bluuebunny/crossref_metadata_2025 huggingface dataset:
New Liquid Membrane Electrode for Determination of Lidocaine in Local Anesthetic Formulations
Authors: Hassan Saad S M , Ahmed Mona A
Published: February 2020

A new lidocaine-responsive liquid membrane electrode based on the use of the lidocaine reineckate ion pair complex in nitrobenzene solvent has been developed. The electrode displays a linear response for 10-2-10-5M lidocaine over the pH range of 3-6.5. The response time varies from 35 s to 1 min depending on the lidocaine concentration. The life span of the electrode is at least 1 month. Excipients and diluents commonly used in local anesthetic formulations do not interfere. Determination of lidocaine in some pharmaceutical preparations gives results with an average recovery of 99% of the nominal values and a mean standard deviation of 1.7% which compare favorably with those obtained by the U.S. Pharmacopeia method.
Gas Chromatographic Determination of Propachlor in Pesticide Formulations: Collaborative Study
Authors: Tomkins David F ,   Collaborators:, Caparoon W C , Galoux I M , Gentry G M , Hodgins W E , Koenig D K , Law M W , Lee B , Liu J , McAfee S E , Spencer D A , Speth R M , Torma L
Published: February 2020

An isothermal gas chromatographic (GC) method for measuring propachlor in formulations was tested by 12 collaborators. Samples are prepared in acetone and determined using a GC column of 10% SP-2250 on 100-200 mesh Supelcoport, and diisobutyl phthalate as internal standard. Collaborators made single determinations on each of 2 similar materials (matched pairs) on 2 days for 3 pairs of samples. The study generated 62 matched pairs which were used in Youden’s matched pair calculations. The coefficients of variation (CV,) for flowable formulations were 0.84 and 1.48%; the CV, for the granular formulation was 1.28%. The method was simple to use and did not reveal any interferences in the samples tested. The method has been adopted official first action as an AOAC-CIPAC method.
Problems of Official Methods and New Techniques for Analysis of Foods and Feeds for Vitamin A
Authors: Thompson James Neville
Published: February 2020

The official methods for measuring vitamin A and carotene in foods and feeds have evolved over several decades. New procedures are needed to permit the use of modern analytical techniques such as liquid chromatography (LC), and to expand the application of official methods to a wide variety of foods. Recent improvements in methodology are reviewed. Emphasis is often placed on the separations achieved by LC, but all factors that affect quantitation, such as sampling, preparation of standards, and protection of the vitamin against oxidation, must be considered in the development of new methods. Many approaches to analysis are possible because of the versatility of LC but not all of them can be used in official methods. Methods for milk, margarine, and feeds can be prepared now for collaborative assays. Although straightforward methods can be developed for the measurement of βcarotene in certain foods, a full examination of provitamins will probably continue to require a flexible approach and special expertise.
How to Produce a Research Report With Ease and Elegance (or How to Publish and Not Perish in the Process)
Authors: Schick Renee
Published: February 2020

Microcomputers can be used by scientists to search online bibliographic sources and to integrate the references into a research report. Commercial programs, such as Sci-Mate, are available to aid in the search of online databases, and the storage of retrieved references and abstracts.
Data Transmission Through the Telephone Network: Protocols, Pitfalls, and Some Examples
Authors: Venable Richard M
Published: February 2020

Invariably, the situation arises where it is desirable to transfer data from one computer to another, especially from small laboratory systems, word processors, or home computers to large mainframe computers. In many of these cases, there are no common storage media; home computers do not have 9-track tape drives and large mainframes do not have 5¼ in. floppy disk drives. Transmission of data through the telephone network is a viable method for data transfer, which is paradoxically both easier than many believe and more difficult than some may claim. One of the keys to successful data transmission is an understanding of telecommunications protocols, i.e., the rules governing intersystem communication through the telephone network. Some of the most common protocols allow exchanging ASCII-coded data at either 300 or 1200 baud. A variety of computer systems can be used, including IBM and DEC mainframes, a Wang word processor, an IBM PC-compatible microcomputer, and the Atari 800 microcomputer. A specific example is the use of the Atari 800 as an APL terminal, complete with the custom character set, standard ASCII text, and data transfer.
Electron Impact Mass Spectroscopy for Identification of Phencyclidine
Authors: Clark Charles C
Published: February 2020

The electron impact mass spectrum of phencyclidine (PCP) was studied using both deuterium-labeled analogs and high-resolution mass spectroscopy. The deuterium-labeled compounds used were d5.PCP having 5 deuterium atoms on the phenyl ring, d10.PCP having 10 deuterium atoms on the cyclohexyl ring, and d15.PCP having deuterium atoms on both the phenyl and cyclohexyl rings. The identities of some major fragments and some possible pathways for their formation are shown. Electron impact mass spectroscopy is shown to be a definitive test for the identification of PCP.
Accuracy of Gercock™ Milkfat Test Bottles: Collaborative Study
Authors: Bradley Robert L ,   Collaborators:, Albright G , Alioto P , Deaver J , Fleming R , Riesterer B , Stukenberg D , Thompson W , Treleven J , Ward S
Published: February 2020

