bluuebunny/crossref_metadata_2025 huggingface dataset:
Specific Detection of Clostridium botulinum Types A, B, E, and F Using the Polymerase Chain Reaction
Authors: Craven Kathy E , Ferreira Joseph L , Harrison Mark A , Edmonds Paul
Published: February 2020

Clostridium botulinum organisms generally produce 1 of 4 neurotoxin types (A, B, E, and F) associated with human illness. Neurotoxin type determination is important in identification of the bacterium. A polymerase chain reaction (PCR) method was developed to identify 24 h botulinal cultures as potential types A, B, E, and F neurotoxin producers as well as other clostridial species which also produce neurotoxins. Components of the PCR and amplification conditions were adjusted for optimal amplification of toxin gene target regions to enable simultaneous testing for types A, B, E, and F in separate tubes using a single thermal cycler. Each primer set was specific for its corresponding toxin type. A DNA extraction procedure was also included to remove inhibitory substances that may affect amplification. This procedure is rapid, sensitive, and specific for identification of toxigenic C. botulinum.
Determination of Fat Content and Fatty Acid Composition in Meat and Meat Products after Supercritical Fluid Extraction
Authors: Berg Hans , Dahlberg LenaDahlberg , Mathiasson Lennart
Published: February 2020

Two different relatively simple, commercially available supercritical fluid extractors (SFE), Leco and Foss-Tecator, were tested for the determination of total fat content in meat and meat products. The fatty acid composition in meat and meat products was also determined after the Foss-Tecator extraction in an aliquot of the extract. Total fat was determined by weighing after the different extraction procedures and the fatty acid composition by gas chromatography after hydrolysis and methylation of the extract. The results for total fat content agreed well with results from a standard method of Schmid, Bondzynski, and Ratzlaff, which uses conventional solvent extraction. Fatty acid composition was compared with the Bligh and Dyer extraction, and showed good agreement. The average relative difference between SFE and Bligh and Dyer of all fatty acids in the sample was <3% for acids exceeding 0.5% of total fatty acid amount. The advantages of SFE over traditional methods are a much lower consumption of hazardous organic solvents and shorter extraction times. To obtain quantitative recoveries by SFE, ethanol was added to the extraction cells before extraction.
Simultaneous Determination of Vitamin A and β-Carotene in Dietary Supplements by Liquid Chromatography
Authors: Sundaresan P Ramnathan
Published: February 2020

Several liquid chromatography (LC) methods for analysis of vitamin A in oods and feeds have been previously reported but only a few have been applied in non-food matrixes. A validated LC method is needed for determination of vitamin A and β-carotene in the various matrixes presented by dietary supplements. The performance of a reversedphase method with methanol–isopropanol gradient elution was evaluated with standard retinyl derivatives and β-carotene. The reversed-phase method is capable of separating retinol from other derivatives such as retinyl acetate, retinyl palmitate, and β-carotene. Two types of extraction were used to extract the analytes from the dietary supplements: a hexane–methylene chloride extraction for soft-gel capsules containing β-carotene, and a direct solvent extraction for dietary supplements in tablet form. The direct solvent extraction consisted of treatment with ethanol and methylene chloride following addition of hot water (55°C). Results with the reversed-phase method for vitamin A and β-carotene in the products examined ( n = 8) indicated excellent method performance. The main form of vitamin A or β-carotene in dietary supplements was the all trans isomer. The reversed- phase method avoids saponification and is rapid, accurate, precise, and suitable for simultaneous determination of retinyl derivatives and β-carotene in dietary supplements.
Routine, High-Sensitivity, Cold Vapor Atomic Absorption Spectrometric Determination of Total Mercury in Foods after Low-Temperature Digestion
Authors: Dabeka Robert W , Bradley Peter , Mckenzie Arthur D
Published: February 2020

