bluuebunny/crossref_metadata_2025 huggingface dataset:
Colorimetric Determination of Caffeic Acid in Plant Materials
Authors: Bajaj Krishan L , Arora Yogesh K
Published: February 2020

A new colorimetric method is described for determining caffeic acid content in plant materials. Caffeic acid is separated by thin layer chromatography from the alcoholic extract, and color is developed using 0.5% aqueous thiosemicarbazide solution under alkaline conditions. The absorbance is read at 475 nm. Lambert-Beer's law is obeyed in the concentration range 0.37-17.5 μg caffeic acid/mL. The method is reproducible and has been applied to the estimation of caffeic acid in carrot roots.
Random Selection of Grid Squares for Scanning by Transmission Electron Microscopy
Authors: Chen Edwin H , Hallenbeck William H , Hesse Carolyn S
Published: February 2020

A practical method is presented for the random selection of grid squares to be scanned by transmission electron microscopy. The only prerequisite for applying the technique is that the electron microscope must have 2-dimensional stage controls which are calibrated in arbitrary units.
Single Step Extraction and Cleanup for Determination of Diuron in Soil
Authors: Kulshrestha Gita
Published: February 2020

A simplified method has been developed for the extraction and cleanup of diuron[3-(3,4-dichlorophenyl)- l,l-dimethyl urea, or Karmex] residues from soil. Soil mixed with Florisil and anhydrous sodium sulfate is eluted with acetone and determined spectrophotometrically. No further cleanup is necessary. Recoveries of diuron from alluvial, black, red, and calcareous soils were >90%.
Identification of Nosiheptide in Feeds and Detection of Residues in Animal Tissues
Authors: Pascal Claude , Gaillard Claude , Moreau Marie-O
Published: February 2020

Nosiheptide is determined in fermentation broths of Streptomyces actuosus either by a microbiological method using Staphylococcus aureus or, more easily, by an automated colorimetric method. The results obtained with both methods correspond well for concentrations greater than 100 μg/mL with a standard deviation of 1-3%. For determination of nosiheptide as a feed additive, the microbiological assay is made more specific by pretreatment with petroleum ether and IN HCL Standard deviation is <4%, and the assay is sensitive to 1 ppm. Nosiheptide is identified in feed containing other frequently used antibiotics by thin layer chromatography with bioautography; sensitivity is 1 ppm. The absence of traces of nosiheptide in tissues of treated swine and broiler is confirmed by microbiological diffusion, sensitive to 0.025 ppm.
Bacillus stearothermophilus Disk Assay for Detection of Residual Penicillins in Milk: Collaborative Study
Authors: Ouderkirk Larry A
Published: February 2020

A collaborative study was performed on a Bacillus stearothermophilus paper disk method designed to detect residual levels of 4 antibiotic drugs in whole market milk. This method is a modification of an earlier procedure developed for the International Dairy Federation. Whole milk samples spiked at low levels with ampicillin, cephapirin, cloxacillin, and penicillin G were sent frozen to 11 collaborating laboratories with instructions to assay them promptly according to the method provided. Five of the laboratories reported inconclusive results due to technical difficulties encountered with the method. The 6 remaining laboratories all detected levels of 0.005- 0.008 μg or unit/mL for penicillin G, ampicillin, and cephapirin and 0.05-0.08 μg/mL for cloxacillin. The most commonly used official methods, the Sarcina lutea (Micrococcus luteus) cylinder plate method and the Bacillus subtilis paper disk method, can detect levels of 0.01 and 0.05 unit penicillin G/mL, respectively. The B. stearothermophilus method is rapid, simple to perform, and more sensitive than present official methods. The method has been adopted as official first action for the detection of penicillins in milk.
Performance Specifications for Infrared Milk Analysis
Authors: Biggs Delmar A
Published: February 2020

Maximum limits of 0.02% are recommended for precision of IR analysis for fat, protein, and lactose, and 0.04% for total solids. Recommended maximum systematic errors are 0.06% for fat, protein, and lactose, and 0.12% for total solids, when instrument results are compared with results of specified AOAC methods. Recommended maximum mean differences between instrument and standard results are based on 95% confidence limits for the mean of 8 samples; precision and systematic errors are calculated as the standard deviation of difference between duplicates for 8 samples, and systematic errors are calculated as the standard deviation of difference between instrument and reference results for 8 samples. Automated sections for milk of Official Methods of Analysis were rewritten to eliminate references to individual instruments, to eliminate possible differences between calibration procedures for different instruments, and to stress important instrument operational characteristics which can have significant effects on instrument performance.
Gas-Liquid Chromatographic Determination of Bromoxynil Octanoate: Collaborative Study
Authors: Helfant Laurence J ,   Collaborators:, Audino J , Grimes G S , Karr J J , Muth G , King W , Norris J , Schapira J , Linde D C Vande , Winstead G
Published: February 2020

The assay of bromoxynil octanoate by a gasliquid chromatographic (GLC) procedure with din-n-butylphthalate as the internal standard was previously subjected to collaboration. The method had a standard deviation of 0.6% but results varied according to the complexity of the formulaation being tested. To reduce the systematic errors of the method, the internal standard was changed to n-docosane. The change in elution time of the marker simplified the chromatogram and reduced the standard deviation of the study to 0.3%. The revised method has been adopted as official first action for determining bromoxynil octanoate.
Analytical Characteristics of Late-Eluting Halogenated Flame Retardants
Authors: Miller Lee J , Puma Bartholomew J
Published: February 2020

