bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibiotic Identification by High Voltage Electrophoresis Bioautography
Authors: Lott Anthony F , Smither Roy , Vaughan David R
Published: February 2020

The high voltage electrophoresis bioautography method is applicable to meat, milk, and animal feeds. Meat is freeze-dried, powdered, and extracted with acetonitrile-water (9 + 1), and the extract is concentrated by evaporation at room temperature. Milk is examined directly or following acetonitrile-water extraction. Feed is extracted with acetonitrile- water. Samples or extracts are applied to preliminary assay plates of antibiotic medium No. 1 at pH 6 and 8, seeded with Micrococcus luteus (ATCC 9341), M. luteus DHSR (ATCC 9341A), Bacillus cereus (ATCC 11778), or B. cereus K250 TR (NCIB 11183), and nutrient agar at pH 7 seeded with B. subtilis BGA. Inactivation of penicillinase indicates beta-Iactam antibiotics. Addition of trimethoprim increases sensitivity to sulfonamides. After 18-24 h incubation at 30°C, plates yielding clear inhibition zones guide selection of conditions for subsequent electrophoresis bioautography. Extracts are applied (5-100 |xL) to 10 mm diameter wells on electrophoresis plates 60 cm long and 40 cm wide, with a gel depth of 1.6 mm. The support medium is 1% agar and 1 % agarose in Tris/succinic acid buffers pH 6 and pH 8. A potential of 1500 V is applied for 1.5 h at 15°C. Following electrophoresis, the migrated antibiotics are visualized by over-layering with antibiotic medium No. 1, pH 6 or 8, seeded with M. luteus or B. cereus spore suspension; plates are incubated for 18-24 h at 30°C. Identification is based on results of preliminary screening together with electrophoretic migration distances and inhibition zone appearances compared with standards
Microbiological Assay for Chloramphenicol Residues
Authors: Singer Carol J , Katz Stanley E
Published: February 2020

Procedures for the assay of chloramphenicol in milk, urine, serum, and muscle tissue are presented. The procedures specify an assay design with all standards as well as samples present on each plate, oxytetracycline in the buffer-diluent for greater sensitivity, a minimal medium to enhance the inhibitory effect of chloramphenicol on the assay organism, and a tetrazolium dye to improve the ability to measure the zones of inhibition. Recoveries of unbound chloramphenicol from bovine urine were 90.8%, from serum 88.3%, from milk 79.3%, from swine muscle 71.3%, and from beef and chicken muscle 61.0 and 61.4%, respectively. The lower levels of measurement in urine and serum were 0.25 ug/mL, 0.025 n-g/mL in milk, and 0.10 |xg/g in muscle tissue
Determination of Small Quantities of Atropine in Commercial Preparations by Liquid
Chromatography with Fluorescence Detection
Authors: Cieri Ugo R
Published: February 2020

A method is presented for the determination of small quantities of atropine in commercial preparations by liquid chromatography (LC) with fluorescence detection. The sample is extracted with CHC13 from basic suspension, the CHC13 is evaporated on the steam bath, and the dry residue is dissolved in a small volume of CH3OH. A reverse phase column is used for the LC analysis; the eluting solvent is prepared by mixing 950 mL CH3OH with 50 mL water containing 1 g of the sodium salt of l-pentanesulfonic acid. The fluorescence detector is set at an excitation wavelength of 255 nm and an emission wavelength of 285 nm. Several commercial tablets and injections containing atropine in combination with other ingredients and a commercial sample of belladonna extract were analyzed by the proposed method. Recoveries of atropine sulfate from aqueous solutions averaged 100.7% with a relative standard deviation (RSD) of 3.35% for atropine sulfate levels of 0.12 mg. Recoveries of atropine sulfate from synthetic injection formulations were 99.8 and 100.0% withRSDsof 2.03and2.35%, respectively; the atropine sulfate concentrations of commercial injections with the same formulations were found to be 97.0 and 100.0% of the labeled amounts with RSDs of 0.53 and 1.46%, respectively
Pesticides, Selected Elements, and Other Chemicals in Infant and Toddler Total Diet Samples, October 1978-September 1979
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 1978 and September 1979. The average concentration, range of concentrations, and calculated average daily intake of the chemicals 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.
Pesticides, Selected Elements, and Other Chemicals in Adult Total Diet Samples, October 1978-September 1979
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 adult Total Diet samples collected in 20 cities between October 1978 and September 1979. 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 are within acceptable limits. The results for samples collected during the same period that represent the diets of infants and toddlers are reported separately.
Digestion of Food Samples for Total Mercury Determination
Authors: Louie Hon Way , Go Danny , Fedczina Mara , Judd Kevin , Dalins John
Published: February 2020

A method of digestion by using a mixture of hydrochloric, nitric, and sulfuric acids has been developed for the determination of total mercury in a wide range of food samples. Good recoveries of mercury were obtained from NBS (National Bureau of Standards) Albacore Tuna and from food samples spiked with inorganic mercury. A detection limit of 0.01g mercury/g can be obtained.
Brine Saturation Technique for Extraction of Light Filth from Rubbed, Ground, and Whole Sage: Collaborative Study
Authors: Freeman Clarence C
Published: February 2020

