bluuebunny/crossref_metadata_2025 huggingface dataset:
An Analytical Survey of Aflatoxins in Tissues from Swine Grown in Regions Reporting 1988 Aflatoxin-Contaminated Corn
Authors: Stubblefield Robert D , Honstead John P , Shotwell Odette L
Published: February 2020

A joint project was undertaken by the Food Safety and Inspection Service (FSIS) and the Agriculture Research Service branches of the U.S. Department of Agriculture to determine the presence of aflatoxins in the U.S. meat supply during a drought year. In 1988, high incidences of aflatoxins occurred in corn grown in regions of the Midwest, Southeast, and South. Six states were identified as having serious aflatoxin contamination in their corn crop: Virginia, North and South Carolina, Texas, Iowa, and Illinois. Swine liver and pillars of diaphragm (muscle) tissues were sampled by federal FSIS inspectors in plants located in these states. A worstcase sampling plan was conducted. Samples were taken in January 1989 from hogs fed corn soon after harvest and in April 1989 from hogs fed corn originally stored and then fed in the spring. A modification of the official AOAC method for the thin-layer chromatography (TLC) determination of aflatoxins in animal tissue was used to permit quantitation by LC with fluorescence detection. The official AOAC TLC confirmation of identity method was used to confirm all positive samples with B1 concentrations >0.04 ppb and M1 concentrations >0.1 ppb. Sixty samples in the January group and 100 samples in the April group were assayed. Concentrations of aflatoxins B1 and M1 in the first group of pig livers ranged from 0.04 to 0.06 ppb. The identity of aflatoxin Bi was confirmed in all positive samples. Aflatoxin M1 could not be confirmed in any of the positive liver samples because the method was insufficiently sensitive for this aflatoxin. No positive muscle samples were found. In the second set, 9 positive livers were determined with B1 concentrations from 0.01 to 0.24 ppb and M1 concentrations from 0.03 to 0.44 ppb. Two samples contained M1 only. None of the corresponding muscle samples contained aflatoxins. Of the 12 positive samples, 5 were from Iowa, 4 from South Carolina, 2 from North Carolina, and 1 from Illinois. Aflatoxins were not detected in any of the samples from Texas or Virginia. One sample from North Carolina contained more than 0.5 ppb total aflatoxins. Blind recovery studies were conducted by including an artificially contaminated liver sample for every 6 samples assayed, and 1 uncontaminated liver sample for every 18 samples. Recoveries of aflatoxins B1, d , and M1 were 71.8%, 73.2%, and 69.8% respectively.
Enzymatic Determination of Free Glutamic Acid in Dried Soups and in Minced Sausages: NMKL1 Collaborative Study
Authors: Hattula M Tapani , Wallin Harriet C ,   Collaborators:, Andersen R , Blomberg K , Carlsson K , Hald B , Huge-Jensen E , Johansson M , Kari T , Larsen Krog L B , Loimaranta J , Yman I Malmheden , Nordbotten A , Reijonen M
Published: February 2020

An enzymatic method for the determination of free glutamic acid in meat products and dried soups was collaboratively studied in 11 laboratories. In the presence of the enzyme glutamate dehydrogenase, L-giutamic acid is oxidatively deaminated by nicotinamide adenine dinucleotide (NAD) to 2-oxoglutarate. In a reaction catalyzed by diaphorase, the NADH thus formed converts 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride to a formazan, which is measured in the visible range at 492 nm. Fourteen samples (7 samples of minced sausage and 7 samples of dried cauliflower soup) with glutamate contents varying between 0.4 and 16 g/kg were included In the study. Materials were distributed to participants as blind duplicates and as split level pairs. The mean relative standard deviation (RSDR) for reproducibility for the dried soup material containing glutamate between 7 and 16 g/kg was 4.6%. RSDR values for samples of minced sausage containing glutamate at lower levels (0.4-1.3 g/kg) were between 12 and 16%.
Potassium as an Index of Fruit Content in Baby Food Products. Part I. Banana-Containing and Apricot-Containing Products
Authors: Harvey Robert A , Theuer Richard C
Published: February 2020

Percentage ingredient labeling has been proposed for baby foods. We determined whether or not the potassium content of baby foods could be used to verify the quantity of fruit when the characterizing ingredients were apricots or bananas, fruits rich in potassium. Official values for potassium in fruit (USDA Handbook No. 8-9) did not agree well with actual analyses. The potassium levels of products of known composition were accurately predicted from analyses of the actual ingredients used to make the foods. For banana-containing monofruit products of variable or unknown composition, potassium analysis led to fruit level estimates consistent with either the known composition or the label declaration. For products of unknown composition made with apricot concentrate, however, potassium analysis led to fruit level estimates lower than the probable fruit content. The quantity of fruit in baby foods made with potassium-rich fruits can be estimated from the potassium content if the potassium value for the fruit is representative of the actual ingredients used to make the product, if potassium analysis is to be used to verify compliance with percentage ingredient labeling, there must be statutory specification of the singlestrength fruit level for fruit reconstituted from concentrate.
Identification of Whale Species by Thin-Layer Isoelectric Focusing of Sarcoplasmic Proteins1
Authors: Ukishima Yoshiyuki , Kino Masahiko , Kubota Hiroyuki , Wada Shiro , Okada Shoji
Published: February 2020