The analytical characteristics of halogenated flame retardants were studied. Suitable electron capture gas-liquid chromatographic conditions were developed, and retention times and sensitivity responses were obtained. The behavior of these industrial chemicals through the AOAC multiresidue method for nonfatty foods was studied using fish as the test substrate. Of the 24 flame retardants investigated, 23 were recovered (85-110%) using the AOAC method.
Separation of Normal Paraffins and Evaluation of Petroleum Contamination in Foods
Authors: Saito Yukio , Takeda Mitsuharu , Uchiyama Mitsuru
Published: February 2020

A method for separating n-paraffins from petroleum hydrocarbons in foods was developed. The method consists of 5 initial steps: digestion of sample with alkali, silica gel column chromatography, molecular sieve adsorption, destruction of the sieve with HC1, and oxidation with KMnO4. Recoveries of n-paraffins added to 55 g oyster at a level of 0.36 ppm ranged from 80% for normal pentadecane to 100% for n-paraffins over 18 carbon atoms. This method also facilitated the analysis of iso-paraffins such as pristane (2,6,10,14-tetramethylpentadecane) and phytane (2,6,10,14-tetramethylhexadecane), and other hydrocarbons, which are thought to be good marker compounds for the estimation of petroleum pollution.
Automated High Pressure Liquid Chromatographic Determination of Uncombined Intermediates in FD&C Red No. 40 and FD&C Yellow No. 6
Authors: Singh Manjeet , Adams Gloria
Published: February 2020

An automated high pressure liquid chromatographic (HPLC) method is presented for the isolation and determination of uncombined intermediates in FD&C Red No. 40 (Allura Red AC) and FD&C Yellow No. 6 (CI No. 15985). Samples of FD&C Red No. 40 containing 0.1-0.4% cresidine sulfonic acid (4-amino-5-methoxy-2-methyl benzene sulfonic acid), 0.1-0.3% Schaeffer's salt (6-hydroxy-2-naphthalene sulfonic acid), 0.02- 0.08% 4,4'- (diazoamino) -bis (5-methoxy-2-methyl benzene sulfonic acid), and 0.1-1.0% 6,6'-oxybis (2-naphthalene sulfonic acid) were prepared and analyzed by this method. Recoveries ranged between 95 and 101%. Sixty samples of FD&C Red No. 40 were analyzed by the automated HPLC method. Results showed good agreement with those of the manual HPLC method. Samples of FD&C Yellow No. 6 containing 0.1-0.4% sulfanilic acid (4-aminobenzene sulfanilic acid), 0.1-0.3% Schaeffer's salt, 0.02-0.08% 4,4'-(diazoamino)-dibenzene sulfonic acid, and 0.2-1.0% 6,6'-oxybis (2-naphthalene sulfonic acid) were prepared and analyzed by this method. Recoveries ranged between 96 and 101%. Forty samples of FD&C Yellow No. 6 were analyzed by the automated HPLC method. Results showed good agreement with those of the manual HPLC method.
High Performance Liquid Chromatographic Determination of Sulfanilic Add, Schaeffer’s Salt, 4,4´-(Diazoamino)-DibenzenensuIfonic Acid, and 6,6´-Oxybis(2-Naphthalenesulfonic Acid) in FD&C Yellow No. 6: Collaborative Study
Authors: Cox Elizabeth A ,   Collaborators:, Beswick R , Bille L , Gasper G , Gunn M , Johnson W , King J , Penta F , Richfield-Fratz N
Published: February 2020

Eight laboratories participated in a collaborative study of a high performance liquid chromatographic procedure for determining sulfanilic acid, Schaeffer's salt, 4,4´-(diazoamino)-dibenzenesulfonic acid (DAADBSA), and 6,6´-oxybis(2-naphthalenesulfonic acid) (DONS) in FD&C Yellow No. 6. The standard deviations for one analysis in any one laboratory for sulfanilic acid at 0.2%, Schaeffer's salt at 0.26%, DAADBSA at 0.1%, and DONS at 1.0% were 0.015%, 0.014%, 0.018%, and 0.077%, respectively. The method has been adopted as official first action.
Fish Species Identification By Thin Layer Polyacrylamide Gel Isoelectric Focusing: Collaborative Study
Authors: Lundstrom Ronald C ,   Collaborators:, Barmore C R , Krzynowek J , LaTerza A F , Little B W , O'Leary G P , Robohm R A , Wiggin K
Published: February 2020

A method for fish species identification by isoelectric focusing of sarcoplasmic proteins on LKB Ampholine PAGplates, pH 3.5–9.5, was collaboratively studied to determine whether photographs of protein patterns from authentic species could be used to identify unknown samples. Seven collaborators were sent 8 unknown samples in duplicate to identify from an 8 × 10 in. photograph of an Ampholine PAGplate showing standard protein patterns from 14 species of fish. The 7 collaborators identified the unknown samples with 93% accuracy. Eight of 14 monkfish samples were not identified correctly and showed protein patterns different from the protein patterns shown in the photographic standard. All of the incorrectly identified samples showed the same protein pattern. The other 7 unknown species were all correctly identified. The method has been adopted as official first action.
Hydroxymethylfurfural and Honey Adulteration
Authors: White Jonathan W , Siciliano James
Published: February 2020

The value of the determination of hydroxymethylfurfural (HMF) in the detection of invert sirup adulteration of honey is examined. Analysis of 481 samples of extracted honey and 41 comb honeys from producers, and samples of honey before and after processing from 8 packers provided basic data for establishing guidelines for HMF content of honey. A sample containing 20 mg/100 g or more should be considered as possibly adulterated and subjected to additional analysis for confirmation of the presence or absence of adulteration. Extremely high (about 50 mg/100 g) values are conclusive, however.
High Pressure Liquid Chromatographic Separation and Identification of Estrogens
Authors: Roos Robert W
Published: February 2020

