bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Calcium by Inductively Coupled Plasma-Atomic Emission Spectrometry, and Lead by Graphite Furnace Atomic Absorption Spectrometry, in Calcium Supplements after Microwave Dissolution or Dry-Ash Digestion: Method Trial
Authors: Siitonen Paul H , Thompson Harold C ,   Method Trial Participants: Anjum S. Choudhry, FDA, Atlanta Center for Nutrient Analysis, Atlanta, GA; Ronald W. Marts, FDA, Kansas City District Office, Lenexa, KS; and Paul H. Siitonen, FDA, National Center for Toxicological Research, Jefferson, AR
Published: February 2020

A 3-laboratory method trial was conducted to evaluate 2 sample digestion procedures and instrumental determination parameters for analysis of calcium and lead in Ca supplements. Calcium supplements were treated by dry-ash digestion or microwave dissolution prior to spectrometric analysis. In each case, Pb was determined by graphite furnace atomic absorption spectrometry and Ca by inductively coupled plasma-atomic emission spectrometry. Blind duplicates of 6 Ca supplement samples were analyzed after each sample treatment procedure. Matrix pairs contained dissimilar Pb levels to cover the analyte range encountered during method development. Calcium content of the Ca supplement samples also reflected the range seen during method development. Stock solutions of Ca and Pb were supplied to collaborators for preparation of quantitation standards to remove a variable external to the method. National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1486, bone meal, was included to assess method accuracy and recovery at NIST certificate Ca and Pb levels for this material (26.58 ± 0.24% Ca and 1.335 ± 0.014 µg Pb/g). Analyses of the NIST SRM yielded 25.9 ± 1.1 and 27.2 ± 2.3% Ca and 1.53 ± 0.19 and 1.26 ± 0.19 µg Pb/g for dryash and microwave procedures, respectively. Statistical analyses of data indicated acceptable repeatability and reproducibility for determination of Pb and Ca in various Ca supplements. With either sample preparation technique, the method Received August 27, 1997. Accepted by JS July 2,1998. is appropriate for determining Pb or Ca in Ca supplements.
Identification and Semiquantitative Estimation of Antibiotics Added to Complete Feeds, Premixes, and Concentrates
Authors: Gafner Jean-Louis
Published: February 2020

Classical microbiological methods for determining antimicrobial compounds in feeds are nonspecific. Thus, there is a need to identify biological activity, and bioautography is used for thispurpose. A routine method for detecting the following antimicrobial sub stances in feeds is described: avilamycin, avoparcin, Zn-bacitracin, erythromycin, flavomycin, furazolidone, lasalocid, monensin, narasin, penicillin, salinomycin, spiramycin, tetracyclines, tylosin, and virginiamycin. Carbadox can be detected by UV light examination of the plates prior to bioautography. Semiquantitative estimations of antibiotic content are compared with quantitative determinations of the above mentioned sub stances in feeds, except erythromycin, penicillin, and tetracyclines. Detection limits range from 0.1 mg/kg (chlortetracycline) to 20 mg/kg (lasalocid). The method involves agar diffusion of buffered samples, a neutral extraction of polyether antibiotics followed bythin-layer chromatography (TLC), and an acid extraction for other antibiotics followed by TLC. Five test bacteria were used for the main detection by agar diffusion: Micrococcus luteusATCC 9341, Staphylococcus aureus ATCC 6538P, Corynebacterium xerosis NCTC 9755, Bacillus cereus ATCC 11778, and B. subtilis ATCC 6633. Identification after TLC was achieved by bioautography with the most sensitive microorganism(s). This method allows one laboratory technician to analyze up to 30 feed samples within 2.5 working days, provided that feeds of the same category are analyzed in the same run, and that labels of additives are available. Qualitative and semiquantitative information are valuable when performing a quantitative antibiotic determination and it provides proof that the activity determined is due to the tested substance. This last feature is essential from the perspective of quality assurance of results.
Dry Rehydratable Film Method for Enumerating Confirmed Escherichia coli in Poultry, Meats, and Seafood: Collaborative Study
Authors: Gangar Vidhya , Curiale Michael S , Lindberg Kathryn , Gambrel-Lenarz Sonya ,   Collaborators:, Adamson E , Barbari W , Brodsky M , Blackwell G , Bryce J , Cook P , Davis B , Deabel J , D’Onorio A , Follmi-Lieder E , Franklin J , Gambrel-Lenarz S , Horne S , James-Davis L , Lindgren S , McIntyre D , Moore J , Moorman M , Puccini M , Pulusani S , Sass A , Saunders L , Schop R , Sigua C A , Sinclair P , Story R , Westmoreland R , Windsor S , Witt J L
Published: February 2020

A rehydratable dry-film plating method for Escherichia coli, the Petrifilm E. coli/Coliform (EC) Count Plate in foods, has been compared with the AOAC INTERNATIONAL most probable number (MPN) method. Eleven laboratories participated in the collaborative study. Three E. coli levels in 8 samples each of frozen raw ground turkey, frozen raw ground beef, and frozen cooked fish were tested in duplicate. Mean log counts for the Petri film plate procedure were not significantly different from those for the MPN procedure for cooked fish samples inoculated with low or high inocula levels, for samples of raw turkey inoculated at medium level, and for beef inoculated at low, medium, and high levels. Repeatability and reproducibility vari ances of the Petrifilm EC Plate method recorded at 24 h were as good as or better than those of the MPN method. The dry rehydratable film method for enumerating confirmed E. coli in poultry, meats, and seafood has been adopted first action by AOAC INTERNATIONAL.
Spectrophotometric Determination of Some Hydrazine Derivatives Using 2,3-Dichloro-5,6-Dicyano-p-Benzoquinone
Authors: Al-Ghannam Sheikha Mohamed , El-Brashy Amina Mohamed , Al-Hussein Laila Abdel-Rahman
Published: February 2020

