bluuebunny/crossref_metadata_2025 huggingface dataset:
Pesticides, Selected Elements, and Other Chemicals in Infant and Toddler Total Diet Samples, October 1979-September 1980
Authors: Gartrell Marcia J , Craun John C , Podrebarac David S , Gunderson Ellis L
Published: February 2020

The U.S. Food and Drug Administration (FDA) conducts Total Diet Studies to determine the dietary intake of selected pesticides, industrial chemicals, and elements (including radionuclides). These studies involve the retail purchase and analysis of foods representative of the diets of infants, toddlers, and adults. The individual food items are separated into a number of food groups, each of which is analyzed as a composite. This report summarizes the results for infant and toddler Total Diet samples collected in 10 cities between October 1979 and September 1980. The average concentration, range of concentrations, and calculated average daily intake of each chemical found are presented by food group. The average daily intakes of the chemicals are similar to those found in the several preceding years and generally are within acceptable limits. The results for samples collected during the same period that represent the adult diet are reported separately.
Amperometric Determination of Phenazopyridine Hydrochloride in a Flowing Stream at the Glassy Carbon Electrode
Authors: Belal Fathalla
Published: February 2020

A flow-injection method is described for the determination of phenazopyridine hydrochloride, based on electrochemical oxidation at the glassy carbon electrode. The suggested method is highly specific and can be used to determine phenazopyridine HC1 in the presence of most drugs commonly found in pharmaceutical dosage forms or administered therapeutically. Applying a constant potential of +950 mV vs Ag/AgCl/3.5M KCI reference electrode, the calibration curve was linear in the 1-30 μg/mL range, with minimum detectability of 0.2 ng (signal-to-noise ratio 2). Good accuracy and precision were obtained when the method was applied to some dosage forms containing phenazopyridine HC1. Although automation was not used in this study, an automated system could be incorporated because the method uses the technique of continuous analysis in a flowing stream.
Electron Capture Gas Chromatographic Determination of Thiabendazole in Yams
Authors: Bardalaye Promode C , Wheeler Willis B
Published: February 2020

A method for the determination of thiabendazole in yams is reported. The method consists of extracting the chopped crops with ethyl acetate followed by distilled water wash and liquid liquid extraction of the chemicals into dilute hydrochloric acid. The sample is further cleaned up by making the aqueous acidic fraction alkaline and repartitioning into ethyl acetate. The determination step includes evaporation of the cleaned up extract to dryness, derivatization with pentamiorobenzoyl chloride, and determination of the derivatized thiabendazole in acetone by gas chromatography with electron capture detection.
Pesticides, Selected Elements, and Other Chemicals in Infant and Toddler Total Diet Samples, October 1980-March 1982
Authors: Gartrell Marcia J , Craun John C , Podrebarac David S , Gunderson Ellis L
Published: February 2020

The U.S. Food and Drug Administration (FDA) conducts Total Diet Studies to determine the dietary intake of selected pesticides, industrial chemicals, and elements (including radionuclides). These studies involve the retail purchase and analysis of foods representative of the diets of infants, toddlers, and adults. The individual food items are separated into a number of food groups, each of which is analyzed as a composite. This report summarizes the results for infant and toddler Total Diet samples collected in 13 cities between October 1980 and March 1982. The average concentration, range of concentrations, and calculated average daily intake of each chemical found are presented by food group. The average daily intakes of the chemicals are similar to those found in the several preceding years and generally are within acceptable limits. The results for samples collected during the same period that represent the adult diet are reported separately.
Ion Chromatographic Determination of Sulfites in Foods
Authors: Anderson Courtney , Warner Charles R , Daniels Daniel H , Padgett Kathlene L
Published: February 2020

Ion chromatography (IC) is shown to be a promising technique for the determination of sulfites (SO2, SO⅔) in foods. Results of a 10 min flash distillation and 10 min IC determination compare favorably with the results from the conventional Monier-Williams method for total sulfite in a variety of food matrices. The IC technique also provides a wealth of additional information, such as (1) sulfite and sulfate (oxidized sulfite) content of the spiking or treatment solution, (2) residual sulfite applied to the food after oxidation losses in the treatment process, (3) free sulfite in foods, and (4) total sulfite in foods. As a further check on the Monier-Williams method, the sulfate content of the trapping solution can be determined by IC. Because the IC technique traps the liberated SO2 in a non-oxidizing rather than an oxidizing medium, it is considered free from interfering sulfides and organic sulfur-containing groups which can give false positives in the Monier-Williams method. IC thus offers a high speed, more sensitive, and cost-effective alternative to conventional techniques for the determination of sulfite in foods.
Liquid Chromatographic Determination of Identity, Content, and Content Uniformity of Desipramine, Fluphenazine, and Promazine
Authors: Beaulieu Normand , Gagné Charles , Lovering Edward G
Published: February 2020

A liquid chromatographic procedure has been developed for the assay, content uniformity, and identification of single active ingredient formulations of desipramine, fluphenazine, and promazine. The drugs are extracted from formulations with methanol or dilute hydrochloric acid and quantitated against an internal standard (norephedrine). The drugs are identified by comparison of retention times with those of the reference standards.
Determination of Oxytetracycline in Premixes and Veterinary Products by Liquid Chromatography
Authors: Chappell Gary S , Houglum Joel E , Kelley Wesley N
Published: February 2020