The use of high pressure liquid chromatography for separating mixtures of various estrogens is described. Separations of as many as 9 estrogens were studied using normal and reverse phase partition systems; the reverse phase system was the most useful. The estrogens were detected at 254 nm, a wavelength that favors their detection at low concentrations. The results of the separation studies were applied successfully to the separation and identification of estrogens in aqueous suspensions of estrogenic substances and to conjugated estrogens in tablets, following hydrolysis of the conjugates. Most estrogen peaks were identified using chromatographic mobilities; in some cases chemical reaction with the estrogen was used to form derivatives to aid identification. In one instance, the ultraviolet-absorbing properties of the estrogen were compared with literature data in order to assign an identity.
Food Safety in Canada—Past, Present, and Future
Authors: Mckinley W Perce
Published: February 2020

I consider analytical chemists the salt of the earth. Not only are they almost always uncommonly gifted—apart from those few who have had trouble confirming my results—they play a paramount role in enabling society to ensure the safety of its food, drugs, air, and water. Without analytical methods, we would still be in the hands of those barbarians the toxicologists (I will pay for this remark), who could carry out analyses in biological terms such as writhings per 100 food tasters but could not tell whether it was the contamination or the cooking.
Improved Method for Thin Layer Chromatographic Analysis of Mycotoxins
Authors: Gimeno Alberto
Published: February 2020

The author’s previously published multimycotoxin method is improved by a series of changes in the development of the citrinin. Importance of the type of UV lamp and the use of a yellow filter are also emphasized.
Extraction of Light Filth from Barley, Oatmeal, and Mixed Dry Infant Cereals: Collaborative Study
Authors: Dent Russell G ,   Collaborators:, Floyd D M , Nagy J , Olsen A R , Quaife J T , Sandarg D E , Senff W A
Published: February 2020

A new method has been developed for the extraction of light filth from oatmeal, barley, and mixed dry infant cereals which involves HC1 digestion followed by wet sieving. The residue is defatted in a paper cup, using isopropanol, and transferred to a 2 L Wildman trap flask with 40% isopropanol. Filth elements are extracted with light mineral oil. Interlaboratory studies resulted in 92 and 86% average recoveries of rodent hairs and insect fragments, respectively. The proposed method has been adopted as official first action.
Pulsed Positive Ion-Negative Ion Chemical Ionization Mass Spectrometry of Animal Drugs: Sulfonamides
Authors: Roach John A G , Sphon James A , Hunt Donald F , Crow Frank W
Published: February 2020

The analysis of sulfa drugs, using pulsed positive ion-negative ion chemical ionization (PPINICI) mass spectrometry (MS), generates both positive and negative spectra in a single experiment. The spectra afforded by PPINICI-MS permit systematic interpretation and prediction of fragmentation for this class of compounds. Comparison of the electron impact and PPINICI spectra of 17 sulfa drugs and selected derivatives demonstrates that the useful information available with this new technique exceeds that afforded by electron impact analysis.
Modification of the Method for Vitamin A in Foods and Feeds for Use with Margarine and Butter: Collaborative Study
Authors: Parrish Donald B ,   Collaborators:, Abel M , Ameiko L , Asarch L , Baillies T , Bueno M , DeRitter E , Ellefson W , Guthrie J , Hamill T , Herod L , Hlavinka L , Hsu J , Kuervers T M , Kuhr P , Landen W O , Moffitt R A , Noel R , Rigby C , Roberts R , Sanchez A S , Sykora C , Thorpe V , Waltking A E , Woodruff M
Published: February 2020

An adaptation of the method for vitamin A in feeds and foods to margarine and butter was studied in 1977 and 1978. The principal change was the use of 2 extractions with an ether-hexane mixture instead of one with hexane. Results of the 1977 test were not good enough to recommend adoption. The 1978 analytical samples consisted of 4 margarines, including a known, and a butter. Data were reported by 11 analysts. Averages for vitamin A (μg/g) and coefficients of variation (%) were, respectively: A (known)—7.2, 5.7; 1—8.2, 11.1; 2—11.4, 3.9; 3—7.6, 10.7; butter—8.5, 13.3; and for carotene: A—5.6, 6.4; 1—6.0, 5.5; 2—0; 3—5.8, 3.8; butter—3.1, 11.8. Carotene results were grouped reasonably closely and tended to be distributed randomly, but vitamin A results had a less random trend. Trifluoroacetic acid was studied as an alternative colorimetric reagent for determining vitamin A, with overall satisfactory results. The modification for determining vitamin A and carotene in butter and margarine, and the use of trifluoroacetic acid as an alternative colorimetric reagent have been adopted as official first action.
Determination of Geotrichum Mold in Citrus Juices: Collaborative Study
Authors: Cichowicz Stanley M , Bandler Ruth ,   Collaborators:, Blacketer S , Kaminski J , Woodward B
Published: February 2020

The sieve mesh sizes (Nos. 8, 16, and 230) specified in the official method for the Geotrichum mold count of fruits and vegetables, 44.079, are inadequate for citrus juices. Citrus tissue passes through the larger mesh screens and clogs the fine mesh No. 230 sieve. The fine citrus tissue prevents the separation of the mold from the product and the liquid. The proposed method changes the sieve series to Nos. 40, 140, and 230 mesh. A compromise is reached which permits the concentration of mold along with the citrus tissue and the elimination of the excess liquid. The method has been adopted official first action.
Analysis of Foods for Lead, Cadmium, Copper, Zinc, Arsenic, and Selenium, Using Closed System Sample Digestion: Collaborative Study
Authors: Holak Walter ,   Collaborators:, Birri J , Colonel G J , Hebert R O , Izzi J , Lim F , McNerney F G , Orczech G , Sulek A , Tepedino N , Walter C C , Woodson A
Published: February 2020