A simple, sensitive, and rapid spectrophotometric method for determining isoniazid, isocarboxazid, and iproniazid phosphate is described. In this method, 2,3-dichloro-5,6-dicyano-p-benzoquinone (a π-acceptor) is used to form charge-transfer complexes with cited drugs (n-donors). The procedure is sensitive enough to permit unit dose assay of the individual drugs in their pharmaceutical formulations. The assay results are in accord with the pharmacopoeial assay results.
Arsenic Determination in Certifiable Color Additives by Dry Ashing Followed by Hydride Generation Atomic Absorption Spectrometry
Authors: Hepp Nancy M
Published: February 2020

The preparations of digested samples of certifiable color additives by dry ashing and wet digestion for arsenic analysis by hydride generation atomic absorption spectrometry (AAS) were compared. The dry ashing technique was based on the preparation used in ASTM D4606-86 for determination of As and Se in coal. The acid digestion method used nitric and sulfuric acids heated by microwaves in sealed vessels. The digested color additives were analyzed for As by using hydride generated from sodium borohydride mixed with the acidified solution on a flow injection system leading to an atomic absorption spectrometer. Dry ashing was preferable to wet digestion because wet digestion yielded poor recoveries of added As. Dry ashing followed by hydride generation AAS gave determination limits of 0.5 ppm As in the color additives. At a specification level of 3 ppm As, the precision of the method using dry ashing was ± 0.4 ppm (95% confidence interval).
Residues of Chlormequat and Mepiquat in Grain—Results from the Danish National Pesticide Survey
Authors: Juhler René K , Vahl Martin
Published: February 2020

The objective of the present work was to establish information on chlormequat and mepiquat residues in grain for human consumption. Chlormequat (2- chloro-N,N,N-trimethylethylammonium, CAS RN 7003-89-6) and mepiquat (1,1-dimethylpiperid- inium, CAS RN 15302-91-7) are plant growth regulators used to stabilize stalks in cereals. The study was part of the Danish National Pesticide Survey, managed by the Danish Veterinary and Food Administration. Samples were collected in autumn 1997. Residue contents were determined with a newly developed liquid chromatographic- tandem mass spectrometric (LC-MS/MS) method for chlormequat analysis. The method was extended to include mepiquat in the present study. Quantitation was done by the internal standards method, using mass chromatograms of the most intense daughter ions of mepiquat (m/z 98), chlormequat (m/z 58), and [13C]-chlormequat (m/z 61, internal standard). For chlormequat, the overall limit of detection (LD) was 6 μg/kg and the limit of determination (LOD) was 10 μg/kg. For mepiquat, LD was 2 μg/kg and LOD was 3 μg/kg. Of 77 samples analyzed, 51 contained chlormequat and 11 contained mepiquat. The highest levels of chlormequat were found in samples of oatmeal (3.76 mg/kg) and rye (1.08 mg/kg). In 9 rye grain samples containing chlormequat, 5 also contained mepiquat. However, in all samples analyzed, the residues of chlormequat and mepiquat were below maximum residue limits.
Chemically Modified Silica Gel with Mercaptopropyltrimethoxysilane as Stationary Phase in Thin-Layer Chromatography
Authors: Marutoiu Constantin , Constantinescu Rodica , Dogar Florenta , Grecu Rodica
Published: February 2020

A polar silica gel R chemically modified with mercaptopropyltrimethoxysilane was prepared. Surface characteristics of the silica gel R before and after chemical modification were determinated by elemental analysis, specific surface area characterization, infrared spectroscopy, and thin-layer chromatography. Eight dyes were separated on the chemically modified silica gel R.
Use of Microwave Digestion and Atomic Absorption Spectrophotometry To Determine Chromic Oxide as a Digestibility Marker in Feed, Feces, and Ileal Content
Authors: García-Rico Leticia , Ruiz Rita E Ramos , Coronado Lourdes Gutiérrez
Published: February 2020

Most conventional digestion procedures, such as dry ashing and wet ashing, are tedious and labor intensive. Microwave digestion is agood alternative, because microwave dissolution is faster, safer, and simpler, and provides more controlled reproducible conditions than conventional methods. The purpose of this study was to develop a microwave digestion method for mineralizing meat and bone meal diets, feces, and ileal contents. Each sample was heated on a hot plate for 10 min, dry ashed at 65°C for 4 h, and transferred into microwave vessels. Then, 10 mL 70% HNO3 was added. Samples were digested for 7,10, and 20 min at 95,90, and 85% power, respectively. After the heating cycle, 6 mL 30% H2O2 was added, and samples were returned to the microwave for a second heating cycle of 1 and 7 min at 95 and 90% power, respectively. Finally, chromium concentration was determined by flame atomic absorption spectrophotometry. The digestion method was validated by using a standard reference material, SRM domestic sludge 2781, with a certified chromium value of 195 ± 9 μg/g. The value obtained in this study was 178 ± 11 μg/g, for a difference of 17 μg/g. Spike recovery experiments resulted in 103.16 and 100.35% recoveries of chromium from diet and feces samples, respectively. Coefficients of variation were 10.8 and 7.8%, respectively.
Determination of Avilamycin in Poultry Feeds by Liquid Chromatography
Authors: Scott Charles A , Yordy Durand W , Coleman Mark R
Published: February 2020

