bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer Utilization in the Food and Drug Administration's Bureau of Foods Mass Spectrometry Laboratory
Authors: Dreifuss Peter A , Dusold Laurence R
Published: February 2020

A network of computers is being used to support the Food and Drug Administration's Bureau of Foods mass spectrometry facility. Five mass spectrometers are each interfaced to at least 2 of the 6 dedicated minicomputers in the laboratory. This multiple interfacing provides data acquisition and processing backup, reducing the overall down-time. Selected data from all of the minicomputers can be sent to FDA's main computers via a digital cartridge tape recorder or paper tape. The digital cartridge tape recorder records data that are output from a minicomputer terminal and then plays it back on a terminal which is on-line with the main computer. This main computer stores and edits data; plots spectra for reports, data banks, and publications; and carries out some data processing. Multiple interfacing also serves to supplement the capabilities of the 8-year-old Finnigan MAT (formerly Varian MAT) SS-100 data system (Sperry-Univac/V-76) with the newer and more powerful Finnigan MAT INCOS (Data General/Nova 3) data system. The SS-100 data system is also enhanced by the substitution of the 110 baud paper tape with a 9600 baud cartridge tape recorder for I/O of system bootstraps, BASIC programs, and raw data.
Ion-Pair High Performance Liquid Chromatographic Separation and Detection of Subsidiary Dyes in Synthetic Food Colors
Authors: Lancaster Frank E , Lawrence James F
Published: February 2020

A high performance liquid chromatographic method utilizing a reverse phase ion-pair technique is presented for separating subsidiary dyes from commercial samples of Amaranth, Sunset Yellow FCF, and Tartrazine. After separation, the subsidiaries or primary dyes are quantitated by using known standards. Recoveries of subsidiaries, l-(4-sulfo-l-naphthylazo)- 2-naphthol-6-sulfonic acid, disodium salt from Amaranth; l-p-sulfophenylazo-2-naphthol- 3,6-disulfonic acid, trisodium salt from Sunset Yellow FCF; 3-carboxy-5-hydroxy-l-p-sulfophenyl-4-phenylazo-pyrazole, disodium salt from Tartrazine, ranged from 92 to 102% at the spiking levels studied (0.06-16%, depending on the subsidiary). The method was successfully applied to the analysis of commercial samples.
Dual Column Chromatographic Method for Determination of N-Nitrosothiazolidine in Fried Bacon
Authors: Pensabene John W , Fiddler Walter
Published: February 2020

A dual column chromatographic procedure is described that permits the determination of N-nitrosothiazolidine (NTHZ), a newly identified nitrosamine, and N-nitrosopyrrolidine (NPYR), the principal volatile nitrosamine, in the same fried bacon sample. The procedure used an acid-Celite, Celite, sodium sulfate column followed by a partially deactivated basic alumina column to isolate NTHZ from bacon for subsequent quantitation by gas chromatography with a thermal energy analyzer (GC-TEA). A limited intralaboratory study gave standard deviations for repeatability and reproducibility of 1.20 and 1.55 ppb, respectively. The recovery of N-nitrosothiomorpholine, the internal standard added at the 10 ppb level, was 93.3 ± 6.03%. The method is also free from artifactual nitrosamine formation.
High Pressure Liquid Chromatographic Determination of Allantoin in Cosmetic Creams and Lotions
Authors: Nakao Kazuo , Honda Keiichi , Yoneya Tohru
Published: February 2020

A sensitive high pressure liquid chromatographic method was developed for the determination of allantoin in cosmetic preparations. The procedure consists of simple cleanup of samples, derivatization with p-nitrobenzaldehyde in N,N-dimethylformamide to an ultraviolet labeled derivative, and reverse phase chromatography on an octadecylsilylated silica column. Ultraviolet absorbance was measured at 270 nm. Recovery was greater than 97% for cosmetic samples, and the minimum limit of detection was 10 ng.
Gas Chromatographic Determination of the Captan Metabolite Tetrahydrophthalimide in Urine
Authors: Schoen Sarah R , Winterlin Wray L
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for the determination of the captan metabolite tetrahydrophthalimide in human urine. The sample is extracted with chloroform and cleaned up on a Florisil column. The extract is then analyzed by GLC, using a nitrogen-phosphorus-selective detector. Recoveries from urine samples fortified at 0.03-0.5 ppm ranged from 82 to 87%, and were qualitatively confirmed by GLC-mass spectrometry.
Gas Chromatographic and Gas Chromatographic-Mass Spectrometric Confirmation of 2,4- and 2,6-Toluenediamine Determined by Liquid Chromatography in Aqueous Extracts
Authors: Snyder Roger C , Brumley William C , Breder Charles V , Fazio Thomas
Published: February 2020