A method for the determination of cadmium, lead, copper, arsenic, selenium, and zinc is presented. This method involves digesting a food sample with nitric acid under pressure and using aliquots of the solution for analysis by suitable techniques. Cadmium, lead, and copper are determined by anodic stripping voltammetry (ASV) after heating with equimolar sodium nitrate/potassium nitrate; arsenic and selenium are determined by atomic absorption spectrophotometry (AAS) after generation of their respective hydrides; zinc is determined by conventional AAS. The combined recoveries and reproducibilities (CVR) of the collaborative study on this multielement analysis are: Cd, 89.14 (17.65) at 0.10–1.0 μg/g; Zn, 96.53 (5.59) at 16.7 and 66.7 μg/g; As, 99.50 (17.02) at 0.5 and 2.0 μg/g; Se, 95.17 (16.52) at 0.5 and 2.0 μg/g; Pb, 92.57 (15.22) at 0.3–3.0 μg/g; Cu, 108.39 (18.30) at 1.0–10.0 μg/g. The method has been adopted as official first action for cadmium, lead, arsenic, selenium, and zinc.
Colorimetry and High Performance Liquid Chromatography of Atrazine Residues in Soil: Comparison of Methods
Authors: Vickrey Thomas M , Karlesky Dori L , Blackmer Gary L
Published: February 2020

The colorimetric method for determining residual atrazine levels in soil is compared with reverse phase high performance liquid chromatography (HPLC). The soil samples are extracted with water-acetonitrile (10 + 90) and the filtrate is partitioned with methylene chloride. For the colorimetric analysis the organic phase is filtered through activity V alumina, collected, and evaporated to dryness. The residue is dissolved first in ethyl ether, and then in water as the ether is removed. The atrazine solution is buffered (citric acid, pH 7.0) and heated with added pyridine. When the reaction is complete, the product is complexed with ethylcyanoacetate, and the solution absorbance is measured at 550 nm. The complex obeys Beer’s law and has a sensitivity of 230 ng for a 1% full scale deflection at 1 AUFS. For the HPLC method, the methylene chloride extract is dried, the chromatographic solvent is quantitatively added (either chloroform or methanol), and the solution is analyzed with a UV detector at 254 nm. Minimum amount detectable for a 1% full scale deflection is 5 ng at 0.01 AUFS. Soil background interferences were investigated for both methods, and buffering the pyridine-triazine reaction solution was the most efficient method for removing the background for colorimetry. The recovery efficiencies for the colorimetric and HPLC methods were 45.5 ± 3.8% and 94.4 ± 3.4%, respectively.
Improvements to Assisted Distillation Cleanup of Pesticide Residues in Animal Fats
Authors: Heath Andrew B , Black Robert R
Published: February 2020

The assisted distillation technique, which was developed for the cleanup of pesticide residues from animal fats, has been improved. Nitric acid cleaning of distillation tubes resulted in a significant improvement in the recoveries of hexachlorobenzene (HCB) and lindane (from 76 to 92% and 84 to 89%, respectively). A larger U-tube condenser was developed that condensed 100% of all pesticides studied. With this new condenser, a study of distillation tube flow rates showed that pesticide recoveries at 600 ml nitrogen/min were generally better than those obtained at any other flow rate although recoveries were satisfactory at 400 and 800 mt/min. Recoveries of pesticides at distillation temperatures of 210–240°C were obtained with tubes cleaned with nitric acid, and using the larger U-tube condenser. The distillation temperature of choice was again 230°C because there was little variation from 220 to 240°C.
Economic Method for Analysis of Fluid Milk for Organochlorine Residues at the 10 ppb Level
Authors: Veierov Dan , Aharonson Nadav
Published: February 2020

A procedure is described to isolate and clean up organochlorines in fluid milk for gas chromatographic (GC-ECD) analysis. Extraction and cleanup are performed in the same glassware, an ordinary separatory funnel. The only chemicals needed are H2SO4 and petroleum ether. Size of milk samples is versatile provided proportions of the chemicals are adjusted accordingly. Recoveries greater than 80% are obtained for 18 common organochlorines added to the milk which correspond well with recoveries with official methods for determining incurred residues. The proposed procedure shows a low lipid carryover (about 1%), and extraneous interferences are minimal. Its inherent simplicity makes the method suitable for standardization, and the small number of operations permit semi- or full automation.
Vacuum Desiccation Methods for Determination of Free Water in Fertilizers: Interlaboratory Comparison
Authors: Duncan Russell D ,   Collaborators:, McBride C H , Hube E J , Kane P , Kemp S T , Rund R C , Sheffield L J
Published: February 2020

A vacuum desiccation method for determining free water in fertilizer, proposed by the International Organization for Standardization (ISO), was compared to the official AOAC vacuum desiccation method (2.013). The combined results of 4 U.S. laboratories showed, on the basis of 5 samples, that precision was better by the ISO method, but results were lower for 4 of the 5 samples. The AOAC method gave a slightly lower result for one sample.
Potentiometric Titration Methods for the Determination of Sodium Chloride in Certifiable Water-Soluble Colors: Collaborative Study
Authors: Brammell Wallace S ,   Collaborators:, Clark F R , Downey R H , Goldberg A , Gorman T , Hensley D , Kiernan H , King J H , Marcus S A , Mogg R , Moore M M , Sulek A M , Tait G , Trcka R , Westwell A
Published: February 2020

