald A
Published: February 2020

Ronstar EC (emulsifiable concentrate) was applied at rates of 4.48 or 8.96 kg ai/ha as a broadcast spray during the winter, in late spring, and in mid-summer to plots in commercial hop fields. Residues of oxadiazon, the active ingredient, and its 4 metabolites (methoxy, alcohol, acid, and phenol) were determined at harvest (1 month after last treatment) in green and dry hops and in hop foliage, by using gas-liquid chromatography after column chromatographic cleanup. Drying the cone increased residues of oxadiazon, but resulted in loss of the methoxy and alcohol metabolites. Oxadiazon residues in hop foliage ranged from 0.058 to 0.163 ppm. Measurable amounts of metabolites were also found in the foliage.
Spectrophotometric Determination of Carbaryl in Grains
Authors: Appaiah Kalapanda M , Ramakrishna Rasamsetti , Subbarao Kadari R , Kapur Omprakash
Published: February 2020

A method has been developed for determining carbaryl (1-naphthyl N-methyl carbamate) in grains, based on hydrolysis of carbaryl with methanolic potassium hydroxide to 1-naphthol, reaction with 4-aminophenazone in the presence of alkaline oxidizing agent, and spectrophotometric measurement at the absorption maximum at 475 nm. The relationship between absorbance and concentration is linear in the range of 0.5-20 μg/mL. The method can be applied to levels as low as 0.3 ppm carbaryl in grains.
Colorimetric Determination of Patulin Produced by Penicillium patulum
Authors: Subramanian Thirugnana
Published: February 2020

A quantitative method has been developed for the determination of patulin, a mycotoxin produced by Penicillium patulum. The fungus was grown separately in well defined liquid minimal medium, and on rice and bread for 15 days. Patulin was extracted with ethyl ether and determined colorimetrically, using phenylhydrazine hydrochloride. Recovery of pure patulin added to bread and rice was also studied. The lower limit of detection was 1 μg/g.
Effect of Adsorption of Histamine to Glass Surfaces on Its Estimation
Authors: Murray John , McGill Alister S
Published: February 2020

Histamine is rapidly adsorbed on the surface of glass containers when stored in aqueous or 10% methanol solution at ambient or sub-zero temperatures. This effect can lead to marked errors in the determination of histamine. Addition of acid to the holding medium or storage in polyethylene containers eliminates this effect
Accuracy of Pesticide Reference Standard Solutions. Part I. Factors Affecting Organic Solvent Evaporation
Authors: Hodgson David W , Watts Randall R
Published: February 2020

A gravimetric experiment was undertaken to identify the factors affecting solvent evaporation from analytical reference standard solutions and to establish the magnitude of the resultant solvent evaporation. The evaporation of organic solvent from standard solutions is affected by: (1) solvent, (2) container type, (3) solution volume, and (4) storage temperature. Solvents with low vapor pressure-to-surface tension ratios have low evaporation rates. Screw-cap containers with precision-made caps and seals have the lowest evaporation rates. The use of large-volume standard solutions reduces the percent solvent loss. Storage at refrigerator or freezer temperatures can reduce evaporation rate by as much as a factor of 7.
Simultaneous Electron Capture Detection of Chlorpyrifos and 3,5,6-Trichloro-2-pyridinol Residues in Peach and Bahia Grass Field Samples Following Gel Permeation Cleanup
Authors: Guinivan Richard A , Thompson Neal P , Bardalaye Promode C
Published: February 2020

A recently published method involving the simultaneous extraction, gel permeation cleanup, and electron capture gas chromatographic detection of residues of the insecticide and acaricide chlorpyrifos and its principal metabolite 3,5,6-trichIoro-2-pyridinol is successfully applied to Lorsban-treated peach and Bahia grass samples. Previous quantitation of these compounds has required 2 separate analytical procedures. Multilevel temperature programming and manipulation of the gel permeation column effluent rate are the only adjustments of experimental parameters necessary to avoid large amounts of gas chromatographic interferences. Chromatographic peaks are more clearly defined and easier to integrate with the multilevel program than they are with 2-step or linear programs. This is one reason that recovery data are improved over those reported for the method as applied in the pea vine work. Residue analyses conducted on field-treated peaches and Bahia grass show the newly published procedure to be sensitive and effective.
Analytical Methods for Drugs in the Next Decade
Authors: Zarembo John E
Published: February 2020

Today’s research for new drug substances is moving toward molecules of much larger molecular weight and complexity than the small, modern drug molecules, e.g., polypeptides, interferon, slow-releasing substances, and blood and plasma components. The complexity of natural products derived from human or other animal bodies requires a new analytical chemistry. Simple tests for drug stability, dissolution, and bioavailability will no longer suffice to provide and ensure purity and structural identity of such drugs. During the next decade, the demands on analytical chemists will increase; more biological organic and physical chemistry will be required by analysts to perform their jobs. Criteria for purity will require even greater chromatographic involvement but this will have to be complemented by nuclear magnetic resonance and mass spectrometry. The demands made on AOAC to validate and approve methods to assay drugs and determine their purity will increase enormously in this next decade. The understanding of drug purity will take on a new meaning because of the complex nature of natural products. Stability indication will be significant only when chemical and biological tests can complement and define the active components and the impurities. AOAC will be required to play a major role in assuring the manufacturer and the public that their drugs are adequately tested, safe, and efficacious.
Glass Capillary Gas Chromatography for Sensitive, Accurate Polychlorinated Biphenyl Analysis
Authors: Bush Brian , Connor Steven , Snow John
Published: February 2020