The confirmation of 2,4- and 2,6-toluenediamine (TDA) in aqueous extracts from boil-in-bags and retortable pouches is described. The extracts were initially analyzed by a high performance liquid chromatographic procedure and any apparent 2,4- and/or 2,6-TDA were quantitated. The liquid chromatographic effluent corresponding to any apparent 2,4- or 2,6-TDA was collected. TDA was then partitioned into ethyl acetate and reacted with trifluoroacetic anhydride (TFAA). The TDA-TFAA derivative formed was confirmed by gas-liquid chromatography (GLC) using a 1.2 m × 0.32 cm nickel column packed with 6% OV-17 on Superpak-20M. Results obtained from analyzing extracts of several retortable pouches and boil-in-bags showed levels of TDA migration ranging from <0.1 to 2.2 ppb (μg/L). Additional confirmation of the TDA-TFAA derivative from retortable pouches by multiple ion detection GC/mass spectrometry is also described.
High Performance Liquid Chromatography with Fluorescence and Ultraviolet Detection of Polynuclear Aromatic Hydrocarbons in Barley Malt
Authors: Joe Frank L , Salemme Jean , Fazio Thomas
Published: February 2020

A simple, rapid method has been developed for the separation and determination of polynuclear aromatic hydrocarbons (PAHs) in barley malt. An ultrasonic- cyclohexane extraction method was used to separate the PAHs from ground barley malt. The cyclohexane extracts were purified by chromatography through a water-deactivated silica gel-alumina column. The eluate from the column was concentrated and purified further by partitioning between dimethyl sulfoxide (DMSO) and cyclohexane. The DMSO extract was diluted with water and the PAHs were extracted back into cyclohexane. The cyclohexane extract was washed with water, dried through sodium sulfate, and evaporated, and the resulting residue was dissolved in 80% aqueous acetonitrile-methanol (1 + 1) and subjected to reverse phase high performance liquid chromatography. Thirty barley malt samples were analyzed using this procedure. Peaks having the same retention time as the carcinogen benzo(a)pyrene were isolated from 18 of the samples, and were equivalent to trace levels ranging from <0.1 to 0.2 ppb. Average recoveries of 11 PAHs, including benzo(a)pyrene, benzo(b)fluoranthene, indeno(l,2,3-cd)pyrene, and benz(a)anthracene, added to 25 g samples at 2.5 and 5 ppb, ranged from 78 to 97%, with a mean relative standard deviation of 6.6%.
Detection of Adulteration in Blackberry Juice Concentrates and Wines
Authors: Wrolstad Ronald E , Culbertson Jeffrey D , Corn Well Christopher J , Mattick Leonard R
Published: February 2020

Adulteration of blackberry juice concentrates and wines with juice of sorbitol-containing fruits was detected by determining carbohydrates by high performance liquid chromatography, gas-liquid chromatography, and thin layer chromatography. Sorbitol is not fermented by yeast and can be detected in wines made from blackberry juice concentrates that contain sorbitol. High levels of sorbitol and quinic and malic acids suggest that an imported blackberry concentrate may have been adulterated with plum. Degradation of anthocyanin pigments during processing and storage limits the utility of pigment analyses in detecting adulteration.
Infant Formula Label Review
Authors: Barnes Roger W
Published: February 2020

The FDA review of infant formula labeling was conducted by a multi-disciplinary team composed of physicians, scientists, and experts in regulations and labeling. The review followed 2 tracks: the development of a general position of what would be necessary if we started with a blank label; and the purchase of many formulas and a critical review of information on the labels. An important part of the review was determining what information was available in the literature and using this information in assessing current practices and the effectiveness of present labeling. The review was divided into several major topics: introduction, definitions, historical perspectives, current regulatory situation, effectiveness of labeling, label review, other issues, and departmental initiatives. The labels review included product attributes, shelf life, retail and home storage instructions, and consumer preparation and use.
Proximate and Elemental Analysis of Infant Formula
Authors: Tanner James T
Published: February 2020

The Nutrient Surveillance Branch has been conducting a survey of infant formula products for Fiscal Year 1981. Each product has been carefully analyzed and the results compared to the label declaration and the minimum-maximum limits specified by the American Academy of Pediatrics’ Committee on Nutrition (CON/AAP). Proximate and elemental analyses were made. Protein, fat, ash, and total solids (moisture) were determined by AOAC methods. Osmolality, density, and fatty acids (linoleic) were also determined. Carbohydrates were calculated by difference and caloric content was calculated by using the general Atwater factors. Elemental analysis for Ca, P, Mg, Fe, Zn, Cu, Mn, Na, and K were performed by induction coupled plasma absorption spectroscopy. Chloride was assayed by potentiometric titration with AgNC3. A summary of the findings from the infant formula survey have been compared with CON/AAP recommendations. In general, there were only a few exceptions where the label claims and the CON/AAP requirements were not met. However, in none of these cases was the difference considered to be of public health significance.
Infant Food Problems and Analytical Aspects of Providing Safe and Wholesome Infant Foods
Authors: Read R B
Published: February 2020

The technology of milk and infant food production, storage, and handling has advanced to the point that infant foods have had an excellent record of being free of recognized health hazards. The Infant Formula Council has published methods specifically for these foods. Methods are included from Standard Methods for the Examination of Dairy Products, Official Methods of Analysis, Bacteriological Analytical Manual, the Manual of Clinical Microbiology, and the U.S. Pharmacopeia. Criteria for microbiological quality have been issued by the Codex Alimentarius Commission, the International Commission for Microbiological Specifications for Foods, and the Public Health Service. Surveys in the United States and Canada have shown that sanitary standards are met with ease.
Spectrophotometric Determination of Aminacrine Hydrochloride in Creams, Jellies, and Suppositories
Authors: Bunch Elaine A
Published: February 2020