Avilamycin was extracted from feed with acetonitrile. Isolation of avilamycin factors from feed matrix interference was accomplishedby normal phase solid-phase extraction with silica as sorbent. Reversed-phase liquid chromatography was subsequently used to separate and quantitate the primary biologically activefactors A and B for determination of chemical potency. This method combines specificity for avilamycins A and B in poultry feeds with simple sample preparation that removes matrix interferences. Recoveries of factor A ranged from 93.29 to 97.26%, with precision (relative standard deviation) ranging from 1.1to 3.4%. Avilamycin factors in feed samples tested ranged from 4.45 to 17.82 μg/g for factor A and from 0.80 to 3.18 μg/g for factor B.
Salmonella in Foods—A New Enrichment Procedure for Use with the TECRA Salmonella Visual Immunoassay: Collaborative Study
Authors: Hughes Denise , Dailianis Angela E , Hill Louise , Curiale Michael S , Gangar Vidhya ,   Collaborators:, Arnold Don , Barrat Christine , Baxter Trisha , Bell Jim , Brooks Robert , Bryant Dennis , Burke Kylie , Burnie Adrienne , Clifford David , Daniels Karen , Danisavich Tom , Deiss Karen , Armando D’Onorio , Faucher Karla , Finkenbiner Dwain , Gangar Vidhya , Gasanov Uta , Gebler Jill , Gerry Ann , Graham Doris , Graham Trudy , Harris Patrick , Hetrick Susan , Hill Louise , Jurgens Jodi , Keating Kathy Jost , Klokman Renee , Le Cherie , Matrozza Mark , McCarthy Rachel , McCawley Cameron , Munyard Steven , Pye Victoria , Rajkowski Kathleen , Ristov Katerina , Rosinko Joyce , Schneider Keith , Schubert Mary Jane , Sloan Edna , Souter Freya , Wilson Maurice , Zuroski Kristy
Published: February 2020

A collaborative study was conducted to compare a new enrichment procedure for the TECRA Salmonella Visual Immunoassay with the reference method given in the U.S. Food and Drug Administration’s Bacteriological Analytical Manual (BAM 7th Ed.). Three food types (milk powder, black pepper, and soy flour) were analyzed in Australia, and 3 food types (milk chocolate, dried egg, and rawturkey) were analyzed in the United States. Thirty eight collaborators participated in the study. No significant differences (p > 0.05) were observed for the pairwise comparison of the proportion of positive samples forthe TECRA method with that for the reference method. The new enrichment procedure for the TECRA method has been adopted First Action by AOAC INTERNATIONAL.
Analysis of β-Carotene in Medical Food by Liquid Chromatography with Matrix Solid-Phase Dispersion
Authors: Chase G William , Eitenmiller Ronald R , Long Austin R
Published: February 2020

A liquid chromatographic method is described for analysis of β-carotene in medical food. The nutrient is extracted from medical food without saponification by matrix solid-phase dispersion and quantitated by isocratic normal-phase chromatography with a Si 60 column and a mobile phase of hexane containing 0.125% (v/v) isopropyl alcohol. The limit of quantitation is 0.02 μg/mL at 436 nm. Standard response was linear over the concentration range of 0.02μ1.0 μg/ml(r2 = 0.99998). Recoveries were determined on a zero control reference material containing added β-carotene at various levels. Recoveries averaged 91.2% (n = 25) with coefficients of variation from 0.50 to 3.10%. The method provides a rapid, specific, sensitive, and easily controlled assay for analysis of β-carotene in fortified medical food. In addition, retinyl palmitate can be assayed simultaneously with an in-line fluorescence detector.
Determination of Fat, Protein, and Total Solids in Ovine Milk by Near-Infrared Spectroscopy
Authors: Albanell Elena , Cáceres Paloma , Caja Gerardo , Molina Ester , Gargouri Ahmed
Published: February 2020

Analysis by near-infrared spectroscopy (NIRS) was investigated as a means of predicting quality parameters of ovine milk. Calibration equations were developed with samples of ovine milk obtained from a flock of Manchega and Lacaune dairy ewes at different stages of lactation for a wide variation in milk composition. Prediction equations for milk protein, fat, and total solids content were developed by use of reflection or transflection methods to measure absorbance values. Accuracies of measurements were compared. R2 (squared multiple correlation coefficient) values were satisfactory in most cases. The highest R2 value for milk protein content (0.92) was obtained in transflectancemode with unhomogenized milk. The highest R2 values for fat (0.99) and total solids (0.98–0.96) content were obtained in both a transflectance mode without sample conditioning and in a transflec tance mode with milk homogenized at 40°C. To validate the calibration, an independent set of 40 milk samples was used. The best r2 (simple correlation coefficient) values for protein, fat, and total solids were 0.92, 0.97, and 0.92, respectively. The study showed that NIRS is a potentially useful technique for evaluating the composition of unhomogenized ovine milk.
Validation of a Gas Chromatographic Method for Determining Fatty Alcohols that Compose Policosanol in Five-Milligram Film-Coated Tablets
Authors: Canavaciolo Victor L González , Hernández Juan Magraner
Published: February 2020