Thin-layer isoelectric focusing was applied to the identification of whale (Cetacea) species by using water-soluble sarcoplasmic proteins of skeletal muscles. Twenty-eight samples consisting of 4 species (10 samples) of baleen whales (Mysticeti) and 8 species (18 samples) of toothed whales (Odontoceti) were analyzed. Each sample (approximately 1 g) was electrophoresed with Ampholine PAGplate, pH 3.5-9.5. The electrophoretic profiles were species-specific on the 4 toothed whale species that did not have a marked intra-species difference, and all 4 baleen whale species. However, the profiles were not specific on the 4 other dolphin species, even though they were discriminable from the other 4 toothed whale species. Numerical values of pls and relative peak heights were obtained by densitometric analysis of the isoelectro-focused protein bands. The bands were also species-specific for the 8 toothed whale species mentioned. The values may be applicable to species identification without the need for a standard sample, which may not be readily obtainable. Experiments on test samples of minke and sei whales showed that bloodletting with ice water made the densities of isoelectro-focused bands thinner, although species identification was still possible by using the Inside part of muscles. Heat treatment at below 60°C for 10 min caused little denaturation; at higher temperatures the protein bands were diminished in a temperature-dependent fashion. Therefore, the present isoelectric focusing analysis should be applicable to small samples of whale meat, excluding several species of dolphins.
Use of the Mycosep Multifunctional Cleanup Column for Liquid Chromatographic Determination of Aflatoxins in Agricultural Products
Authors: Wilson Thomas J , Romer Thomas R
Published: February 2020

A liquid chromatographic (LC) technique has been developed that uses the Mycosep™ multifunctional cleanup (MFC) column. MFC columns provide a rapid 1-step extract purification. They are designed to retain particular groups of compounds that may create Interferences in analytical methods. At the same time, MFC columns allow compounds of interest to pass through. In the method presented, test samples are extracted in a blender with acetonitrile-water (9 + 1). A portion of the extract is forced through an MFC column designed especially for analysis of numerous mycotoxins. Analytical interferences are retained, while aflatoxins pass through the column. Aflatoxins B1 and G1 are converted to their hemiacetals by heating a mixture of purified extract and water-trifluoroacetic acid-acetic acid (7 + 2 + 1) at 65°C for 8.5 min. An aliquot of this mixture is analyzed by isocratic LC with acetonitrile-water mobile phase and fluorescence detection. A detection limit of less than 0.5 ng/g for aflatoxin B1 was obtained. Average recoveries greater than 95% total aflatoxins (B1, B2, G1, and G2) and coefficients of variation of less than 3% were obtained. The method was successfully applied to the following commodities: com, almonds, pistachios, walnuts, peanuts, Brazil nuts, milo, rice, cottonseed, corn meal, corn gluten meal, fig paste, and mixed feeds.
Precolumn 𝘖-Phthalaldehyde Derivatization and Reversed-Phase Liquid Chromatography of S-Methylmethioninesulfonium in Satsuma Mandarin Juice
Authors: Sumitani Hidenobu , Suekane Sachiko , Sakai Yasue , Tatsuka Kiyoaki
Published: February 2020

Experiments were conducted to determine the amount of S-methylmethlonlnesulfonium (MMS) in Satsuma mandarin Juice using a precolumn 𝘖-phthalaldehyde (OPA) derivatization and reversedphase liquid chromatography. Favorable analytical conditions that allowed MMS analysis were achieved by using OPA/3-mercaptopropionlc acid (MPA) as a derivatization agent with fluorescence detection (excitation at 330 nm, emission at 450 nm). A C18 reversed-phase column with 5 μm particle size and a length of 250 mm was used. Resolution of MMS/OPA/MPA derivative was accomplished with a linear gradient eluent (30mM sodium acetate buffer solution, pH 7.3, and 70% (v/v) methanol). Quantitative analysis of MMS by the internal standard method using β-alanine gave highly reproducible result with a coefficient of variation less than 3%. Recovery of MMS added to Juice samples was 105%. MMS content in Satsuma mandarin Juice was 28.2μM.
Precision Parameters of Methods of Analysis Required
for Nutrition Labeling. Part II. Macro Elements—Calcium,
Magnesium, Phosphorus, Potassium, Sodium, and Sulfur
Authors: Horwitz William , Albert Richard , Deutsch Mike J , Thompson Neville J
Published: February 2020

A previous paper reviewed the precision of analyses for the major macronutrients—fat, protein, and carbohydrates— as well as moisture/solids, ash, and "fiber." A similar review is now presented for the macro inorganic nutrients—calcium, magnesium, phosphorus, potassium, sodium, and sulfur. The precision parameters among laboratories (standard deviations, S; relative standard deviations, RSD; and repeatability, r, and reproducibility, R, values) are not characterized by any conventional distribution. The typical precision of the methods of analysis for these elements In food can be expressed solely as a logarithmic function of concentration, Independent of analyte, matrix, and method. The average RSDR value from each collaborative assay found in the literature Is used as the numerator in a ratio containing, as the denominator, the value calculated from the logarithmic function: RSDR(%) = 2( 1 -0.5 log C) where C Is the concentration as a decimal fraction. If this ratio, designated as HORRAT, Is above 2, the method Is probably unacceptable with respect to precision. About 20% of the 465 interlaboratory data sets studied for this paper show an RSDR exceeding the acceptable limit, with an overall average HORRAT of 1.2 at C ranging from about 20 x 10-6(20 ppm) to about 10-1 (10%). The variability, although high, may be acceptable for the purpose of nutrition labeling.
Analytical Strategy for the Regulatory Control
of Residues of Chloramphenicol in Meat: Preliminary Studies
in Milk
Authors: Keukens H J , Aerts M M L , Traag W A , Nouws J F M , De Ruig W G , Beek W M J , Den Hartog J M P
Published: February 2020