A new approach to the isolation of light filth from the 3 commercial forms of sage was studied collaboratively. It incorporates a simple isopropanol defatting, followed by saturation of the product with brine by alternately heating and cooling, and subsequent trapping of filth from tap water with olive oil. This method circumvents the use of hazardous, expensive solvents and more time-consuming pretreatment procedures. Overall recoveries were 92.1% for rodent hair and 78.7% for insect fragments on clean, easy-to-read papers. An additional blending step was necessary to obtain satisfactory recovery of rodent hair fragments from whole sage. The method has been adopted official first action for light filth in rubbed and ground sage only.
Harmonization of the Standardization of Reference Substances for the Analysis of Pesticide Products
Authors: Pavel Konrad
Published: February 2020

Quantitative analysis of pesticide products is often based on analytical procedures that require substances of precisely known purity as reference materials. In addition, samples of "pure" active ingredient (AI) are needed for registration purposes, in part for the determination of some physical-chemical properties, and also for submission to the authorities. Pure AIs from several pesticides are available commercially or from particular institutes. Some pure pesticides, especially those of newly developed products, must be provided by the manufacturer. Substances like these have a variety of names, such as pure AI, pure pesticide, reference material, pure standard, or analytical grade sample. It is suggested that internationally uniform names be given to highly purified substances and to other samples that are used as reference materials for determination and certification of purity and other quality criteria. DAPA recommends that 2 kinds of reference materials be distinguished: primary reference substance and working standard, and offers draft guidelines for standardization and draft certification forms for reference materials. Finally, it is proposed that CIPAC (Collaborative International Pesticides Analytical Council) or FAO (Food and Agriculture Organization) publish corresponding papers.
Analysis of Diazinon for Impurities and Degradation Materials
Authors: Karr James J
Published: February 2020

Several samples of commercial diazinon were analyzed for impurities and degradation products. A serious impurity identified as sulfotepp (S-TEPP) was found to be present in all of the samples examined; however, the levels of S-TEPP ranged from a low of about 250 ppm to 5500 ppm. The unusually high levels of S-TEPP were correlated with specific suppliers of diazinon. AH of the analytical work, including the quantitative measurements, was carried out using gas chromatographic (GC) techniques and specific detectors. The focus of this study was directed to the presence of S-TEPP in the commercially produced samples of diazinon, and whether the S-TEPP is concentrated in the diazinon or produced as a result of other manufacturing or formulating processes. Specifically, diazinon is the toxicant used in the commercial controlled-release formulation, a microencapsulated insecticide used for residual pest control in and around residential and commercial buildings. The result of the study firmly establishes the role of S-TEPP as being a carryover contaminant and not the result of a degradation process. Other impurities were identified with the aid of a mass spectrophotometer in the electron-impact mode.
Rapid Thin Layer Chromatographic Determination of Aflatoxin M1 in Powdered Milk
Authors: Serralheiro Maria Luisa , Quinta Maria Lurdes
Published: February 2020

A method has been developed for the detection of aflatoxin Mi in milk. The toxin is extracted with chloroform, the extract is evaporated, and the residue is partitioned between carbon tetrachloride and an aqueous saline-methanol solution. The toxin is once again extracted with chloroform from the methanol solution and analyzed by thin layer chromatography. The limit of detection of Mi in powdered milk is 0.5 μg/ kg; recoveries of added Mj are about 83%. The limit of detection can be improved to 0.3 μg/kg if the plate is sprayed with an aqueous solution of H2S04 after development.
Deoxynivalenol in Hard Red Winter Wheat: Relationship Between Toxin Levels and Factors That Could Be Used in Grading
Authors: Shotwell Odette L , Bennett Glenn A , Stubblefield Robert D , Shannon Gail M , Kwolek William F , Plattner Ronald D
Published: February 2020

A study was made of deoxynivalenol (DON) incidences and levels in 1982 hard red winter (HRW) wheat grown in areas of Nebraska and Kansas known to have scabby wheat. Samples of wheat harvested in the areas were collected from elevators and analyzed for DON by gas chromatography with an electron capture detector. Of the 161 samples analyzed, 42% contained s i ppm; 68% contained <2 ppm; 90% contained ^4 ppm. There were differences in the occurrence of DON in the 5 areas identified in eastern Nebraska and Kansas. The mean level of DON decreased from north to south in these areas in the following order: 2.81,2.73,2.05,1.52, and 0.83 ppm. An area in north central Kansas had a mean level of DON of 0.50 ppm. Correlations were made between DON incidences and levels in HRW wheat and factors used in grading wheat. The occurrence of DON was highly correlated with percent total kernels damaged by mold, percent total defects, and percent total scab damage.
Second Derivative Ultraviolet Spectroscopy and Sulfamic Acid Method for Determination of Nitrates in Water
Authors: Simal Jesus , Lage Maria Asuncion , Iglesias Isabel
Published: February 2020

Second derivative ultraviolet (UV) spectroscopy is used for the identification and quantitation of nitrates in water, with satisfactory precision and accuracy. Nitrite interference is eliminated with sulfamic acid; interference from organic matter can be cancelled with the use of second derivative UV spectroscopy. The nitrites can be calculated indirectly.
Antibiotic Residues in Animal-Derived Food
Authors: Livingston Robert C
Published: February 2020

Antibiotics are used extensively in food-producing animals to maintain optimal health and promote growth. The use of these drugs has the potential to leave drug-related residues such as parent drug and metabolites in meat, milk, and eggs. For those drugs that require a withholding period to ensure that residues in the food products are below established tolerances, methods of analysis are required. The majority of approved antibiotics are assayed by microbiological methods. Although these methods are suitable for screening for drug residues, they often lack the specificity and precision required of regulatory methods. Present requirements for regulatory methods have resulted in the submission of physical-chemical methods in support of New Animal Drug Applications for antibiotics.
Methods for Determination of Ionophore-Type Antibiotic Residues in Animal Tissues
Authors: Weiss George , Macdonald Alexander
Published: February 2020