No novel approaches to improving the accuracy of the Babcock test glassware for milkfat determination have appeared in years. Recent development of a test bottle wherein the calibrated neck of a Gerber bottle was attached to the bulb of a Babcock bottle showed promise. When the normal calibrated portion of the neck was changed from 8% to 5%, accuracy was further improved. Divisions between each percentage mark allowed 2× the accuracy in reading. Eight qualified testing laboratories collaboratively studied both 8% and 5% Gercock milkfat test bottles, using the AOAC method 16.065. Results were similar to those obtained by the Mojonnier method. Standard deviations were smaller among laboratories when the 5 % Gercock test bottle was used. Use of the 5% Gercock bottle has been adopted official first action as an addition in 16.065.
Distillation Method for Determination of Moisture in Spices: Collaborative Study
Authors: Sanna Louis A ,   Collaborators:, Bennett R , Bruce W , Edwards F , Guarino P , Ikeda T , Loney E , Monaco D , Pasek R , Rosner L , Sica S , Sloane R , Williams T , Woodbury J
Published: February 2020

AOAC method 30.005 for determination of moisture in spices by distillation was collaboratively studied to revalidate its reliability. Using toluene as the solvent system, repeatability and reproducibility were acceptable for basil. Using hexane as the solvent for red pepper produced less satisfactory results. The method has been adopted official first action.
Gas Chromatographic Method for Ethylene Dibromide in Grains and Grain-Based Products: Collaborative Study
Authors: Sawyer Leon D , Walters Stephen M ,   Collaborators:, DeCocco F , DePalma R , Ferm R L , Grieb J , Henderson L , Maxstadt J J , McCarthy J , Nowak G W , Pardue J R , Richelieu M E , Saudarg D
Published: February 2020

Nine laboratories analyzed samples of whole grain, intermediate, and ready-to-eat products for ethylene dibromide (EDB) residues. Supplied samples of wheat, rice, and flour contained both fortified and incurred EDB; corn bread mix, baby cereal, and bread contained only fortified EDB. The whole grains and intermediates were analyzed by the same basic procedural steps as in the official method for multifumigants: They were extracted by soaking in acetone-water (5 + 1). The baby cereal and bread were analyzed by a modification of the Rains and Holder hexane co-distillation procedure. EDB was determined by electron capture gas chromatography operated with an SP-1000 column. All products contained 3 different levels of EDB and were analyzed as blind duplicates. Overall mean recoveries ranged from 85.2% for 69.6 ppb to 105.0% for 4.35 ppb, both in baby cereal. Interlaboratory relative standard deviations ranged from 5.7% for 869 ppb in wheat to 20.2% for 69.6 ppb in baby cereal, both fortified. Mean levels of incurred EDB in wheat, rice, and flour were 926.7, 982.0, and 49.9 ppb, respectively; corresponding relative standard deviations were 9.9, 7.7, and 13.1%. The method was adopted official first action.
Simplified Cleanup and Capillary Gas Chromatographic Analysis of Residues of Aldicarb and Its Oxidation Products in Chrysanthemum Leaves
Authors: McGarvey Brian D , Chiba Mikio , Broadbent A Bruce
Published: February 2020

An efficient simplified method for the extraction, cleanup, and capillary gas chromatographic (GC) analysis of residues of aldicarb, aldicarb sulfoxide, and aldicarb sulfone in chrysanthemum leaves is presented. Samples are extracted with methanol and cleaned up using columns consisting of 0.2 g Nuchar-Attaclay in disposable pipets. The 3 compounds are easily quantitated by capillary GC with splitless injection and thermionic-specific detection. Recovery of the 3 compounds at 2 levels from spiked leaves ranged from 74.3 to 90.9%. The detection limit of the GC analysis, with a 1 μL injection, is 0.01 μg/mL for aldicarb and aldicarb sulfone, and 0.06 p.g/mL for aldicarb sulfoxide.
Liquid Chromatographic Determination of Fluridone Aquatic Herbicide and Its Metabolite in Fish and Crayfish
Authors: West Sheldon D , Day Edgar W
Published: February 2020

A residue method is described for determination of the aquatic herbicide fluridone (1-methy1-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)- pyridinone) and its metabolite (1-methy1-3-(4-hydroxyphenyl)-5-[3- (trifluoromethyl)phenyl]-4(1H)-pyridinone) in fish and crayfish tissues. Both compounds are extracted from tissues with methanol, and the extracts are subjected to acidic hydrolysis to release conjugated forms of fluridone and the metabolite. Sample extracts are purified by liquidliquid partitioning and Florisil Sep-Pak® column chromatography. Both compounds are separated and measured by reverse phase liquid chromatography with UV detection at 313 nm. In the absence of interfering peaks, the method has a detection limit of approximately 0.04 ppm of either compound. Overall, recoveries averaged 96% for fluridone and 78% for the metabolite for all tissue types combined.
Atomic Absorption Spectrometric Determination of Calcium, Copper, Iron, Magnesium, Manganese, Potassium, Sodium, and Zinc in Animal Feeding Stuffs: Interlaboratory Collaborative Studies
Authors: Ruig Willem G De ,   Collaborators:, Gast C H , Grimbergen A H M , Guis B , Hoekman B J , HoUman P C H , Hoogh P de , Huijbregts A W M , Leeuwen J van , Meer J M van der , Moh Oey Teng , Teunis G P , Vertregt N , Veen N G van der
Published: February 2020

A draft standard method is presented for the determination of Ca, Cu, Fe, Mg, Mn, K, Na, and Zn in animal feeding stuffs. The method specifies dry ashing of samples and detection by atomic absorption spectrometry (AAS). The applicability of the method for various concentrations of the elements was tested in a series of 3 collaborative studies. The feeding stuffs investigated include pulp pellets, grass, mixed feed, fish meal, milk powder, maize, sheep feed, lupin, milocorn, feather meal, and blood meal. Relative standard deviations, repeatability, and reproducibility are given. The reproducibility of the method was acceptable for the following approximate minimum quantities: Na and K, 1000 mg/kg; Ca and Mg, 100 mg/kg; Zn, Mn, and Cu, 10 mg/ kg; Fe, 10-200 mg/kg, depending on the product.
Thin Layer Chromatographic Identification of Phenothiazine Derivative Drugs: Interlaboratory Study
Authors: Steinbrecher Kurt ,   Collaborators:, Brunner C A , Newton J M , Newton R T , Robinette M L , Santiago A , Scroggins H S , Sics U , Wojtowicz E J
Published: February 2020