A cold vapor atomic absorption spectrometric method was developed for the subnanogram-per-gram determination of total Hg in a wide variety of foods. Foods were weighed into 50 mL polypropylene centrifuge tubes and dried without charring at 55°C in a circulating oven. Samples were then digested at 58°C with HNO3, HCl, and H2O2. After matrix modification with solutions of 2% Mg(NO3)2, 0.01% Triton X-100, and Cu(II) at 10 μg/mL, samples were analyzed by using a CeTAC Technologies M-6000A dedicated Hg analyzer. Based on a 2 g sample weight, the detection limit of the method over 12 batches averaged 0.30 ng/g wet weight and ranged from 0.03 to 0.6 ng/g. Recoveries of Hg added to 17 different foods, analyzed in a routine manner, averaged 97%, and individual recoveries ranged from 77 to 107%. Accuracy was confirmed by analysis of 7 biological reference materials from the National Research Council of Canada and the National Institute of Standards and Technology. Stabilization of low concentrations of Hg in solutions containing no sample was required to prevent loss of Hg from blanks. In a comparison of NaCl, potassium dichromate, and Au(III), chloride was much more effective for stabilization than the other two, and HCl was used for subsequent stabilization.
Comparison of Magnesium Sulfate and Sodium Sulfate for Removal of Water from Pesticide Extracts of Foods
Authors: Schenck Frank J , Callery Patrick , Gannett Peter M , Daft Jonathan R , Lehotay Steven J
Published: February 2020

Water-miscible solvents, such as acetone and acetonitrile, effectively extract both polar and nonpolar pesticide residues from nonfatty foods. The addition of sodium chloride to the resulting acetonitrile–water or acetone–water extract (salting out) results in the separation of the water from the organic solvent. However, the organic solvent layer (pesticide extract) still contains some residual water, which can adversely affect separation procedures that follow, such as solid-phase extraction and/or gas chromatography. Drying agents, such as sodium sulfate or magnesium sulfate, are used to remove the water from the organic extracts. In the present study, we used nuclear magnetic resonance spectroscopy to study the composition of the phases resulting from salting out and to compare the effectiveness of sodium sulfate and magnesium sulfate as drying agents. The study showed that considerable amounts of water remained in the organic phase after phase separation. Sodium sulfate was a relatively ineffective drying agent, removing little or no residual water from the organic solvent. Magnesium sulfate proved to be a much more effective drying agent.
Determination of Docosahexaenoic Acid and n-3 Fatty Acids in Refined Fish Oils by H-NMR Spectroscopy: IUPAC Interlaboratory Study
Authors: Igarashi Tomoji , Aursand Marit , Sacchi Raffaele , Paolillo Livio , Nonaka Michio , Wada Y ,   Collaborators:, Arata Y , Bildsoe H , Falcigno L , Fauhl C , Guillou C , Halvorsen J , Honma E , Ijuuin Y , Kushida K , Martin G J , Miyake Y , Optum O I , Oshima Y , Remaud G , Retif M , Robins R , Satake M , Shimidzu N , Tsuchiya F , Watanabe K , Watanuki C
Published: February 2020

A high-resolution proton nuclear magnetic resonance (NMR) method for determining the concentration (mg/g) of docosahexaenoic acid (DHA), the molar proportion (mol%) of DHA, and the molar proportion of total n-3 fatty acids in fish oils was validated by an IUPAC interlaboratory study (the Commission VI-6 on Oils, Fats, and Derivatives WG 3/98). Thirteen laboratories from 5 countries tested 6 pairs of blind duplicate fish oils: a refined tuna oil, 2 extracted tuna oils, an extracted bonito oil, an extracted salmon oil, and an extracted sardine oil ranging from 9 to 30 mol% DHA and from 20 to 35 mol% n-3 fatty acids. Before 1D-proton NMR measurements with 300–500 MHz instruments, oil samples were weighed and diluted with deuterochloroform solution containing ethylene glycol dimethyl ether as internal standard. To achieve precise performance, a detailed procedure for signal area measurement was described in the protocol, and all participants were instructed about the critical importance of following the protocol. Statistical performances with invalid and outlier data removed were as follows: repeatability relative standard deviations (RSDr) ranged from 0.91 to 2.62% and reproducibility relative standard deviation (RSDR) ranged from 1.73 to 4.27% for DHA concentration (mg/g); RSDr ranged from 0.39 to 2.06%, and RSDR ranged from 0.59 to 3.46% for mol% DHA; RSDr ranged from 0.23 to 0.90% and RSDR ranged from 0.85 to 2.01% for mol% total n-3 fatty acids. The method is expected to be recommended by IUPAC.
Efficacy of Glutaraldehyde Disinfectant Against Cryptosporidium parvum in the Presence of Various Organic Soils
Authors: Wilson James , Margolin Aaron B
Published: February 2020