An analytical strategy Is described for the regulatory control of residues of the veterinary drug chloramphenicol (CAP) In meat. Screening is performed directly in meat by a simple immunochemical card test with a limit of detection of about 2 μg/kg. Statistical evaluation of a collaborative study involving 13 laboratories showed that at CAP concentrations exceeding 8 μg/kg, no false negatives are found (N = 554). In positive samples, CAP Is quantltated with a routinely applicable, collaboratively tested column liquid chromatographic method with a limit of detection of about 1 μg/kg. At concentrations exceeding 10 μg/kg, the Identity of CAP Is established by Its UV spectrum obtained by using diode-array UV/VIS detection. A further confirmation can be obtained by the combination of gas chromatography/ mass selective detection In the electron Impact mode. Using 2 diagnostic Ions (m/z 225 and 208), the limit of identification Is about 5 μg/kg. The combination of the different analytical principles ensures reliable quantitation and Identification of CAP in positive samples, as established experimentally in Incurred samples and spiked samples (n > 100), and theoretically by the estimation of the uncertainty factor. The proposed set-up makes a regulatory program possible in which screening can be performed In a simple laboratory environment, followed by quantitation and Identification under more sophisticated conditions. Preliminary experiments Indicate that the analytical strategy Is also applicable to the control of CAP in milk. Application of mass spectrometry with negative chemical ionization permits the confirmation of CAP concentrations as low as 0.2 μg/L.
Determination of Cloxacillin and Penicillin V in Milk
Using an Automated Liquid Chromatography Cleanup
Authors: Moats William A , Malisch Rainer
Published: February 2020

A number of screening tests will detect β-lactam antibiotics at levels of less than 10 ng/mL in milk. However, confirmatory procedures of comparable sensitivity are not available. A method using an automated liquid chromatography (LC) cleanup sensitive to 1 ng/mL was developed for penicillin V and cloxacillin. Milk was deproteinlzed with 2 volumes of acetonitrlle. Methylene chloride and hexane were added to the filtrate to separate the water layer containing the antibiotics. The filtrate could also be evaporated directly. The water layer was concentrated and loaded onto a polymeric LC column in 0.01 M pH 7 buffer with the aid of an autosampler. The penicillins were eluted with an acetonitrlle gradient from pH 7 buffer (100%, 0-3 mln) to pH 7 buffer-acetonltrlle (40 + 60,25 mln). Fractions containing each compound were collected and rechromatographed Isocratlcally on the same column type in 0.01 M H3P04-acetonltrlle (58 + 42 for cloxacillin; 62 + 38 for penicillin V). The cleanup can be fully automated. The approach is applicable to other penicillins, but suitable conditions for analysis of fractions for each compound must be developed. Recoveries for penicillin V were 88 ±2% at 1 ppm, 89 ±10% at 0.1 ppm, and 87 ±13% at 0.01 ppm. For cloxacillin, recoveries were 97 ±5% at 1 ppm, 90 ±4% at 0.1 ppm, and 89 ±8% at 0.01 ppm.
Extraction of Light Filth from Fish Paste and Sauce (Bagoong)
Not Containing Spice: Collaborative Study
Authors: Glaze Larry E
Published: February 2020

A collaborative study was conducted to validate a new method for the extraction of light filth from fish paste and sauce (Bagoong) not containing spice. A 225 g test portion is digested by boiling in a mixture of acid and emulsifying agents. Light filth is isolated by wet sieving on a No. 230 plain weave sieve with Tergitol, a deaeration boil in 40% isopropanol, and flotation with mineral oil and 40% isopropanol in a Wildman trap flask. Three spiking levels were used in the study for rat hairs and Insect fragments; 1 level was used for whole or equivalent insects. For rat hairs, recoveries at the low, medium, and high levels averaged 77,94, and 76%, respectively. Recoveries of Insect fragments for these levels averaged 92,88, and 93%, respectively; recoveries of whole or equivalent Insects averaged 85,70, and 80%, respectively. The method was adopted first action by AOAC International for the extraction of light filth from fish paste and sauce (Bagoong) not containing spice.
Production and Characterization of Antibodies Against Neosaxitoxin
Authors: Chu Fun S , Huang Xuan , Hall Sherwood
Published: February 2020

Antibody against neosaxitoxin (neo-STX) was obtained from rabbits after immunization with neo- STX conjugated to either keyhole limpet hemocyanln (KLH) or bovine serum albumin (BSA). An indirect enzyme-linked Immunosorbent assay (ELISA), In which either neo-STX-BSA or neo-STXKLH was coated to the mlcroplate, was used to monitor the antibody titer. Although high antibody titers were obtained from rabbits after immunization with both immunogens, only antibody obtained from rabbits immunized with neo-STX-KLH was useful for Immunoassay. Competitive indirect ELISA revealed that the antibodies obtained from rabbits Immunized with neo-STX-KLH are specific for neo-STX but also have good cross-reactivity with STX. The concentrations causing 50% inhibition binding of neo-STX-BSA to the anti-neo-KLH by neo-STX, STX, and decarbamoyl-STX (DC-STX) were 0.9,8.0, and 53.1 ng/mL, respectively. Saxitoxin conjugated to polylyslne (STX-PLL) was also used as the coating reagent In the indirect ELISA. The concentrations causing 50% inhibition binding of antl-neo-STX-KLH to STX-PLL coated on the mlcrotiter plate by neo-STX, STX, and DC-STX were 1.2,4.1, and 36.1 ng/mL, respectively. With this newly developed antibody, ELISA could be a very effective method for monitoring seafood for both neo-STX and STX.
Nonenzymatic-Gravimetric Determination of Total Dietary Fiber in Fruits and Vegetables
Authors: Li Betty W , Cardozo Maria S
Published: February 2020