A thin layer chromatographic method for the identification of phenothiazine derivative drugs was studied collaboratively by 8 laboratories. Twenty phenothiazine drugs were examined by each collaborator. The identification scheme depends on the color of the sprayed spots and the Rf values relative to the Rf of chlorpromazine (RCHL) in 4 solvent systems. In 98.13% of the cases, a correct identification could be made; the remaining drugs were reduced to a choice between pairs of phenothiazines. With respect to chlorpromazine, the data showed a significant decrease in variability of RCHL values compared with Rf values in the 4 solvent systems.
Gas Chromatographic Determination of Lindane (Gamma Isomer of BHC) in Maneb-Lindane Liquid Pesticide Formulations
Authors: Grorud Robert B
Published: February 2020

Lindane from liquid insecticide-fungicide formulations containing lindane with maneb can be determined by gas chromatography using 3% OV-1 or 5% SE-30 columns. Lindane is extracted with acetone, and an aliquot is diluted to volume with anhydrous methanol and injected on-column. The internal standard, diethyl phthalate, has a retention time of 6 min and lindane has a retention time of 12 min, allowing injection every 15 min. Within-laboratory analysis of 3 typical formulations indicates good precision with coefficients of variation ranging from 0.45 to 1.58%. The method can be easily adapted to other liquid or dust formulations of lindane
Determination of Ochratoxin A in Animal Feed and Cereal Grains by Liquid Chromatography with Fluorescence Detection
Authors: Cohen Huguette , Lapointe Michel
Published: February 2020

A liquid chromatographic (LC) method is described for determination of ochratoxin A in animal feeds and cereal grains. Samples are initially extracted with chloroform-ethanol (8 + 2) and 5% acetic acid in water. Extracts are purified using a silica gel cartridge followed by a cyano cartridge. The samples are evaporated, diluted to a known volume, and analyzed using a 10 cm column of 3 μm Cm and a fluorescence detector. The method was applied to a variety of animal feeds and cereal grains at levels of 1.0-0.005 ppm added ochratoxin A. The overall recovery was 90.6% ± 3.6.
Analytical Methods for Measuring Uric Acid in Biological Samples and Food Products
Authors: Pachla Lawrence A , Reynolds Donald L , Wright D Scott , Kissinger Peter T
Published: February 2020

Daring the last 7 decades, uric acid methodology has kept pace with the introduction of state-of-the-art technology (e.g., spectroscopy, electrochemistry, chromatography) or the discovery of unique chemical processes (e.g., redox, enzymatic). We envision this practice will continue in the future. There never will be a single analytical method applicable for biofluids or foodstuffs. Therefore, it is imperative that the analyst not only understand the advantages and disadvantages of a procedure, but also thoroughly understand its underlying chemical and technological principles. Since many procedures available for analysis of biofluids and foodstuffs rely on identical chemical or technological principles, this report shall review both sample types and the available spectroscopic, electroanalytical, and chromatographic methods
Use of Solid Phase Florisil Cartridges to Separate Fat from Semivolatile Organic Compounds in Adipose Tissue
Authors: Chiang Tom C H , Liao Wenta , Williams Llewellyn R
Published: February 2020

A quick method for separation of semivolatile organic compounds from fat in adipose tissue has been developed. This method uses commercially available solid phase cartridges for sample cleanup. The results indicate that the recoveries, from hexane-extracted fat, of 4 representative classes of organic compounds range from 86.2 to 116%. The solid phase cartridges provide excellent separations of the fat from the analytes; no extraneous interference peaks were detected in the gas chromatograms. The method requires only 0.1 g sample and is quick and simple to use. Although results are reported for samples containing 1-14 ppm, the final extract can be concentrated to a volume allowing detection between 10 and 100 ppb.
Determination of Sulfur Dioxide in Foods by Modified Monier-Williams Distillation and Polarographic Detection
Authors: Stonys Dalia B
Published: February 2020

A rapid, sensitive polarographic method is presented for determining sulfiting agents in foods and beverages. The method is based on the modified Monier-Williams distillation followed by polarographic detection by differential pulse polarography or square wave voltammetry. A clearly defined wave is obtained by both techniques, with a current maximum at a potential (E) of about -600 mV vs an Ag/ AgCl reference electrode. The reaction is based on the reduction of sulfur dioxide at a dropping mercury electrode. Peak current was linear over the range 0-20 μg/mL. Quantitation is done by linear regression analysis of standard addition data or by using a standard calibration graph. Screening levels of less than 1 ppm total S02 were easily achieved in the foods analyzed, which had levels from less than 1 ppm (cereals) to thousands of parts per million (dried fruit). Recoveries from fortified samples ranged from 70 to 108% at fortification levels of 20, 100, and 1000 μg/g.
Mass Spectral Investigations on Trichothecene Mycotoxins. II. Detection and Quantitation of Macrocyclic Trichothecenes by Gas Chromatography/Negative Ion Chemical Ionization Mass Spectrometry
Authors: Krishnamurthy Thaiya , Sarver Emory W , Greene Sharon L , Jarvis Bruce B
Published: February 2020