The opportunistic protozoan Cryptosporidium parvum is highly resistant to disinfectants, including those specifically used for processing reused medical equipment in hospitals. C. parvum oocysts were dried onto glass and steel grooved penicylinders and challenged with 2.5% glutaraldehyde solution in the presence of 3 types of soil with exposures at 10 min, 90 min, and 10 h. The influence of organic soils on disinfection was measured with 5% fetal bovine serum (FBS), 10% FBS, and 5 mg mucin/mL. An in vitro excystation procedure and cell culture infection assay were used to determine survivability of oocysts after the germicide challenge. In the presence of organic soil, all oocysts removed from carriers excysted and infected cell monolayers after all germicide contact times. However, excystation was observed only from oocysts that received no protection from organic soil after 10 h exposure. In these samples, no infection was observed in the cell monolayers. The results of this research demonstrate the importance of thorough cleaning of medical equipment before disinfection.
Determination of Phenolic Compounds in Dietary Supplements and Tea Blends Containing Echinacea by Liquid Chromatography with Coulometric Electrochemical Detection
Authors: Luo Wenhong , Ang Catherina Y W , Gehring Theresa A , Heinze Thomas M , Lin Lawrence J , Mattia Antonia
Published: February 2020

Analytical methodologies with ultrasonic extraction and liquid chromatography (LC) were developed for the determination of phenolic compounds in dietary supplements containing Echinacea. The phenolic compounds determined by these methods included caftaric acid, chlorogenic acid, cynarin, echinacoside, and cichoric acid. Samples from tablets, capsules, and bags of tea blends were extracted by sonication for ≤30 min with methanol–water (60 + 40). The extracts were centrifuged and filtered, and the filtrates were diluted and analyzed by LC using a reversed-phase column and coulometric electrochemical (EC) detection. The mobile phase was acetonitrile–ammonium formate buffer, pH 3.5 (15.3 + 84.7) containing tetrabutyl ammonium hydrogen sulfate as an ion-pairing reagent. Extraction conditions (e.g., composition of the extraction solvent and sonication time) were optimized for different types of samples. Intra- and interday analytical variations were determined, and intraday analyses were performed by 2 independent analysts using 2 different LC systems. Results were generally comparable. The LC method with EC detection showed better sensitivity and selectivity when compared with LC with ultraviolet detection, although results were similar for the 2 methods for major compounds, i.e., caftaric acid, echinacoside, and cichoric acid. The identities of these major compounds found in samples were confirmed by LC/electrospray ionization mass spectrometry.
Simultaneous Determination of Eleven Dyes and Their Aluminum Lakes in Drugs
Authors: Ishikawa Fusako , Shigeoka Sutemi , Nagashima Machiko , Takahashi Misako , Kamimura Hisashi
Published: February 2020