A gas chromatographic method using a packed column and 1-eicosanol as an internal standard was developed and validated for determination of the aliphatic fatty alcohols that compose policosanol in 5 mg film-coated tablets. The alcohols were analyzed as trimethylsilyl (TMS) derivatives, prepared with N-methyl-N-trimethylsilyltrifluoroacetamide. The method can detect degradation products with high retention times without interfering with the peaks of the active principle. Good linearity (correlation coefficient = 0.9996) and accuracy (recovery = 100.44%) were proven over a range of 50-150% of the nominal concentration. Within-day and between-day precisions at the nominal 100% value met the acceptance criteria (<2%). Ruggedness was examined through an intralaboratory experimental study in which 7 operational changes were made and the observed results were quantitation, repeatability, resolution, and relative retention time. Among these results, only the relative retention time (tC28,C20) was significantly affected when the column used was 2.1 m instead of 3.1 m. Repeatability and reproducibility (r = 0.1506 and R = 0.2450, respectively) were obtained from a uniform-level interlaboratory test. The method is suitable for quality control and stability studies of these tablets.
Routine Detection of Salmonella Species in Water: Comparative Evaluation of the ISO and PROBELIA™ Polymerase Chain Reaction Methods
Authors: Coquard Dominique , Exinger Alfred , Jeltsch Jean-Marc
Published: February 2020

Water is one of the main transmission routes for Salmonella spp., the causative agents of salmonellosis in humans and animals. This worldwide sanitary problem requires rapid and accurate analyses to be realized so that advisories for exposed people are timely and reliable. Because the traditional method, the ISO 6340 method, does not meet the criterion of rapidity, there was a need for a quicker method. To fulfill this need, a comparative evaluation between the ISO method and one based on polymerase chain reaction (PCR), the PROBELIA, was performed. Waters from different origins were tested either directly or after artificial contamination with selected Salmonella strains isolated from the environment. The results clearly demonstrate that the PCR-based method can advantageously replace the ISO 6340 method. It is quicker, less labor intensive, reproducible, and provides results that match perfectly to those obtained by the ISO method. Furthermore, the PROBELIA method meets the requirements for an efficient sanitary survey: high numbers of samples processed at the same time, reduced cost, and results within 2 days.
Optimization and Validation of a Minicolumn Method for Determining Aflatoxins in Copra Meal
Authors: Arim Rosario H , Aguinaldo Aida R , Tanaka Toshitsugu , Yoshizawa Takumi
Published: February 2020

A minicolumn (MC) method for determining aflatoxins in copra meal was optimized and validated. The method uses methanol–4% KCI solution as extractant and CuSO4 solution as clarifying agent. The chloroform extract is applied to an MC that incorporates “lahar,” an indigenous material, as substitute for silica gel. The “lahar”-containing MC produces a more distinct and intense blue fluorescence on the Florisil layer than an earlier MC. The method has a detection limit of 15 μg total aflatoxins/kg sample. Confirmatory tests using 50% H2SO4 and trifluoroacetic acid in benzene with 25% HNO3 showed that copra meal samples contained aflatoxins and no interfering agents. The MC responses of the copra meal samples were in good agreement with their behavior in thin-layer chromatography. This modified MC method is accurate, giving linearity-valid results; rapid, being done in 15 min; economical, using low-volume reagents; relatively safe, having low-exposure risk of analysts to chemicals; and simple, making its field application feasible.
Application of Polymerase Chain Reaction–Single Strand Conformational Polymorphism (PCR–SSCP) to Identification of Flatfish Species
Authors: Céspedes Ana , García Teresa , Carrera Esther , González Isabel , Carrera Esther , Fernández Alicia , Hernández Pablo E , Martín Rosario
Published: February 2020

A method of DNA analysis based on polymerase chain reaction–single strand conformational polymorphism (PCR–SSCP) was developed to verify the authenticity of labeled raw and frozen fillets of some flatfish species. PCR was used to amplify a short fragment (201 bp) of the mitochondrial cytochrome b gene, which was denatured and analyzed by native polyacrylamide gel electrophoresis for detection of SSCPs. Species-specific patterns of DNA bands were obtained for sole (Solea solea), European plaice (Pleuronectes platessa), flounder (Platichthys flesus), and Greenland halibut (Reinhardtius hippoglossoides).
Multiresidue Determination and Confirmation of Imidazolinone Herbicides in Soil by High-Performance Liquid Chromatography/Electrospray Ionization Mass Spectrometry
Authors: Krynitsky Alexander J , Stout Steven J , Nejad Huns , Cavalier Thomas C
Published: February 2020

A new multiresidue method was developed to determine 6 imidazolinone herbicides in 5 different soil types, using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESMS). Good recoveries and sensitivity were obtained for the compounds investigated at the 2.0 ppb limit of quantitation. A 50 g portion of soil was extracted with 0.5N NaOH. A portion of the extract was acidified to precipitate humic acids, and the supernatant was loaded onto a preconditioned tC-18 solid-phase extraction (SPE) cartridge and eluted with ethyl acetate. Further cleanup was achieved by using a tandem strong-anion-ex- change SPE/strong-cation-exchange (SCX) SPE. Analytes were eluted from the SCX SPE with saturated KCI in methanol. After cleanup, the sample was desalted with an RP-102 SPE cartridge. Quantitation was achieved by monitoring the [M + H]+ ions for each compound, with a time-scheduled selective-ion-monitoring program (positive mode). The extraction and cleanup procedure produced a purified extract for MS confirmation using 3 ions with “in-source” collision-induced dissociation.
A Fully Automated System for Analysis of Pesticides in Water: On-Line Extraction Followed by Liquid Chromatography- Tandem Photodiode Array/Postcolumn Derivatization/ Fluorescence Detection
Authors: Patsias John , Papadopoulou-Mourkidou Euphemia
Published: February 2020