A simple method is described for preparing Apiezon L-coated glass capillary columns for polychlorinated biphenyl (PCB) analysis. The mass represented by each of 72 chromatographic peaks separated on this column from a mixture of Aroclors 1221,1016,1254, and 1260 was determined; the mixture could then be used as a universally applicable calibration standard for analysis of environmentally modified polychlorinated biphenyl mixtures at the parts per billion (ng/g) level. Analytical sensitivity is <10 ng/mL for total PCBs and <0.1 ng/mL for individual PCB congeners.
High Performance Liquid Chromatographic Method for Determination of Temephos in Technical and Formulated Products: Collaborative Study
Authors: Miles James W , Mount Dwight L
Published: February 2020

An HPLC method for the determination of temephos in temephos technical and formulated products has been subjected to an international collaborative study with 14 laboratories participating. Samples were extracted with ethyl acetate and eluted on a silica gel column with ethyl acetate-hexane (1 + 9); p-nitrophenyl p-nitrobenzoate served as the internal standard. Collaborators were furnished samples of technical, 20 and 50% emulsifiable concentrates, 50% water-dispersible powder, and 1% sand granules. The coefficients of variation of the values obtained on the 5 samples were 1.21,2.02,1.26,1.89, and 9.90%, respectively. The method has been adopted official first action.
Detection of Invasiveness of Mammalian Cells by Escherichia coli: Collaborative Study
Authors: Mehlman Ira J , Romero Aida , Atkinson John C , Aulisio Calvin , Sanders Arvey C
Published: February 2020

In a collaborative study of 2 standard procedures (Procedure I, presented in J. Assoc. Off. Anal. Chem. 60, 546-562 (1977) and Procedure II in the Bacteriological Analytical Manual, 1978), 7 laboratories evaluated the invasive potential of Escherichia coli. Monolayers of HeLa cultures were infected with E. coli (infectivity ratio 100 bacteria/mammalian cell) suspended in 2 menstrua: heat-inactivated fetal bovine serum (Procedure I) and 0.2% bovine albumin Fraction V dissolved in Earle’s buffered salts (Procedure II). After uptake of the bacteria, intracellular growth, and differential staining, the percentages of HeLa cells containing a minimum of 5 bacteria were determined microscopically. All laboratories correctly identified invasiveness of E. coli by Procedure I; 5 of 6 laboratories recognized invasiveness by Procedure II. Although Procedure I was more reproducible than Procedure II, repeatability did not differ significantly. Procedure I was adopted official first action for presumptive recognition of invasiveness in E. coli.
High Pressure Liquid Chromatographic Determination of Aflatoxins by Using Radial Compression Separation
Authors: Shepherd Eric C , Phillips Timothy D , Heidelbaugh Norman D , Hayes A Wallace
Published: February 2020

A rapid method for the determination of aflatoxins was developed using high pressure liquid chromatography and a radial compression separation system. A standard solution of aflatoxins B1, B1, G1, G2, and M1 was analyzed at flow rates of 2.0 and 6.0 mL/min. Retention times, peak heights, and peak areas were reproducible over a 3-day period. Coefficients of variation for aflatoxin B1 at 2.0 and 6.0 mL/min were, respectively, 1.04 and 0.87% (retention time); 2.9 and 4.7% (peak height); and 8.2 and 4.7% (peak area). At 6.0 mL/min there was an approximate 25% loss in sensitivity but a greater than 50% reduction in retention time. Separation of all the aflatoxins was excellent using a dual flow rate of 2.0 mL/min with a change to 8.0 mL/min at 15 min post-injection. The applicability of the radial compression separation system for the rapid determination of aflatoxins in human tissues was also tested. Spiked samples of liver, serum, and urine showed good resolution of all aflatoxin peaks at the higher flow rates.
Caution on Nitric Acid Digestion of Organic Samples in Closed Systems
Authors: Borggaard Ole K , Willems Marta
Published: February 2020

There is a risk of explosion when organic samples are digested with nitric acid in a closed vessel at elevated temperatures for elemental analysis. Sample size and the size, material, and thickness of bomb walls should be carefully considered. Digestion in an open flask may be a safer alternative.
Defining a Lowest Level of Reliable Measurement for Lead in Foods
Authors: Capar Stephen G , Subjoc Cheryl A
Published: February 2020