A 3-step extraction method was developed for the simultaneous determination of 11 dyes and their aluminum lakes in drugs. The dyes were first extracted with warm water (approximately 60°C) and were cleaned up by solid-phase extraction with a tC18 cartridge. Aluminum lake dyes that remained in the precipitate were extracted with 0.02M NaOH. Aluminum in the dye lakes was reextracted into the organic layer with acetylacetone–butyl acetate (1 + 9, v/v), as an acetylacetone chelate, and was quantified by atomic absorption spectrometry. The dye portions of the aluminum lakes remained in the aqueous layer and were cleaned up in the same way as the dyes. The dyes and the dye portions of the aluminum lakes were quantified by ion–pair liquid chromatography with a photodiode array detector within 20 min. The recoveries of dyes from drug fortified at 10 μg of each dye per pill were 87.0–102.2%, and the recoveries of dyes from drugs fortified at 50 μg of each dye lake per pill were 82.9–101.6%, except for recoveries of indigo carmine. In 40 ethical and over-the-counter drugs, dyes that were not indicated in the package insert information for drugs were detected in 5 samples. The highest amount of dye found in a drug was 1169.5 μg erythrosine, which was detected in a capsule of antibiotic. Aluminum lake dyes were detected in 8 samples of various dosage forms.
Simultaneous Determination of Dapsone and Pyrimethamine by Derivative Spectrophotometry in Pharmaceutical Formulations
Authors: Toral M Inés , Tassara Andrés , Soto César , Richter Pablo
Published: February 2020

A simple and fast method was developed for the simultaneous determination of dapsone and pyrimethamine by first-order digital derivative spectrophotometry. Acetonitrile was used as a solvent to extract the drugs from the pharmaceutical formulations, and the samples were subsequently evaluated directly by digital derivative spectrophotometry. The simultaneous determination of both drugs was performed by the zero-crossing method at 249.4 and 231.4 nm for dapsone and pyrimethamine, respectively. The best signal-to-noise ratio was obtained when the first derivative of the spectrum was used. The linear range of determination for the drugs was from 6.6 × 10−7 to 2.0 × 10−4 and from 2.5 × 10−6 to 2.0 × 10−4 mol/L for dapsone and pyrimethamine, respectively. The excipients of commercial pharmaceutical formulations did not interfere in the analysis. Chemical and spectral variables were optimized for determination of both analytes. A good level of repeatability, 0.6 and 1.7% for dapsone and pyrimethamine, respectively, was observed. The proposed method was applied for the simultaneous determination of both drugs in pharmaceutical formulations.
Enumeration of Total Aerobic Microorganisms in Foods by SimPlate® Total Plate Count–Color Indicator Methods and Conventional Culture Methods: Collaborative Study
Authors: Feldsine Philip T , Leung Stephanie C , Lienau Andrew H , Mui Linda A , Townsend David E ,   Collaborators:, Arling V , August L , Barham D , Bohnert M , Boville A , Brookman S , Chavey C , Clements S , Davis R , Devane S , Dissel S , Gartside S , Hagel D , Hernandez C , Hopkins S , Howell M , Humbert F , Hunsucker J , Jackson J , Koch S , Kuber C , Lamb J , Lewis L , Lightfoot B , Lin W , Musch S , Nieves K , Poumeyrol M , Qvist S , Rice J , Solis D , Terry J , in’t Veld P , Voermans R , Warburton D , Welch J
Published: February 2020

The relative efficacy of the SimPlate® Total Plate Count–Color Indicator (TPC–CI) method (SimPlate 35°C) was compared with the AOAC Official Method 966.23 (AOAC 35°C) for enumeration of total aerobic microorganisms in foods. The SimPlate TPC–CI method, incubated at 30°C (SimPlate 30°C), was also compared with the International Organization for Standardization (ISO) 4833 method (ISO 30°C). Six food types were analyzed: ground black pepper, flour, nut meats, frozen hamburger patties, frozen fruits, and fresh vegetables. All foods tested were naturally contaminated. Nineteen laboratories throughout North America and Europe participated in the study. Three method comparisons were conducted. In general, there was <0.3 mean log count difference in recovery among the SimPlate methods and their corresponding reference methods. Mean log counts between the 2 reference methods were also very similar. Repeatability (sr) and reproducibility (sR) standard deviations were similar among the 3 method comparisons. The SimPlate method (35°C) and the AOAC method were comparable for enumerating total aerobic microorganisms in foods. Similarly, the SimPlate method (30°C) was comparable to the ISO method when samples were prepared and incubated according to the ISO method.
Analysis of Scutellaria lateriflora and Its Adulterants Teucrium canadense and Teucrium chamaedrys by LC–UV/MS, TLC, and Digital Photomicroscopy
Authors: Gafner Stefan , Bergeron Chantal , Batcha Laura L , Angerhofer Cindy K , Sudberg Sidney , Sudberg Élan M , Guinaudeau Hélène , Gauthier Robert
Published: February 2020