A visible spectrophotometric method has been developed for the quantitation of aminacrine hydrochloride in creams, jellies, and suppositories. Aminacrine hydrochloride was extracted into acidic ethanol and its visible spectrum was recorded. The amount present was calculated by determining the net absorbance between the absorbance maximum at about 402 nm and one-half the sum of the absorbances of the minima at about 389 and 412 nm. Aminacrine and a trace contaminant, 9(10H)-acridone, were independently identified by different thin layer chromatographic systems.
Simple Colorimetric Method for Determination of Pyridoxine Hydrochloride (Vitamin B6) in Pharmaceuticals
Authors: Sane Ramesh T , Doshi Vipul J , Joshi Sanjay K
Published: February 2020

A simple colorimetric method is described for the determination of pyridoxine hydrochloride (vitamin B6). The method is based on the measurement of an orange species formed when pyridoxine hydrochloride is treated with diazotized dapsone and sulfanilamide in a mixture of trichloroacetic acid and sulfuric acid at room temperature, followed by treatment with an aqueous solution of sodium carbonate. Compounds such as thiamine hydrochloride, cyanocobalamin, and common excipients such as starch and talc which are present in various formulations with pyridoxine hydrochloride do not interfere in the reaction. Statistical validation showed that the method was highly precise and accurate. Results agree well with those obtained by other methods reported in the literature.
Improved Lipoxygenase Method for Measuring cis,cis-Methylene Interrupted Polyunsaturated Fatty Acids in Fats and Oils
Authors: Madison Bryan L , Hughes William J
Published: February 2020

An improved lipoxygenase method is described for the determination of cis,cis-methylene interrupted polyunsaturated fatty acids in fats and oils. The methodology is designed to overcome mechanical problems which in the past may have contributed to poor precision. This method provides improved repeatability which is imperative for assay methods used for quality control and other purposes
Applicability of a Carbamate Insecticide Multiresidue Method for Determining Additional Types of Pesticides in Fruits and Vegetables
Authors: Krause Richard T , August E Michael
Published: February 2020

Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbof uran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered.
High Resolution Gas Chromatographic Analysis of Nonpolar Chlorinated Hydrocarbons in Human Milk
Authors: Bush Brian , Snow John T , Connor Steven
Published: February 2020

A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene. The detection limit for individual compounds is about 0.05 ng/g when 30 g milk is analyzed. Total PCBs can be estimated with a detection limit of 1-5 ng/mL milk. Analytical precision is better than ±10% for all compounds at 20-50 ng/mL whole milk.
Simple Colorimetric Method for Determination of Episulfides, Using, 4-(p-Nitrobenzyl)-Pyridine
Authors: Petroski Richard J
Published: February 2020

Episulfides were determined by a simple colorimetric assay using 4-(p-nitrobenzyl)-pyridine, which has been used previously for the detection and analysis of epoxides, organophosphates, and other alkylating agents. With episulfides, absorbance was directly proportional to concentration up to an absorbance of at least 1.0. No interference was observed with a variety of non-episulfide sulfur-containing substances. The colorimetric method is useful in monitoring 1-cyanoepithioalkane formation from the degradation of glucosinolates containing terminal double bonds.
Modification of Klein’s Wet Ashing Procedure for Determination of Mercury
Authors: Vibhakar S , Nagaraja Krishnarajpet V , Kapur Omprakash
Published: February 2020

An investigation of the use of HC1 in Klein’s method (25.108-25.115) to prevent loss of mercury during wet digestion resulted in consistently good recoveries from jowar and fish samples. Recoveries for the modified method ranged from 90.9 to 97.0% compared with 14.4 to 35.5% for the original method.
High Pressure Liquid Chromatographic Determination of an O-Methyl, Methyl Ester Derivative of Ochratoxin A
Authors: Phillips Timothy D , Stein Aron F , Ivie G Wayne , Kubena Leon F , Hayes A Wallace , Heidelbaugh Norman D
Published: February 2020

The mycotoxin ochratoxin A (OA) was derivatized to an O-methyl,methyl ester (Me2) with diazomethane and then determined by high pressure liquid chromatography (HPLC). Both OA and OA-Me2 were chromatography by reverse phase HPLC with a mobile phase of acetonitrile-water (60 + 40). An increase in retention time of 309 s was observed with OA-Me2 which was detectable at 254 nm at levels as low as 3 ng. Recovery of OA as OA-Me2 from chicken kidney homogenates and human plasma was quantitative following simple extraction and cleanup procedures, reaction with diazomethane, and HPLC analysis. The novel method described should prove useful for measuring and confirming OA in tissues and in further studies on the biological fate of this mycotoxin.
Microbiological Determination of Lincomycin in Feeds and Supplements Containing High Concentrations of Bentonite
Authors: Stahl Gerald L , Kratzer D Dal
Published: February 2020