A fully automated system for on-line solid phase extraction (SPE) followed by high-performance liquid chromatography (HPLC) with tandem detection with a photodiode array detector and a fluorescence detector (after postcolumn derivatization) was developed for analysis of many chemical classes of pesticides and their major conversion products in aquatic systems. An automated on-line-SPE system (Prospekt) operated with reversed-phase cartridges (PRP-1) extracts analytes from 100 mL acidified (pH = 3) filtered water sample. On-line HPLC analysis is performed with a 15 cm C18 analytical column eluted with a mobile phase of phosphate (pH = 3)-acetonitrile in 25 min linear gradient mode. Solutes are detected by tandem diode array/ derivatization/fluorescence detection. The system is controlled and monitored by a single computer operated with Millenium software. Recoveries of most analytes in samples fortified at 1 μg/L are >90%, with relative standard deviation values of <5%. For a few very polar analytes, mostly Λ/-methylcarbamoyloximes (i.e., aldicarb sulfone, methomyl, and oxamyl), recoveries are <20%. However, for these compounds, as well as for the rest of the N-methylcarbamates except for aldicarb sulfoxide and butoxycarboxim, the limits of detection (LODs) are 0.005-0.05 μg/L. LODs for aldicarb sulfoxide and butoxycarboxim are 0.2 and 0.1 μg, respectively. LODs for the rest of the analytes except 4-nitrophenol, bentazone, captan, decamethrin, and MCPA are 0.05-0.1 μg/L. LODs for the latter compounds are 0.2-1.0 μg/L. The system can be operated unattended.
Use Patterns and Residual Levels of Organophosphate Pesticides on Vegetables in Trinidad, West Indies
Authors: Yen Ivan Chang , Bekele Isaac , Kalloo Carlyle
Published: February 2020

The twin-island state of Trinidad and Tobago produces much of the fresh fruit and vegetables consumed locally, although some are exported to Europe and North America. On average, approximately 1500 tons of pesticides are imported annually, of which about 10-15% are organophosphates. A survey of local farmers revealed that a wide range of pesticides are used and that the same pesticides are used on several crops to control different pests. Application rates exceeding manufacturers' recommendations are also common, as is the disregard of recommended preharvest intervals after pesticide application. Praedial larceny and subsequent sale of freshly sprayed crops also contribute to the risks posed to consumers by pesticide residues. A market basket survey of produce conducted between October 1996 and May 1997 in Trinidad for organophosphate pesticides showed that 10% of produce exceeded the internationally acceptable maximum residue limits (MRLs) for the respective pesticides. Celery constituted 6.5% of all such samples, with over 83% of celery samples exceeding the MRL. Organophosphate pesticides detected were methamidophos, triazophos, prophenofos, diazinon, ethion, pirimiphos methyl, malathion, and dimethoate, with the first 4 being the most commonly detected. There is an urgent need for comprehensive monitoring and control of pesticides on produce by local regulatory agencies, especially because the above data relate only to one class of pesticides. The education of farmers on safe operating practices regarding pesticide application and observation of recommended preharvest intervals for applied pesticides is also required.
Authentication of Straight Whiskey by Determination of the Ratio of Furfural to 5-Hydroxymethyl-2-Furaldehyde
Authors: Jaganathan James , Dugar Sumer M
Published: February 2020

Bureau of Alcohol, Tobacco and Firearms regulations require that a straight whiskey be aged in a freshly charred oak barrel for a minimum of 2 years and that it not be colored with added caramel. The regulations, however, permit addition of caramel in blended whiskeys. Blended whiskeys are usually produced by mixing a straight whiskey with neutral spirits which causes loss of color intensity. Caramel addition is permitted to compensate for this loss. Thus, it is not possible to authenticate the standard of identity of a straight whiskey by measurement of color intensity. Our investigations suggest that furfural (2-furaldehyde) and 5-hydroxymethyl-2-furaldehyde are imparted into a straight whiskey during aging in a freshly charred oak barrel. Caramel, on the other hand, imparts only 5-hydroxymethyl-2-furaldehyde. Thus, the measurement of the concentrations of furfural and 5-hydroxymethyl-2-furaldehyde and their ratio could effectively authenticate the standard of identity of straight whiskeys. This study shows that straight whiskeys aged in freshly charred oak barrels for a period of 2 years or more have a 2:1 or higher ratio of furfural to 5-hydroxymethyl-2-furaldehyde. A high-performance liquid chromatographic method for the determination of furfural and 5-hyroxy- methyl-2-furaldehyde at low parts-per-million levels is described.
Chromatographic Methods for Analysis of Aminoglycoside Antibiotics
Authors: Isoherranen Nina , Soback Stefan
Published: February 2020

Aminoglycosides are antimicrobial agents used frequently in treatment of human and animal diseases caused by aerobic, gram-negative bacteria. Because of the toxicity of these compounds, considerable effort has been attributed to analysis of aminoglycoside content in drug preparations, in serum and urine specimen in therapeutic drug monitoring, and in edible animal tissues in residue control. The present review emphasizes the analytical problems associated with aminoglycoside analysis. Screening methods based on microbiological and immunological procedures were briefly discussed. Gas chromatography and especially high-performance liquid chromatography appeared the most widely used chemical methods for the analysis of these compounds. Due to lack of volatility, chromophore, and hydrophility of aminoglycosides, most methods applied derivatization for enhancement of their chromatographic characteristics. The applicability and advantages of the various derivatization procedures were discussed in detail. A wide variety of detection methods, including mass spectrometry have been used. Packed column separation was generally used for gas chromatographic separation. In liquid chromatography, reversed phase, ion pair, ion exchange, and normal phase separation has been employed. Mass spectrometry, as a detection method, was discussed in detail. Extraction procedures from body fluids and tissues were emphasized. The performance and the operational conditions of the methods were described and detailed information of the data was provided also in table format.
Multiresidue Chromatographic Method for the Determination of Macrolide Residues in Muscle by High-Performance Liquid Chromatography with UV Detection
Authors: Juhel-Gaugain Murielle , Anger Béatrice , Laurentie Michel
Published: February 2020