Methods using liquid chromatography with UV detection (LC–UV), thin-layer chromatography (TLC), and digital photomicroscopy were developed to distinguish between the different species of Scutellaria lateriflora L. and its adulterants Teucrium canadense L. and T. chamaedrys L. Chemically, the 70% ethanol extract of S. lateriflora is characterized by the presence of flavonoids—predominantly baicalin, lateriflorin, dihydrobaicalin, and baicalein. The major compounds of the 70% ethanol extract of T. canadense are phenylpropanoids, with verbascoside as the most prominent, and a variable amount of teucrioside. Teucrioside is the major compound in T. chamaedrys, but it is not present in S. lateriflora. The presence of phenylpropane glycosides can therefore be used to distinguish between the S. lateriflora L. and the two Teucrium species by LC–UV and TLC. The abundant strap-shaped tri-chomes on the stem, as well as bristle-like tri-chomes on the leaf, are typically seen microscopically for T. canadense, whereas the waxy cuticle with numerous glandular scales is found in T. chamaedrys. These cell structures were used to determine the adulteration of S. lateriflora crude herb with either of the two Teucrium species.
Quantitative Analysis of Forskolin in Coleus forskohlii (Lamiaceae) by Reversed-Phase Liquid Chromatography
Authors: Schaneberg Brian T , Khan Ikhlas A
Published: February 2020

A rapid method was developed for the evaluation of forskolin in Coleus forskohlii Briq. (Lamiaceae). Forskolin was quantitated in the root and stem of dried C. forskohlii and in 17 market products by reversed-phase liquid chromatography (LC) with a photodiode array detector at 210 nm. The temperature was held constant at 30°C, and the retention time of forskolin was approximately 6.8 min. The samples were extracted with acetonitrile by sonication. The precision of the method was confirmed by a standard deviation <5.0% (n = 3), and forskolin recovery was 99.1%. Limit of detection was 1.5 μg/mL, and the response was linear through zero from 6.3 to 630 μg/mL with a correlation coefficient (R2) of 0.9998. Identity of the marker compound was confirmed by an LC/mass spectrometry experiment. The method was successful in the qualitative and quantitative evaluation of the marker compound in C. forskohlii plant material and in market products claiming to contain C. forskohlii.
Determination of Ephedra Alkaloids by Liquid Chromatography/Tandem Mass Spectrometry
Authors: Sullivan Darryl , Wehrmann James , Schmitz John , Crowley Richard , Eberhard Jeffrey
Published: February 2020

In conjunction with an AOAC Task Group on dietary supplements, a liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was validated for measurement of 6 major alkaloids in raw ephedra sinica herb, ephedra extracts, ephedra tablets, complex dietary supplements containing ephedra, and a high-protein drink mix containing ephedra. The amount of ephedrine-type alkaloids present was determined by LC with mass selective detection. Six replicates of each matrix were analyzed on 3 separate occasions. The presence of 6 ephedrine-type alkaloids was detected at a level >0.5 μg/g based on a 0.5 g sample. The standard curve range for this assay is from 0.02 to 1.0 μg/mL. Appropriate dilutions covered a wide range of specific alkaloid concentrations. The calibration curves for all 6 analytes had correlation coefficients >0.995.
Determination of Omeprazole in Bulk and Injectable Preparations by Liquid Chromatography
Authors: Schubert Alexandre , Werle Almeci L , Schmidt Cleber A , Codevilla Cristiane , Bajerski Lisiane , Chiappa Ricardo , Cardoso Simone G
Published: February 2020