A microbiological method is described for determining lincomycin in complete feeds, supplements, andpre-mixes greater than 100 g/ton and containing high levels of bentonite. The AOAC method currently used is unsatisfactory for analyzing feeds with concentrations of bentonite greater than 5.5%. Study indicates that low lincomycin recoveries from high level bentonite feeds are a function of aqueous contact and subsequent binding. The present method involves an alternative extraction technique using formamide as the primary extractant. A binary solvent system of ethanol and phosphate buffer aids in the extraction, miscibility, and conversion to water solubility for subsequent testing. Forty-one feeds containing as high as 60% bentonite were assayed by the reported method and gave a mean recovery of 106% and a range of 94-114%. An inter-laboratory confirmation study produced a mean recovery of 103%, with a range of 93-114%. A factorial analysis of variance of the interactive effects between lincomycin level and bentonite level within the AOAC method and within the bentonite method showed no interactions which would influence percent recovery in either assay method.
Extraction and Cleanup Procedures for Determination of Diarylphosphates in Fish, Sediment, and Water Samples
Authors: Muir Derek C G , Grift Norbert P
Published: February 2020

Methods for determination of triaryl/alkylphosphates (TAPs) in water, fish, and sediment have been extended to determination of the diarylphosphate (DAP) degradation products. DAPs were extracted from water (adjusted to pH 0.5) by use of XAD-2 resin and determined by gas-liquid chromatography as butyl esters. Recovery of diphenylphosphate (DPP) and o-, m-, p-dicresylphosphates (DoCP, DmCP, DpCP) were >95% in water samples fortified at 1,10, and 50 μg/L. DAPs were extracted from fish with methanol and the extracts were cleaned up on reverse phase (C18) silica cartridges. Recoveries were μ87% for DPP, DoCP, DmCP, and DpCP in fish muscle fortified at 50, 100, and 500 ng/g. Sediments were refluxed with aqueous methanol and DAPs were recovered by use of XAD-2 resin. Recoveries of DAPs from sediments fortified at 50 and 100 ng/g were μ76%. Interferences (1-10 ng/g) from phosphorus or nitrogen-containing GLC peaks prevented subng/g level analysis for DAPs in sediment and fish extracts.
Isomerization of Retinyl Palmitate Using Conventional Lipid Extraction Solvents
Authors: Mulry Mary C , Schmidt Ronald H , Kirk James R
Published: February 2020

The use or a chlorotorm-ethanol-water solvent system for the direct extraction of retinyl palmitate isomers from fortified food products was previously shown to be unsuitable because significant isomerization of all-trans-retinyl palmitate occurred during the extraction. This study investigated the extent of isomerization of retinyl palmitate in various extraction solvents when subjected to gold fluorescent laboratory light. Purified solutions of all-trans-retinyl palmitate in hexane were diluted with methyl t-butyl ether, hexane, methylene chloride, and stabilized chloroform and subjected to gold fluorescent laboratory light for 2, 4, and 6.5 h. Similar solutions were subjected to light or kept in the dark for 3.5 h. All-trans-, 9-cis-, and 13-cis-retinyl palmitate esters in the solutions were determined by using normal phase high performance liquid chromatography with fluorometric detection. Results demonstrated a noticeable increase in the 9-cis-retinyl palmitate concentration and a corresponding decrease in all-trans-retinyl palmitate concentration with time, in chloroform and methylene chloride compared with hexane. Chlorinated solvents in the absence of light did not promote isomerization of retinyl palmitate. Use of chlorinated solvents for the extraction of vitamin A esters should be avoided because they promote isomerization of retinyl palmitate when subjected to light, including gold fluorescent laboratory light.
Determination of Magnesium, Iron, and Zinc in Fertilizers by Flame Atomic Absorption and by Inductively Coupled Plasma Emission Spectroscopy: Comparison of Methods
Authors: Aten Carl F , Bourke John B , Walton John C
Published: February 2020

Determination of Mg, re, and Zn by inductively coupled plasma emission spectroscopy (ICP) and by the official flame atomic absorption spectrophotometric (FAA) method were compared. Samples were acid digests of commercial fertilizers. Neither matrix effects nor spectral interferences were encountered in the ICP analyses. Linear regression shows that the slopes obtained by plotting ICP results vs FAA results for each element differ from unity by less than 5%.
Discussion of Statistical Methods for Determining Purity of Citrus Juice
Authors: Brown Morton B , Cohen Eli
Published: February 2020

It is difficult to develop statistical methods to determine the purity of fruit juice because of country-to-country and environmental differences among fruit. A test of an unknown sample of citrus juice can err in 2 ways: Pure juice can mistakenly be rejected as adulterated, or adulterated juice can be accepted as pure. Many of the statistical procedures proposed maymisclassify a high proportion of samples of pure juice as adulterated. It is necessary to develop a statistical test that will only rarely reject samples of pure juice, and will have a good chance of rejecting adulterated juice.
Procedure for Cooking Seafood Products
Authors: King Frederick J
Published: February 2020

As a result of experience gained using procedure 18.003, a revision is proposed. The revised procedure has been adopted.
Gas-Liquid Chromatographic Screening Method for Six Synthetic Pyrethroid Insecticides
Authors: Bolygó Glek , Zakar Ferenc
Published: February 2020

A method was developed for simultaneously determining 6 synthetic pyrethroid insecticides (fenpropanate, tetramethrin, permethrin, cypermethrin, fenvalerate, and deltamethrin) in apple, orange, grape, lemon, tomato, green pepper, and paprika, and sugar beet root and leaves. The pesticides were extracted with acetone and partitioned into methylene chloride. The extract was purified by column chromatography on active carbon-magnesia-diatomaceous earth and then on alumina. Analysis by gasliquid chromatography with 63Ni electron capture detection was completed in 6 min on a 3% SE-30 liquid phase, using a short column. Recoveries from fortified samples ranged from 68 to 89% in the range of 0.3-1.O ppm and from 67 to 83% in the range of 0.02-O.2ppm.
Identification and Estimation of the Alkaloids of Rauwolfia serpentina by High Performance Liquid Chromatography and Thin Layer Chromatography
Authors: Cieri Ugo R
Published: February 2020