Methods for the analysis of polyether antibiotics in animal tissues and fluids are described. For monensin and nigericin, only methods based on bioautography are available. For lasalocid, in addition to TLC bioautography for quantitation in chicken skin and fat, LC methods based on fluorescence detection have been developed for quantitation in animal blood, milk, liver, skin, and fat. In addition, a confirmatory method for lasalocid is described; this is based on purification by LC followed by silylation and pyrolysis gas chromatography-positive chemical ionization mass spectrometry.
Chromatographic Methods for Determination of Macrolide Antibiotic Residues in Tissues and Milk of Food-Producing Animals
Authors: Moats William A
Published: February 2020

Tylosin, an antibiotic developed specifically for agricultural use, and erythromycin are the main macrolide antibiotics used in animal production. Two-dimensional thin layer chromatography has been used for detection of tylosin in poultry meat, eggs, and milk and for erythromycin in poultry meat. Detection limits reported are, for tylosin, 0.1 ppm in poultry meat, 0.05 ppm in egg, and 0.01 ppm in milk,'and for erythromycin, 0.25 ppm in poultry meat. Liquid chromatography (LC) has also been used for determination of tylosin in milk, blood, and tissues of animals. Samples (milk, blood serum, or tissue homogenates in water or pH 2.2 buffer) were deproteinized with acetonitrile, tylosin was partitioned into methylene chloride, and the extracts were concentrated and dissolved in acetonitrile. Chromatography was done on a reverse phase end-capped C18 column using 0.002-0.005M ammonium dihydrogen phosphate-acetonitrile-methanol (10 + 60 + 30-5 + 80 + 15). Solvent composition was varied with the type of sample analyzed. The method will detect 0.1 ppm tylosin in tissues and less in milk and blood serum. The LC method was more sensitive than microbiological assays for detection of tylosin in tissues of treated swine; recoveries of tylosin by the LC method were frequently several-fold higher.
Liquid Chromatographic Determination of Thiamine in Infant Formula Products by Using Ultraviolet Detection
Authors: Ayi Benjamin K , Yuhas David A , Moffett Kathryn S , Joyce Deidre M , Deangelis Nicholas J
Published: February 2020

A liquid chromatographic (LC) method has been developed for determination of thiamine in infant formula products. The method involves the following steps: (a) dissolution of the formula with water, (b) pH adjustment to induce protein precipitation, (c) filtration, (d) concentration of thiamine by using a cation exchange column and extraction system, (e) cleanup of adsorbed thiamine and other contaminants on the ion exchange column by washing with water and then methanol, (f) elution of thiamine with a mixture of methanol-2M potassium chloride buffer, (g) analysis for thiamine by liquid chromatography. Thiamine is separated from its phosphate esters, the mono-, di-, and triphosphates, as well as its antagonists oxythiamine and pyrithiamine on a 6 p-m particle size column and a mobile phase of 40mM triethylammonium phosphate buffer-methanol (pH 7.7) (90 + 10). The method is reproducible, with relative standard deviations ranging from ± 0.76 to ± 1.2%, depending on the infant formula product tested. Recovery of thiamine from various infant formula products is greater than 99%. Analysis for thiamine of several commercially available infant formulas at different levels of fortification gave results that ranged from 122 to 216% of the declared levels. These results agree well with those obtained using the AOAC fluorometric method.
Gas Chromatographic-Mass Spectrometric Detection of Adulteration of Natural Lime Oils
Authors: Alessandro Rocco T , Adams James M , Miskiewicz Michael A
Published: February 2020

Distilled and expressed lime oils were characterized by glass capillary gas chromatography. Components present at concentrations greater than 0.1% were identified by mass spectrometry. Expressed oils contained less than 1% monoterpene alcohols, whereas distilled oils contained more than 10%. Expressed oils contained sabinene and 4 times as much beta-pinene as distilled oils. Adulteration was detected by finding component area percents and/or their ratios to be outside the 95% confidence intervals established for pure oils.
Analysis of Pharmaceutical Dosage Forms for Oxfendazole: II. Simultaneous Liquid Chromatographic Determination of Oxfendazole and Trichlorfon in Equine Paste
Authors: Fleitman Jeffrey , Neu Daniel , Benjamin Eric
Published: February 2020

A reverse phase liquid chromatographic procedure is described for the simultaneous determination of oxfendazole [2-(methoxycarbonylamino)- 5-phenylsulfinylbenzimidazole] and trichlorfon [(2,2,2-trichloro-1-hydroxyethyl)phosphonic acid dimethyl ester] in equine paste. The sample is extracted by sonication in methanol. Insoluble excipients are removed by centrifugation and an aliquot plus internal standard are diluted with dilution solvent (water-acetonitrile-phosphoric acid, 80 + 20 + 1). The samples are filtered and injected onto a Partisil-5 ODS-3 column with acetonitrile-0.01M phosphate buffer pH 6.0 (20 + 80) as mobile phase. Method specificity is confirmed using an absorbance ratioing technique. The method yields mean recoveries of 100.9 and 100.0% for trichlorfon and oxfendazole, respectively. Dependence of chromatographic performance characteristics on mobile phase organic content, pH, and buffer concentration is also reported.
Thin Layer Chromatographic Determination of Deoxynivalenol in Processed Grain Products
Authors: Trucksess Mary W , Flood Michael T , Page Samuel W
Published: February 2020