A general, sensitive gas chromatographic/negative ion chemical ionization mass spectrometric (GC/NICIMS) method of analysis was developed for the detection and quantitation of several polar, thermally labile, toxic macrocyclic trichothecenes. The procedure involves the conversion of the molecules to their corresponding alcohols (verrucarols) by alkaline hydrolysis, followed by derivatization of the hydrolysate with heptafluorobutyrylimidazole and analysis by GC/MS technique under negative ion chemical ionization conditions. Nanogram (250 ng) quantities of several macrocyclic trichothecenes with different verrucarol and ester moieties were analyzed successfully with good precision by this procedure. The method was applicable for the accurate determination of at least low ppb levels of these macrocyclic trichothecenes in environmental samples, such as fungal products, fermentation broths, and plant samples. This is the first reported, well developed, sensitive, and applicable method for the detection and quantitation of these compounds in naturally occurring samples.
Quantitative Determination of Total Glucosinolates in Rapeseed and Meal Digests
Authors: Saini Harpal S , Wratten Neil
Published: February 2020

A method has been developed for the quantitative determination of total glucosinolates in enzymic digests of seeds and meals of rapeseed cultivars. The method is based on the determination of the glucose released after myrosinase digestion and subsequent deproteinization, using the glucose oxidase-peroxidase system with 4-aminophenazone as the oxygen acceptor. The myrosinase was prepared from white mustard seeds and partially purified to remove other glucose-liberating enzyme activities. Endogenous enzyme activities in the samples analyzed were also removed by heat treatment before analysis. These conditions allow a rapid and specific estimation of total glucosinolates that is particularly useful in rapeseed breeding programs. The parameters affecting the optimum yield of hydrolytic product (glycose) from the seeds of 2 rapeseed varieties known to contain a high (cv. Target) and a low (cv. Tower) level of glucosinolate contents have been examined. Addition of glucose to the digestion mixtures gave good recoveries (95%) and close agreement between replicates (±5%).
Determination of Residual Chlorinated Solvents in Decaffeinated Coffee by Using Purge and Trap Procedure
Authors: Heikes David L
Published: February 2020

A purge and trap method developed for the analysis of volatile halocarbons (VHCs) in table-ready foods has been applied to the determination of residual chlorinated solvents in decaffeinated coffee. Samples are stirred in water and purged with nitrogen for 0.5 h in a water bath at 100°C. The analytes are collected on a duplex trap composed of Tenax TA and XAD-4 resin, eluted with hexane, and determined by gas chromatography (GC) with a thick-film, widebore capillary column and Hall electrolytic conductivity detector. The higher levels of residual chlorinated solvents are also confirmed by full scan GC/mass spectrometry. Samples are analyzed for several chlorinated solvents including methylene chloride, chloroform, 1,2-dichloroethane, methyl chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene. Eleven decaffeinated instant coffees and 14 decaffeinated ground coffees representing 9 different commercial brands were analyzed by this method. Residues of methylene chloride, chloroform, methyl chloroform, and trichloroethylene were found. Highest levels occurred in ground coffees—up to 640 ppb methylene chloride. Recoveries of these 4 chlorinated solvents detected from fortified samples ranged from 96 to 106%. Brews from 3 instant and 3 ground coffee samples contained up to 1.1 ppb and 4.8 ppb methylene chloride, respectively. In addition, the resulting grounds from the brewing process were analyzed and contained up to 14 ppb methylene chloride and up to 13 ppb trichloroethylene. The limit of quantitation for these coffee grounds was 4 ppb for methylene chloride. Chromatograms from this purge and trap method are clean, enabling levels of about 10 ppb and 0.4 ppb to be achieved for chlorinated solvents in decaffeinated coffees and their brews, respectively.
Gas Chromatographic Method for Determination of Permethrin in Pesticide Formulations: Collaborative Study
Authors: Tyler J F C
Published: February 2020

A gas chromatographic method for determination of permethrin in technical and formulated products has been developed and subjected to a collaborative study involving 19 participating laboratories. Each sample was dissolved in methyl isobutyl ketone containing n-octacosane as internal standard and analyzed by gas chromatography on a glass column with 3% OV-210 on Chromosorb W-HP. Each collaborator was furnished with reference standard and 5 samples of technical material (90-95%), 8 emulsifiable concentrates (10-50%), 2 wettable powders (20-30%), one dustable powder (1-2%), and one mter-dispersible granules (1-2%) for analysis. The coefficients of variation of the results obtained ranged from 0.79 to 4.24%. The method has been adopted as official first action by AOAC.
Amino Acid Analysis for Meat Protein Evaluation
Authors: Ashworth Raymond B
Published: February 2020

The Food Safety and Inspection Service procedure for determination of essential amino acid content of mechanically processed products from red meat animals and poultry is based on hydrolysis of a powder prepared by blending samples in acetone-chloroform. The hydrolysis procedure incorporates thioglycolic acid to prevent loss of tryptophan. Aliquots of prepared hydrolysates are injected into a liquid chromatographic system, using gradient elution on an ionexchange column for separation. The system also uses post-column hypochlorite oxidation coupled with orthophthalaldehyde reagent and fluorescence detection. Modification of the elution program allows concurrent determination of tryptophan with minimal added cost. Chromatograms from beef, pork, and poultry products show adequate separation and quantitation of β-alanine, 1-methyl-histidine, and 3-methyl-histidine, indicating that the procedure could be used to estimate muscle content of products. A colorimetric procedure for assay of hydroxyproline was introduced and validated as an adjunct method for protein quality estimation.
Liquid Chromatographic Determination of Acetaminophen in Tablets: Collaborative Study
Authors: Krieger David J
Published: February 2020