A liquid chromatographic method for the assay of oxytetracycline in premixes and veterinary products is described. Premix samples are extracted with acidified methanol, diluted with mobile phase, and filtered before chromatography on a C-8, reverse phase .column. The assay method separates oxytetracycline from epioxytetracycline, tetracycline, and chlortetracycline. Total elution time for oxytetracycline is less than 5 min at 1.5 mL/min. Five spiked premix samples each of 2 and 50 g/lb had a coefficient of variation of 3.5 and 4.5% and a mean recovery of 99 and 104%, respectively. The results of premixes and veterinary products assayed by this method compared closely with those of the same samples assayed by the official AOAC microbiological method.
Reevaluation of Monier-Williams Method for Determining Sulfite in Food
Authors: Warner Charles R , Daniels Daniel H , Joe Frank L , Fazio Thomas
Published: February 2020

The Monier-Williams distillation procedure has a long history of successful use for determining sulfite in fruit products and wine; however, a systematic evaluation of its accuracy and precision with other food matrices has not been undertaken. We found that the Monier-Williams distillation yielded >90% recovery of sulfite added to foods such as table grapes, hominy, dried mangoes, and lemon juice. Less than 85% recovery was obtained with broccoli, soda crackers, cheese-peanut butter crackers, mushrooms, and potato chips. These results may, in fact, accurately reflect the residual levels of sulfite if a portion of the sulfite undergoes irreversible reaction with some food components. Analysis of commercial food products gave sulfite levels ranging from 1400 ppm in dried apple slices to 25 ppm in cream sherry
Gas Chromatographic Analysis of Milk for Deoxynivalenol and Its Metabolite DOM-1
Authors: Swanson Steven P , Dahlem Andrew M , Rood Harold D , Côte Louis-Marie , Buck William B , Yoshizawa Takumi
Published: February 2020

A gas chromatographic method is described for the determination of deoxynivalenol (DON) and its metabolite DOM-1 in milk. Milk samples were extracted with ethyl acetate on a commercially available disposable extraction column, followed by hexane-acetonitrile partitioning. Final purification was accomplished on a reverse phase C-18 cartridge. The trimethylsilyl ether (TMS) derivatives of DON were prepared, chromatographed on an OV-17 column, and quantitated with an electron capture detector. Chromatography of the TMS derivatives of milk extracts was compared to that of the corresponding heptafluorobutyryl derivatives. The limit of detection using TMS derivatives was 1 ng/mL for both toxins with recoveries averaging 82% ± 9% at 2.5 and 10 ng/ mL milk for DON and 85% ± 6% at 10 ng/mL for DOM-1.
Titrimetric Determination of Vitamin B6 Using Chloramine-T, Bromamine-T, and Bromamine-B
Authors: Jayaram Beby , Gowda Netkal M Made
Published: February 2020

Simple titrimetric methods have been developed for determination of the vitamin pyridoxine (PRX) in solution, using aromatic N-haloamines, chloramine-T, bromamine-T, and bromamine-B. The method is based on oxidation of PRX by the N-haloamines; the oxidation involves a 2-electron change. The reaction products, pyridoxal and sulfonamides, were identified. The effects of variables, such as pH of the medium and the presence of foreign ions, and pyridoxal, pyridoxalamine, glycerol, and alcohol, on the rate of oxidation were studied. The methods are useful for determining PRX in pharmaceutical formulations and for assaying its cadmium complex. Statistical evaluation showed that analytical results are accurate to within 1%.
Simple Colorimetric Method for Determination from Pharmaceutical Preparations
Authors: Sane Ramesh T , Malkar Vishwanath B , Nayak Vinay G , Sapre Dhananjay S
Published: February 2020

A simple colorimetric method is described for the determination of terbutaline sulfate. The method is based on measurement of a colored species formed when terbutaline sulfate is treated with diazotized dapsone and p-nitroaniline at room temperature. Compounds such as starch, talc, and common excipients do not interfere in the reaction. Statistical validation showed that the method was highly precise and accurate. The results agree well with those obtained by other methods reported in the literature.
Rapid and Simple Determination of Oxyphenbutazone in Dosage Forms by Biamperometric Titration
Authors: Šebková Daniela , Šafařík Luděk
Published: February 2020

Oxyphenbutazone was determined in the presence of glacial acetic acid, hydrochloric acid, and potassium bromide by bromometric titration with biamperometric end point indication. The course of the titration was followed with double platinum electrode with 100 mV of polarizing voltage
Parameters and Definitions in Harmonization of Collaborative Analytical Studies
Authors: Parkany M
Published: February 2020

IUPAC, AOAC, and ISO participate in developing, validating, and adopting analytical methods for international use. Harmonization of the different interests of these organizations is desirable, as is harmonization of parameters of precision of test methods. ISO Technical Committee 69 is responsible for standards that deal with statistical interpretation of test results and data, sampling procedures, and precision of test methods.
Analytical Quality Control in United Kingdom Water Industry, with Particular Reference to Harmonized Monitoring Scheme for River Water Quality
Authors: Tetlow J A , Hunt D T E
Published: February 2020

The development of river water quality monitoring in the United Kingdom and the parallel development of analytical quality control (AQC) procedures within the UK water industry are described. Some results are presented for a sequential scheme of AQC which seeks to ensure comparability of analytical results obtained by different laboratories. The problems and advantages of such a scheme are examined, and future developments in nationally coordinated AQC in the water industry are discussed.
Improved Spray Reagent for Thin Layer Chromatographic Method for Detecting Uric Acid: Collaborative Study
Authors: Ferrera Robert S , Boese Jack L , Thrasher Joel J
Published: February 2020