The thin layer chromatographic (TLC) method of Trucksess et al. (J. Assoc. Off. Anal. Chem. (1984) 67, 40-43) was modified for the determination of deoxynivalenol (DON) in high-sugar breakfast cereals, corn syrup, and beer. Celite was added to the substrate before extraction with acetonitrile-water (84 + 16). After filtration through an aluminacharcoal-Celite (0.5 + 0.7 + 0.3) column, the filtrate was evaporated to dryness and redissolved in water, which was passed through an octylsilyl reverse phase column. DON was eluted with anhydrous ethyl ether. The residue remaining after the eluate was evaporated to dryness was dissolved in CHCl3-acetonitrile (4 + 1) and chromatographed on AlCVimpregnated silica gel TLC plates. The blue fluorescent DON spot was quantitated fluorodensitometrically after the TLC plate was heated at 120°C for 7 min. Recoveries of DON added to breakfast cereals at 100, 200, and 400 ng/g levels and to syrup and beer at 50, 100, and 200 ng/g levels averaged 86%. The limit of determination in these products was about 50 ng/g.
Thin Layer Chromatographic Method for Determination of Deoxynivalenol in Wheat: Collaborative Study
Authors: Eppley Robert M , Trucksess Mary W , Nesheim Stanley , Thorpe Charles W , Pohland Albert E ,   Collaborators:, Applegate S L , Bean G A , Chang H , Chatel R , Deteghem C van , Gibson G E , Gilbert J , Gross A F , Howell M V , Nowicki T W , Scott P M , Seitz L M , Subryan L , Terhune S , Ware G
Published: February 2020

A collaborative study of a rapid method for the determination of deoxynivalenol (DON) in winter wheat was successfully completed. The method involves sample extraction with acetonitrile-water (84 + 16), cleanup using a disposable column of charcoal, Celite, and alumina, and detection by thin layer chromatography after spraying with an aluminum chloride solution. Each of the 15 collaborators analyzed 12 samples, 2 of which were naturally contaminated, and 10 to which DON was added, in duplicate, at levels of 0,50,100,300, and 1000 ng/ g. Average recoveries of DON ranged from 78 to 96% with repeatabilities of 30-64% and reproducibilities of 33-87%. The results of the study show that false positives were not a problem and that all of the analysts could detect DON at the 300 ng/g level or higher. The method has been adopted official first action.
Absence of Isomerization of Retinyl Palmitate, Retinol, and Retinal in Chlorinated and Nonchlorinated Solvents Under Gold Light
Authors: Landers Gary M , Olson James A
Published: February 2020

Purified solutions of all-trans retinyl palmitate, retinol, and retinaldehyde in chloroform, methylene chloride, or hexane were exposed to white light or gold fluorescent light or were kept in the dark, and the resulting isomer distributions were determined by LC (liquid chromatography). No significant isomerization of any of the retinoids occurred either in the dark or on exposure to gold light in any of the solvents tested. However, a large amount of the 9-cis isomer and only much smaller amounts of other cis isomers were produced when retinol or retinyl palmitate in chloroform or methylene chloride solution was exposed to white light. The isomerization pattern of retinyl palmitate in chloroform was not altered by the addition of free-radical scavengers, addition of an organic base, or substitution of deuterochloroform for chloroform as solvent. Use of other polar solvents such as tetrahydrofuran, acetone, or methanol produced isomer distributions similar to those obtained in chloroform solution. Retinol and retinyl palmitate in hexane solution, on exposure to white light, were isomerized much less extensively than in chloroform or methylene chloride and produced a significant amount of the 13-cis, as well as the 9-cis, isomer. Isomerization of retinaldehyde in chloroform or in methylene chloride solution under white light yielded 13-cis, 11-cis, 9-cis, and 7-cis isomers, in order of decreasing amount, whereas in hexane solution, only the 13-cis and 9-cis isomers were produced in significant quantity
Measurement of Aldrin in Air by Gas Chromatography with Sorbent-FiUed Trapping Tube
Authors: Wallace Brian G , Sherren Andrew J
Published: February 2020

An alternative procedure to the National Institute for Occupational Safety and Health (NIOSH) method has been developed for the determination of aldrin in air. In this alternative procedure, the isooctane gas bubbler is replaced by a stainless steel trapping tube packed with Tenax GC. Radiochemical techniques have been used to validate the use of Tenax GC as an efficient adsorbent for aldrin. The main advantages are a higher trapping efficiency, elimination of the need to replenish frequently the volatile solvent, and the ease of transporting trapping tubes from sampling sites to the laboratory. A sample of 120 L of air is recommended to achieve a limit of determination of 0.04 μg/cu. m.
Determination of Nitrate in Forages by Using Selective Ion Electrode: Collaborative Study
Authors: Carlson Michael P , Schneider Norman R ,   Collaborators:, Everson R , Johnson J , Kosse K , Krause J , McMahon T , Ray A , Ross F , Rottinghaus G , Thiex N , Torma L
Published: February 2020

Each of 10 collaborating laboratories analyzed 4 blind duplicate pairs of forage samples for nitrate, by using a potentiometric method. Two forage controls and a 100 000 mg KNO3/L standard were also provided. Nitrate was extracted into an aqueous Al2(SO4)3 solution containing 70 mg KNO3/L and quantitated with a nitrate-selective electrode. Standards were prepared using extracting solution as diluent. Nitrate concentrations in forage samples ranged from <0.50 to 4.35% KNO3. Repeatability coefficients of variation (CV0) ranged from 1.74 to 3.61%, and reproducibility coefficients of variation (CV1) ranged from 6.92 to 7.66%. Mean recovery of a 0.55% KNO3 spike was 94.5%. The method has been adopted official first action.
Detection of Adulteration in Commercial Cranberry Juice Drinks and Concentrates
Authors: Hong Victor , Wrolstad Ronald E
Published: February 2020