A reverse phase liquid chromatographic method previously reported for the determination of acetaminophen in tablets was collaboratively studied by 5 laboratories. Each collaborator received duplicate samples of a synthetic tablet formulation and 3 powdered commercial tablet composites. The composites represented single-component and multi-component proprietary products and a single-component generic product. The pooled repeatability (CVD„) and reproducibility (CVDJ values for the proprietary tablets were 0.89 and 1.34%, respectively. For the generic tablets, these values were 0.66 and 0.74%, respectively. The pooled recovery value for acetaminophen added to the synthetic formulation was 98.9 ± 0.7% (n = 10) with a CV of 0.75%, CVD„ of 0.37%, and CVD„ of 0.78%. The overall repeatability of the method was 0.64%, and the overall reproducibility was 0.95%. The method has been adopted official first action.
Sulfuric Acid Cleanup and KOH-Ethanol Treatment for Confirmation of Organochlorine Pesticides and Polychlorinated Biphenyls: Application to Wastewater Samples
Authors: HernÁndez Felix HernÁndez , Benet Francisco J.LÓpez , Escriche Julio Medina , Ubeda Juan C.BarberÁ
Published: February 2020

The efficacy of sulfuric acid cleanup and KOH-ethanol hydrolysis confirmation was studied for 22 organochlorine pesticides and 2 polychlorinated biphenyls (PCBs). Mean recoveries for different treatment times are given. The method was applied to analysis of several wastewater samples by gas chromatography with electron capture detection. Organochlorine compounds were extracted by using separatory funnels and 15% diethyl ether in hexane as extractant. All the compounds studied could be analyzed except trifluralin, dichloran, dieldrin, and endrin, which were destroyed after treatment with concentrated H2S04. The pesticides found most commonly in the samples analyzed were fenson, tetradifon, lindane, methoxychlor, and dicofol.
Pesticide Residues in Lake Albufera, Valencia, Spain
Authors: Carrasco Jose M. , Planta Milagros , Gomez-Casals Vicente , Moragues Vicente
Published: February 2020

Analysis of water samples from the lake in Albufera, Valencia, indicates that the pesticides molinate, benthiocarb, and fenitrothion do not reach levels that are lethal to fish.
Microwave Oven Drying Method for Total Solids Determination in Tomatoes:Collaborative Survey
Authors: Wang Samuel L.
Published: February 2020

A survey was conducted among 8 laboratories in Ontario to check the reproducibility and accuracy of their microwave solids analyzers for total solids determination in tomatoes, using the official AOAC microwave oven drying method. This study showed that the reliability of the AOAC method was closely related to the performance of the microwave solids analyzer for tomato samples. Certification of microwave solids analyzers was recommended to assure the validity of analytical results by the AOAC method.
Comparison of Emmerie-Engel Method and Gas Chromatographic Method for Determination of Supplemental α-Tocopheryl Acetate in Feed Concentrates
Authors: Labadie Michael P , Boufford Charles E
Published: February 2020

The determination of supplemental a-tocopheryl acetate in high potency vitamin E powders and oils was compared using the Emmerie- Engel method and gas chromatography (GC). The Emmerie-Engel reaction requires saponification, extraction of the saponiflable fracaon, and quantitation by colorimetry. GC analysis requires only an extraction and/or dilution before quantitation. These are represented essentially by AOAC methods 43.147-43.151 (colorimetry) and 43.152-43.159 (GC) for high potency vitamin E concentrates. Each method was statistically evaluated for precision and sample-to-sample reproducibility. Each Emmerie-Engel value was divided by the GC value obtained for the same sample; an average of 1.049 with a coefficient of variation of 2.89% was obtained. It was concluded that (he GC procedure was superior to the Emmerie-Engel method, and ahould be the official procedure for determination of supplemental a-tocopheryl acetate in feed concentrates.
Simultaneous Analysis of Nivalenol and Deoxynivalenol in Cereals by Liquid Chromatography
Authors: Lauren Denis R , Greenhalgh Roy
Published: February 2020

A sensitive method is described for determination of nivalenol (NIV) and deoxynivalenol (DON) in cereals by using reverse phase liquid chromatography and UV detection at 222 nm. The sample is extracted with acetonitrile-water (85 + 15) and an aliquot is purified by passage through a combined column of cation exchange resin and alumina-carbon (20 + 1). Analysis at this stage is possible with some samples but the method recommends passing an aliquot through a carbon minicolumn after evaporation and solubilization in methanol. Interference from coextracted compounds at this point is negligible. Recoveries of both NIV and DON from spiked extracts taken through the full method were in the range 83-94%. The relative standard deviation, based on 5 replicate determinations from each of 2 corn samples, was approximately 5% for both NIV and DON. With a 10 fiL injection, the minimum contamination (3 x signal/noise ratio) able to be detected in cereal samples was about 0.015 μ NIV/g and 0.05 μ DON/g. The cleaned up extracts are also suitable for analysis by gas chromatography.
Identification of Mammalian Feces by Coprostanol Thin Layer Chromatography: Method Development
Authors: Hoskin George P , Bandler Ruth
Published: February 2020