An accurate, simple, reproducible, and sensitive liquid chromatographic method was developed and validated for the determination of omeprazole in powder for injection and in pellets. The analyses were performed at room temperature on a reversed-phase C18 column of 250 × 4.6 mm id, 5 μm particle size. The mobile phase, composed of methanol–water (90 + 10, v/v), was pumped at a constant flow rate of 1.5 mL/min. Detection was performed on a UV detector at 301 nm. The method was validated in terms of linearity, precision, accuracy, and ruggedness. The response was linear in the range 32–48 μg/mL (r2 = 0.9976). The relative standard deviation values for intra-and interday precision studies were 1.22 and 1.56% for injectable and 2.13 and 2.45% for pellets, respectively. Recoveries ranged between 95.81 and 100.48%.
Clay-Based Affinity Probes for Selective Cleanup and Determination of Aflatoxin B1 Using Nanostructured Montmorillonite on Quartz
Authors: Huebner Henry J , Phillips Timothy D
Published: February 2020

A study was conducted to investigate the selective cleanup and determination of aflatoxin B1 (AfB1) from contaminated media. Composite adsorbents were formulated from calcium montmorillonite clay, which possesses a high affinity and enthalpy of adsorption for AfB1. Nanostructuring techniques were used to construct various formulations of the clay-based composite media. In AfB1 adsorption studies with prototypical affinity columns, these composites offered narrowly defined, reproducible capacity ranges. Composite recoveries of AfB1 from spiked grains exhibited linear trends that correlated well with the range of spike levels. Composite columns provided lower recoveries of AfB1 from naturally contaminated corn than did immunoaffinity columns; however, recoveries were consistent and purified extracts were free of inter-fering compounds, as determined by liquid chro-matography with fluorescence detection.
Immunochemical-Based Method for Detection of Hazelnut Proteins in Processed Foods
Authors: Ben Rejeb Samuel , Abbott Michael , Davies David , Querry Jessica , Cléroux Chantal , Streng Christine , Delahaut Philippe , Yeung Jupiter M
Published: February 2020

A competitive enzyme-linked immunosorbent as-a say (ELISA) was developed to detect hazelnut by using polyclonal antibodies generated against a protein extract of roasted hazelnut. No cross-reactivity was observed in tests against 39 commodities, including many common allergens, tree nuts, and legumes. Hazelnut protein standard solutions at 0.45 ng/mL [inhibition con-centration (IC80) of the competitive test] were clearly identified by the ELISA. An extraction and quantification method was developed and optimized for chocolate, cookies, breakfast cereals, and ice cream, major food commodities likely to be cross-contaminated with undeclared hazelnut during food processing. No sample cleanup was re-quired when extracts were diluted 10-fold. Recovery results were generated with blank matrixes spiked at 4 levels from 1 to 10 μg/g hazelnut protein. With the developed extraction and sample handling procedure, hazelnut proteins were recovered at 64–83% from chocolate and at 78–97% from other matrixes. A confirmatory technique was developed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western transfer. The developed methods were applied to a small market survey of chocolate products and al-lowed the identification of undeclared hazelnut in these products.
Determination of 2-Hydroxy-4-Methoxybenzaldehyde in Roots of Decalepis hamiltonii (Wight & Arn.) and Hemidesmus indicus R.Br.
Authors: Nagarajan Subban , Jagan Mohan Rao Lingamallu
Published: February 2020