Thirty-one samples of commercial cranberry juice drink and one sample of commercial cranberry juice concentrate were analyzed for nonvolatile acids and anthocyanidin profiles by liquid chromatography (LC). Ultraviolet-visible spectral measurements were used to measure pigment concentration, polymeric color, and percent polymeric color. Nineteen of the 31 samples analyzed were found to be adulterated. The adulterated samples exhibited nonvolatile organic acid profiles indicative of added malic and/or citric acid. Anthocyanidin profiles of the adulterated samples showed the presence of substantial quantities of delphinidin and malvidin, neither of which are present in cranberries in significant amounts. Grape skin extract is believed to be the added colorant.
Identification of O,O-Dialkyl-S-MethyIpnosphorodithioate Residues in Fish
Authors: Yurawecz Martin P , Puma Bart J
Published: February 2020

O,O-Dialkyl-S-methylphosphorodithioates were found in Mississippi River buffalo fish caught near several chemical plants and oil refineries in Hartford and Wood River, IL. These chemicals, which have not been previously recognized as environmental or food contaminants, were identified and quantitated by a procedure similar to the AOAC multiresidue method for organochlorine and organophosphorus pesticides, using gas chromatography (GC) with flame photometric detection (FPD). The key to their identification was a GC/FPD retention time pattern that was virtually the same as that for the diazomethane reaction products of a commercial zinc dialkyl dithiophosphate motor oil additive. GC/mass spectrometry (MS) showed that the compound producing the largest GC/FPD peak contained butoxy groups. The identification of this compound as O,O-di(2-methyIpropyl)-S-methyIphosphorodithioate (Compound C) was confirmed by GC/MS analysis by comparison with the authentic material. The buffalo fish contained 0.15 ppm Compound C and 0.5 ppm total O,O-dialkyl-S-methyIphosphorodithioates. Subsequent analyses of fish from other areas showed that these contaminants were not limited to the Hartford-Wood River area. Lower residue levels of Compound C, ranging from 0.01 to 0.05 ppm, were found in fish from the Mississippi River at Sauget, IL, and from the Delaware River and Newark Bay in NJ.
Harmonization of Collaborative Study Protocols
Authors: Horwitz William
Published: February 2020

The 2 major protocols for the design, conduct, and interpretation of collaborative analytical studies—those from AOAC and the International Organization for Standardization—are already fairly well harmonized. The statistical models are identical and the outlier tests are essentially the same. The major differences are in symbols and terminology and in the specification of the minimum number of laboratories and replicates.
Collaborative Testing of Methods for Food Analysis
Authors: Mälkki Y
Published: February 2020

The complex composition of foods makes their analysis difficult. Results of collaborative tests with food materials often show greater coefficients of variation than with other matrices. Some critical points in collaborative testing of foods are discussed.
View of the International Dairy Federation on Interlaboratory Analytical Studies
Authors: Grappin R
Published: February 2020

The International Dairy Federation develops and studies methods for the analysis of milk and milk products. A first draft of an IDF protocol for conducting interlaboratory studies is presented. Major features of the protocol are type and number of participating laboratories; nature, duplication, and number of sample materials; final design (numbers of samples and laboratories); statistical analysis of the data; report of the final results.
Design and Conduct of Collaborative Studies: CIPAC Collaborative Experience in Pesticide Formulations
Authors: Henriet J , Martijn A
Published: February 2020

CIPAC has set up procedures for carrying out interlaboratory studies on analysis of technical pesticide materials and formulations. CIPAC studies comprise several steps: allocation of leadership; method survey and selection; pre-collaborative trial; full collaborative study; evaluation of results and final decision on acceptance.
Liquid Chromatographic Determination of Monensin in Chicken Tissues with Fluorometric Detection and Confirmation by Gas Chromatography-Mass Spectrometry
Authors: Takatsuki Keigo , Suzuki Shigeru , Ushizawa Isamu
Published: February 2020

An accurate, sensitive method is described for the determination of monensin residue in chicken tissues by liquid chromatography (LC), in which monensin is derivatized with a fluorescent labeling reagent, 9-anthryldiazomethane (ADAM), to enable fluorometric detection. Samples are extracted with methanol-water (8 + 2), the extract is partitioned between CHCl3 and water, and the CHC13 layer is cleaned up by silica gel column chromatography. Free monensin, obtained by treatment with phosphate buffer solution (pH 3) at 0°C, is derivatized with ADAM and passed through a disposable silica cartridge. Monensin-ADAM is identified and quantitated by normal phase LC using fluorometric detection. The detection limit is 1 ppb in chicken tissues. Recoveries were 77.6 ± 1.8% at 1 ppm, 56.7 ± 7.1% at 100 ppb, and 46.5 ± 3.7% at 10 ppb fortification levels in chicken. Gas chromatography-mass spectrometry is capable of confirming monensin methyl ester tris trimethylsilyl ether in samples containing residues >5 ppm.
Determination of Glyphosate Herbicide and (Aminomethyl)phosphonic Acid in Natural Waters by Liquid Chromatography Using Pre-Column Fluorogenic Labeling with 9-Fluorenylmethyl Chloroformate
Authors: Miles Carl J , Wallace Louis R , Moye H Anson
Published: February 2020