Existing methods for the identification of mammalian fecal particles in foods have not heen completely satisfactory because visual identification of small particles is difficult. In addition, identification of feces by determining the presence of fecal alkaline phosphatase is limited to specimens in which the enzyme has not been inactivated, and it does not work well with feces from herbivores. A new method has been developed which uses coprostanol as a fecal indicator. Coprostanol is a heat-stable sterol found in the feces of mammals and some birds. A hexane extract of the suspect particle is applied to the preadsorbent zone of a silica gel thin layer chromatography plate which has been impregnated with 5% phosphomolybdic acid in ethanol. The plate is developed in diethyl ether-heptane (55 + 45), heated, and examined visually for the presence of coprostanol. Amounts of rat feces as small as 0.15 mg and cow feces as small as 0.5 mg have been identified using this method.
Determination of Desaminosulfamethazine, Sulfamethazine, and N4-Acetylsulfamethazine by Gas Chromatography with Electron Capture Detection and Confirmation by Gas Chromatography-Chemical Ionization Mass Spectrometry
Authors: Matusik Jean E , Guyer Greg C , Geleta Jaroslav N , Barnes Charlie J
Published: February 2020

An electron capture gas chromatographic method for the determination of sulfamethazine was modified to separate and quantitate simultaneously sulfamethazine and 2 of its metabolites, N4-acetylsulfamethazine and desaminosulfamethazine. The modified method was applied to incurred residues in a veal calf depletion study and to incurred residues in swine tissues. With capillary column gas chromatography-positive ion chemical ionization mass spectrometry, confirmation of the identities of incurred desaminosulfamethazine, N4-acetylsulfamethazine, and sulfamethazine in tissues was obtained from a single injection.
Proton Magnetic Resonance Spectroscopic Determination of Bethanechol Chloride in Tablets
Authors: Hanna George M , Lau-Cam1 Cesar A
Published: February 2020

A simple and reliable proton magnetic resonance spectroscopic method was developed for the assay of bethanechol chloride in tablets. The proposed method entails a minimum of procedural steps and reagents. The recovery of bethanechol chloride from synthetic formulations was 99.9 ± 0.4% (n = 15), CV = 0.4%. Mean assay values for 25 and 10 mg commercial tablets were 100.5% (n = 8) and 99.7% (» = 7) of declared, respectively. A detailed interpretation of the proton magnetic resonance spectrum is also presented.
Spectrophotometric Determination of Cyclamate in Foods: NMKL Collaborative Study
Authors: Sjoberg Anna-Maija K , Alanko Timo A
Published: February 2020

A spectrophotometric method for the determination of cyclamate was collaboratively studied in 9 laboratories. Ethyl acetate is added to extract cyclamate from acidic aqueous solution into water, and the cyclamate is then quantitatively converted to /V,./V-dichlorocyclohexylamine by adding excess hypochlorite. A',A'-Dichlorocyclohexylamine is determined by measuring its UV absorption at 314 nm. Six samples, 3 soft drinks with cyclamate levels of 0.36-0.47 g/kg and 3 jams with levels of 1.23-1.50 g/kg, were included in the study. Average recoveries of cyclamate were 99.7% in the soft drinks and 103.8% in the jams. Reproducibility coefficients of variation were 6.7% for the soft drinks and 4.4% for the jams.
Rapid Determination of Methyl Mercury in Fish and Shellfish: Collaborative Study
Authors: Hight Susan C
Published: February 2020

A modification of the official AOAC method for determining methyl mercury in fish and shellfish was studied in 8 laboratories. Methyl mercury is isolated from homogenized, acetone-washed tissue by adding HC1 and extracting into toluene the methyl mercuric chloride produced. The extract is analyzed for methyl mercuric chloride by electron capture gas chromatography. Collaborators determined methyl mercury in blind duplicate homogenates at 2 levels in tuna and at 1 level in swordfish and oysters. Collaborators also analyzed single homogenates of swordfish and oysters containing methyl mercury at a second level. Both fortified and unfortified tissues were analyzed. Methyl-bound mercury in the commodities ranged from 0.50 to 2.30 μg Hg/g. Reproducibility coefficients of variation ranged from 4 to 15%. Accuracy, measured by comparison to reference values, ranged from 92 to 101%. Recovery from fortified homogenates ranged from 86 to 98%. Reference values and unfortified levels were determined in the author's laboratory by replicate analysis of fortified
Colorimetric Determination of Tetracycline Hydrochloride in Pharmaceutical Preparations
Authors: Saha Utpal
Published: February 2020

A simple, sensitive, and rapid colorimetric method is presented for the estimation of tetracycline hydrochloride as the pure drug and in formulations. The proposed method is based on the reaction of tetracycline HC1 with cupric chloride in an alkaline medium to give a yellowish green solution whose absorbance is measured at 400 nm against a reagent blank. The color obeys Beer's law in the concentration range of 0-20 μg/mL. Molar absorptivity and Sandell's sensitivity of the yellowish-green copper complexes of tetracycline HC1 are 1.99 x 104 Lmol-1 cm-1 and 0.0241 ppm, respectively.
Thin-Layer Chromatographic Determination of Erythromycin and Other Macrolide Antibiotics in Livestock Products
Authors: Petz Michael , Solly Roy , Lymburn Moira , Clear Mike H
Published: February 2020