Procedures are outlined for defining and demonstrating a lowest level of reliable measurement for Pb in foods. The method of analysis studied was a dry ash sample mineralization with quantitation by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode. Past experience with analyses for Pb in foods indicated that the lowest measurement of Pb in foods was limited by the Pb contributed from the reagents, apparatus, and laboratory environment. The magnitude of contamination from these 3 sources was investigated. Once a specific source of contamination was identified, attempts were made to eliminate or minimize the amount of Pb it contributed to the analysis. After contamination was controlled to the degree our facilities would allow, low level Pb determinations were performed on infant formula.
Application of Gel Permeation Chromatography and Nonaqueous Reverse Phase Chromatography to High Performance Liquid Chromatographic Determination of Retinyl Palmitate and α-Tocopheryl Acetate in Infant Formulas
Authors: Landen William O
Published: February 2020

A high performance liquid chromatographic (HPLC) method was developed for determining retinyl palmitate and α-tocopheryl acetate in infant formulas. The lipid-soluble components were extracted from the aqueous phase by homogenizing in a solvent mixture of isopropanol and methylene chloride with magnesium sulfate added to remove water. The vitamins were fractionated from the lipid material by using high pressure gel permeation chromatography (HP-GPC) followed by quantitation using nonaqueous reverse phase (RP)-HPLC. Three μStyragel (lOOÅ) columns connected in series were used for HP-GPC fractionation of sample extracts in methylene chloride. A Zorbax ODS (6 μm) column and methylene chloride-acetonitrile-methanol (30 + 70 + 0.2) were used for RP-HPLC quantitation. The 32 commercial infant formulas that were analyzed represent a wide variety of formulations manufactured at various fortification levels. Vitamin A results ranged from 89 to 242% of the declared levels. Vitamin E values, determined as the supplemental form a-tocopheryl acetate, ranged from 83 to 272% of the' declared levels. Determination of vitamin A in 6 samples and vitamin E in one sample by this method and the official AOAC method gave comparable results. This method, which requires no saponification, was successfully used to determine vitamins A and E in ready-to-use, liquid concentrated, and powdered infant formulas.
Gas Chromatographic Determination of Propionates as Paranitrobenzyl Ester in Bakery Products
Authors: Takatsuki Keigo , Sakai Keiichi
Published: February 2020

A procedure was developed to determine propionates used as mold inhibitors and preservatives in bakery products. Propionates were extracted from the sample with water alkalinized by potassium carbonate. Water was evaporated, and the residue was reacted with paranitrobenzyl bromide in dimethylformamide- water (90 + 10) at room temperature to convert propionates to paranitrobenzyl ester, which was determined with a gas chromatograph equipped with a flame ionization detector. Bakery products, such as bread, sponge cake, cookies, and biscuits, were analyzed by this procedure. Recoveries from samples fortified with propionates ranged from 94 to 101%, with a standard deviation of 3.32. The concentrations determined were 50 to 2500 μg/g sample.
Extract for Stable Isotope Ratio Isolation of Vanillin from Vanilla Analysis: Interlaboratory Study
Authors: Guarino Philip A
Published: February 2020

The Technical Committee of the Flavor and Extract Manufacturers' Association collaboratively tested 3 methods for isolation of vanillin from vanilla extract. Each of the 3 methods provided vanillin which was useful for the intended purpose, although 2 of the selected methods were preferred by the collaborators. The vanillin isolated by each of the 3 methods was suitable for stable isotope ratio analysis to determine whether the vanillin was of natural origin or had been added to the extract.
Verification of Authenticity of Apple Juice
Authors: Brause Allan R , Raterman Joseph M
Published: February 2020

A series of instrumental analyses is described for verification of apple juice authenticity. Liquid chromatography is used to determine sugars and individual phenolics, atomic absorption spectroscopy is used to determine potassium, standard AOAC methods are used to test for polyphenolics arid formol indexes, and stable carbon isotope ratio analysis (SCIRA) is used to detect high fructose corn syrup. These tests will identify fraudulent but not poorly processed apple juice.
Composite Sampling in the Determination of Pyrethrins in Fruit Samples
Authors: Ryan John Joseph , Pilon Jean-Claude , Leduc Raymonde
Published: February 2020

A residue method is described for measuring up to 6 naturally occurring pyrethrins in several varieties of fruits. Fresh samples are extracted into acetone, partitioned between water and hexane-dichloromethane, and cleaned up by adsorption on a Florisil column followed by elution with acetone-hexane (15 + 85). Residues are detected and quantitated by gas chromatography with electron capture detection. Detection limits for single 10 g samples are about 10-30 ng/g. The method was applied to a survey of pyrethrins in fruit samples. Because of the high tolerance (1 ppm) allowed for pyrethrins, the expected low incidence, and the low detection limits of the method, composite samples (up to 5-6) of fruit were used to quickly determine residue levels. This procedure allowed 130 samples to be processed in the time normally needed for 30-40. Provided the above conditions can be met, composite sampling is proposed as an attractive approach to data gathering in pesticide residue analysis.
Field Screening Method for Above-Tolerance Residues of Dithiocarbamate Fungicides
Authors: Ott Daniel E , Gunther Francis A
Published: February 2020