An analytical method has been developed for determination of glyphosate herbicide and its major metabolite, (aminomethyl)phosphonic acid (AMFA), in natural waters. Sample pretreatment consisted of filtration, addition of phosphate buffer, concentration by rotary evaporation, and a final filtration before derivatization with 9-fluorenylmethyl chloroformate. The derivatives were separated by anion exchange liquid chromatography and measured with a fluorescence detector. Standard curves were linear over 3 orders of magnitude and minimal detectable quantities were 10 ng/mL for glyphosate and 5 ng/mL for AMPA. The 20-fold concentration factor realized in sample preparation corresponds to ppb method detection limits for glyphosate and AMPA in natural waters. Recovery and storage studies were performed and are discussed.
Determination of Halogenated Phenols in Raw and Potable Water by Selected Ion Gas Chromatography-Mass Spectrometry
Authors: Sithole Bishop B , Williams David T , Lastoria Chester , Robertson John L
Published: February 2020

Pentafluorobenzylation and in situ acetylation are compared in the determination of phenol and halogenated phenols in water samples. The latter technique is considered superior to the former for determining phenols at the ng/L level because of less background interference and better recoveries (80% or better except for pentachlorophenol and trichloroguaiacol which had recoveries of about 60%). Further evaluation of the in situ technique by electron capture gas chromatography and gas chromatography-mass spectrometry shows that the latter, in the selected ion monitoring mode, is more suitable because, unlike GCECD, it can confirm and quantitate all phenols. In particular, GCECD could not detect even high levels of phenol and the monohalogenated phenols. Phenols at 5-473 ng/L were detected in some Canadian drinking water supplies by the in situ acetylation technique combined with GC-MS.
Liquid Chromatographic Determination of Leuco Base in FD&C Blue No. 1
Authors: Scher Alan L , Murray H Dean
Published: February 2020

Methods are described for the determination of leuco base in FD&C Blue No. 1 by reverse phase liquid chromatography and for the preparation and standardization of leuco base stock solution. The stock solution is prepared by reductive titration of the color with TiCl3. Solutions of the color and of leuco base are chromatographed by isocratic elution, which is followed by a wash and equilibration that can be omitted for screening. Peak area and height calibrations were linear. At the specification level, the 99% prediction limits were 5.00 ± 0.14% (area) and 5.00 ± 0.37% (height). Limits of determination were 0.29% (area) and 0.73% (height) at the 99.5% confidence level. Recoveries were 97-101% for leuco base added to FD&C Blue No. 1 at levels of 1-6%.
Development of Poultry Rapid Overnight Field Identification Test (PROFIT)
Authors: Cutrufelli Mark E , Mageau Richard P , Schwab Bernard , Johnston Ralph W
Published: February 2020

A poultry rapid overnight field identification test (PROFIT) has been developed as a screening test which is practical, economical, and easy to perform and interpret for use in field environments to determine the presence of poultry tissue (chicken and turkey) in raw whole tissue or ground/formulated meat products. The basis of the test is an agar-gel immunodiffusion technique used with a printed template pattern and stabilized reagent paper discs. The test shows adequate sensitivity and specificity for its intended purpose. Key components are stable for at least 1 year if they are stored at refrigerator conditions. The design of the test is such that it can be made commercially available as a complete, stable, test kit suitable for use by any type of inspection program concerned with verification of poultry species in meat and/or poultry products that are subject to regulatory or quality controls
Liquid Chromatographic Method for Determination of Oxythioquinox in Technical and Formulated Products: Collaborative Study
Authors: Slahck Stephen C ,   Collaborators:, Aaron L B , Bennett O O , Elliott R M , FontaniUa A O , Jurgens D , Korger P D , Laster W G , Launer J E , Law M W , Lim B M , Muniz J , Polli R L , Schulz R P , Skelly N E , Stroh S , Tengler H
Published: February 2020

A liquid chromatographic method for determination of oxythioquinox (Morestan®) in oxythioquinox technical and formulated products has been developed and collaboratively studied in 14 laboratories. Samples are dissolved in chloroform containing n-valerophenone as an internal standard, diluted with acetonitrile, and analyzed by reverse phase chromatography. Collaborators analyzed blind duplicate samples of oxythioquinox technical and 25 WP. Coefficients of variation were 1.06 and 1.72% for the technical and 25 WP samples, respectively. The method has been adopted official first action.
Gas Chromatographic-Thermal Energy Analysis Method for iV-Nitrosodibutylamine in Latex Infant Pacifiers: Collaborative Study
Authors: Thompson Harold C , Billedeau Stanley M , Miller Barbara J ,   Collaborators:, Clarkson S , Feit M , Hotchkiss J , Miller B , Yu W
Published: February 2020