In a collaborative study, 7 laboratories successfully analyzed 8 different samples, in duplicate, by a manual potentiometric titration method. These same samples were used by 7 different laboratories in a concurrent collaborative study of the automated potentiometric titration method. The samples are dissolved in water and acidified, and soluble chloride is determined by titration with silver nitrate to the potentiometric end point. The methods are applicable to all water-soluble certifiable colors except D&C Red No. 19, at levels >0.03% sodium chloride, although there is a positive error at very low levels for the automated titration. In halogenated fluoresceins, any iodide or bromide is determined as sodium chloride, but the maximum amount normally present is equivalent to <0.2% sodium chloride. The sodium chloride content of the collaborative samples ranged from 0.04 to 18.2% for the manual method, and from 0.11 to 18.1% for the automated method. In general, except at very low sodium chloride levels, the precision of the automated method was good, although not as high as that for the manual method; single determination coefficients of variation ranged from 1.5 to 13.5% for the former, and from 1.2 to 2.7% for the latter. Recovery of 0.45% added sodium chloride ranged from 62 to 96%, and for 4.5% added sodium chloride it varied from 94 to 99% by the automated method. Recoveries ranged from 96 to 104% for 0,45% added sodium chloride and from 98 to 102% for 4.5% added sodium chloride by the manual method. The coefficient of correlation of the sample means for the manual and the automated methods was 0.9999%. The methods have been adopted as official first action.
Determination of Total Fat in Meat and Meat Products by a Rapid, Dry Column Method
Authors: Maxwell Robert J , Marmer William N , Zubillaga Marta P , Dalickas Gail A
Published: February 2020

A rapid, dry column method is proposed for determining fat in meat and meat products. Unlike AOAC procedures 24.005 and 24.006, this procedure measures total rather than crude fat. A 5 g sample is blended with anhydrous sodium sulfate in a mortar and is then reduced to a fine powder with Celite 545. The fat is eluted on a glass column, using dichloromethane-methanol (9+1). Solvent is removed from the eluate, and the resulting residue is weighed to calculate total fat of the sample. A determination takes 2.5 hr or less. Fat levels ranged from 7 to 90% in 15 meat samples. Quadruplicate determinations by this method and duplicate determinations by 24.005 (a) yielded overall means of 29.9 and 29.3% fat, respectively. Repeatability was 0.3% fat. The 0.6% mean difference is significant (P = 0.05) and represents a more complete extraction of polar lipids by the proposed method. Results of determinations by this method are compared with results by an accepted but laborious chloroform/methanol procedure for total fat recovery. Overall means and standard deviations of replicate determinations on 4 meats containing 4–30% fat were 12.8±0.1 with this method and 12.7±0.1 with the reference method.
Aflatoxigenic Potential for Aspergilli on Sucrose Substrates
Authors: Llewellyn Gerald C , Jones Hudson C , Gates James E , Eadie Thomas
Published: February 2020

Sucrose concentrations of 3, 10, 20, and 30% in Czapek Dox broth served as the carbon source for growth, aflatoxin production, and sporulation for Aspergillus parasiticus NRRL 2999 and A flavus NRRL 3557, 5862, and 5013. All cultures produced mycelial growth and sporulated in all sucrose concentrations during the 12-day growth period. The area of mycelial mat coverage per hour increased directly with increased sugar concentrations. The 20 and 30% sucrose concentrations inhibited mycelial growth for 5862. The 30% sucrose cultures of 3557 and 5862 failed to produce detectable levels of aflatoxins. All other isolates produced B1 and G1 in an approximately 4:1 ratio in all sucrose concentrations. Only 2999 was a substantial producer of aflatoxin in all 4 sucrose cultures, ranging from 72 to 96 μg/mL medium. A. flavus 5013 produced the most toxin, 144 and 126 μg/mL medium in the 10 and 20% sucrose cultures, respectively. The 10 and 20% sucrose cultures were most conducive to aflatoxin production. Since these sucrose levels correspond closely to the levels in many food and drink products, especially home-made products, care and attention should be taken to keep them free of aflatoxigenic spores. Extensive mycelial growth and sporulation, even in aflatoxigenic strains, do not necessarily result in comparably high aflatoxin levels. Routine extraction and quantitation procedures for aflatoxin were applicable and provided satisfactory results.
Extraction, Cleanup, and Quantitative Determination of Aflatoxins in Corn
Authors: Thean James E , Lorenz David R , Wilson David M , Rodgers Kathleen , Gueldner Richard C
Published: February 2020

A method is proposed for extraction and cleanup of corn samples for the quantitation of 4 aflatoxins by high pressure liquid chromatography (HPLC). After aqueous methanol extraction, ammonium sulfate treatment, and partition of aflatoxins into chloroform, sample extracts are partially purified on Sep-Pak cartridges or small columns packed with HPLC grade silica; cleanup requires only 13 mL solvent/sample. Aflatoxins B1, B2, G1, and G2 in the purified extract are resolved in ca 10 min by normal phase HPLC on a microparticulate (5 μm) silica gel column with a 50% water-saturated chloroform-cyclohexaneacetonitrile- ethanol solvent, and are measured by ultraviolet fluorescence in a silica gel-packed flowcell. Recoveries of added aflatoxins B1, B2, G1, and G2 were 84–118 % at levels of 1.5–125 μg/kg
Stability and Molar Absorptivity of Aflatoxin M1 in Acetonitrile-Benzene (1 + 9)
Authors: Stubblefield Robert D
Published: February 2020