A collaborative study was conducted to validate the substitution of an improved single spray in the official AOAC thin layer chromatographic method for identifying uric acid (UA) from bird and insect excreta. The proposed reagent, which is a dilute aqueous solution of ferric chloride and potassium ferricyanide, requires neither a heating step nor a pH indicator. Its preparation time, specificity, and sensitivity to low levels (5-50 ng) of UA were compared with those of the official sprays. The improved spray took 1/5 as long to prepare as the official sprays. Neither the proposed spray nor the official sprays gave false positive reactions with compounds similar to UA. For bird and insect excreta samples, at the 95% confidence limits, the false negative rate was between 0 and 9.7% for the proposed spray and between 0.7 and 18.7% for the official sprays. Sensitivity results showed that the proportion positive for the proposed spray was significantly higher (P<0.05) than for the official sprays at the 15 ng UA level. The proposed changes have been adopted official first action.
Liquid Chromatographic Determination of Hydrazine in Polyvinylpyrrolidone
Authors: Matsui Fumiko , Sears Roger W , Lovering Edward G
Published: February 2020

A liquid chromatographic method for determination of hydrazine in polyvinylpyrrolidone (PVP) has been developed. After PVP is dissolved in acetate buffer, hydrazine is derivatized with benzaldehyde to form benzalazine, and is quantitated on a silica column using p-dinitrobenzene as the internal standard. The minimum quantitatable level of hydrazine is about 180 ppb, but with changes in the sampling procedure, this could readily be lowered to 90 ppb. Reproducibility on repeat analysis is about ± 10%. The method was used to analyze 16 lots of PVP from 3 commercial sources. Results ranged from nondetectable to 11 600 ppb; recoveries from spiked samples in most cases were 84% or better. Hydrazine levels tended to be lower in the higher molecular weight samples.
Chemical Derivatization Analysis of Pesticide Residues. X. Analysis of Ten Acid Herbicides in Natural Waters
Authors: Lee Hing-Biu , Stokker Yvonne D , Chau Alfred S Y
Published: February 2020

An improved and augmented gas chromatographic (GC) method using a capillary column and electron capture detector was developed for determination of 10 common acid herbicides in natural water. The herbicides were extracted with methylene chloride after the water sample was acidified to pH < 1. Concentrated extracts in acetone were derivatized with pentafluorobenzyl bromide (PFBBr) to form the corresponding PFB esters. Derivatives were cleaned up on a deactivated silica gel column. A SE-54 fused silica capillary column was used to separate and identify the products. Using this procedure, the method was successfully validated for herbicide concentrations as low as 0.05 μg/L in natural waters. Recoveries of water samples fortified with the 10 herbicides ranging from 1.0 to 0.05 μg/L were 73 to 108% with the exception of picloram which was only 59% recovered at 0.1 μg/L.
Derivative Spectrophotometric Determination of Some Corticosteroids in Combinations with Other Drugs
Authors: El-Yazbi Fawzy A , Korany Mohamed A , Abdel-Razak Omayma , Elsayed Mahmoud A
Published: February 2020

Three 2-component mixtures, namely, dexamefhazone-chlorpheniramine maleate, prednisolone-chlorpheniramine maleate, and prednisolone-salicylic acid, have been assayed using their first (D1,) and second (D2) derivative spectra in methanol, delta absorption (ΔA), and second derivative of Δ A (Δ D2) spectra in methanol-methanolic HC1. In the first 2 mixtures, chlorpheniramine maleate was determined by measuring its Δ D2 value at 278 nm, while dexamethazone and prednisolone were analyzed by measuring their D1 values at 248 nm. Prednisolone and salicylic acid were analyzed in combination by using their respective D2 spectral responses at 272 and 314 nm. The results obtained are reasonably reproducible with a relative standard deviation <2%. The method has been successfully applied to the analysis of these drugs in their pharmaceutical formulations.
Rapid Quantitative Thin Layer Chromatographic Screening Procedure for Sulfathiazole Residues in Honey
Authors: Neidert Eli , Baraniak Zig , Sauvé André
Published: February 2020

A procedure is presented for the quantitative determination of sulfathiazole residues in honey. Induced fluorescence of sulfathiazole is measured by fluorescent scanning densitometry; sulfaquinoxaline is added as an internal standard for quantitation. Recovery is greater than 98% and results are linear over the range 0.05-0.60 mg/kg. The detection limit, CL (k = 3), is 0.02. The procedure allows a single analyst to process 50-60 samples/day.
Detection of Beet Sugar Adulteration of Honey
Authors: White Jonathan W , Meloy Robert W , Probst Jerry L , Huser William F
Published: February 2020

Quantitation of oligosaccharide-bound galactose by galactose oxidase treatment of the higher sugar fraction is useful to screen honeys with normal stable carbon isotope ratio values for the presence of beet sugar products. For 23 beet sugar products tested, the mean bound galactose value was 30.1 mg/100 g (as galactose); for 81 honeys, the mean was 3.1 mg/100 g, s = 4.4. Nine percent of the honey samples tested had values in the beet sugar range, so additional testing by other procedures is required for confirmation of adulteration, i.e., samples with 8-80 mg/100 g bound galactose should be further tested.
Automated Determination of Ethanol and Wine Extract with Precision Density Meter, Automatic Sampler, and Programmable Calculator
Authors: Ruppert Jerry R
Published: February 2020