Most gravimetric methods for total dietary fiber (TDF) determination require the complete removal of starch and the partial removal of protein with various combination of enzymes In buffers at different pH values and at temperatures much above ambient condition. A hydrolysis step Is crucial In dietary fiber analysis of samples, such as cereals and legumes, which contain appreciable amounts of starch. However, many vegetables and most fruits contain very little or no starch, and they are often eaten uncooked. It would be unnecessary to use high temperatures and enzymes on these types of samples. Initially, we found that hexane and dilute alcohol extractions of a few selected fruits and vegetables gave residue weights comparable to those after enzymatic treatments. We were able to show later that simply suspending the samples in delonized water for 90 mln at 37°C and then adding 95% ethanol also yields TDF values similar to those obtained from other published methods. Comparison data obtained by using variations of the AOAC/TDF method are presented for 10 fruits and vegetables.
Liquid Chromatographic Method for Determination of Glycerol in Wine and Grape Juice: Collaborative Study
Authors: Caputi Arthur , Christensen Eric , Biedenweg Nancy , Miller Susan
Published: February 2020

An Ion-exchange liquid chromatographic method for the determination of glycerol in wine, white grape juice, and pink grape juice was collaboratively studied by 8 laboratories. Eight wine types and 12 juice samples were provided to each collaborator. Using a strong cation column, blind duplicates and standards were analyzed by an external standard method. Separate statistical evaluations were run on wine, white grape juice, and pink grape juice data. The averages of the relative standard deviations for repeatability, excluding outlying results, were 1.25% for the wine samples, 7.32% for the white grape juice samples, and 8.63% for the pink grape juice samples. The averages of the relative standard deviations for reproducibility, excluding outlying results, were 2.79% for the wine samples, 16.97% for the white grape juice samples, and 19.10% for the pink grape juice samples. The method has been adopted first action by AOAC International.
Total Diet Study of Lead and Cadmium in Food Composites: Preliminary Investigations
Authors: Dabeka Robert W , Mckenzie Arthur D
Published: February 2020

In a trial for a comprehensive total diet study, 105 food composites were prepared in the summer of 1985, and another 105 composites in the late fall of 1985. Lead and cadmium were determined In all composites. The mean, median, and range of lead concentrations in the samples were 29.9, 14.7, and 1.42-407 ng/g, respectively. The estimated dietary Ingestion of lead by the average adult Canadian was 36.4 μg/day. The mean, median, and range of cadmium concentrations were 13.7, 5.4, and <0.07- 297 ng/g. Dietary ingestion of cadmium by adults averaged 14.5 μg/day. Sample planning and contamination control for trace element determinations of the study are discussed.
1H NMR Spectroscopic Method with Chiral Eu(III) Shift Reagent for the Determination of the Enantiomeric Composition of Naproxen
Authors: Hanna George M , Lau-Cam Cesar A
Published: February 2020

A simple method based on the use of 1H NMR spectroscopy with chiral Eu(lll) shift reagent is described for the determination of (S)-(+)- and (R)-(-)-naproxen In the presence of each other. To enhance the coordinating affinity of the substrate for the lanthanide Ion, the sample was first derivatized to a mixture of methyl esters, which in the presence of Eu(hfc)3 formed short-lived diastereomeric complexes with sufficient nonequivalency In the 1H NMR spectrum. Optimum complexing conditions corresponded to concentrations of substrate and Eu(hfc)3 of 0.1 M each in CDCI3. In this matter, the enantiomeric ester-methyl protons and α-methyl protons yielded well-resolved resonance signals of utility in the measurement of enantiomeric compositions. Recovery studies demonstrated that the proposed method Is quantitative.
Liquid Chromatographic and Spectral Analysis of the Stereoisomers of Dimethylaminorex
Authors: Noggle F Taylor , Clark C Randall , Derutter Jack
Published: February 2020

The Individual enantiomers of cls- and trans-3,4-dlmethylamlnorex were prepared by treating ephedrines or pseudoephedrines with cyanogen bromide. These compounds represent potential designer drug modifications of aminorex and 4- methylaminorex, which have appeared recently in the clandestine drug market. The UV spectra for these compounds are typical of phenethylamlnetype compounds, and FTIR spectra allow for differentiation of cls- and trans-lsomers. The mass spectra for the dimethylamlnorex stereoisomers show characteristic fragments at m/z 57,118, and 190. The cls- and trans-lsomers were separated In a reversed-phase liquid chromatographic system on a C18 stationary phase, with the cls-lsomer displaying the higher capacity factor.
Capillary Column Gas Chromatographic Method for Analysis of Encapsulated Fish Oils and Fish Oil Ethyl Esters: Collaborative Study
Authors: Joseph Jeanne D , Ackman Robert G
Published: February 2020