A solvent mixture of acetonitrile-benzene (1+9) was investigated as a means to eliminate instability of aflatoxin M1 standard solutions prepared with chloroform. Solutions (10.0 μg/mL) were prepared and sealed in glass ampules that were opened as needed for absorbance measurements on the individual solutions over a 13-month period. A coefficient of variation of 0.69& for the absorbance readings indicated that the solutions were stable. In addition, numerous powdered milk extracts containing aflatoxin M1 were dissolved in both chloroform and acetonitrile-benzene (1+9), and the solutions were spotted on TLC plates and developed. Densitometric measurement of the developed zones showed no differences due to the spotting solvent. The molar extinction coefficient was determined in acetonitrilebenzene (1+9) on 4 different M1 solutions from 2 separate crystalline aflatoxin M1 preparations; the value was 18,815 ± 24.
Sephadex LH-20 Cleanup, High Pressure Liquid Chromatographic Assay, and Fluorescence Detection of Zearalenone in Animal Feeds
Authors: Cohen Huguette , Lapointe Michel R
Published: February 2020

A high pressure liquid chromatographic (HPLC) method is described to determine zearalenone in animal feeds at levels as low as 0.01 ppm. Samples are extracted with chloroform-ethanol and initially purified using a SEP-PAK silica cartridge, followed by column chromatography using Sephadex LH-20. Separation by normal phase HPLC is followed by fluorescence detection. Recoveries at levels of 1.0–0.01 ppm averaged greater than 90%. Confirmation included HPLC analysis of the sample and a zearalenone standard, using 3 different excitation wavelengths, and comparison of fluorescence responses obtained. The method was successfully applied to the analysis of 1 corn and 3 cornmeal samples. Zearalenone was detected in all 4 samples at levels of 0.379–19.2 ppm.
Semiautomated Method for Analysis of Nitroglycerin in Sublingual Tablets: Collaborative Study
Authors: Juhl Yvonne H ,   Collaborators:, Alpert M Y , Holmes A , Perrizo C H , Roberts R W , Thornton L K
Published: February 2020

This method is a semiautomated version of the current USP XX method for content uniformity testing of nitroglycerin tablets. Nitroglycerin is hydrolyzed to nitrite in aqueous alkali. The nitrite thus formed diazotizes procaine, which then is coupled with Bratton-Marshall reagent; the absorbance of the resultant color is read at 550 nm. Six collaborators were supplied with 6 composites of sublingual tablets, representing 3 different dosage levels. Results agreed with those obtained by the author using the USP composite assay method. The coefficients of variation ranged from 0.20 to 0.70%. The method is sensitive enough for individual tablet assays (0.15 mg nitroglycerin). The method has been adopted as official first action.
Gas-Liquid Chromatographic Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Human Milk
Authors: Tessari John D , Savage Eldon P
Published: February 2020

A method for the detection of organochlorine pesticides and polychlorinated biphenyls (PCBs) in human milk is described. The method involves quantitative extraction of human milk with acetone and hexane. The pesticide and PCB residues are extracted from the milk fat with acetonitrile (ACN) and then partitioned back into hexane by aqueous dilution of the ACN extract. The ACN partitioning is followed by cleanup with Florisil column chromatography, eluting with 6 and 15% mixtures of ethyl ether-hexane. The 6% eluate is concentrated and transferred to a silicic acid column for separation of PCBs from pesticide residues. Compounds are quantitated by gas-liquid chromatography. Recovery studies demonstrated that the procedure provides 68–103% recovery for pesticides and PCBs.
Atomic Absorption Methods for Analysis of Soil Extracts and Plant Tissue Digests
Authors: Isaac Robert A
Published: February 2020

The principles of operation and basic equipment of atomic absorption spectroscopy are described. Its advantages over flame emission include higher specificity, fewer interferences, improved detection limits, lower flame temperature requirements, and simpler instrumentation. Analysis procedures which have proved successful in our laboratories are detailed. They include dry ashing and wet digestion for analysis of plant tissues, and exchangeable cations, extractable cations, and acid dissolution for soils analysis.
Detection of Adulterated Maple Products by Stable Carbon Isotope Ratio
Authors: Carro Odette , Hillaire-Marcel Claude , Gagnon Marcel
Published: February 2020

The relatively low 13C content in sugar from maple (Acer saccharum Marsh) indicates a C3 photosynthetic cycle. Cane and corn sugars are characterized by a C4 photosynthetic cycle having a higher content of 13C. Thus, it is possible to detect the addition of cane or corn sugar to maple products. Analyses carried out on hundreds of sap, syrup, and sugar samples from many locations established a calibration curve for mixtures of cane or corn sugar with maple sugars or syrups. Because of the natural range of maple sugar 13C content, an optimum detection level of 3% adulteration is possible on a maple sugar sample of unknown origin. Thus, the isotopic composition 13C/12C is proposed as a method of determining authenticity and detecting adulteration of maple products.
Automated Determination of Salts in Water-Soluble Certifiable Color Additives by Ion Chromatography
Authors: Fratz D Douglas
Published: February 2020

A previously developed ion chromatographic method for the determination of salts in watersoluble certifiable color additives was automated, using a Model 12 Dionex ion chromatograph equipped with a program controller and programmable computing integrator. Programs were written for the program controller for continuous automated analysis of up to 59 samples in about 20 h, with periodic regeneration of the suppressor column and automatic shut-down. All data were processed through the integrator, programmed to give results in weight/weight percent. Recoveries were performed on 4 anions: chloride, phosphate, bromide, and sulfate. Twenty-five color additives could be analyzed by the method. Standard deviations in the determinations ranged from 0.01 to 0.16 at addition levels of 0.20–9.45; with 6 replications. Recoveries for addition levels of 0.2–5.0; with 2 replications fell within the range of 84.0–105.0;. Approximate lower limits of detection for each anion were as follows: chloride, 0.07;; phosphate, 0.10;; bromide, 0.06;; sulfate, 0.07;.
High Performance Liquid Chromatographic Determination of Vitamin A in Margarine, Milk, Partially Skimmed Milk, and Skimmed Milk
Authors: Thompson James N , Hatina George , Maxwell William B
Published: February 2020