Each of 5 collaborating laboratories determined volatile N-nitrosamines in 3 blind quadruplicate sets of latex rubber infant pacifier samples, using a gas chromatographic-thermal energy analysis (GCTEA) method. Volatile N-nitrosamines are extracted from cut-up pacifier nipples with CH2C12. The extract is concentrated and subjected to high temperature purge and trap, and the nitrosamines are eluted from the trap and determined by GC-TEA. N-Nitrosodibutylamine (NDBA) was the only nitrosamine found in sufficient concentration to allow analysis. NDBA concentrations of the 3 sets of samples were 82.6,21.0, and 7.12 ng/g rubber. The repeatability relative standard deviations ranged from 7.46 to 24.0% and the reproducibility relative standard deviations from 7.46 to 29.2%. The minimum detectable level of NDBA by this method is 3.6 ng/g rubber. The method has been adopted official first action.
Enumeration of Total Bacteria and Coliforms in Milk by Dry Rehydratable Film Methods: Collaborative Study
Authors: Ginn Roy E , Packard Vernal S , Fox Terrance L ,   Collaborators:, Arnold E , Barnett J , Bulthaus M , Bushman P , Case R , Crevey N , Fenelon M , Fuqua R , Gilman C , Hawkinson J , Heady J , Hendrickson H , Koenig E , Messer J , Mullen R , Phillips M , Santorello J , Slamp R , Wehr M , Zimmerman A
Published: February 2020

Eleven laboratories participated in a collaborative study to compare the dry rehydratable film (Petrifilm® SM and Petrifilm® VRB) methods, respectively, to the standard plate count (SPC) and violet red bile agar (VRBA) standard methods for estimation of total bacteria and coliform counts in raw and homogenized pasteurized milk. Each laboratory analyzed 16 samples (8 different samples in blind duplicate) for total count by both the SPC and Petrifilm SM methods. A second set of 16 samples was analyzed by the VRBA and Petrifilm VRB methods. The repeatability standard deviations (the square root of the between-replicates variance) of the SPC, Petrifilm SM, VRBA, and Petrifilm VRB methods were 0.0S104, 0.0444, 0.14606, and 0.13806, respectively; the reproducibility standard deviations were 0.7197, C.06380, 0.15326, and 0.13806, respectively. The difference between the mean Iog10 SPC and the mean logio Petrifilm SM results was 0.027. For the VRBA and Petrifilm VRB methods, the mean log10 difference was 0.013. These results generally indicate the suitability of the dry rehydratable film methods as alternatives to the SPC and VRBA methods for milk samples. The methods have been adopted official first action.
DNA Colony Hybridization Method Using Synthetic Oligonucleotides to Detect Enterotoxigenic Escherichia coli: Collaborative Study
Authors: Hill Walter E , Wentz Barry A , Payne William L , Jagow James A , Zon Gerald ,   Collaborators:, Boutin B K , Codor J , Crouch R J , Forney E D , Gemski P , Jagow J A , Kaper J B , Madzo S C , Meyer R , Moseley S L , Murray B E , Noah C W , Rhea U S , Rubin F A , Ruby R M , Singleton E , Tardio J L , Varney G W , Weagant S D , Wohlhieter J A , Womble D D , Wong P , Zink D L
Published: February 2020

The genes that encode several of the enterotoxins produced by Escherichia coli have been cloned by recombinant DNA techniques. When the nucleotide sequence of these genes is determined, defined sequence oligonucleotides that include a part of these genes may be synthesized. A 22-base DNA hybridization probe was produced for each of 2 heatstable E. coli enterotoxin (ST) genes: STH, from strains originally isolated from humans; and STP, from strains first found in pigs. For this study, 32P end-labeled DNA probes, sonicated calf thymus DNA, and 3 known and 20 unknown (10 ST-positive and 10 ST-negative) strains were sent to each of 23 collaborators. Cultures were spotted onto an agar-based medium and grown into colonies, which were transferred by blotting to cellulose filters, lysed by alkali and steam, and used for DNA colony hybridization with the ST DNA probes. Strains containing an ST gene were recognized as dark spots on an autoradiogram. Of the 460 samples analyzed, 440 (95.7%) were correctly classified by the collaborators. The method has been adopted official first action.
Determination of Sulfite in Food by Flow Injection Analysis
Authors: Sullivan John J , Hollingworth Thomas A , Wekell Marleen M , Newton Richard T , Larose Jack E
Published: February 2020

A method is described for the determination of sulfite levels in food products by flow injection analysis (FIA). The method is based on the decolorization of malachite green by S02, which is isolated from the flowing sample stream by means of a gas diffusion cell. The FIA method has a detection limit in food sample extracts of 0.1 ppm S02 (3 times peak height of blank), which corresponds to 1-10 ppm S02 in a food product, depending on the extraction procedure used. At the 5 ppm SO2 level in a food extract, the precision of replicate injections is ± 1-2%. The method was tested on a variety of both sulfite-treaied and untreated food products and the results compared favorably with those obtained by the Monier-Williams, colorimetric (pararosaniline), and enzymatic (sulfite oxidase) methods. The average differences from the FIA results were 19, 11, and 12%, respectively, for those samples (n = 12) above SO ppm S02. At lower levels the results were somewhat more erratic due to inaccuracies of the various methods at low concentrations.
Analysis of Eleven Triazines in Natural Waters
Authors: Lee Hing-Biu , Stokker Yvonne D
Published: February 2020

A gas chromatographic method was developed for the analysis of 11 triazine herbicides in natural waters. Triazine residues were extracted from water by methylene chloride and cleaned up on a 10% deactivated Florisil column, using 3% methanol in benzene as eluant. Extracts were quantitated, in 2 separate runs, on an Ultrabond 20M and a 3% OV-1 column connected to a nitrogen-phosphorus detector. These extracts could also be analyzed on a 30 m DB-1 capillary column in a single run. This method has been validated at 10, 1, and 0.1 u.g/L by using fortified distilled water and Lake Ontario water, and was also validated at 1.0 μg/L with 2 other natural water samples. Recoveries of the 11 triazines at all levels of fortification were between 87 and 108%, except simetone and simetryne were about 80% recovered in a few cases. Detection limit for all 11 triazines in this method is 0.025 μg/L.
Determination of Residues of Alachlor and Its Metabolite in Corn, Soybeans, and Potatoes as Heptafluorobutyryl-2,6-Diethylaniline
Authors: Newsome W Harvey , Collins Peter , Lewis David
Published: February 2020