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of tilmicosin, tylosin, spiramycin, and its major metabolite neospiramycin was developed that is suitable for porcine, bovine, and poultry muscles. Macrolide residues were extracted from muscle with acetonitrile, fat was removed by liquid-liquid extraction with isooctane, and the extract was then cleaned on Bond Elut C18 cartridges. The HPLC separation was performed on an Inertsil ODS3 C18 column (150 × 4 mm) with 0.05% trifluoroacetic acid-acetonitrile in a gradient mode. Two different chromatographic gradients were used for tilmicosin-tylosin and spiramycin-neospiramycin, and the detection wavelengths were 287 and 232 nm, respectively. The method was validated from ½ the maximum residue limit (MRL) to 4 times the MRL with pork muscle samples. Mean recoveries were 60, 63.5, 51, and 42% for tilmicosin, tylosin, spiramycin, and neospiramycin, respectively. The detection limits are 15 μg/kg for tilmicosin and tylosin, 30 μg/kg for spiramycin, and 25 μg/kg for neospiramycin. Linearity, precision, and accuracy of the method were also tested.
Liquid Chromatographic Determination of para-Toluenesulfonamide in Edible Fillet Tissues from Three Species of Fish
Authors: Meinertz Jeffery R , Schmidt Larry J , Stehly Guy R , Gingerich William H
Published: February 2020

Chloramine-T (N-sodium-N-chloro-p-toluene-sulfonamide) is a candidate therapeutic drug for treating bacterial gill disease, a predominant disease of a variety of fish species. Research has been initiated to obtain the U.S. Food and Drug Administration’s (FDA) approval for the use of chloramine-T on a variety of fish species. An attribute of a therapeutic aquaculture drug that must be characterized before the FDA approves its use is depletion of the drug’s marker residue (the drug’s parent compound or metabolite of highest concentration in an edible tissue). para-Toluenesulfonamide (p-TSA) is the primary degradation product and marker residue for chloramine-T in rainbow trout. To conduct residue depletion studies for chloramine-T in fish, a robust analytical method sensitive and specific for p-TSA residues in edible fillet tissue from a variety of fish was required. Homogenized fillet tissues from rainbow trout (Oncorhynchus mykiss), walleye (Stizostedion vitreum), and channel cattish (Ictalurus punctatus) were fortified at nominal p-TSA concentrations of 17, 67, 200, 333, and 1000 ng/g. Samples were analyzed by isocratic reversed-phase liquid chromatography (LC) with absorbance detection at 226 nm. Mean recoveries of p-TSA ranged from 77 to 93.17%; relative standard deviations ranged from 1.5 to 14%; method quantitation limits ranged from 13 to 18 ng/g; and method detection limits ranged from 3.8 to 5.2 ng/g. The LC parameters produced p-TSA peaks without coelution of endogenous compounds and excluded chromatographic interference from at least 20 chemicals and drugs of potential use in aquaculture.
Confirmatory Test Results on Milk from Commercial Sources that Tested Positive by ß-Lactam Antibiotics Screening Tests
Authors: Moats William A
Published: February 2020

U.S. Department of Agriculture, Agricultural Research Service, Meat Science Research Laboratory, Beltsville, MD 20705 Fifty-four milk samples from commercial sources that tested positive for β-lactam antibiotics were analyzed by a multiresidue liquid chromatographic (LC) procedure based on LC fractionation. Penicillin G and cephapirin were the β-lactam antibiotics found most frequently. Some samples did not contain detectable β-lactam antibiotics. In a few, the presence of a β-lactam antibiotic was suspected because certain LC fractions tested positive for antimicrobial activity, which was no longer present in a replicate treated with β-lactamase. However, the unknowns could not be identified by LC analysis.
Identification of Shark Species by Polyacrylamide Gel Isoelectric Focusing of Sarcoplasmic Proteins
Authors: Weaver LaShawn A , Lundstrom Ronald C , Colbert A Ann
Published: February 2020

Isoelectric focusing of muscle proteins is a fast and highly reproducible technique that has been used to identify fish species. Application of isoelectric focusing of sarcoplasmic proteins is described for identification of shark species. Sarcoplasmic protein patterns from muscle tissue of single individuals from 26 shark species and multiple individuals from 2 of the 26 shark species are shown on 1 mm thick polyacrylamide gels. Eight of these species showed pattern polymorphisms in major and minor bands; however, no individual within a species displayed the same protein pattern as that in any other species. Protein banding patterns of each species were visually distinguishable, and patterns generated on the basis of defined parameters were analyzed by a computer to obtain isoelectric points of bands, to produce schematic representations of banding patterns, and to distinguish between species-specific patterns. Isoelectric focusing appears to be an excellent method for identifying sharks. Additionally, isoelectric focusing of muscle proteins is readily applicable as a forensic tool to identify the species of shark samples received as evidence for law enforcement actions supporting shark fishery management plans.
An Immunoassay Method for Rapid Detection of Staphylococcus aureus in Cosmetics, Pharmaceutical Products, and Raw Materials
Authors: Hughes Denise , Dailianis Angela , Hill Louise
Published: February 2020