A field screening method has been developed for detecting above-tolerance residues of dithiocarbamate (DTC) fungicides on fruits and vegetables. A harvested crop might be condemned as unfit for market if above-tolerance DTC residues are present; however, by using this screening method, a grower might be able to postpone harvesting a crop until the screening test indicates that residues have dissipated below the tolerance level. The method depends on carbon disulfide generated from DTC fungicides at an elevated temperature into the headspace gas above the contents of a septum-sealed reaction flask, with hydrochloric acid and stannous chloride present. The syringe-withdrawn, headspace carbon disulfide then reacts with the appropriate chromophore reagent already in the syringe. The lower limit of detectability is about 2 ppm DTC fungicide from 30 g chopped crop. A single test can be completed in about 90 min; the average time per test when several are conducted sequentially is considerably shorter.
Toxicology of Lead: Primer for Analytical Chemists
Authors: Biddle Garfield N
Published: February 2020

Through the years, considerable amounts of Pb have been mobilized into our environment, and Pb may represent one of the most ubiquitous of all toxic metal contaminants. Excluding occupational exposure, the general population receives almost 70% of its total exposure to Pb from food. Other important sources of exposure include drinking water and air; minor sources include tobacco products, decorative glassware, and other types of food utensils. For young children, ingestion of Pb-containing soil or dust via normal hand-to-mouth activity or, in extreme cases, pica (the abnormal intake of soil, paint chips, etc.) may represent a significant source of exposure. The severity of clinical manifestations of Pb toxicity depends on both duration and intensity of exposure. Infants and young children are more susceptible to the effects of Pb than are adults. Although there is little debate over the serious consequences of acute, high-level Pb exposure, both controversy and concern have been expressed about the degree of risk that may be associated with chronic exposure to Pb levels that are closer to contemporary levels in the general environment. This concern is particularly high with regard to infants and young children, who may undergo Pb-induced changes that have long-term neurological impact (e.g., learning deficits, gross and/or fine motor dysfunction, impaired cognitive abilities).
The Analytical Blank: Sources and Effects on Lead Analyses
Authors: Skogerboe Rodney K
Published: February 2020

The influence of the analytical blank on the reliability of an analysis is often of paramount importance. It is shown that the magnitude of the blank and the degree of uncertainty associated with it usually limits the ability to complete quantitative analyses at lower concentration levels. Specific sources of lead contamination are discussed and data are presented that indicate the possible contributions from each source. Although exceptions surely occur, it appears that lead contributions from the laboratory environment and/or ancillary analytical equipment and materials are often the primary factor in determining the blank level and the variability therein.
Food Analysis for Lead Using Furnace Atomic Absorption and a L’vov Platform
Authors: Koirtyohann S Roy , Kaiser Millie L , Hinderberger Edward J
Published: February 2020

Furnace atomic absorption is a very sensitive method for determination of lead and other trace metals in variety of samples, but it is prone to matrix interferences. A majoi improvement in the method is achieved by the use of a L’vov platform, a small piece of graphite placed inside the furnace tube, onto which the sample solution is pipetted. The temperature of the platform rises more slowly than that of the tube wall during the atomization cycle, and sample vaporization is delayed until the furnace atmosphere is at a high and nearly constant temperature. The resulting atomization behavior is more consistent and less matrix-dependent for numerous analyte elements, including lead. Results are further improved by addition of ammonium phosphate to all samples and standards as a matrix modifier. For example, in comparing analyte sensitivity (slope of the absorbance vs concentration curve) in a variety of food sample types to the sensitivity in dilute HNO3, the average lead response showed 60 ± 15% suppression due to the sample matrices. Use of the L’vov platform and matrix modifier virtually eliminated the suppression and improved the precision.
Quantitative Determination of 1-131, Cs-137, and Ba-140 in Milk: Collaborative Studies
Authors: Shuman Frederick G D , Easterly David G , Baratta Edmond J
Published: February 2020

The official method for Cs-137 in milk by gamma-ray spectroscopy was extended to include 1-131 and Ba- 140. A collaborative study was performed on this method applied to 1-131 concentration in cow's milk; the original collaborative study of the method including all 3 nuclides was reviewed. In the 1-131 study, 1 aliquot of a milk sample containing 82 pCi/L was sent to each of 60 laboratories for triplicate analyses. From 40 responses, the mean of the reported values was 81.6 pCi/L, indicating a method bias below the 5% statistical detectability limit. Within- and between-laboratory coefficients of variation (CVs) were 7 and 8%, respectively. In the 3-nuclide study, 2 samples were sent to 25 laboratories for triplicate analyses; one sample contained 633,305, and 515 pCi/L, respectively, of 1-131, Cs-137, and Ba-140 and the other contained 98,52, and 72 pCi/L. For the high-activity sample, within-laboratory CVs were 4-5% for the 3 nuclides and between-laboratory CVs were 4-7%. For the low-activity sample, the corresponding results were 6-9% and 8-16%. The method bias was statistically significant at 95% confidence only for Cs-137 in the high-activity sample; reported results were 3% below the known concentration. The extended method was adopted official first action.
Drug Quality Assessment Methods. I. Gas-Liquid Chromatographic Assay and Identification of Seven Barbiturates
Authors: Black Donald B , Kolasinski Halina , Lovering Edward G , Watson James R
Published: February 2020