A method is described for determination of 4 macrolide antibiotics in livestock products. Erythromycin, tylosin, oleandomycin, and spiramycin were extracted from animal tissues, milk, and egg with acetonirrile at pH 8.5. Cleanup was done by adding sodium chloride and dichloromethane, evaporating the organic layer, and subsequent acid/ base partitioning. After the antibiotics were separated by thin-layer chromatography (TLC), they were reacted with xanthydrol and could be detected as purple spots down to 0.02 mg/kg without interference by other commonly used therapeutic drugs (23 were tested). Anisaldehyde- sulfuric acid, cerium sulfate-molybdic acid, phosphomolybdic acid, and Dragendorff s reagent proved to be less sensitive as visualizing agents. For quantitation, TLC plates were scanned at 525 nm. Recoveries were between 71 and 96% for erythromycin and tylosin in liver, muscle, and egg at the 0.1-0.5 mg/kg level and 51% for erythromycin in milk at the 0.02 mg/kg level (coefficient of variation = 10-18%). Bioautography with Bacillus subtilis was used to confirm results, in addition to TLC analysis of derivatized antibiotics and liquid chromatography with electrochemical detection. Various derivatization procedures for erythromycin were investigated for improved ultra-violet or fluorescence detection in liquid chromatography.
Simplified Method for Determining Polychlorinated Biphenyls, Phthalates,and Hexachlorocyclohexanes in Air
Authors: Stein Vincent B , Amin Thakor A , Narang Rajinder Singh
Published: February 2020

A simplified method for determining polychlorinated biphenyls (PCBs), phthalates, and benzene hexachlorides (BHCs) in air has been developed. Florisil is used as the adsorbent, and compounds are elated by liquid chromatography with 10% 2-propanol in hexane. PCBs are separated from phthalates plus BHCs on a cyanopropyl column with a gradient containing 10% 2-propanol in hexane and 100% hexane as the mobile phase. Two fractions are collected: one contains PCBs and the other contains phthalates plus BHCs, which ve then determined by gas chromatography using a 63Ni electroncapture detector and a DB-5-bonded, fused-silica capillary column.
Pesticide Residues in Lake Albufera, Valencia, Spain
Authors: Carrasco Jose M , Planta Milagros , Gomez-Casals Vicente , Moragues Vicente
Published: February 2020

Analysis of water samples from the lake in Albufera, Valencia, indicates that the pesticides molinate, benthiocarb, and fenitrothion do not reach levels that are lethal to fish.
Microwave Oven Drying Method for Total Solids Determination in Tomatoes:Collaborative Survey
Authors: Wang Samuel L
Published: February 2020

A survey was conducted among 8 laboratories in Ontario to check the reproducibility and accuracy of their microwave solids analyzers for total solids determination in tomatoes, using the official AOAC microwave oven drying method. This study showed that the reliability of the AOAC method was closely related to the performance of the microwave solids analyzer for tomato samples. Certification of microwave solids analyzers was recommended to assure the validity of analytical results by the AOAC method.
Titrimetric Determination of Iodine-Bromine Numbers of Some Edible Oils Using Three N-Chloroimides
Authors: Jayasree Narayanan , Indrasenan Parameswaran
Published: February 2020

Three simple titrimetric methods have been developed to determine iodine-bromine numbers of some edible oils, such as coconut, gingelly, groundnut, mustard, olive, palm olein, and sunflower, using 3 N-chloroimides. The 3 N-chloroimides are N-chlorophthalimide, N-chlorosuccinimide, and N-chlorosaccharin, all of which have recently been developed as potential oxidimetric titrants for use in aqueous acetic acid medium. The proposed excess back-titration methods have advantages over existing methods in terms of ease of extraction into aqueous acetic acid layer, shorter reaction time of NCSA method, and stability of N-chloroimides in solid state.
Liquid Chromatographic Methods for Assay of Carbamazepine, 10,11-Dihydrocarbamazepine,
and Related Compounds in Carbamazepine Drug Substance and Tablets
Authors: Cyr Terry D , Matsui Fumiko , Sears Roger W , Curran Norman M , Lovering Edward G
Published: February 2020

Liquid chromatographic (LC) methods have been developed for the determination of carbamazepine, the impurity 10,11-dihydrocarbamazepine, and related compounds in carbamazepine drug substance and tablets. The LC methods specify a 5 jxm diol column and a mobile phase of acetonitrile-methanol-0.05% aqueous acetic acid (5 + 5 + 90). Iminodibenzyl and iminostilbene, starting materials for some routes of synthesis, elute late in the LC system; therefore, a thinlayer chromatographic method for their detection at the 0.05% level has been developed. Eight tablet and 13 raw material samples from several sources were examined. The impurities most frequently found were 10,11-dihydrocarbamazepine and a compound identified as 10- bromocarbamazepine at levels up to 1.3 and 0.5%, respectively; minimum detectable amounts were about 0.01 and 0.03%, respectively.
Pesticide Confirmation by Triple Stage Quadrupole Mass Spectrometry:
Etrimfos and Dimethoate
Authors: Cairns Thomas , Siegmund Emil G
Published: February 2020

The production of a protonated molecular ion, MH+, for a pesticide under investigation is often preferred for primary identification purposes. However, the lack of fragment ions under such chemical ionization conditions can place the burden of proof on a single ion species for confirmation. Although a single ion representing the molecule at the correct retention time on a packed column or high-resolution capillary column might seem to have furnished sufficient evidence for unambiguous confirmation, in a number of cases additional specificity can improve the analytical result. With the introduction into commerce of triple stage quadrupole (TSQ) instruments, the possibility of improving the degree of specificity by chemical ionization has emerged for practical pesticide residue confirmation analysis. Use of collision-activated dissociation (CAD) experiments to form daughter ions from the protonated molecular ion of 2 representative organophosphorus pesticides has provided a second dimensional plane of characterization for confirmatory purposes at incurred residue levels
Pentafluorobenzylation Derivatization for Determination of Chlorinated Herbicide Acids
Authors: Gurka Donald F , Shore Fred L , Pan Shu-Teh
Published: February 2020