Alachlor [2-chloro-2'6'-diethyl-N-(methoxymethyl)acetanilide] was determined by hydrolysis to 2,6-diethylaniline with 6N HC1 and quantitation of the heptafluorobutyryl derivative by gas chromatography with electron capture detection. 2,6-Diethylaniline was isolated from the hydrolysate by steam distillation, derivatized with heptafluorobutyric anhydride, and the derivative was purified by chromatography on silicic acid with 60% toluene in hexane as eluant. Recoveries from potatoes, soybeans, and corn spiked at levels from 3 to 26 ppb averaged 81,90, and 96% respectively.
Determination of the Composition of Gentamicin Sulfates by 1H and 13C Nuclear Magnetic Spectroscopy
Authors: Busson Roger , Claes Paul J , Vanderhaeghe Hubert
Published: February 2020

The British Pharmacopoeia test controlling the composition of gentamicin sulfate is based on CW 60 MHz magnetic resonance spectroscopy. Application of this method to FT 90 MHz spectra was evaluated. Results clearly show the limitations of this technique and point out the need for more reliable assay methods. Thus a 13C nuclear magnetic resonance (NMR) procedure for quantitative analysis of gentamicin sulfate was developed. Ratios of 4 gentamicin components (C1, C2, C1., and C2.) were obtained from peak height measurements of selected resonance signals in spectra recorded under steady-state conditions. Relative response factors were determined from spectra of a reference mixture or, alternatively, from spectra of the individual pure components. Results obtained by the 13C NMR method were in agreement with those obtained by liquid chromatography using pre-column derivatization.
Liquid Chromatographic Determination of Coumarin Anticoagulants in Tablets
Authors: Moore Ella , Lau-Cam Cesar
Published: February 2020

A simple and rapid liquid chromatographic method is described for the qualitative and quantitative determination of 5 coumarin anticoagulants in tablet composites and individual tablets. Analyses are carried out on a C18 reverse phase column using tetrahydrofuran-methanol-water-acetic acid (35 + 10 + 65 + 0.1) as mobile phase and photometric detection at 311 nm. The coefficients of variation for 10 consecutive injections of a mixed standards solution ranged from 0.28% for ethyl biscoumacetate to 0.78% for acenocoumarol. Standard recoveries were as follows: acenocoumarol, 99.3%; dicumarol, 99.6%; phenprocoumon, 101.6%; and warfarin sodium, 99.0%. The method was linear between 2 and 8 μg of drug injected. Assay results agreed favorably with those of the USP XX methods for dicumarol, phenprocoumon, and warfarin, and the NF XIV method for acenocoumarol. In addition, close correspondence was found with the results previously reported for the same drugs by a semiautomated spectrophotometric method. The content uniformity testing of individual 50 mg dicumarol tablets and 5 mg warfarin sodium tablets by the proposed method gave average (SD) values of 100.32% (0.64) and 101.00% (0.14), respectively, whereas these values were 101.60% (1.81) and 101.80% (0.18), respectively, by the method of USP XX.
Liquid Chromatographic Determination of Spiramycin Residues in Chicken Tissues
Authors: Nagata Tomoko , Saeki Masanobu
Published: February 2020

A liquid chromatographic (LC) method is described for determination of spiramycin residues in chicken muscles. The drug is extracted from muscles with acetonitrile, the extract is concentrated to 3-4 mL and rinsed with n-hexane followed by ethyl ether, and the drug is extracted with chloroform. LC analysis is carried out on a Zorbax BP-C8 column, and spiramycin is detected spectrophotometrically at 231 nm. Recoveries of spiramycin added to chicken muscles at 0.2 and 0.1 ppm were 93.9 and 89.0%, respectively. The detection limit was 5 ng for spiramycin standard, and 0.05 ppm in chicken muscles.
Determination of Morantel-Related Residues in Bovine Milk by Electron Capture Gas Chromatography
Authors: Lynch Martin J , Burnett Donald M , Mosher Franklyn R , Dimmock Mary E , Bartolucci S Richard
Published: February 2020

A gas chromatographic assay was developed to determine major residues of morantel in bovine milk over a range that is suitable for monitoring residues of the drug. The method is based on hydrolysis of the N-methyl-tetrahy dropyrimidine portion of morantel and its metabolites to N-mefhyl-1,3-propanediamine, and converting the diamine to an N,N-bis-(2-nitro-4-trifluoromethylphenyl) derivative. The addition of an internal standard, the N-desmethyl-N-ethyl homolog of pyrantel, to the milk sample circumvents any potential problem that could arise from variable reaction yields, and eliminates the true recovery as a factor affecting the accuracy and precision of the procedure. The concentrations of the derivatives are determined by pulsed electron capture gas chromatography over a linear dynamic range that is equivalent to 12.5-50 ppb morantel. The method was evaluated at the 0, 12.5,25, and 50 ppb levels in fortified bovine milk, and in a withdrawal sample containing physiologically incurred morantel residues. Mean values of 14 ± 1.7,24 ± 3.7, and 47 ± 6.9 were found for the fortified samples, approximately 3 ppb for control milk, and 16 ± 1.7 ppb for the withdrawal sample.