A procedure is presented for the identification and estimation of some of the alkaloids of Rauwolfia serpentina by high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). Two extraction procedures were studied, one essentially similar to the current AOAC method, and one using warm methanol. For HPLC, a μPorasil column, methanol as eluting solvent, and a fluorometric delector were used. Rescinnamine was detected at 330 nm, at which wavelength reserpine fluorescence is negligible. Reserpine was detected at 280 nm, where rescinnamine fluorescence is small. Other alkaloids detected were raubasinine, ajmalicine, yohimbine, ajmaiine, and serpentine. For TLC, CHCI3-CH3OH 197+ 3) and CHCI3-CH3OH (80 + 20) were used as developing solvents and spots were detected under long- and shortwave UV light. A semiquantitative IICprocedure was also developed for serpentine, the content of which was found to be in the 0.2-0.25% range.
Gas-Liquid Chromatographic Determination of Dehydroacetic Acid in Squash and Wine
Authors: Daniels Daniel H , Warner Charles R , Selim Sami , Joe Frank L
Published: February 2020

A gas-liquid chromatographic procedure has been developed for the determination of the preservative dehydroacetic acid (DHA) in frozen cut squash and white wine. The cleanup procedure uses the acidic character of DHA to enhance separation from interfering substances. Recoveries were 93-104% from squash fortified at 30, 65, and 130 ppm and 96-99% from wine fortified at 50, 100, and 200 ppm. The method can be used to establish that the amount of DHA used in squash does not exceed the permissible level of 65 ppm.
Argon Plasma Emission Spectrometry of Uranium in Phosphatic Materials
Authors: Norman J D , Stumpe Louis A , Trimm Joe R , Johnson Frank J
Published: February 2020

A method is described for the determination of uranium by using a dc argon plasma emission spectrometer. Problems and interferences found in the method previously reported are overcome by using an improved sample pretreatment. A new synergistic system, 2% oxalic acid adjusted to pH 4.5 with triethanolamine, is used to quantitatively back-extract uranium from trioctylphosphine oxide in cyclohexane. This improved method yields excellent results for >1 ppm uranium in nitric and hydrochloric acid solutions of phosphate rocks, phosphoric acids, phosphate fertilizers, phosphogypsums, organic phosphates, and waste solutions. Recovery data are given for synthetic and certified standards.
Determination of Glucose, Sucrose, Lactose, and Ethanol in Foods and Beverages, Using Immobilized Enzyme Electrodes
Authors: Mason Marc
Published: February 2020

An enzyme electrode coupling immobilized oxidase enzymes with a hydrogen peroxide-sensitive electrode is described. An enzyme or enzymes are immobilized in a thin microporous membrane which titsdirectly over a platinum anode held at +0.700 V relative to a Ag/AgCl2 reference electrode. When an enzyme substrate diffuses into the membrane, hydrogen peroxide is produced. The hydrogen peroxide is then oxidized at the platinum anode, producing anelectrical current that is directly proportional to hydrogen peroxide concentration, and hence substrate concentration. Glucose and sucrose in cereal samples, lactose in cheese, and ethanol in beer and wine were determined using enzyme electrodes. Relative precision of replicate analyses was better than ±2% and agreement with AOAC methods was good.
Evaluation of a Testing Program for Aflatoxin in Corn
Authors: Whitaker Thomas B , Dickens James W
Published: February 2020

A computer model that accounts for sampling and analytical variability was developed to simulate the aflatoxin testing program administered by the North Carolina Department of Agriculture (NCDA) to regulate aflatoxin in corn meal. Monte Carlo solution techniques were employed to account for conditional probabilities that rise from multiple samples being used in the testing program. The NCDA testing program was then evaluated by applying the computer model to a hypothetical group of 1000 corn meal lots with the same distribution of aflatoxin concentrations as was observed among aflatoxin assays made by NCDA on commercial lots of corn meal from 1977 to 1980. The average of the 1000 lots assayed was 17.7 parts per billion (ppb). The model predicted that 79.5% of the lots would be accepted and 20.5% of the lots would be rejected by the NCDA testing program. The accepted and rejected lots contained an average of 5.7 and 64.2 ppb aflatoxin, respectively. The testing program accepted 7.3% of the lots with more than 20 ppb aflatoxin (consumers' risk) and rejected 1.0% of the lots with 20 ppb or less (processors' risk). A correct decision was made 94% of the time.
Ion-Pair Partition Chromatography of Mef enamic Acid with Tetraalkylammonium Cations: Development of Analytical Method from Extraction Data
Authors: Adams William M
Published: February 2020

The ion-pair partition properties of mef enamic acid with the methyl, ethyl, n-propyl, and n-butyl homologs of tetraalkylammonium cation were studied in relation to a model of an assay procedure for acidic drugs. Variables studied included identity and concentration of pairing ion and composition of extracting solvents. Resulting data were used to develop a partition chromatographic assay procedure. Standard recoveries averaged 99.01 ± 0.82%. Assays of commercial capsules were reproducible
Detection and Determination of Error in Analytical Methodology. Part II. Correction for Corrigible Systematic Error in the Course of Real Sample Analysis
Authors: Cardone Mario J
Published: February 2020