Use of density meters has become the preferred method in many alcohol beverage laboratories to determine the concentration of ethanol in wines and spirits. Density converted to SG (20/20) is also the basis of an official AOAC method to determine extract of wine. Automation of the latter procedure is inhibited by the necessity to access AOAC Table 52.008 to convert SG (20/20) of the dealcoholized wine sample to percentage of sucrose by weight. The author reduced the most commonly used portion of that table (1-30% sucrose by weight) to a third degree polynomial, enabling the use of a density meter, an automatic sampler, and a computer or programmable calculator to automatically determine alcoholic content and wine extract from a sample of wine and its distillate. The absolute error between AOAC Table 52.008 and the author’s polynomial equation is less than ± 0.002 percentage of sucrose by weight for the range 1-30% sucrose by weight.
Liquid Chromatographic Determination of Flucytosine in Capsules
Authors: Shostak Donald , Klein Clifford
Published: February 2020

A liquid chromatographic method has been developed for determination of flucytosine in capsules. Flucytosine and p-aminobenzoic acid, the internal standard, are separated on a C18 reverse phase column using water-methanol-acetic acid mobile phase containing 1-octanesulfonic acid sodium salt. Compounds are detected photometrically at 285 nm. Mean assay results for 250 and 500 mg commercial capsules were 101.5% (n = 5) and 100.2% (n = 5) of declared, respectively. Mean recovery of flucytosine added to commercial capsules was 99.3 %.
Analysis for Total Sulfite in Foods By Using Rapid Distillation Followed By Redox Titration
Authors: Devries Jonathan W , Ge Hoon , Ebert Frank J , Magnuson Joel M , Ogawa Mark K
Published: February 2020

A rapid and accurate analysis for total sulfite as sulfur dioxide has been developed for foods and food products. The method, which combines a selective distillation cleanup procedure with the selective redox titration of sulfite ion by iodine, has been applied to a variety of foods and food products over a period of time with no significant interference encountered in any matrixes other than garlic and leeks. For the foods analyzed, the method typically shows a detection limit of 10 ppm, a relative standard deviation of 7.5% (compared with 10.4% for similar matrixes by the Monier-Williams method), and recoveries of 97.9 ± 6.4%. Comparison of results for this method with those obtained using the Monier-Williams method showed a mean value for the distillation/ titration method of 241 ppm compared with 242 ppm for the Monier- Williams method. A correlation of 0.991 and odds of a difference between methods of 10.7% (Student's paired t-test(1- α) × 100) were obtained for those matrixes where no interferences were encountered with either method.
Gas Chromatographic Determination of Fenpropimorph Residues in Citrus Fruit
Authors: Lafuente MarÍa Teresa , Tadeo José Luis , Tuset Juan José
Published: February 2020

A rapid gas chromatographic method for determining fenpropimorph residues in citrus fruit is reported. The fungicide is extracted with hexane after pH adjustment of the fruit homogenate. A short liquidliquid partitioning process is performed before gas chromatography on an OV-17 column with nitrogen-phosphorus specific detection. The limit of detection of the method was 0.01 mg/kg, based on a 25 g sample. Recovery was always higher than 70%. Fenpropimorph residues in "Washington Navel" oranges and "Hernandina" Clementine fruits dipped in a 1500 mg/L fungicide solution were determined. The fungicide remains mainly in the peel, with levels less than 0.1 mg/kg in the pulp. Fungicide residues in the peel decrease during storage, mainly in Washington Navel peel, where values decreased from 5.2 to 2.8 mg/kg.
Flame Absorption Spectroscopic Determination of Cadmium, Copper, Iron, Lead, and Zinc in Mussels
Authors: Solchaga Margarita , Montoro Rosa , Guardia Miguel Dela
Published: February 2020

A rapid method is proposed for determination of Cd, Cu, Fe, Pb, and Zn in mussel samples. The elements are extracted with concentrated nitric acid in borosilicate glass tubes at 90°C for 1 h, and determined by flame atomic absorption spectroscopy. Detection limits for a 300 mg sample corresponded to 0.3 μg Cd/g, 0.7 μg Cu/g, 33 μg Fe/g, 0.7 μg Pb/g, and 6 μg Zn/g. The coefficient of variation for 20 independent analyses was 7% for Cd, 7% for Cu, 6% for Fe, 14% for Pb, and 8% for Zn. Recoveries were 107 ± 3% for Cd, 90 ± 3% for Cu, 94 ± 1% for Fe, 90 ± 5% for Pb, and 96 ± 3% for Zn. The accuracy of the method was determined by analyzing NBS Oyster Tissues.
Atomic Absorption Spectrophotometnc Determination of Chromium in Foods
Authors: Farré Rosaura , Lagarda M Jesús , Montoro Rosa
Published: February 2020

A method is reported for determination of chromium in foodstuffs. Organic matter is digested with nitric acid, followed by oxidation to Cr(VI) and extraction with methyl isobutyl ketone (MIBK) after HC1 addition. Chromium determinations are performed by flame absorption spectroscopy. Absence of interferences is verified and recovery tests are performed on food samples. Quantitation limit (3.8 ng/mL), accuracy (NBS Standard Reference Material 1573 Tomato Leaves, 4500 ± 500 ng/g, found 3860 ± 409 ng/g), and precision (CV for vegetable matrix = 9.05%, CV for animal matrix = 14.95%) of the procedure are evaluated.
Kinetic Potentiometric Determination of Peroxidase in Plants, Using Fluoride-Selective Electrode
Authors: Skaltsa Helen D , Koupparis Michael A , Philianos Skevos M
Published: February 2020