A gas chromatographic (GC) method using a capillary column for analysis of encapsulated fish oils and ethyl esters was studied collaboratively in 21 laboratories. Each collaborator analyzed 6 soft-gelatin encapsulated samples; 5 were trlacylglycerol oils (one was a blind duplicate), and one was an ethyl ester concentrate of omega-3 (n-3) polyunsaturates. Constituent fatty acids of the oils were converted to methyl esters by base-catalyzed transesterlflcatlon of the oils; any free acids in the oils were esterlfied by subsequent reaction with BF3/CH3OH. The ethyl ester concentrate required no further derlvatlzation. Results were reported as area percentages of 24 analytes of nutritional or biochemical interest. In addition, weights (mg/g sample) of EPA (all-c/s-5,8,11,14,17-elcosapentaenolc acid or 20:5n-3) and DHA (all-c/s- 4,7,10,13,16,19-docosahexaenoic acid or 22:6n-3) were determined through the use of the internal standards, respectively, methyl tricosanoate (23:0) and ethyl 23:0, for the methyl and ethyl esters. The only instrumentation specifically required was a flexible fused silica capillary GC column coated with a bonded polyglycol such as Carbowax-20M, an oxygen scrubber Installed In the carrier gas supply line, and a flame Ionization detector (FID). Most of the collaborators experienced little difficulty In applying the method, and, of 2526 values reported, only 4.3% were identified as outlier values. The reproducibility relative standard deviations (RSDR) compared favorably in most instances with, or were substantially better than, those of 2 earlier collaborative studies of fish oils. Because the variances were homogeneous, standard deviations and relative standard deviations determined on the area percent analyses of the blind duplicate oils were pooled to give the following mean values: sr = 0.15, RSDr = 4.88%, sR = 0.41, and RSDR = 12.91%. Analytes that rarely occur at greater than 0.5% In marine oils (22:0,22:4n-6,22:5n-6,24:0, and 24:1) were not Included in these calculations. The method was adopted first action by AOAC International as an American Oil Chemists' Society (AOCS)-AOAC method.
Rapid and Simple Coulometric Measurements of Peroxide Value in Edible Oils and Fats
Authors: Oishi Mitsuo , Onishi Kazuo , Nishijima Motohiro , Nakagomi Kazuya , Nakazawa Hiroyuki , Uchiyama Shunichi , Suzuki Shunichi
Published: February 2020

A rapid coulometric method was developed for the measurement of peroxide value In edible oils and fats. The sample size and reagents volumes In this method are considerably less than those in the American Oil Chemists' Society method. Iodine produced by the reaction of the Iodide Ion and peroxide In the sample Is electrochemlcally reduced at the carbon-felt electrode more rapidly than it is with lodometric titration. The present method Is successfully applied to the measurements of edible oils and fats, and the coulometric results obtained are consistent with those obtained by iodometry.
Analysis of 5-Vinyl-l,3-Oxazolidine-2-Thione by Liquid Chromatography
Authors: Quinsac Alain , Ribaillier Daniel , Rollin Patrick , Dreux Michel
Published: February 2020

5-Vlnyl-1,3-oxazolldlne-2-thlone (5-VOT) Is a goltrlgenlc compound released by enzymatic degradation of progoltrln, the major glucoslnolate occurring In rapeseed meal. A liquid chromatographic (LC) method for determination of 5-VOT in a biological environment Is presented. Complete extraction of 5-VOT has been carried out by complexatlon with phenyl mercury acetate under cyclohexanlc conditions, and then by decomplexation using an aqueous sodium thlosulfate solution. These reactions displace 5-VOT from an aqueous to an organic medium, and then back again to the aqueous condition, thus assuring high selectivity of the extraction. Precise quantitation of 5-VOT Is completed in 10 mln by reversed-phase liquid chromatography using an isocratic elutlon with UV detection and a specially made synthetic Internal standard. Concentration steps by solid-phase chromatography and evaporation can be introduced In the analytic procedure to lower the detection limit of 5-VOT in the sample used from 100 to 0.5 ppb. Using sow milk samples, the method was tested by small measured additions of 5-VOT. The recovery rate of the product was very good (>97%). Different phases used to achieve a sensitive, rapid, and precise method are described.
Development and Validation of a Multiresidue Method for β-Agonists in Biological Samples and Animal Feed
Authors: Ginkel Leendert A van , Stephany Rainer W , Rossum Hennie J Van
Published: February 2020

An analytical strategy for the detection of β-agonlsts containing either an N-tert-butyl or N-sopropyl group is described. Extract purification Is based on Immunoaffinity chromatography; final detection, identification, and determination are by gas chromatography/mass spectrometry. To prepare the immunoaffinity chromatography materials, poly-valent antibodies are raised against clenbuterol and cimaterol. The immunoglobulin G fractions of the corresponding rabbit antlsera are isolated and coupled onto an activated Sepharose™ matrix. The prepared columns gave quantitative recovery for a large number of structurally related β-agonists at the 200 ng level. To quantitate and control falsenegative results, Isotope-labeled internal standards are used. For animal feed and bovine urine, analytical recoveries were close to 100% for all compounds except salbutamol (56 ± 5%). Recoveries from liver were in the range of 60-70% (salbutamol, 40-50%). Limits of detection, based on the corresponding most abundant Ion, were In the range of 0.05-0.2 μg/kg or μg/L. Limits for Identification, based on the simultaneous detection of 4 diagnostic ions, were In the range of 1-2 μg/kg or μg/L. Repeatability and within-laboratory reproducibility, expressed as percent relative standard deviation, were all well below 15%, which fulfills the EC criteria for reference methods. The multiresidue method Is an efficient, cost-effective way to determine Illegal growth-promoting N-terf-butyl and N-Isopropyl phenylethanolamlnes.
Detection of Beet Sugar Adulteration of Orange Juice by Liquid Chromatography/Pulsed Amperometric Detection with Column Switching
Authors: White Richard D , Cancalon P E
Published: February 2020

A recently reported method for the quantitation of extraneous beet sugar In orange juice is based on the monitoring of unique oligosaccharides present in beet medium invert sugar (BMIS). Modifications are reported here that expedite the method and render it better suited for monitoring a large number of samples on a routine basis. A switching valve that allows the simple sugars to go to waste after the first column prevents overloading of the analytical column and detector. Furthermore, the retention and column re-equilibration times were significantly reduced. Results of spiking studies of BMIS In orange juice are reported. The estimated limit of detection is 5% BMIS, with a coefficient of variation of 0.1 %.
Liquid Chromatographic Method for Determination of Methamidophos in Technical Products and Pesticide Formulations: CIPAC Collaborative Study
Authors: Hanks Alan R
Published: February 2020