Pentafluorobenzyl and methyl esterification methods for several common herbicide acids have been evaluated and compared. Gas chromatography,' electron capture instrumental detection limits for 2 of 7 pentafluorobenzyl esters were better than the corresponding methyl esters, and comparable for the other S herbicide esters. The linear dynamic concentration range was generally wider for the methyl esters. Gas chromatography of some pentafluorobenzyl derivatives was complicated by coelution of certain derivatives with each other and with byproducts of the derivatization reaction. The ruggednessoptimized pentafluorobenzylation procedure was subjected to linear dynamic range and detection limit studies. The choice between methyl or pentafluorobenzyl esters is contingent on the relative importance of detection limits and linear dynamic range
Determination of Naptalam and Its Metabolite in Foods, as 1-Naphthylamine, Using Liquid Chromatography with Oxidative Electrochemical Detection
Authors: Worobey Brian L , shields Brian J
Published: February 2020

A new method is described for the determination of the herbicide naptalam and its metabolite l-naphthylamine in several foods. The method is sensitive, selective, and extremely rapid compared with previously reported methods. Liquid chromatography with electrochemical detection (LC/ECD) is used to determine l-naphthylamine produced from the metabolism or base hydrolysis of naptalam in asparagus, peaches, and cranberries. These foods were spiked with naptalam at 0.05 and 0.11 ppm and hydrolyzed with 30% NaOH with concomitant distillation of l-naphthylamine. Aliquots of the distillate were injected onto a reverse-phase PRP-1 LC column for separation of l-naphthylamine from coextractives near the solvent front and detection at an applied potential of +0.83 V using an amperometric electrochemical detector in the oxidation mode. Recoveries ranged from 89% ± 2% to 97% ± 8% for all foods at both spiking levels. Accuracy of these recoveries was confirmed by use of "C-radioIabeled naptalam and radioassay by liquid scintillation spectrometry of the "C-l-naphthylamine released.
Titrimetric Determination of Nonesterified Fatty Acids in Intravenous Fat Emulsions
Authors: Cyr Terry D , Lawrence Robert C , Lovering Edward G
Published: February 2020

A titrimetric method, suitable for use at a limit of 5 mEq/L, has been developed for the determination of total noncsterified fatty acids in intravenous fat emulsion preparations. The method differentiates titrant consumed by the nonesterified fatty acids from that consumed by egg yolk phospholipids, usually present as an emulsifying agent. The total nonesterified fatty acids in 8 products from 4 manufacturers were in the range from 0.4 to 3.8 mEq/L. The mean standard deviation of the method is 0.09 mEq/L.
Synthesis, Identification, and Acute Toxicity of Some 7V-AlkyI Derivatives of 3,4-Methylenedioxyamphetamine
Authors: Noggle F Taylor , Deruiter Jack , Coker Samuel T , Clark Randall C
Published: February 2020

A series of iV-alkyl derivatives of 3,4-methylenedioxyamphetamine (MDA) was prepared in an effort to characterize these potential drugs of abuse. These secondary amines were synthesized via reductive amination of the corresponding ketone with alkylamines. The ultraviolet absorption spectra for these compounds produced almost equally intense absorbance at 234 and 285 nm. The compounds were separated by liquid chromatography using reverse phase (c18) procedures with a ternary mobile phase mixture. Toxicity studies showed all of the compounds to have LDM values similar to A'-methyl MDA (MDMA).
Extraction of Light Filth from Whole Leaves of Alfalfa, Lemon Balm, Papaya, and Spearmint: Collaborative Study
Authors: Nakashima Marvin J , Glaze Larry E
Published: February 2020

Results are reported for a collaborative study to extend AOAC method 44.A06-44.A08 to extraction of light filth from whole leaves of alfalfa, lemon balm, papaya, and spearmint. A 5 g (spearmint) or 10 g (alfalfa, lemon balm, papaya) test portion is defatted with isopropanol in a simple reflux apparatus. Rat hairs, insect fragments, and whole insects are isolated by wet sieving on a No. 230 sieve, a deaerating boil in 40% isopropanol, and flotation with mineral oil-heptane (85 + 15) from Tween 80-Na„EDTA (1 + 1) and 40% isopropanol in a Wildman trap flask. Each product was spiked at a different level. For rat hairs, recoveries averaged 82.2% from alfalfa, 88.9% from lemon balm, 80.6% from papaya, and 79.6% from spearmint. Recoveries of whole or equivalent insects from these products averaged 66.1, 218.8, 69.4, and 85.4%, respectively; recoveries of insect fragments from these products averaged 89.6, 94.4, 94.1, and 88.1%, respectively. The method has been adopted official first action for extraction of light filth from whole leaves of alfalfa, papaya, and spearmint. The extension of the method to lemon balm was not recommended because of interferences by intrinsic whole insects, which were the same species as the spike material.
Lensless Fourier transform electron holography applied to vortex beam analysis
Authors: Harada Ken , Ono Yoshimasa A , Takahashi Yoshio
Published: February 2020

Lensless Fourier transform holography has been developed. By treating Bragg diffraction waves as object waves and a transmitted spherical wave as a reference wave, these two waves are interfered and recorded as holograms away from the reciprocal plane. In this method, reconstruction of holograms requires only one Fourier transform. Application of this method to analyze vortex beams worked well and their amplitude and phase distributions were obtained on the reciprocal plane. By combining the conventional holography with the developed lensless Fourier transform holography, we can reconstruct and analyze electron waves from the real to reciprocal space continuously.