A kinetic potentiometric method is described for the determination of peroxidases in vegetables and medicinal plants. It is based on the measurement of fluoride ion liberation rate from the peroxidase-catalyzed reaction of p-fluorophenol with hydrogen peroxide, sing the fluoride ion-selective electrode. The calibration curve is linear in the range 1-10 mU/mL with a precision of 1-3%. No interference was found from plant extracts, and recoveries were 97-107% (mean 100.9%). The method is rapid (2 min per measurement) and applicable to highly colored or turbid solutions. The method was applied for the determination of peroxidase activity in various plants of Greek flora. Plants of Leguminosae were found to be the richest source.
Carbon Isotope Ratios of Various Fruits
Authors: Krueger Dana A , Krueger Rae-Gabrielle , Krueger Harold W
Published: February 2020

Carbon stable isotope ratio analysis (SIRA) has been applied to detect adulteration of apple, orange, honey, and other products with cane or corn sugars. We analyzed numerous other fruits to determine the applicability of carbon SIRA to detecting adulteration in these fruits as well. The results indicate that the use of carbon SIRA may be generalized to most fruits of commercial importance.
Potential and Advantages of Immunochemical Methods for Analysis of Foods
Authors: Newsome W Harvey
Published: February 2020

The technique of immunochemical analysis, including the principles involved, is described and the various types of assay are discussed. Application of these methods to the analysis of foods for residues of pesticides, contaminants, drug residues, and natural constituents is reviewed. Compared with conventional methods, immunoassays offer similar detection limits and greatly simplified sample preparation procedures.
Liquid Chromatographic Determination and Identification of Morantel-Related Residues as Precursors of 3-(3-Methyl-2-Thienyl) Acrylic Acid (CP-20,107) in Bovine Milk
Authors: Lynch Martin J , Mosher Franklyn R , Brunner Linda A , Bartolucci S R
Published: February 2020

A simple liquid chromatographic (LC) method was developed to determine and identify incurred morantel-related residues in bovine milk by converting them to 3-(3-methyl-2-thienyl) acrylic acid (CP-20,107). Key techniques in this method involve short-term digestion of milk in HC1 to release residues convertible to CP-20,107, isolation and alkaline hydrolysis of these precursors to CP-20,107, and recovery of the product for LC analysis. Photochemical conversion of CP-20,107 to its cisisomer and separation by LC identifies the residue. A homolog (pyrantel), which is used as an internal standard, is hydrolyzed to 3-(2- thienyl) acrylic acid. These acrylic acid isomers are readily resolved by LC. The method was evaluated over the 1-4 ppb (ng/mL) range for accuracy and precision to assess its utility for withdrawal studies. Bovine milk supplemented with morantel at 1,2, and 4 ppb and assayed in replicate (n = 7-8) over 4 trials gave mean values and standard deviations of 1.0 ± 0.11,2.0 ± 0.24, and 4.0 ± 0.44 ppb, respectively. A milk specimen containing physiologically incurred residues of morantel assayed 2.1 ± 0.19 ppb in replicate (n = 5).
Determination of Depletion and Statistical Distribution of Morantel-Related Residues in Bovine Milk Following Administration of Morantel Tartrate to Dairy Cows
Authors: Lynch Martin J , Mosher Franklyn R , Dimmock Mary E , Brunner Linda A , Babcock William E , McManus Robert F , Wheelhouse Robert K
Published: February 2020

Residue depletion studies were conducted in dairy cattle to monitor morantel-related residues in milk following oral administration of morantel tartrate (Rumatel®). Eleven lactating cows of various ages, periods of lactation, and known milk production were orally dosed with the bolus formulation of morantel tartrate with an actual dose range of 8.4-9.8 mg/kg body weight. Representative samples of milk were collected at 10-14 h intervals post-dose, and subsamples were assayed for the major and minor hydrolysis products of morantel-related residues, MAPA and CP-20,107. Residues assayed as precursors of MAPA peaked at the second milking (24 h post-dose) and were below 25 ppb (range: <12-24 ppb). Precursors of CP-20,107, which confirm the identity of morantel, also peaked at 24 h post-dose (range: 2.1-3.3 ppb) and declined rapidly thereafter. A statistical model was used to project the level of residues at the upper limit of 99 % of the total target animal (i.e., dairy cattle) population with 95% confidence. The calculated peak levels from this model were 50 and 5.0 ppb for morantelrelated residues convertible to MAPA and CP-20,107, respectively.
Determination of Cyclopiazonic Acid in Peanuts and Corn by Thin Layer Chromatography
Authors: Lansden John A
Published: February 2020

A thin layer chromatographic system including densitometry has been developed for determining cyclopiazonic acid in peanuts and corn. Samples are extracted with methanol-chloroform (20 + 80); the extract is stripped of most interferences by partitioning with aqueous sodium bicarbonate followed by acidification and repartitioning with chloroform. After thin layer chromatography and derivatization with dimethylaminobenzaldehyde- HCl spray, the toxin is quantitated by reflection densitometry at 540 nm. The recovery of cyclopiazonic acid averages 90% for peanuts and 85% for corn. The absolute detection limit is 25 ng per spot which translates to a detection limit of 125 μg/kg for a 50 g sample.
Extraction and Determination by Gas Chromatography of S,S,S-Tri-n-Butyl Phosphorotrithioate (DEF) in Fish and Water
Authors: Habig Clifford , Nomeir Amin , Digiulio Richard T , Abou-Donia Mohamed B
Published: February 2020