Saponification and subsequent evaporation of extracts can cause losses of vitamin A during analysis and thus cause erratic results. These steps were therefore avoided by measuring retinyl palmitate and β-carotene directly in hexane extracts of milk and margarine. Extracts were purified before high performance liquid chromatography(HPLC) by washing with aqueous alcohol. Retinyl palmitate was measured at 325 nm after chromatography on LiChrosorb Si60, 5 μm, using ethyl ether–hexane (2+98) as the solvent system. Milk (2 mL) was shaken with absolute ethanol (5 mL) and hexane (5 mL). Water (3 mL) was added and, after mixing and centrifugation, 100 μL hexane layer was injected. Margarine (5 g) was dissolved in hexane (100 mL). After 5 mL of the hexane solution was washed with 60% ethanol and centrifuged, a 50 μL aliquot was injected. The results of the retinyl palmitate estimation in milk agreed with those obtained by a fluorometric method; the results in margarine agreed with those obtained by saponification, extraction, and HPLC. The coefficients of variation on analysis of 10 replicate samples of milk and margarine were 3 and 4.5%, respectively. The analysis of margarine for vitamin A was completed by measuring β-carotene with a detector set at 453 nm; the coefficient of variation of this measurement was 3% (10 replicates).
Turbidimetric Microbiological Determination of Oxytetracycline Hydrochloride in Finished Feeds and a Feed Premix: Collaborative Study
Authors: Mueller-Brennecke Dorothy L , Reed Shirley J , Waisner Debra L ,   Collaborators:, Ahrens S , Barbiers A R , Black L , Bryant H H , Carter G G , Hasselberger M L , Inglis J M , Koester J , Kunold L , Mayernik J J , Plude R J , Ragheb H S , Rippere R A , Scheiner J M , Schock D , Scroggs R E , Winely C L , Wood R T
Published: February 2020

New automated and manual turbidimetric microbiological assay methods for oxytetracycline (OTC) in finished feeds and a feed premix were submitted to 17 collaborating laboratories for comparison with the official AOAC method. Six finished feeds of 50 and 100 g/ton levels and one premix containing 20 g OTC/lb were sent to the collaborators. Results were received from 12 laboratories. Six laboratories provided results derived from the Autoturb System and 7 laboratories performed the turbidimetric analyses manually. All 12 laboratories assayed the samples by the AOAC cylinder-plate method. Ranges of recoveries expressed as percent were 89.5–102.0, 91.2–97.0, and 91.4–96.0 for the AOAC, Autoturb turbidimetric, and manual turbidimetric methods, respectively. Average recoveries were 96.3, 93.4, and 93.6%, respectively. The mean relative standard deviation values were 5.7, 6.3, and 7.2, respectively. There was little significant difference between the turbidimetric methods and the AOAC method; however, the turbidimetric methods were faster.
DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules
Authors: Squella Juan A , Nunez-Vergara Luis J , Aros Maximo
Published: February 2020

Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at –0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively
Determination of Residues of Fensulfothion and Its Metabolites in Chinese Cabbage, Japanese Radish, and Turnips
Authors: George Donald A
Published: February 2020

A method was developed using a selective nitrogen-phosphorus detector to determine the combined total residues, as the oxygen analogs, of fensulfothion (O,O-diethyl O-[p-(methylsulfinyl)-phenyl] phosphorothioate) and its 3 metabolites. The procedure was used to determine harvest residues in Chinese cabbage, Japanese radish, and turnips treated with 2 application rates of fensulfothion. Residues found after application of 2 oz active ingredient (AI)/100 lineal ft of row ranged from 0.026 ppm for Japanese radish to 1.543 ppm for turnip greens. When the application rate was doubled, the amount of residue found was approximately doubled.
Gas-Liquid Chromatographic Determination of Tertiary-Butylhydroquinone (TBHQ) in Dried Fish, Frozen Shrimp, Vegetable Oils, Butter, and Margarine
Authors: Toyoda Masatake , Ogawa Shunjiro , Tonogai Yasuhide , Ito Yoshio , Iwaida Masahiro
Published: February 2020

Tertiary-butylhydroquinone (TBHQ) is extracted from foods with ethyl acetate, the solvent is evaporated, the residue is dissolved in n-hexane–ethyl acetate (99+1), and the TBHQ is selectively transferred into an aqueous layer (2% sodium chloride) as a separation from food interferences. Finally, TBHQ is reextracted with n-hexane–ethyl acetate (1+1), concentrated, and determined by flame ionization gas-liquid chromatography. Dried fish, frozen shrimp, vegetable oils, and edible fats were analyzed by the method. More than 85% was recovered when the samples were fortified with 100 ppm TBHQ. Detection limit was 1.0 ppm TBHQ.
Enzyme Immunoassay for Staphylococcal Enterotoxin A
Authors: Kauffman Peter E
Published: February 2020

An enzyme immunoassay procedure specifying alkaline phosphatase-labeled enterotoxin A was used to determine enterotoxin in standardized solutions and food extracts. Staphylococcus aureus Cowan 1 cells were used to separate unbound from antibody-bound enterotoxin. The method is sensitive to 2 ng enterotoxin A/mL; cross reactions with other staphylococcal enterotoxins did not interfere with the specificity. The method is sensitive and precise enough to serve as a reliable alternative to radioimmunoassay for enterotoxin A.
Radiocarbon (14C) Method for Authenticating Natural Cinnamic Aldehyde
Authors: Hoffman Patrick G , Salb Mary Conjour
Published: February 2020