A reversed-phase liquid chromatographic (LC) method for the determination of technical methamidophos and 5 different formulated products was collaboratively studied in 18 laboratories. Samples were dissolved in water, separated by LC, and detected at 210 nm. Quantitation was done by peak area measurements. Relative standard deviations for repeatability and reproducibility ranged from 0.35 to 0.80 and from 1.14 to 1.60, respectively. The method has been approved first action by AOAC International as a CIPAC-AOAC method.
Comparison of Three Methods for Calculating Protein Content in Developing Apple Flower Buds
Authors: Khanizadeh Shahrokh , Buszard Deborah , Zarkadas Constantinos G
Published: February 2020

Three methods (Kjeldahl, sulfuric acid-hydrogen peroxide, and summation of amino acid content) for determining and calculating the protein content of apple flower buds were compared. Quantitation of protein content based on summation of amino acids appears to be the most accurate method. A new nitrogen:protein conversion factor (5.51) was calculated based on total amino acid analysis. This new conversion factor could replace the conventional 6.25 factor for estimating total protein content of apple flower bud by the Kjeldahl method. However, Kjeldahl is not an accurate method for estimating protein content in apple flower bud tissue, regardless of the conversion factor, and probably would not be a good method for estimation of protein in other plant species.
Training Modules To Develop Analytical Proficiency for Pharmaceutical Chemists
Authors: Kenyon, Allen S , Kirchhoefer Ross D , Layloff Thomas P
Published: February 2020

As a part of a training program for new personnel in pharmaceutical analysis and for visiting scientists from other government laboratories, the Division of Drug Analysis (DDA) developed training modules to raise the job performance of incoming college students, technical aides, and newly hired chemists to an acceptable level. The modules include Liquid Chromatography, Gas Chromatography, Dissolution Testing, Thin-Layer Chromatography, Ultraviolet-Visible Spectrophotometry, Infrared Spectrophotometry, and Data Collection and Recording (as related to preparing worksheets in accordance with the requirements of the U.S. Food and Drug Administration). Each module is designed to be delivered in minimal time. By using a combination of commercial audiovisual materials and a training concept developed at DDA, the targeted group can be trained with minimal supervision. This approach does not require experienced analysts to be placed as full-time, one-on-one trainers; thus, the cost of the training is cut. The training scheme could be extended to other applications in industry, academia, or government by targeting training modules to their characteristic operation. These modules are also used as refresher courses for experienced analysts who have not practiced these techniques recently. The modular concept provides an excellent way to train employees quickly.
Rapid Analysis for Ivermectin Residue in Liver and Muscle Tissue by Liquid Chromatography
Authors: Reising Kyle P
Published: February 2020

A rapid procedure has been developed for the isolation and determination of ivermectin in liver and muscle tissue. The analyte is extracted from the target tissue with isooctane and isolated by coagulation of extraneous matrix residue at reduced temperature. A fluorescent derivative is prepared and analyzed by liquid chromatography. Recoveries of ovine, bovine, and porcine liver and muscle tissues fortified within a 0-60 ppb range averaged 75%, with a 12.7% coefficient of variation.
Ergot Alkaloids in Grain Foods Sold in Canada
Authors: Scott Peter M , Lombaert Gary A , Pellaers Peter , Bacler Stanley , Lappi Judy
Published: February 2020

Six pharmacologically active ergot alkaloids (ergonovine [ergometrine], ergosine, ergotamine, ergocornine, α-ergokryptine, and ergocristine) were determined by liquid chromatography with fluorescence detection in over 400 samples of grain foods. The survey was conducted over a 6-year period for rye flour, wheat flour, and bran/bran cereal, and a 5-year period for rye bread/crispbread; triticale flour was analyzed over a total of 3 years. The predominant alkaloids found were ergocristine and ergotamine. Rye flour was the most contaminated food; the incidence of alkaloid-positive samples was 118/128, annual mean concentrations of total alkaloids in positive samples ranged from 70 to 414 ng/g, and 1 sample contained as high as 3972 ng total alkaloids/g. In wheat flour, total alkaloid concentrations were much lower than in rye flour, with annual means in positive samples (68/93) of 15-68 ng/g. Bran/bran cereal had alkaloid concentrations similar to those in wheat flour, with annual means of 12-69 ng total alkaloids/g positive samples (incidence 29/35). Triticale flour was also an important source of ergot alkaloids; incidence was 24/26, and annual mean total alkaloid concentrations in positive samples were 46-283 ng/g. Ergot alkaloids were found in rye bread (46/100) and other heat-processed rye flour products (6/14). Annual mean total alkaloids in positive rye bread/crispbread samples ranged from 4.8 to 100 ng/g; the latter included a sample with 1248 ng total alkaloids/g.
Liquid Chromatographic Determination of Fumonisins B1 and B2 in Corn and Corn Products
Authors: Stack Michael E , Eppley Robert M
Published: February 2020