A simple, low-cost, fast method for the extraction and cleanup of DEF (S.S.S-tri-ii-butyl phosphorotrithioate) from fish tissues and water samples was developed. The method combines extraction and cleanup in one step. The basis of the method is passing water samples or aqueous tissue homogenates containing DEF through a C-18 disposable cartridge. DEF is eluted from the cartridge by acetone or ethyl acetate. The eluates are analyzed by gas chromatography using a thermionic-specific detector. The method detects levels as low as 100 parts per trillion (ppt) in water samples; recovery efficiency from spiked fish tissues was greater than 95%. In addition, detectable levels of DEF were recovered from liver, brain, and muscle tissue of fish exposed to this compound. The method has a potential for use with other pesticides.
Isolation and Liquid Chromatographic Determination of the Cyclic Peptide Mycotoxin Cyclosporin A from Rice
Authors: Edwards Judson V , Lillehoj Eivind B
Published: February 2020

A simple method for determination and quantitation of a cyclic peptide mycotoxin, cyclosporin A, in rice is presented. Rice inoculated with Trichoderma polysporum (Link ex Pers.) was extracted with methylene chloride after 4 weeks of incubation. Cyclosporin A was isolated from extracts by using open bed gel filtration column chromatography (LH-20, acetonitrile) and monitored with thin layer chromatography and reverse phase liquid chromatography coelution with a standard. Preliminary thin layer chromatographic methods were developed. Cyclosporin A was detected by iodine and after partial acid hydrolysis by ninhydrin and UV light. A liquid chromatographic method was developed that used a reverse phase disposable cartridge cleanup and isocratic chromatography with a reverse phase octadecylsilica column and a UV detector set at 212 nm. Recovery of cyclosporin A from spiked rice samples (mg/g range) was 85%.
Glucuronidase Assay in a Rapid MPN Determination for Recovery of Escherichia coli from Selected Foods
Authors: Andrews Wallace H , Wilson Clyde R , Poelma Paul L
Published: February 2020

Glucuronidase is present in most strains of Escherichia coli but absent in most other enteric microorganisms; therefore, an assay for this enzyme is useful for determining the presence of the organism. The substrate 4-methylumbelliferyl beta-D-glucuronide (MUG) is incorporated into either lauryl tryptose (LT) broth or EC medium; the inoculated tubes are then incubated under specified conditions and examined under longwave UV light for the presence of a fluorogenic glucuronidase end product. When compared with the 10-day most probable number (MPN) procedure of AOAC, the LT-MUG and the EC-MUG tests required 24 and 96 h, respectively, and gave comparable mean log MPN values for samples of crabmeat, sunflower kernels, and walnut pieces. However, false-positive and falsenegative reactions were observed with foods tested by both of these rapid methods. Overall, method sensitivity was not compromised by using the LT-MUG rather than the EC-MUG method. Incorporation of 25 αg MUG/mL into LT broth resulted in diminished fluorescence of positive reactions, whereas MUG concentrations of 50 and 100 αg/mL provided decisive fluorogenic reactions.
Comparison of Ion-Pair and Ion-Exchange Liquid Chromatography for Assay of Dalapon Products
Authors: Stevens Timothy S , Chritz Karen M
Published: February 2020

The accuracy of the AOAC official first action ion-pair liquid chromatographic assay for dalapon grasskiller products was studied by comparison with an independent ion-exchange liquid chromatographic method. No statistically significant difference in assay results was seen between the latter method and the AOAC official method for the assay of sodium salt, mixed sodium/magnesium salt, or the free acid forms of dalapon.
Determination of N-Nitrosodimethylamine Levels in Some Canadian 2,4-D Amine
Formulations
Authors: Hindle Ralph W , Armstrong J Fred , Peake Adeline A
Published: February 2020

Levels of/V-nitrosodimethylamine (NDMA) were determined in 112 samples of 2,4-dichlorophenoxyacetic acid, (2,4-D), formulated as the dimethylamine salt, collected over a 2 year period from products on the Canadian market. A sample aliquot is partitioned with dichloromethane, and the co-extracted dimethylamine is removed by cleanup on a silica gel column. The eluates containing NDMA are concentrated, an internal standard of /V-nitrosodipropylamine is added, and nitrosamine levels are determined using a gas chromatograph interfaced with a thermal energy analyzer. Recoveries of NDMA and N-nitrosodiethylamine spiked into samples were 103 ± 16 and 96.3 ± 9.8%, respectively. Of the 112 samples analyzed, 92 were below 1 part per million (ppm) relative to the amount of 2,4-D in the samples, 16 were between 1 and 5 ppm, and 4 were greater than 5 ppm. The gas chromatographic column used is compared to a conventional packing material for volatile nitrosamine analysis. Formation of NDMA during cleanup and analysis was shown not to occur.
Liquid Chromatographic Determination of Saccharin in Beverages and Sweets: NMKL Collaborative Study
Authors: Sjoberg Anna-Maija K , Alanko Timo A
Published: February 2020

A reverse phase liquid chromatographic method for the determination of saccharin in a soft drink and a juice was collaboratively studied in 8 laboratories. Collaborators were supplied with 3 samples of the soft drink and 3 samples of the juice containing sodium saccharin levels of 40-100 mg/L. Average recoveries of sodium saccharin were 95.3% for the soft drink and 98.0% for the juice. The reproducibility coefficients of variation were 16.9% for the soft drink and 10.4% for the juice. In addition, a mini-collaborative study was conducted for the determination of saccharin in 3 samples of sweets produced commercially. Five collaborators analyzed the samples, which contained saccharin at levels of 100-600 mg/kg according to the maker's specifications. Saccharin was extracted with water and ethanol and chromatographed using a modified liquid chromatographic method. The reproducibility coefficient of variation was 12.4% for the sweets.
Determination of Total Lipid and Lipid Subclasses in Meat and Meat Products
Authors: Maxwell Robert J
Published: February 2020