The roots of Decalepis hamiltonii and Hemidesmus indicus are aromatic and possess the crystalline compound 2-hydroxy-4-methoxybenzaldehyde as the major compound (>90%) in their volatile oils. A gas chromatographic procedure was developed for the assay of 2-hydroxy-4-methoxybenzaldehyde in both fresh and dried roots of different origin. Benzyl butyrate was used as the internal standard. Among the methods tried, steam hydrodistillation was suitable for extraction of the volatile oils. The quantity of this aromatic compound varied from 0.03 to 0.54%.
Comparison Between a Bioassay and Liquid Chromatography– Fluorescence–Mass Spectrometryn for the Determination of Incurred Enrofloxacin in Whole Eggs
Authors: Donoghue Dan J , Schneider Marilyn J
Published: February 2020

The objective of this study was to compare a bioassay with a liquid chromatography–fluorescence–mass spectrometryn method for detection of enrofloxacin (ENRO) in incurred eggs. The bioassay developed by our laboratories involves an agar diffusion microbiological method using Klebsiella pneumoniae as an indicator organism. Results demonstrate that both methods are capable of detecting incurred fluoroquinolone residues in eggs. During the 3-day dosing period of hens (Days 1–3) and following drug withdrawal (Days 5, 7, and 9), both of these methods were able to detect incurred ENRO in eggs above the zero tolerance established by the U.S. Food and Drug Administration. The LC–fluorescence–MSn method has the benefit of providing confirmation for fluoroquinolones, while the bioassay may be used as an effective, rapid screening method for detection of fluoroquinolone residues in eggs.
Sample Preparation for Determination of Macrocyclic Lactone Mycotoxins in Fish Tissue, Based on On-Line Matrix Solid-Phase Dispersion and Solid-Phase Extraction Cleanup Followed by Liquid Chromatography/Tandem Mass Spectrometry
Authors: Laganà Aldo , Bacaloni Alessandro , Castellano Maryanna , Curini Roberta , De Leva Ilaria , Faberi Angelo , Materazzi Stefano
Published: February 2020

A new method based on matrix solid-phase dispersion (MSPD) on-line with a solid-phase extraction (SPE) cleanup process followed by liquid chromatography with tandem mass spectrometry (LC/MS/MS) is presented for the determination of 3 macrocyclic lactone mycotoxins in fish tissues: zearalenone, α-zearalenol, and β-zearalenol. The sample was prepared in a device that used a reversed-phase material (C18) or a normal-phase material (neutral alumina) as a matrix dispersing agent, and a graphitized carbon black cartridge was used for sequential cleanup by SPE. LC/MS/MS was used for selective determination. Isocratic elution with acetonitrile–methanol–water was used for LC separation; for MS/MS, 2 types of interfaces (a pneumatically assisted electrospray ionization interface or an atmospheric pressure chemical ionization interface) were evaluated and compared in terms of the intensity of the total ion current produced by each analyte. The use of highly selective MSPD on-line with SPE for sample preparation before analysis allowed the removal of interfering matrix compounds `present in tissue extracts that would otherwise cause severeionization suppression of zearalenone and its metabolites during the ionization process. Average recoveries at 100 ng/g were between 83 and 103% with C18 and ≥67% with neutral alumina; the relative standard deviations were <11% with C18 and <18% with alumina. The limits of detection ranged from 0.1 to 1.0 ng/g. Sample preparation is simple to perform, no special technical equipment is required, and solvent volumes are minimal.
Multiplex Polymerase Chain Reaction Method for Detection of Bovine Materials in Foodstuffs
Authors: Gao Hong-Wei , Zhang Da-Bing , Pan Ai-Hu , Liang Wan-Qi , Liang Cheng-Zhu
Published: February 2020