A liquid chromatographic (LC) method is described for determining fumonisin B1 (FB1) and fumonisin B2 (FB2), metabolites of Fusarium moniliforme, in corn and corn products. The metabolites are extracted with methanol-water (3 + 1), and the extract is added to a disposable strong anion exchange column. After the FB1 and FB2 are eluted from the column with methanol-acetic acid (199-1-1) and the eluate is evaporated to dryness, the metabolites are derivatized with o-phthaldialdehyde and 2- mercaptoethanol to make highly fluorescent derivatives. Reversed-phase LC with fluorescence detection is used for the final separation and determination. The estimated limit of quantitation is 10 ng/g for each metabolite. The average recoveries from corn were 67% for FB1 and 71% for FB2, with relative standard deviations of 5% for FB1 and 3% for FB2. The identities of the fumonisins were confirmed by mass spectrometry. Applications of the method include the analyses of corn meal and breakfast cereals.
Co-occurrence of Cyclopiazonic Acid and Aflatoxins in Corn and Peanuts
Authors: Urano Takashi , Trucksess Mary W , Beaver Rodney W , Wilson David M , Dorner Joe W , Dowell Floyd E
Published: February 2020

Fifty samples of peanuts and 45 samples of com, collected in Georgia during 1990, were examined for the co-occurrence of cyclopiazonic acid (CPA) and aflatoxins (AF). The corn was collected from fields in Georgia, before harvest, under the mycotoxin- monitoring program of the U.S. Department of Agriculture's Agricultural Research Service. The peanuts were designated for oil production or animal feed because of visible damage to the nutmeats. CPA was determined by reversed-phase liquid chromatography (RPLC) using a linear gradient. Solvent A was methanol-water (85 +15), and solvent B was 4 mM ZnS04 in methanol-water (85 +15). The gradient started at 0% B and reached 100% B at 10 min. AF were determined by RPLC with postcolumn iodination. Of the 45 corn samples analyzed, 51 % were contaminated with CPA (<25-2800 ng/g, av. 467 ng/g), and 87% were contaminated with AF (1-2300 ng/g, av. 252 ng/g). Of the 50 peanut samples, 90% contained CPA (<50- 2900 ng/g, av. 460 ng/g), and 100% contained AF (3- 22 000 ng/g, av. 1685 ng/g). The identity of CPA was confirmed in selected samples of corn and peanuts by mass spectrometry.
Determination of Polynuclear Aromatic Hydrocarbons in Seafood by Liquid Chromatography with Fluorescence Detection
Authors: Perfetti Gracia A , Nyman Patricia J , Fisher Sheryl , Joe Frank L , Diachenko Gregory W
Published: February 2020

Modification of a previously published method for determination of polynuclear aromatic hydrocarbons (PAHs) produces very clean seafood extracts in less than half the time. After alkaline digestion of the seafood, PAHs were partitioned into 1,1,2- trichlorotrifluoroethane. The resulting extract was cleaned up by solid-phase extraction on alumina, silica, and C18 adsorbents and then analyzed by gradient reversed-phase liquid chromatography with programmable fluorescence detection. Average recoveries of 12 PAHs [acenaphthene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)- fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(ghi)perylene, and indeno(1,2,3-cd)pyrene] from 5 different matrixes (mussels, oysters, clams, crabmeat, and salmon) spiked at low partsper- billion levels ranged from 76 to 94%. Estimated limits of quantitation ranged from 0.01 to 0.6 ppb PAHs in extracts that were free of matrix interferences. Results of analyses of a mussels standard reference material obtained from the National Institute of Standards and Technology were in good agreement with the certified values.
Determination and Confirmation of cis-9-Tricosene in Technical Materials by Capillary Gas Chromatography and Gas Chromatography/Mass Spectrometry
Authors: Ko Jinren , Nguyen Jack , Burleson Jim
Published: February 2020

A capillary gas chromatographic (GC) method was developed for the quantitation of cis-9-tricosene in technical material. This method is capable of resolving cis-9-tricosene from the trans-9-tricosene isomer and other impurities in technical 9-tricosene. Samples are dissolved in methylene chloride and analyzed by splitless GC using docosane as an internal standard. The integrity and purity of the peak of interest were confirmed by GC/mass spectrometry. The overall recovery of this method was 101.3 ± 0.82%. The correlation coefficient of the standard calibration curve was 0.9999. The system and method precision for cis-9-tricosene were 0.18 and 0.20%, respectively. The reproducibility of the method by different analysts was within 0.5%.
Determination of Total Vitamin C in Various Food Matrixes by Liquid Chromatography and Fluorescence Detection
Authors: Dodson Karen Y , Young Edna R , Soliman Abdel-Gawad M
Published: February 2020

A liquid chromatographic method was developed for quantitation of total vitamin C content in various food matrixes. The method includes extraction with 3% mete-phosphoric acid-acetic acid and oxidation of ascorbic acid to dehydroascorbic acid with Norit, followed by reaction with ophenylenediamine to form a fluorescent derivative. The fluorescent derivative is separated on a µBondapak C18 (10 µm) column with methanol-water (55 + 45) and detected fluorometrically. This method is demonstrated to be suitable for several sample matrixes, including complex matrixes of canned corn, potatoes, green beans, potato chips, and cereals. Other products analyzed include infant formula, medical foods, fruit juice, and multivitamin tablets. Recoveries are in the range of 90-108%. Comparison of results with those by the AOAC fluorometric method shows excellent agreement.
Liquid Chromatographic Assay for Naphazoline and Antazoline in Ophthalmic Preparations
Authors: Bocic Ronny , Vallejos Cristobal , Alvarez-Lueje Alejandro , LÓpez Fernando
Published: February 2020

A liquid chromatographic (LC) analysis has been developed for determining naphazoline and antazoline in ophthalmic preparations. The LC system is designed so that a variety of ophthalmic solutions containing naphazoline and antazoline can be analyzed with precision.
Determination Of Total Fat In Meat And Meat Products By Solvent Extraction After Hydrochloric Acid Hydrolysis: NmkL Interlaboratory Study
Authors: Croon Lars-Börje , Wallin Harriet C
Published: February 2020