A new perspective in the functional operation of corrigible errors is presented. If the incorrigible errors, calibration, and direct interference are absent, the new proposed calculation procedure will provide a correct analytical result; results obtained by the method of standard additions will agree with results from the conventional standard curve technique on the same sample; and different methods will produce the same analytical result on the same sample within the variance of the random error of the method(s). The technique is also a diagnostic tool for the detection and determination of the corrigible constant and proportional errors.
Today’s Chemical Realities
Authors: Horwitz William
Published: February 2020

The difficulty with current food safety laws arises from the apparent inability of the toxicologist to determine the biological significance of the extremely low concentrations that the chemist can currently measure. In discussions of this technical ability, however, the practical limitations of chemical measurement science are rarely mentioned. Some of these limitations are: (1) The reliability of identification and quantitation decreases exponentially as concentration decreases; (2) at very low concentrations baseline effects become the limiting factor; and (3) the cost of the analysis becomes exorbitant. The practical reality of trace chemical analysis in the interlaboratory environment must answer the question: When does the cost of the analysis exceed the value of the information gained as to the identity and amount of the material present, considering also the uncertainties associated with the analysis itself and with the biological effect of that concentration? The current practical limit of measurement is in the low parts per billion, e.g., aflatoxin contamination. 2,3,7,8-Tetrachlorodibenzodioxin can be determined in fish at the moderate parts per trillion level, but at an estimated cost in salaries and expenses of roughly $1000 per individual value reported, without capitalizing our $2,000,000 mass spectrometry laboratory.
High Pressure Liquid Chromatographic Determination of Capsaicin in Oleoresin and Personal Protection Aerosols
Authors: Law Mark W
Published: February 2020

A simple and accurate high pressure liquid chromatographic method has been developed for determination of capsaicin in oleoresin capsicum and mineral oil-based aerosol formulations intended for personal protection. Capsaicin, the main ingredient responsible for the spicy pungency of various hot peppers and paprika, is extracted with acetonitrile and aliquots are analyzed on a 10 μm C18 column at 280 nm with acetonitrile-water (45 + 55) mobile phase. Dihydrocapsaicin is also extracted and is simultaneously quantitated with propiophenone as an internal standard.
Identification of Chlorinated Nitrobenzene Residues in Mississippi River Fish
Authors: Yurawecz Martin P , Puma Bart J
Published: February 2020

Residues of lower chlorinated nitrobenzenes have been found at levels up to about 1 ppm in 8 samples of Mississippi River fish. Electron capture gas chromatography (EC/GC) was used for determination after extraction and cleanup using a procedure based on the AOAC multiresidue method for organochlorine and organophosphorus pesticides in nonfatty foods. The residues found included 2-, 3-, and 4- chloronitrobenzene and 2,3- and 3,4-dichloronitrobenzene; identity was confirmed by GC/mass spectrometry. GC retention times for 15 monochloro-through pentachloro-substituted nitrobenzene congeners were determined with OV-101 and mixed OV-101 + OV-210 columns at 130 °C In studies of the nonfatty food extraction and cleanup procedures of the AOAC method, recoveries of 15 chlorinated nitrobenzenes from spiked fish samples ranged from 68 to 116%. GC of cleaned up fish extract aliquots equivalent to 20 mg sample allowed quantitation of individual congeners at levels of about 0.025 and 0.005 ppm with 3H and 63Ni EC detectors, respectively. The contamination of Mississippi River fish with chlorinated nitrobenzenes appears to be localized in a 150 mile section of the river extending from St. Louis, MO, to Cape Girardeau, MO; no chlorinated nitrobenzenes (<0.005 ppm) were detected in Mississippi River fish caught above or below this region of the river or in fish from the lower Missouri River, which joins the Mississippi River near St. Louis.
Differential Pulse Polarographic Determination of Iodine in Foods and Nutritional Products
Authors: Thompson Donald , Lee Susan , Allen Rebecca
Published: February 2020

A differential pulse polarographic procedure is described for the analysis of iodine in foods and nutritional products. Samples with iodine concentrations ranging from 5000 to 0.2 ppm have been successfully analyzed using this procedure. Precision averaged between 2 and 10% relative to the iodine level measured. Recoveries of added iodine ranged from 89 to 108% with external standards, and 97-100% by an analyte additions technique. Samples analyzed include dried almonds, whey protein concentrate, nonfat dried milk, sea kelp, vitamin-mineral nutritional supplements, diet meal replacement products, dried green beans, dried mushrooms, and wheat germ.
Add Methanolysis and Gas Chromatographic Determination of Brominated Vegetable Oils in Soft Drinks
Authors: Lawrence James F , Chadha Rajinder K , Conacher Henry B S
Published: February 2020