A gas-liquid chromatographic (GLC) procedure has been developed for the assay and identification of amobarbital, butabarbital, heptabarbital, mephobarbital, pentobarbital, phenobarbital, and secobarbital in single component capsule, elixir, injectable, suppository, and tablet formulations. After extraction into chloroform from an acidified aqueous mixture of the product, the drug is eluted isothermally from a methylphenylsilicone GLC column at 210 or 240°C and quantitated relative to thiamylal internal standard. Results were in good agreement with those obtained using pharmacopeial assay methods. The method is suitable for the rapid assessment of commercial formulations.
High Performance Liquid Chromatographic Determination of Primidone in Tablets
Authors: Roberts Stanley E
Published: February 2020

A high performance liquid chromatographic (HPLC) method is described for the quantitative determination of primidone in tablets. A ground tablet sample is diluted directly in the mobile phase, at a concentration of about 1 mg/mL of primidone, mixed and deaerated, and filtered. The resulting solution is then quantitated by HPLC. The average spike recoveries for the 50 mg and 250 mg tablets were 101.2% and 99.0%, respectively. The average recovery for an authentic mixture formulated at the 250 mg level was 100.1% with a relative standard deviation of 0.45%.
Evaluation of Glutaraldehyde and Hydrogen Peroxide for Sanitizing Packaging Materials of Medical Devices in Sterility Testing
Authors: Eskenazi Samuel , Bychkowski Olga E , Smith Marilyn , Macmillan James D
Published: February 2020

External surfaces of packaging materials used for sterile medical devices may introduce contaminants into working areas used for sterility testing. Light wiping with tissues moistened with alkaline 2% glutaraldehyde (Cidex) or 3% hydrogen peroxide effectively reduced counts on 5 X 8 cm strips of packaging material (Tyvek) inoculated with 107 spores of Bacillus subtilis. The ability of antimicrobial agents to penetrate packaging material and kill contaminants on the medical device was tested by inoculating filter membranes with ca 100 cells of Pseudomonas aeruginosa or Staphylococcus aureus or ca 100 spores of Bacillus subtilis. A sterile square of test packaging material placed over the inoculated membrane (direct method) or 0.5 cm above the membrane (indirect method) was wiped with the antimicrobial agent. Except for polyethylene film (3 mil), all materials tested, including glassine and several types of coated and uncoated Tyvek, were penetrated by the agents, killing cells on the inoculated membranes. Death rates varied, depending on the organism, packaging material, and testing method. It is suggested that penetration tests be performed before using antimicrobial agents for sanitizing packaging materials during sterility tests.
Improved Method for High Pressure Liquid Chromatographic Determination of Chlorophacinone in Mouse Tissue
Authors: Addison Joseph B
Published: February 2020

A simplified method is described for the determination of chlorophacinone, 2-[(p-chlorophenyl)- phenylacetyl]-l,3-indandione, in homogenized mice. Chlorophacinone is extracted with acetonitrile. After Florisil cleanup, the extract is injected into a high pressure liquid chromatograph for reverse phase chromatography on a polar Lichrosorb NH2 (10 μm) column, with a mobile phase of acetonitrile-water (80 + 20). An injection containing 70 ng chlorophacinone produces 1/2 scale peaks at 254 nm with a full scale absorbance of 0.1 unit, an order of magnitude improvement over the sensitivity reported earlier with a 280 nm detector. Six homogenized mice samples and six spiked homogenized mice samples were quantitatively analyzed for trace levels of chlorophacinone by this method. Recoveries from spiked samples, as determined by peak height measurement, were >95%. Mean retention time for the chlorophacinone peaks in all samples was 6.05 ± 0.05 min. Chlorophacinone levels determined in homogenized whole mouse samples ranged from 0 to 63 ppm.
Simultaneous Liquid Chromatographic Determination of Thiabendazole, o-Phenylphenol, and Diphenyl Residues in Citrus Fruits, Without Prior Cleanup
Authors: Kitada Yoshimi , Sasaki Michiko , Tanigawa Kaoru
Published: February 2020

A simple, rapid, efficient method has been developed for determining thiabendazole, o-phenylphenol, and diphenyl in citrus fruits by using high performance liquid chromatography, with fluorescence or ultraviolet detection. The compounds are extracted with ethyl acetate and separated from soluble fruit components on a LiChrosorb RP-8 column. Recovery of these compounds added to citrus fruits at 5 or 50 ppm levels was >93%; the limit of detection for the compounds is 1 ppm.
Evaluation of CH Stretch Measurement for Estimation of Fat in Aqueous Fat Emulsions Using Infrared Spectroscopy
Authors: Mills Bernice L , Van De Voort F R
Published: February 2020