Current interest in physiological and nutritional activities of the sterol, polyunsaturated fatty acid, and polar lipid fractions of meats and other foods indicates that analytical methods for lipids should be evaluated on their ability to recover and quantitate these classes. Current methods of lipid isolation furnish an extract that is dependent on the solvent(s) used, the type of food material, the temperature of extraction, and the relative proportions of the lipid classes present. Extraction with ethers or other relatively nonpolar solvents removes principally the neutral fats and nonpolar lipids. For an approximation of the crude fat content, such extraction is often sufficient, because the nonpolar fraction generally constitutes over 90% of the total lipids present. The polar lipids include the biochemically important (ω-3) and (ω-6) polyunsaturated fatty acid classes; thus, the method of lipid extraction of food products becomes relevant for a more complete and valuable characterization of their nutritional value. The various methods of lipid determination for meat products are examined for their total recovery of these important lipid groups. A sequential extraction in conjunction with subsequent analytical methods is recommended.
Thin Layer Chromatographic/Bioautographic Method for Identification of Antibiotic Residues in Animal Tissues
Authors: Neidert Eli , Saschenbrecker Peter W , Tittiger Frank
Published: February 2020

An analytical method for the identification of the residues from 14 commonly used antibiotics is presented. The technique is based on selective tissue extraction followed by thin layer chromatography (TLC)/bioautography. Antibiotic residues are extracted from the tissues with methanol and methanol-HCl (98 + 2). The methanol extract is further extracted with chloroform to isolate groups of antibiotics. The extracts are spotted onto TLC plates and developed in suitable solvent systems. Developed plates are placed on set medium seeded with Bacillus subtilis and a bioautograph is produced. The locations of zones of inhibition are used to identify antibiotic residues. Recoveries of antibiotics were quantitative, while the effect of naturally inhibiting components of the matrix was minimized. The sensitivity of the method can be adjusted through minor modifications, which allows its use in routine regulatory analysis.
Determining Multifumigants in Whole Grains and Legumes, Milled and Low-Fat Grain Products, Spices, Citrus Fruit, and Beverages
Authors: Daft James
Published: February 2020

Whole grain and legumes, milled and low-fat products, spices, citrus fruit, and dry beverage ingredients are leached with purified, acidified acetone-water solutions. Portions of these leachates are then backextracted with purified isooctane. Liquid beverages are directly extracted with the isooctane. Six to 10 nL of each isooctane extract is then screened for 11 fumigant residues by gas chromatography (GC) using electron-capture and Hall electroconductivity detectors, and dual 20% OV-101 columns. Further confirmation of residue identity is done on 20% OV-225/20% OV-17 (2.5 + 1 mixed-bed) and 10% SP-1000 columns. The analytes determined include methyl bromide, methylene chloride, carbon disulfide, chloroform, ethylene dichloride, methyl chloroform, carbon tetrachloride, trichloroethylene, chloropicrin, ethylene dibromide, and tetrachloroethylene, using mixed-component reference solutions. Average recoveries from fortified grain range from 25 to 85%; methyl bromide and chloropicrin were recovered the least. Recoveries from the other kinds of food samples range from 43 to 111%. Advantages of this procedure are (/) clean sample extracts, (2) ppb detection limits, (3) residue stability, (4) relative speed, quality control, and safety of the analysis, and (5) results which gave an accurate picture of residual fumigants in grain and food products.
Multiresidue Method for Determining Substituted Urea Herbicides in Foods by Liquid Chromatography
Authors: Luchtefeld Ronald G.
Published: February 2020

A method is described for determining substituted urea herbicides in foods. The residues are extracted from the product with methanol, and the food coextractives are removed by using solvent partitioning and Florisil column chromatography. The extract is analyzed using liquid chromatography with postcolumn photodegradation, chemical derivatization with orthophthalaldehyde, and spectrofluorometry. Recoveries were determined by spiking 8 different food products with 6 phenylureas—chlorbromuron, chloroxuron, diuron, fluometuron, linuron, and metobromuron—at 0.05 and 0.5 ppm. Three determinations were made at each level for each product. Average recovery at 0.05 ppm was 95% (with a standard deviation of 7.9%), and at 0.5 ppm, 98% (with a standard deviation of 6.9%).
Determination of Nitrogen, Phosphorus, and Potassium in Water-Soluble Fertilizers by Inductively Coupled Plasma Emission Spectrometry
Authors: Nygaard Danton D. , Sotera John J.
Published: February 2020

A modification of an inductively coupled plasma (ICP) emission spectrometer is described that enables the simultaneous determination of nitrogen, phosphorus, and potassium in water-soluble fertilizers. A quartz extension tube is added to the ICP torch to exclude air from the plasma, thus allowing accurate nitrogen determination without adversely affecting sensitivity for other analytes. The modification also requires an 18 mg/L argon coolant flow to protect the tube from the heat of the plasma. Detection limits are 20 mg/L for nitrogen and 50 μg/L for phosphorus and potassium. Three NBS reference salts and 2 commercially available fertilizers were analyzed by the method, and results are in excellent agreement with known values.
Scheme for Validation of an Analytical Protocol: Semiautomated Kjeldahl Nitrogen Determination
Authors: Fisher Murray T , Gurnsey Catherine
Published: February 2020