A gas chromatographic method has been developed for determination of brominated vegetable oils in citrus-flavored soft drinks. Oils were extracted from the drinks with ethyl ether and subjected to acidcatalyzed methanolysis. The resulting brominated methyl esters (dibromostearate, tetrabromostearate, and hexabromostearate) were separated and quantitated as single peaks on a 3% OV-3 column. Chromatography columns were stable for about 3 months of daily use; then the first 15 cm of column packing material was replaced or a new column was prepared. A number of citrus soft drinks were analyzed and contained 3.5-3.9 mg brominated oil/10 fl. oz. Recoveries from spiked samples after organic extraction and methanolysis were 94.5-105%.
Alcohol Proof Determination from Absolute Specific Gravity (20°C/20°C) Using Oscillating U-Tube Digital Density Meter with Programmable Calculator
Authors: Stewart LeRoy E
Published: February 2020

Proof determination using a digital density meter has been difficult at temperatures other than 60°F because no single table for conversion exists as does for apparent specific gravity. The instrument operates more satisfactorily and temperature stability is easier to achieve at temperatures closer to ambient. Because 20°C is widely accepted by the scientific community as the temperature for calibration of equipment and standardization of tests, that temperature was chosen as the basis for the program the author has written to convert specific gravity (20°C/20°C) to proof. AOAC Table 52.003 was the source of data for this program. A table relating specific gravity (20°C/20°C) to proof was also generated from the formula of the International Organization of Legal Metrology (IOLM). Proofs determined using the calculator program and the tables of AOAC, IOLM, and NBS compare favorably.
First-Derivative Spectroscopic Determination of Acetaminophen and Sodium Salicylate in Tablets
Authors: Tobias David Y
Published: February 2020

A first-derivative spectroscopic method for the simultaneous determination of acetaminophen and sodium salicylate in tablets was developed. Solutions of this drug combination in acidic ethanol were analyzed using their respective spectral responses at 258.5 and 317.0 nm. The method, which can be used for tablet composite assay and content uniformity analysis, is linear for acetaminophen concentrations ranging from 0.0 to 21.6 μ/mL, and for sodium salicylate concentrations ranging from 0.0 to 36.0 μ/mL. Relative standard deviations for the assay of both drugs in commercial tablets were <2%, and recoveries of acetaminophen and sodium salicylate from spiked samples were 99.7 and 100.1%, respectively. The results obtained by first-derivative spectroscopy were in agreement with the results of a liquid chromatographic procedure for acetaminophen and a fluorometric method for sodium salicylate. The technique used for the selection of wavelengths for analysis is also described.
Enzyme-Linked Immunosorbent Assay of Ochratoxin A in Barley
Authors: Morgan Michael R A , Mcnerney Ruth , Chan Henry W-S
Published: February 2020

A noncompetitive, double antibody enzyme-linked immunosorbent assay for ochratoxin A using microtitration plates has been developed and applied to samples of barley. The anti-ochratoxin A antiserum, which is used at high dilution, does not cross-react significantly with ochratoxin B or ochratoxin α, Assay sensitivity for determination of the toxin in barley samples is 60 ng/kg. Minimal sample preparation is required before assay.
Brine Saturation Technique for Extracting Light Filth from Canned Crabmeat and Shrimp: Intralaboratory Study
Authors: Freeman Clarence C
Published: February 2020

An intralaboratory study was made of a new technique for isolating light filth from canned shrimp and crabmeat. Recoveries of 93.8% for insect fragments and 89.4% for rodent hair plus the brevity and simplicity of the new technique make it superior to the 2 existing official methods for these products.
Identification and Semiquantitation of Monensin Sodium in Animal Feeds by Thin Layer Bioautography
Authors: Martinez Elizabeth E , Shimoda Wilbert
Published: February 2020

A bioautographic technique for the determination of monensin sodium contamination in animal feeds is described. The feeds are extracted in aqueous methanol and the initial monensin extracts are isolated by filtration through an alumina column. These eluates are partitioned between 5% NaCl and methylene chloride, and are further purified through a Sephadex LH-20 column. A 10 mL eluate containing the monensin is collected from the Sephadex column and evaporated, and the residue is dissolved in methylene chloride. Aliquots are spotted on a thin layer plate and monensin is detected by a thin layer bioautographic technique, using Bacillus subtilis as the test organism. The reliable limit of sensitivity is 100 ppb, but 10 ppb can be detected. This technique can be used to semiquantitate monensin by comparing the zones of inhibition of unknown test samples against monensin standards.
Liquid Chromatographic Determination and Mass Spectrometric Confirmation of Chloramphenicol Residues in Animal Tissues
Authors: Bories George S F , Peleran Jean-Claude , Wal Jean-Michel
Published: February 2020

A rapid and sensitive liquid chromatographic (LC) method for determination of trace amounts of chloramphenicol (CP) in animal tissues has been developed. Chloramphenicol identity is confirmed by gas chromatography-mass spectrometry (GC-MS). CP can be routinely quantitated by LC at 10 ppb with 75% recovery, and GC-MS selected ion monitoring permits complete identification at concentrations as low as 5 ppb. Residues were determined in chicken tissues after intramuscular injection of CP. Depletion was rapid with no residues detected in muscle after 8 h, while 15-30 ppb CP was still determined and identified in the liver.
Density Meter Determination of Proof of Ethanol-Water Solutions: A Comment
Authors: Kovar Jan
Published: February 2020