Measurement of infrared absorption by the use of a CH stretch filter which isolates wavelengths in the order of 3.4-3.5 μm has been suggested as a replacement for the conventional carbonyl stretch absorption measurement or as an additional measurement for the estimation of fat in aqueous fat emulsions. To determine the merits of this CH stretch measurement, a study was conducted with a series of natural fats selected for their differences in average molecular weight, fatty acid composition, and degree of unsaturation. In this study, the use of the CH stretch filter, the C ═ 0 stretch filter, or the combination thereof could predict the fat content with equal accuracy if the fat was consistent in average molecular weight and degree of unsaturation. For a fat which varied in its degree of unsaturation, the CH filter measurement could be used in conjunction with the iodine value to produce accurate results. The combination C ═ 0 filter, CH filter, and the iodine value produced the most accurate results when the intent was to analyze a variety of fats on a single calibration.
Microdetermination of Ethylene Dibromide in Air by Gas Chromatography
Authors: Dumas T , Bond E J
Published: February 2020

Using a new, sensitive photo-ionization detector in a portable gas chromatograph that operates at ambient temperature, a method was developed for determining ethylene dibromide in air as low as 19 ppb. Vapor standards were prepared for calibration of the detector; concentrations in these standards were accurately determined by using a flame ionization detector. This detector was previously calibrated with an aqueous standard of ethylene dibromide. Using the 2 gas chromatographs, the loss of ethylene dibromide through sorption from the atmosphere of the vapor standards was determined. Solubility of ethylene dibromide in water was also established at 3 temperatures, using the flame ionization detector.
Spectrophotometric Determination of Oxidizing Substances in Food-Grade Hydrochloric Acid
Authors: Levey Brian J , Reigler Paul F
Published: February 2020

A spectrophotometric method has been developed for the determination of oxidizing substances in food-grade hydrochloric acid. The method is based on the reaction of oxidizing substances with potassium iodide to form triiodide ion (I-3) whose absorbance is then measured at 485 nm. Oxidizing substances is reported as fig Cl2/mL. The method is applicable to oxidizing substances in the range of approximately 9-37 μgCl2/mL.
The Infant Formula Act of 1980
Authors: Newberry Raymond E
Published: February 2020

The Infant Formula Act of 1980 is one of the most specific and detailed acts ever passed by Congress. It establishes minimum nutrient requirements, defines adulteration, provides for establishing nutrient and quality control procedures, prescribes recall procedures, and specifies inspection requirements.
Vitamin Analysis in Infant Formulas
Authors: Granade Alvin W
Published: February 2020

The methodology used by the Atlanta Regional Laboratory, U.S. Food and Drug Administration, for determination of vitamins in infant formulas is summarized. Analytical findings for 11 vitamins are presented by manufacturer in terms of the requirements of the Infant Formula Act and percentage of the manufacturer’s label declaration.
Gas-Liquid Chromatographic Determination of Chlordimeform and Its Metabolites in Cargo Rice and Husk
Authors: Fan De-Fang , Ge Shin-Ding
Published: February 2020

A specific method is described for the alkali flame ionization gas-liquid chromatographic determination of chlordimeform (N-(4-chloro-o-tolyl)-N,N-dimethylformamidine) and 3 potential metabolites in cargo rice and husk. Samples are extracted with absolute alcohol or hexane, and cleaned up on neutral alumina columns. Residues of chlordimeform and its metabolites are chromatographed directly on a column of 1% DEGS coated on 60-80 mesh 405 support (PEG 20M bonded phase). The detection limits for chlordimeform, 4-chloro-o-toluidine, 2,2’-dimethyl- 4,4’-dichloroazobenzene, and N-formyl- (4-chloro-o-toluidine) are 0.03, 0.028, 0.11, and 0.43 ppm for cargo rice and 0.03,0.028,0.22 and 0.43 ppm for husk, respectively.
13C/12C Ratios of Citrus Honeys and Nectars and Their Regulatory Implications
Authors: White Jonathan W , Robinson Frank A
Published: February 2020

Application of isotope ratio testing for adulteration to predominantly citrus honeys without using the recommended confirmatory testing has caused regulatory difficulties for several Florida honey packers. It is demonstrated that δ13C of citrus honey is significantly less negative than that of other honey types. Analysis of citrus nectar shows that the less negative values are not due to the inadvertent mixing of cane or corn syrups used for spring feeding of the bee colonies previous to the citrus nectar flow. Means for identifying citrus honey and specific limiting values of δ13C for adulteration testing of this honey type are proposed.
High Performance Liquid Chromatographic Determination of Bifidobacterium bifidum Growth Factors in Human Milk
Authors: Ashoor Samy H , Monte Woodrow C
Published: February 2020