The TECRA Staphylococcus aureus Visual Immunoassay allows a presumptive positive or negative result for the presence of S. aureus to be obtained within 26 h, in contrast to 4-5 days by traditional cultural methods. Presumptive positive immunoassay results are confirmed by streaking the enrichment broth onto conventional agar media. A validation study was undertaken to compare the TECRA assay with a cultural reference method based on the Bacteriological Analytical Manual (8th Ed.), which is also consistent with U.S. Pharmacopoeia requirements. The products tested included a range of cosmetics (toothpaste, shampoos, conditioners, sunscreens, moisturizers, lip and eye creams) and pharmaceuticals (cough mixtures, laxatives, ulcer treatments, infant formulae, antiseptic cream), as well as some pharmaceutical ingredients. Samples were inoculated with S. aureus at 10-20 cfu/g, and then enriched for 24 h at 35°-37°C at a product-to-sample ratio of 1:100. Two different enrichment broths were used for the study: Tryptone Soya Broth with 4% Tween 80 and Modified Letheen Broth. For both enrichment broths, results of the immunoassay and the reference method showed close correlation. The TECRA S. aureus Visual Immunoassay provides a rapid and convenient alternative to cultural methods and provides advantages to industry, such as greater speed of product and ingredient release and faster tracing of contamination problems. Because the immunoassay may be read either visually or with the aid of a plate reader, there is no need for an initial outlay on capital equipment. However, the assay can be automated if required.
Determination of Emamectin Benzoate in Medicated Fish Feed
Authors: Farer Leslie J , Hayes John , Rosen Jack , Knight Peter
Published: February 2020

A method was developed to quantitate emamectin benzoate in fish feed at levels between 5 and 15 ppm. The active ingredient is extracted from 20 g medicated feed into aqueous-methanolic solvent by overnight shaking. A solid-phase extraction procedure using a 2 g C18 cartridge is then used to concentrate the active residue and remove interfering matrix components. The extracted drug and internal standard are eluted from the cartridge, evaporated to dryness, and reconstituted in methanol. A control feed sample and fortified control working standard are simultaneously prepared. Remaining interferences and sample analysis are further separated on a gradient liquid chromatographic system. Recovery of emamectin benzoate from fortified feeds ranged from 97 to 100%, with a coefficient of variation (CV) of 1.2%. Determination of emamectin benzoate in medicated feeds resulted in CVs ranging from 2.3 to 4.2% and recoveries of 88 to 98% of label claim.
Multiresidue Determination of Abamectin, Doramectin, Ivermectin, and Moxidectin in Milk Using Liquid Chromatography and Fluorescence Detection
Authors: Schenck Frank J , Lagman Lawrence H
Published: February 2020

Abamectin, doramectin, ivermectin, and moxidectin are macrocyclic lactones derived from soil dwelling actinomycetes, and are very effective against nematode, insect, and arthropod infestations. These compounds, known as endectocides, have been approved for use in beef cattle in the United States; however, they are currently not approved for use in dairy cattle. Abamectin, doramectin, ivermectin, and moxidectin residues were isolated from milk by a series of liquid-liquid extraction steps, derivatized with trifluoroacetic anhydride, and determined by liquid chromatography with fluorescence detection. Recovery studies were performed in 2 laboratories. Recoveries of >80%(1-30 ng/mL) were achieved for all 4 compounds.
Determination of Amoxicillin in Trout by Liquid Chromatography with UV Detection after Derivatization
Authors: Sørensen Lambert K , Hansen Heļga , Snor Lena
Published: February 2020

A liquid chromatographic (LC) method based on solid-phase extraction was developed for determination of amoxicillin in muscle tissue of rainbow trout. The compound was extracted in an aqueous solution by precipitation of organic material with a mixture of sulfuric acid and sodium tungstate. The extract was processed by solid-phase extraction on an end-capped phenyl sorbent, and concentrated on a divinylbenzene-co-ΛN-vinylpyrrolidone polymeric sorbent. The extract was derivatized and analyzed by reversed-phase gradient LC on a C18 column with UV detection at 323 nm. The method detection limit was 2.9 μg/kg. Mean recovery in muscle was 80.5% (range 10-200 μg/kg). The method was applied to fillets from trout offered feed containing amoxicillin in an aquaculture pilot plant. Amoxicillin was detected in muscle tissue shortly after administration but not 3 weeks later. The relative repeatability standard deviation for incurred residues in muscle tissue was 6.4% (range 11-143 μg/kg).
Mass Peak Profiling from Selected-Ion Recording Data as a Tool for Regulatory Analyses
Authors: Grange Andrew H , Sovocool G Wayne
Published: February 2020

Identification of compounds in mixtures of environmental contaminants or synthetic products is essential for regulatory analyses. Exact masses of ions determined by high resolution mass spectrometry provide unique elemental compositions only for low-mass ions (<150 Da). Using mass peak profiling from selected-ion recording data (MPPSIRD) to acquire additional mass spectral data and a profile generation model (PGM) for automated interpretation of the data, provides elemental compositions for ions with m/z up to 600, based on incontestable properties of atoms, their exact masses, isotopic abundances, and valences. In this study, MPPSIRD and a PGM were used to identify intended and unintended products resulting from attempted syntheses of 2 thermolabile, nonionic, phosphorothioate compounds. The products were volatilized from a probe inserted into a VG70-250SE double-focusing mass spectrometer. High mass resolution substituted separation in the mass domain for the temporal separation of most components provided by chromatographic techniques. MPPSIRD and the PGM identified the correct composition for M+• by rejecting all other compositions that were possible within the error limits of the exact mass determinations for M+• MPPSIRD was used with 10 000-24 000 resolution to determine exact masses of ions prominent in mass spectra and to isolate signals from different ions with the same nominal mass. Superposition of volatilization peaks of ions and linked scans (constant magnetic field to electrostatic sector voltage ratio) correlated fragment ions with the molecular ion. The PGM determined the compositions of fragment ions, using the number of atoms of each element in the molecular ion as limits. Fragmentation schemes based on these ions and the tables of exact masses and relative abundances provided a preponderance of evidence for the product identities.
Kuwait's Total Diet Study: Dietary Intake of Organochlorine, Carbamate, Benzimidazole and Phenylurea Pesticide Residues
Authors: Sawaya Wajih N , Al-Awadhi Fawzia A , Saeed Talat , Al-Omair Ali , Ahmad Nissar , Husain Adnan , Khalafawi Sherif , Al-Omirah Husam , Dashti Basma , Al-Amiri Hanan , Al-Saqer Jameela
Published: February 2020