A method has been developed using quantitation of 14C by liquid scintillation to differentiate natural from synthetic cinnamic aldehyde. The method uses the isolation of cinnamic aldehyde from cinnamon and the determination of the percent modern carbon (14C), to detect the presence of petroleum-derived cinnamic aldehyde.
Comparison of Methods for Determining Penicillamine in Bulk Drug and Formulations
Authors: Vollmer Paul J , Lee Jenny , Jaffe Thomas G
Published: February 2020

The mercuric acetate method (Method I) cited in the Code of Federal Regulations (CFR) as the official method for determining the penicillamine content of a drug was compared with a nonaqueous amine titration (Method II), a nonaqueous acid titration (Method III), and a hydroxylamine assay (Method IV). Quantitative determinations were made for 3 types of penicillamine samples: commercial lots of bulk drug, capsules, and test solutions containing known amounts of penicillamine and EDTA. Method III proved unsatisfactory in the bulk drug determinations. Method II, although slightly less precise than Method I, gave generally satisfactory results for the bulk drug and capsule samples. Method IV was the only method to give satisfactory results in the presence of EDTA.
Mass Spectral Identification and Gas-Liquid Chromatographic Determination of Methyl 4-Chloroindolyl-3-Acetate in Canned and Frozen Peas
Authors: Heikes David L
Published: February 2020

Methyl 4-chloroindolyl-3-acetate (MCIA), a naturally occurring auxin, has been identified in canned and frozen peas by gas-liquid chromatography (GLC)/mass spectrometry. Eight samples were analyzed for MCIA using slightly modified official AOAC multiple pesticide residue procedures employing GLC with microcoulometric detection. Levels of MCIA averaged 0.20 ppm for canned peas and 0.16 ppm for frozen peas. Recovery of MCIA from a fortified sample was 40%.
High Pressure Liquid Chromatographic Determination of Satratoxins G and H in Cereal Grains
Authors: Stack Michael E , Eppley Robert M
Published: February 2020

A high pressure liquid chromatographic (HPLC) method is described for the detection and quantitative determination of satratoxins G and H in cereal grains. The toxins are extracted from the sample by blending with methanol-water (55+45) in the presence of hexane, followed by partitioning into chloroform. The chloroform extract is further purified on a 10 g silica gel column. A high pressure liquid chromatograph, equipped with a microparticle silica gel column and a 254 nm absorbance detector, is used for the determination. Additional confirmation of identity is obtained by mass spectrometry or by a brine shrimp bioassay of the HPLC eluates corresponding to the retention times of satratoxins G and H. The recoveries of added satratoxins G and H from wheat samples averaged 65% for G and 71% for H (200–1000 mg/kg). The coefficients of variation (CV) were 15% for G and 14% for H. The lower limit of detection was 200 μg/kg for wheat. Analysis of corn, oats, and barley samples (400 μg/kg of each toxin added) gave comparable recoveries. Only the corn extract exhibited HPLC interferences at the retention time for satratoxin H. The method was also used to analyze samples of corn, oats, wheat, barley, and rice on which Stachybotrys atra had been cultured.
Comparison of Gas and Liquid Chromatography for Determination of Anilazine in Potatoes and Tomatoes
Authors: Lawrence James F , Panopio Luz G
Published: February 2020

Anilazine (2,4-dichloro-6-(2-chloroanilino)-1,3,5-triazine), a triazine fungicide, is extracted from potatoes or tomatoes with acetonitrile. An aliquot of the filtered extract is partitioned between methylene chloride and water. The organic phase is concentrated and passed through a 3% deactivated Florisil column for cleanup. The eluted anilazine is then concentrated and determined by liquid chromatography (LC) on LiChrosorb RP-8 column with a mobile phase of acetonitrile–water (55+45) and detection at 275 nm, the absorption maximum of anilazine. Twenty-five nanograms produces a 5 cm peak under the conditions used. Detection limit is about 0.02 ppm in both vegetables. A comparison is made with gas chromatography, using either an electron capture (EC) or nitrogen–phosphorus alkali-flame ionieation (NP) detector. Separations are carried out on a 4% SE-30 + 6% SP-2401 column at 195°C at 40 mL/min. Detection limits for all systems studied are about 0.02–0.05 ppm in the samples studied. Recoveries over a concentration range of 0.2–10.0 ppm are greater than 80% with the extraction procedure employed and LC determination.
Comparison of Three Methods for Determining Aflatoxins in Sunflower Seed Meals
Authors: Trucksess Mary W , Stoloff Leonard
Published: February 2020

Methods developed for the determination of aflatoxins in peanut products, in cottonseed products, and in ginger were compared for their applicability to sunflower seed meal. The peanut products method was inapplicable. Separation from interferences adequate to obtain a limit of determination for aflatoxin B, around 1 ng/g and recovery of total added aflatoxins of about 97% could be achieved with either the cottonseed or ginger methods. The cleanest extract and the most rapid operation were obtained with the ginger method.
Evaluation of High Pressure Liquid Chromatography and Gas-Liquid Chromatography for Quantitative Determination of Sugars in Foods
Authors: Iverson John L , Bueno Martin P
Published: February 2020

A method has been developed for separation and determination of 5 sugars in foods. Mixtures of sugars were separated by high pressure liquid chromatography (HPLC) with a μBondapak/carbohydrate column and acetonitrile-water (80 + 20) as the mobile phase. For the gas-liquid chromatographic (GLC) determination, the sugars were reacted with hydroxylamine hydrochloride to give the oximes, which were then converted to trimethylsilyl derivatives. The derivatives were separated on an 8 ft column containing 3% JXR as the liquid phase. The GLC preparative time was considerably longer than that for HPLC. Both methods were applied to the determination of fructose, glucose, sucrose, maltose, and lactose in processed foods. Recovery studies showed better accuracy for the HPLC method. Because of incomplete derivatization and/or the formation of anomers, the GLC method was not applicable to all foods.