An isocratic high performance liquid chromatography (HPLC) method has been developed for the determination of Bifidobacterium bifidum growth factors in human milk. The method involves the gradual addition of 3 volumes of ethanol to the milk sample, filtration, and analysis of the growth factors in the filtrate by HPLC. The HPLC system consisted of a carbohydrate analysis column, a water-acetonitrile (70 + 30) solvent system, a flow rate of 1.0 mL/min, and a refractive index detector. The method is simpler and requires less time than the present microbiological method. Moreover, it revealed for the first time the presence of 2 separable growth factors in all human milk samples tested. The HPLC method developed is sensitive and can be used to monitor the type and the amount of growth factors in mothers’ milk during lactation.
Evaluation of Fluorometric Determination-Thin Layer Chromatographic Identification of Aminacrine Hydrochlbride in Drug Preparations
Authors: Bunch Elaine A
Published: February 2020

Utilizing the fluorescent property of aminacrine hydrochloride and a filter fluorometer, a fluorometric method for aminacrine hydrochloride in drug combinations was developed, collaboratively studied, and adopted as official first action in the 11th edition of Official Methods of Analysis. Identity was confirmed by thin layer chromatography (TLC). Additional analytical work was undertaken with a grating fluorometer to support a change in the method status to official final action. The grating instrument recorded the aminacrine hydrochloride spectrum as opposed to the total fluorescence emission measured by the filter instrument. The spectrum of aminacrine hydrochloride showed that the molecule was exhibiting self-absorption of the emitted radiation even at concentrations of 10-6M and that the ratio of the 2 peaks in the emission spectrum varied with concentration. Additional analyses of an authentic cream preparation that also contained sulfanilamide gave an average recovery of 86.0% for aminacrine hydrochloride in 10 replicate portions. Because of these observations, the current Associate Referee’s recommendation to delete the fluorometric procedure from the 13th edition of Official Methods of Analysis was adopted. A recommended deletion of the TLC identification test was also adopted.
Comparison Between Potentiometric Titration and Enzyme-Catalyzed Determination of Hydrogen Peroxide
Authors: Chin Henry B , Cortes Antoni
Published: February 2020

A titrimetric procedure has been recommended for the determination of residual amounts of hydrogen peroxide on packaging surfaces as a result of its use as a sterilant. Enzymatic assays have been described for the determination of hydrogen peroxide in various substrates. We compared the enzymatic assay based on the oxidation of leuco crystal violet by peroxidase and the potentiometric titration procedure for the determination of hydrogen peroxide in distilled water, as required in the approval of this material as a packaging sterilant. The correlation between the 2 procedures is 0.976.
Interlaboratory Calibration Results of Polychlorinated Biphenyl Analyses in Herring
Authors: Musial Charles J , Uthe John F
Published: February 2020

Twenty-three laboratories from 13 countries in continental Europe, Scandinavia, the British Isles, and North America participated in a polychlorinated biphenyl (PCB) Check Sample Program conducted under the auspices of the International Council for Exploration of the Sea (ICES). PCBs were determined in unspiked and spiked (1.00 mg Aroclor 1254/kg oil) herring (Clupea harengus harengus) oil by the participants, each of which used his or her own cleanup and quantitation techniques; a common Aroclor 1254 mixture was used as a standard and a common quantitation technique was used for comparative purposes. Results for the unspiked oil ranged from 0.48 to 3.416 mg PCB/kg oil, while spiked oil results ranged from 0.70 to 3.891 mg/kg. Calculated spike recoveries ranged from 22 to 136%. Serious deficiencies were found in most steps in the procedures. No evidence was found to support the use of a common PCB standard or a common method of calculation using packed column chromatography. The chromatographic stationary phase used appeared to affect the PCB levels obtained. Florisil cleanup adsorbent yielded higher mean results for both unspiked and spiked oils than did alumina. Large coefficients of variation were found (25-50%), the principal source of which was systematic error (interlaboratory).
Gas-Liquid Chromatographic Determination of Polychlorinated Biphenyls and a Selected Number of Chlorinated Hydrocarbons in Serum
Authors: Burse Virlyn W , Needham Larry L , Korver Margaret P , Lapeza Chester R , Liddle John A , Bayse David D
Published: February 2020

A method is proposed for concurrently determining the levels of multiple intact exogenous compounds in serum, particularly polychlorinated biphenyls (PCBs) as Aroclor (AR) 1254 and chlorinated hydrocarbons (CHs). Bovine serum pools containing in vivo-bound PCBs (as AR 1254) and in vitro-spiked CHs are used to evaluate the method, which encompasses serum denaturation with methanol, mixed solvent extraction, multiple solvent fractionation from activated silica gel, and determination by electron capture gas-liquid chromatography. Mean recoveries of the in vitro-spiked 9 CHs at levels of 2.0-29.1 ppb ranged from 52.8 to 98.4% from trial environmental pools; mean recoveries of the in vivobound PCBs (as AR 1254) were 114.1 and 92.6% at levels of 10 and 50 ppb, respectively.
Gas-Liquid Chromatographic Determination of Volatile Phenols in Matured Distilled Alcoholic Beverages
Authors: Lehtonen Matti
Published: February 2020