The State of Kuwait in cooperation with the U.S. Food and Drug Administration (FDA) conducted a Total Diet Study (TDS) to estimate intakes of pesticide residues by the population. The levels of organochlorine (OC) pesticides, carbamates, benzimidazoles, and phenylureas in the TDS core list are reported here. The TDS core list was established through a national food consumption survey. All food items (140 for the Kuwaiti adult) were prepared as eaten and analyzed for the pesticides mentioned above. The FDA's multiresidue methods in Volume I of the Pesticide Analytical Manual were used in gas, liquid, and gel permeation chromatographic analyses. Only vegetable and fruit samples contained pesticide residues (mg/kg), including the carbamates 1-naphthol (1.4) and 3H-carbofuran (0.94) in carrots; the OC pesticide vinclozolin (0.47), 3H-carbofuran (0.66), and fenuron (0.6) in kiwi fruit; the OC pesticide procymidone (0.32) and carbendazim (0.5) in grapes; 3H-carbofuran (5.0) in apricots; the OC pesticides captan (0.013) and thiabendazole (0.63) in pears; captan (0.035) in plums; and carbendazim (0.4) in mandarin oranges. The levels of 3H-carbofuran found in both apricots and kiwi fruit exceeded the maximum residue limits (MRLs) of the Food and Agriculture Organization/World Health Organization (FAO/WHO) of the United Nations. The daily intakes of pesticides by the different population groups are discussed in light of the FAO/WHO acceptable daily intakes.
Analysis of Interlaboratory Performance in the Determination of Total Selenium in Water
Authors: Steinhoff Peter J , Smith Brain W , Warner Dewey W , Möller Gregory
Published: February 2020

This study explored the performance of experienced laboratories in the analysis for total selenium in water by a variety of analytical methods. The goal of the study was to examine intra- and interlaboratory variability. Replicates (n = 7) of 7 sample types that included a reference material of known Se concentration, natural waters, and treated wastewaters were submitted to 7 laboratories with prequalified Se analytical experience. Results of the study indicated wide ranges in minimum and maximum results, distinct differences in laboratory precision, and routine reporting of numerical results below statistical limits of quantitation. Hydride generation as a sample introduction technique demonstrated superior performance. In general, the study supports a caution advisory about using low-level Se data, especially results lower than about 10 µg Se/L, without quantitating the statistical uncertainty of the data. Because this study used data from samples that were submitted in bulk to participating laboratories prequalified for Se analytical expertise and experience, it can be considered a best-case demonstration of performance.
Gas Diffusion Flow Injection Analysis with Bulk Acoustic Wave Detection and the Applications for Determining Nitrogen, Carbon, or Sulfite Species in Varieties of Complex Matrixes
Authors: Yao Shou-Zhuo , Su Xiao-Li
Published: February 2020

A new flow injection analysis technique was developed for determining nitrogen, carbon, or sulfite species in varieties of complex matrixes. The method is based on the use of a bulk acoustic wave detector in combination with gas diffusion separation. Samples were injected into a carrier stream of water, merged with a reagent stream of an appropriate pH where the analyte was converted into a gaseous species, and diffused across a Teflon microporous membrane into a recipient stream. Then the trapped ionic compound in the recipient stream was monitored on-line with a bulk acoustic wave detector on the basis of sensitive response to changes of the solution conductance. The method is applied successfully for determining ammonium in Kjeldahl digest obtained from amino acids and blood proteins; total carbon, total inorganic carbon, and total organic carbon in waste and river waters; sulfite in wines and fruit juices; nitrate, nitrite, ammonium, and total inorganic nitrogen in natural waters; and total ammonia and total carbon dioxide in blood. The throughput, detection limit, and precision of the proposed method varied from 20 to 78 samples/h, 1 to 10 μM, and 0.6 to 1.8%, respectively. The method was validated by comparison with conventional procedure such as titration, spectrophotometry, or gas-sensing electrode. Theoretical background, the potential interference, and influencing factors, including composition of the acceptor and donor streams, flow injection parameters, cell constant and operating voltage of the sensor, and temperature are also discussed in detail.
Cross-Validation in Linear Discriminant Analysis of Triacylglycerol Structural Data from Istrian Olive Oils
Authors: Favretto Luciana Gabrielli , Campisi Barbara , Favretto Luciano , Simonetti Maria Stella , Cossignani Lina , Damiani Pietro
Published: February 2020

This paper describes the differentiation and classification of olive oil samples produced in the Istrian peninsula in 3 areas characterized by different climatic conditions: Capodistria and Parenzo and Pola. The triacylglycerol (TAG) fraction of 41 samples of virgin olive oil was analyzed. In particular, TAG stereospecific analysis was performed to obtain the positional distribution of the fatty acids in the glycerol backbone. The quantitative data were evaluated by using Linear Discriminant Analysis, and the results obtained showed a differentiation of the olive oil samples according to their geographical origin. A cross-validation procedure, the Leave-One-Out classifier, was applied to test the adequacy of the discriminant model.