The official method for density meter determination of proof is lightly biased because the meter is standardized with specific values in vacuum, which is not strictly compatible with the recommended table, that explicity requires "apparent," i.e., "in air" values for entry.
Fluoride Ion-Selective Electrode Determination of Sodium Monofluoroacetate in Meat Baits and Formulations
Authors: Livanos George , Milham Paul J
Published: February 2020

Hot aqueous alkaline conditions were used to delluorinate sodium monofluoroacetate (Compound 1080) with a mean efficiency of 98% and a coefficient of variation of 2%. The liberated fluoride was determined by ion-selective electrode. These procedures were used to analyze meat baits and commercial 1080 formulations. Compound 1080 (1–50 mg) was extracted from meat baits into 50% (v/v) acetone–water by blending, followed by ultrasonic agitation and digestion on a steam bath. The extract was filtered and the solids were agitated ultrasonically in more extracting solvent. The combined extracts were concentrated by evaporation prior to alkaline hydrolysis. This technique was well adapted to processing the large sample sizes encountered during analysis of whole baits (<400 g). After correction for co-extracted inorganic fluoride, the typical recovery was 86% with a coefficient of variation <7%. Proprietary 1080 formulations (>90% w/w powders) were simply dissolved in water and diluted before alkaline hydrolysis. Recoveries for added reagent grade material, after correction for free fluoride, averaged 97% with a coefficient of variation 2%.
Capillary Gas Chromatographic Determination Products of Naphthalene in Bran and Wheat Germ
Authors: Kacprza Jurgen L , Robert Geyer , Chongchit Cooper
Published: February 2020

A method is described for determining naphthalene in bran and wheat germ products. The method involves distilling the naphthalene from a water–cereal mixture and then extracting the distillate with hexane. A 10 μL aliquot of the hexane extract is injected into a gas chromatograph equipped with a capillary column. Dodecan-l-ol is used as the internal standard. Mean recoveries, standard deviations (SD), and coefficients of variation (CV) for samples of unprocessed bran, unprocessed wheat germ, bran flakes breakfast cereal, and sultana bran breakfast cereal, spiked with naphthalene at various levels, were 1.0 ppm spike, mean 0.98, SD 0.09, CV 9.5%; 2.5 ppm spike, mean 2.37, SD 0.22, CV 9.4%; 5.0 ppm spike, mean 4.86, SD 0.19, CV 4.0%; 10 ppm spike, mean 9.25, SD 0.38, CV 4.1%. The mean recoveries exceeded 90% in each case. The detection limit for the method was about 0.5 ppm.
Recommended Modification of Dilution Procedure Used for Bacteriological Examination of Shellfish
Authors: Cook David W , Pabst Gerard S
Published: February 2020

The dilution procedure recommended by the American Public Health Association for use in bacteriological analysis of shellfish samples may cause an underestimation of the number of bacteria in shellfish. Modifications of that procedure to include preparation of the first dilution of the shellfish homogenate on a weight rather than a volume basis, and the inoculation of 1 g portions of the shellfish from a dilution of the homogenate, have been shown to significantly increase the recovery of fecal coliform bacteria from oyster samples. It is recommended that these modifications be adopted by the American Public Health Association.
Reverse Phase Liquid Chromatographic Determination of Intermediates and Subsidiary Colors in D&C Green No. 5
Authors: Bailey John E
Published: February 2020

A reverse phase liquid chromatographic method is presented for the simultaneous determination of 2-amino-5-methylbenzenesulfonic acid, 5-amino-2-methylbenzenesulfonic acid, External D&C Violet No. 2, and the lower sulfonated subsidiary color in D&C Green No. 5. The method uses octadecylsilanized silica gel as the stationary phase and gradient elution with a mobile phase of aqueous acetonitrile solutions containing ammonium acetate. A wide dynamic range is achieved in a single analysis with quantitation of the intermediates at relatively low levels, up to 0.2% (w/w) each, and subsidiary colors at relatively high levels, up to 3.0% (w/w) each. In addition, the method separates the 3 primary disulfonated isomers of D&C Green No. 5 as well as numerous unidentified components. The results of a recovery study and a survey of 16 commercial samples and the pharmacology sample are presented. Recoveries of the intermediates and subsidiary colors from samples of D&C Green No. 5 ranged from 96.8 to 103.8%. The calibration and recovery data are treated statistically to evaluate the performance of the method.
Evaluation of Capillary Gas Chromatography for Pesticide and Industrial Chemical Residue Analysis. I. Comparison of Retention Ratios Obtained on Methyl Silicone-Coated Capillary Columns with Published Values for Packed Columns
Authors: Fehringer Norbert V , Walters Stephen M
Published: February 2020

Many residue laboratories use the retention ratio data compiled by the Food and Drug Administration in its Pesticide Analytical Manual (PAM) for the tentative identification of pesticide and industrial chemical residues detected in food samples. These data were compiled using packed gas chromatographic columns. A study was undertaken to determine if these retention ratios could be used when applying capillary gas chromatography to residue analysis. Retention ratios of a selected group of 108 of the materials listed in the PAM tables were determined isothermally with split injection on 4 WCOT capillary columns obtained from 3 commercial suppliers and coated with 4 different methyl silicone coatings. Of the tested reference materials, 90 displayed retention ratios that matched the PAM values on all columns, 10 differed on at least one of the 4 columns, and only omethoate and monocrotophos gave retention ratios differing on all 4 columns.