Definitive validation of an analytical protocol is not always possible. A scheme for performing an alternative type of validation is presented. The scheme is tested on a commonly used chemical procedure for assaying total nitrogen. This alternative validation scheme uses 5 approaches: tests of robustness to recovery of working standards, assay of fortified in-house control materials to assess recovery from typical material, prescribed means of measuring within- and between-batch precision of the assay of typical material, comparison with alternative assay procedures, and determination of analogous certified reference materials to enable calculation of total error. The scheme uses the results of the 5 approaches to obtain a performance profile for the assay. The scheme does not rely on involved statistical modeling or data treatment, yet provides the laboratory worker with a systematic approach to a within-laboratory validation of an analytical protocol.
Regression Analysis of Use-Dilution Disinfectant Test Data as an Alternative to Current Registration Practices
Authors: Walter George R , Trout J Richard
Published: February 2020

The historical application of probit analysis applied to the use-dilution disinfectant test is discussed. Attention is focused on earlier work which either deleted or incompletely applied confidence limits leading to much current controversy in disinfectant test interpretation. It is proposed that the probit analysis approach applied to disinfectants is indeed feasible and that a more complete application of confidence limits to the assay will yield more reliable data than those currently required for disinfectant product registration with the Environmental Protection Agency. A suggested modified registration protocol using probit analysis is offered as an alternative to the current registration guidelines.
Application of Near Infrared Reflectance Spectroscopy to Compositional Analysis of Commercial Pig Feed Mixes
Authors: Chen Shih-Ling Y , Hsu Ali , Lee Mane-Lane
Published: February 2020

Official samples of commercial pig feed mixes taken for routine inspection were analyzed by near infrared reflectance spectroscopy (NIRS). Separate calibrations were established for pre-starting pig, starting pig, growing pig, finishing pig, and lactating sow feeds. Mean correlation coefficients and standard errors of calibration, respectively, obtained by comparing NIRS values with conventional chemical analysis values, were as follows: calibration set (about 35 samples per category)-moisture 0.87,0.44%; protein 0.90,0.75%; fiber 0.8b, 0.49%; analytical set (about 15 samples per category)—moisture 0.73, 0.42%; protein 0.90, 0.72%; fiber 0.83, 0.40%. Mean coefficients of variation for NIRS were moisture 3.9%, protein 4.2%, and fiber 14.8%; those for conventional analyses were moisture 2.7%, protein 1.1%, and fiber 11.7%. The results indicated that for moisture, protein, and fiber determinations in commercial pig feed mix products with various and unknown formulations, successful rapid NIRS analysis could be achieved by using a filter-type spectrometer and advanced mathematical data treatments. Among 246 samples inspected, protein content in 70% of them exceeded by 1-8% the legal minimum protein level. Application of NIRS provides an accurate and prompt on-line technique for feed mix analysis during the formulation process and can be beneficial to the operation of feed mills. For official inspection, the technique might serve as a preliminary screening method.
Amino Acid Analysis in Feeds and Feedstuifs Using Precolumn Phenylisothiocyanate Derivatization and Liquid Chromatography—Preliminary Study
Authors: Beaver Rodney W , Wilson David M , Jones Helen M , Haydon Keith D
Published: February 2020

A method for the determination of amino acids in feed hydrolysates is described. The method uses precolumn phenylisothiocyanate (PITC) derealization and liquid chromatography on reverse phase columns with UV detection at 254 nm. The precision of the method on replicate samples of a wheat hydrolysate ranges from 1.9 to 6.7% relative standard deviation for the amino acids examined. (Met and Cys were not determined.) Recoveries were near 100% for most amino acids. Comparisons of the values obtained by PITC method with accepted wines show good agreement in wheat and poultry feed samples.
Optimization of Sweep Codistillation Apparatus for Determination of Coumaphos and Other Organophosphorus Pesticide Residues in Animal Fat
Authors: Brown Robert L , Farmer Clinton N , Millar Roderick G
Published: February 2020

Optimum conditions have been developed for the quantitative recovery of coumaphos from animal fat by using a commercial sweep codistillation unit. Under the conditions specified (255°C distillation temperature, 250 mL/min of nitrogen, 60 min sweep time) and using Florisil trapping, the mean recovery of coumaphos was 91% with a coefficient of variation of 6%. Other organophosphorus pesticides recovered include diazinon, chlorpyrifos, ethion, and bromophos-ethyl with recoveries ranging from 90 to 96% and coefficients of variation ranging between 4 and 6%.
Coplanar Polychlorinated Biphenyls in Aroclor and Kanechlor Mixtures
Authors: Kannan Narayanan , Tan Abe Shinsuke , Wakimoto Tadaaki , Tatsukawa Ryo
Published: February 2020

Three congeners of coplanar PCBs (non-0-0 -chlorine-substituted polychlorinated biphenyls) were determined in representative commercial PCB preparations. The 3,3,4,4 -tetrachlorobiphenyl was highest in Kanechlor 400 (8500 μg/g) and Aroclor 1248 (6060 μg/ g) followed by Kanechlors 300, 500, and 600 and Aroclors 1242, 1254, and 1260 in that order. The toxic 3,3',4,4',5-pentachlorobiphenyl and 3,3',4,4',5,5'-hexachlorobiphenyl were also detected in those mixtures. The highest concentrations of 3,3',4,4',5-pentachlorobiphenyl were found in Kanechlor 400 (89.3 μg/g) and Aroclor 1248 (62.3 μg/g) followed by Kanechlors 500, 300, and 600 and Aroclors 1254,1242, and 1260 in that order. The 3,3',4,4',5,5-hexwhlorobiphenyl was detected in all Kanechlor mixtures, with the highest concentration (1.16 μg/g) in Kanechlor 500. However, among Aroclor mixtures, it was detected only in Aroclor 1254 at a concentration of 0.66 jtg/g. The importance of these toxic constituents in PCB mixtures is worth considering in view of widespread pollution of the environment by PCBs.