A gravimetric method including acid hydrolysis and solvent extraction according to SBR (Schmid, Bondzynski, and Ratzlaff) for the determination of total fat in meat and meat products was collaboratively studied in 12 laboratories. The study aimed at investigating whether an older SBR method for the determination of fat in meat and meat products, published by the Nordic Committee on Food Analysis in 1974, could be simplified without significant losses in precision. The study samples consisted of 12 materials in the form of 6 matched pairs of meat types: ham, beef trimmings, pork loin, black pudding, sausage, and liver pate. The fat contents of the samples varied between 2.6 and 44.4 g fat per 100 g. The participating laboratories were asked to analyze the samples by both the old and the new methods. The results indicated that there was no significant difference between the results obtained by the 2 methods. The precision of the revised method in most respects meets the U.S. Department of Agriculture, Food Safety and Inspection Service requirements on methods for the analysis of meat and meat products. The relative standard deviation for repeatability of the method varied from 0.93% for the 44.5 g/100 g level of fat to 4.5% for the 2.5 g/100 g level. The relative standard deviation for reproducibility varied correspondingly between 1.2 and 6.1%. For samples with a fat content <5 g/100 g, the revised method gave somewhat lower fat concentrations than the older method. However, the mean differences were small and did not exceed the precision (repeatability and reproducibility) of the method. Ten of the 12 participating laboratories found the revised method easier to work with than the original method
Optimization, Automation, and Validation of the Solid-Phase Extraction Cleanup and On-Line Liquid Chromatographic Determination of N-Methylcarbamate Pesticides in Fruits and Vegetables
Authors: De Kok André , Hiemstra Maurice
Published: February 2020

A fully automated liquid chromatographic (LC) method was developed for the determination of 21 N-methylcarbamates and 12 of their metabolites. Our previously developed solid-phase extraction (SPE) cleanup method can now be performed using an automated SPE cleanup apparatus. The cleaned-up extract is injected on-line into the LC carbamate analysis system, which is based on a reversed- phase LC separation, postcolumn hydrolysis of the carbamates on a solid-phase catalyst, reaction of the methylamine formed with ophthalaldehyde reagent, and fluorescence detection of the derivatives. The optimized method was evaluated. Recovery and repeatability data were collected for 13 representative carbamates and 12 metabolites on 12 different food product types. The reliability of the method in routine analysis of fruit and vegetable samples is demonstrated. Registration of the analytical results of control samples in Shewhart charts during a year of routine analysis has demonstrated the excellent performance of this complete method. The limits of determination are in the 5-50 μg/kg (ppb) range. Sample throughput is about 20 per 24 h. Data are presented on real residues of N-methylcarbamates found in fruits and vegetables during 4 years of routinely applying this multiresidue method
Liquid Chromatographic Determination of Methazole in Technical and Formulated Products: Collaborative Study
Authors: Belkind Benjamin A
Published: February 2020

An isocratic normal-phase liquid chromatographic (LC) method for measuring methazole in technical and formulated products was collaboratively studied by 12 laboratories. Samples of technical or formulated products are dissolved in 1,4-dioxane-hexane containing 2-chloro-5-nitrobenzophenone as internal standard. Following centrifugation and further dilution, the sample is analyzed by LC on a 25 cm x 4.6 mm stainless steel column packed with 5 μm silica, with ultraviolet detection at 254 nm. Premixed 1% 2-propanol in hexane is used as the mobile phase. Peak areas are obtained at the retention times corresponding to the internal standard and methazole. The quantity of active ingredient is determined by comparing the area ratio of active ingredient to internal standard in the sample with the same ratio in a single calibration solution. Collaborators were provided with 1 Youden matched pair for each of the technical, 75% wettable granular, and 4 lb/gal flowable products studied. The reproducibility relative standard deviations (RSDR) for the product types studied were 1.05% for technical, 1.80% for granular, and 4.76% for flowable. The method has been adopted first action by AOAC International.
δ18 Measurements in Water for Detection of Sugar
Beet-Derived Syrups in Frozen Concentrated Orange Juice:
Collaborative Study
Authors: Doner, Landis W , Brause Allan R , Petrus Donald R
Published: February 2020

Stable isotope ratio mass spectrometry has shown that pure frozen concentrated orange juices (FCOJ) of 63-67° brix possess a mean δ18 value of +14.28%o, with a standard deviation of 1.80. Beet invert syrups, which are produced using ground water, possess negative values. As a result, δ18 values decrease on addition of such syrups to FCOJ. Samples with values less than +8.9%o (3 standard deviations from the mean for pure FCOJs) can confidently be considered as adulterated. A collaborative study was conducted in which a pure FCOJ and 4 samples adulterated to various levels with medium beet invert syrup were sent to each of 6 collaborators. In all but 2 instances, juices containing more than 10% beet syrup would have been classified as adulterated by the collaborators; none would have classified pure juice as adulterated. The plot of mean δ18 values for all collaborators at each adulteration level has a correlation coefficient >0.999. The method has been adopted first action by AOAC International.
Rapid Isolation Of The Sterol Fraction In Edible Oils
Using A Silica Cartridge
Authors: Bello Ada C
Published: February 2020

A commercial silica cartridge was used successfully to separate the fraction of the unsaponifiable components of edible oils containing the sterols and some related compounds. Analysis by gas chromatography indicates that there is good agreement between the results from samples obtained by the new rapid method and those isolated using the time-consuming thin-layer chromatographic technique. This paper presents comparison data for 7 vegetable oils (peanut, soy, corn, rapeseed, olive, sesame, and coconut), a 2-component blend (olive and soy), and a commercial milk product erroneously labeled cholesterol-free.