Volatile phenols in matured spirits were determined by gas-liquid chromatography as their 2,4-dinitrophenyl derivatives. Phenol, o-cresol, m-cresol, p-cresol, guaiacol, p-ethylphenol, p-ethylguaiacol, eugenol, and p-(n-propyl)guaiacol, which occurs only in dark rum, were studied at concentrations ranging from 0 to 2 ppm depending on the phenol and the beverage. Scotch, Spanish, and Japanese whiskies, unlike other whiskies examined, contained o-, m-, and p-cresols. Cresols occur in whiskies as a consequence of the raw materials used, in particular peated malt. The level of p-ethylguaiacol is usually somewhat higher in cognac and other brandies than in whiskies. Dark rums differ from the other spirits examined in containing p-(n-propyl)guaiacol, and, typically, higher levels of p-ethylphenol, p-ethylguaiacol, and eugenol. These phenols also occur in higher quantities in some white rums than in whiskies and brandies. Two discriminant functions were obtained by discriminant analysis, which did not, however, allow the spirits to be classified adequately into their respective groups. By using these functions, 82% of the whiskies, 57% of the brandies, and 50% of the rums were correctly grouped.
High Pressure Liquid Chromatographic Assay for Prednisone in Bulk Drug Substances and Tablets
Authors: Graham Robert E , Biehl Edward R , Uribe Margarito J
Published: February 2020

A high pressure liquid chromatographic (HPLC) method was developed for the assay of prednisone in bulk drug substances and tablets. The sample was dissolved in water-methanol and an aliquot was analyzed by using HPLC. The average recovery of prednisone added to a prednisone tablet composite was 99.5% with a coefficient of variation of 1.07%. Prednisone was determined in 46 tablets (1-50 mg prednisone/tablet) formulated by 22 manufacturers, using the HPLC method and the USP blue tetrazolium assay. The results show that the HPLC method is more specific and faster than the USP method.
Simultaneous Detection of Some Fusariotoxins by Gas-Liquid Chromatography
Authors: Bata Aŕpád , Ványi Andŕas , Lásztity Radomir
Published: February 2020

A method was developed for the simultaneous determination of 6 Fusarium mycotoxins (deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, T-2 toxin, karenon-x, and zearalenone). Cereal samples were first extracted with ethyl acetate, then with a mixture of methanol-water. The crude extracts were combined and purified by silica gel chromatography. The purified extract was reacted with BSTFA (N,O-bis(trimethylsilyl)-trifluoroacetamide) to form the derivative, and chromatographed on an SE-52 wallcoated open tubular column. Kováts’ retention index was determined for the 6 mycotoxins investigated. Recoveries and standard deviations were determined forpure toxin mixed in cereal. Recovery was 70-80%; relative standard deviation was 10-18%. The method developed was applied to different cereal samples.
High Pressure Liquid Chromatographic Determination of Xanthomegnin in Grains and Animal Feeds
Authors: Carman Allen S , Kuan Shia S , Francis Octave J , Ware George M , Gaul Jean A , Thorpe Charles W
Published: February 2020

A high pressure liquid chromatographic (HPLC) method is described for the determination of xanthomegnin in grains and mixed animal feeds at levels ranging from 150 to 1200 ng/g. This is equivalent to actual amounts of xanthomegnin injected on the HPLC system at from 15 to 120 ng/injection. Xanthomegnin is extracted with chloroform and 0.1M phosphoric acid. An aliquot of the crude extract is purified by column chromatography using a commercially available silica gel cartridge. Xanthomegnin is then separated from the remaining interferences by HPLC with a reverse phase C-8 column, and subsequently determined by absorbance detection at 405 nm. Elapsed time for the method from initial extraction to final HPLC determination is approximately 1 h. Recoveries of xanthomegnin added to grains and animal feeds at levels from 150 to 1200 ng/g averaged 82% with a coefficient of variation of 10.2%.
Determination of Copper, Nickel, and Chromium in Foods
Authors: Holak Walter
Published: February 2020

A collaboratively studied method for Pb, Cd, As, Se, and Zn that uses a closed system digestion technique has now been extended to include 3 additional elements, Cu, Ni, and Cr. Cu is determined by either atomic absorption spectrophotometry or anodic stripping voltammetry, depending on the concentration. Ni and Cr are determined by differential pulse polarography. Analysis of National Bureau of Standards reference materials by this procedure gives values in close agreement with the accepted values. Recoveries from applesauce and chicken spiked at 0.6-4 μg/g are in the 92-101% range. The sensitivity of the multielement procedure is 0.34,0.14, and 0.24 μg/g for Cu, Ni, Cr, respectively, at the 90% confidence level.
High Pressure Liquid Chromatographic Determination of Tartrazine in Rice Milk Following Ion-Pair Extraction with Tri-N-Octylamine
Authors: Puttemans Marc L , Dryon Louis , Massart Desiré L
Published: February 2020

Tartrazine is separated from the dried and powdered rice milk matrix by elution with methanol-ammonia mixtures, the extract is purified by ion-pair extraction with tri-n-octylamine and back-extraction with sodium perchlorate, and the dye is determined by high pressure liquid chromatography.