Rapid identification of bovine materials in animal foodstuffs is essential for effective control of a potential source of bovine spongiform encephalophathy. A convenient polymerase chain reaction (PCR)-based assay was developed for detection and identification of a bovine-specific genomic DNA sequence in foodstuffs. Simultaneously the assay assessed the DNA quality of the experiment system by amplification of a highly conserved eucaryotic DNA region of the 18-S ribosomal gene, helping to check the reliability of the test result. The amplified bovine-specific PCR product was a genomic DNA fragment of lactoferrin, a low copy gene that was different from a commonly used bovine-specific mitochondria sequence for identification of bovine materials. The specificity of this method was confirmed by the absence of detectable homologous PCR product using reference foodstuff samples that lacked bovine-derived meat and bonemeals, or genomic DNA samples from vertebrates whose offals are commonly included in animal feeds. This method could detect the presence of bovine material in foodstuffs when the samples contained >0.02% bovine-derived meat and bone meal. Furthermore, it was not affected by prolonged heat treatment. The specificity, convenience, and sensitivity of this method suggest that it can be used for the routine detection of bovine-derived materials.
3M™ Petrifilm™ Staph Express Count Plate Method for the Enumeration of Staphylococcus aureus in Selected Dairy Foods: Collaborative Study
Authors: Silbernagel Karen M , Jechorek Robert P , Carver Charles N , Horter Barbara L , Lindberg Kathryn G ,   Collaborators:, Aleo V , Anderson G , Bannach B , Bulthaus M , Cha K , Dixon K , Hemming B , Horter B , Iannucci; M , Johnson A , Johnson K , Kaufer A , Kemp S , King J , Kupski B , Kusch S , Luebbert B , Lyke H , Makepeace; C , Otten N , Schomogy T , Strand S , Xiong C
Published: February 2020

The 3M™ Petrifilm™ Staph Express Count plate method was compared with AOAC Official Method 975.55 for the enumeration of Staphylococcus aureus in selected foods. Five foods—ice cream, raw milk, yogurt, whey powder, and cheese—were analyzed for S. aureus by 12 collaborating laboratories. For each food tested, the collaborators received 8 blind test samples consisting of a control sample, a low inoculation level, a medium inoculation level, and a medium inoculation level with background flora, each in duplicate. The mean log10 counts for the methods were comparable for all 5 foods. The repeatability and reproducibility variances of the 24 h Petrifilm Staph Express Count plate method were similar to those of the 72 h standard method.
Spectrophotometric Method for Estimation of Alkaloids Precipitable with Dragendorff's Reagent in Plant Materials
Authors: Sreevidya Narasimhan , Mehrotra Shanta
Published: February 2020

A rapid, easy, and simple spectrophotometric method was developed for the estimation of total alkaloids precipitated by Dragendorff's reagent (DR) in plant materials. It is based on the formation of yellow bismuth complex in nitric acid medium with thiourea. The yellow-colored complex formed obeys Lambert-Beer's law in the concentration range of 0.06–50 μg/mL with λmax at 435 nm. Using this method, the alkaloidal percentage of certain alkaloids (ajamalicine, papaverine, cinchonine, piperine, berberine) and some plant materials containing alkaloids (Berberis aristata, Solanum nigrum, and Piper longum) were determined. The method was compared with other methods. It can be used for routine analysis of commercial samples by industries dealing with herbal drugs for standardization of plant materials containing alkaloids and for alkaloid-containing pharmaceutical products.
Gas Chromatographic Method for Putrescine and Cadaverine in Shrimp
Authors: Rogers Patricia L , Staruszkiewicz Walter F , Benner Ronald A
Published: February 2020

A gas–liquid chromatographic method developed for the determination of putrescine and cadaverine in fishery products was modified for application to the determination of diamines in shrimp. Addition of potassium chloride and hydrochloric acid to the methanol–water extraction solvent resulted in increased recovery of the diamines and minimized gel formation. The recovery of putrescine increased on average from 64 to 98%, and the recovery of cadaverine increased from 85 to 93%. The chromatographic separation of the derivatized diamines was significantly improved with a change from an OV-225 column (cyanopropyl methyl phenyl methyl silicone) to a more polar HP-Innowax column (crosslinked polyethylene glycol). Background levels of putrescine and cadaverine in known high-quality shrimp ranged from 0 to 0.7 ppm. Shrimp that failed sensory examination generally contained putrescine at levels >4.8 ppm and cadaverine at levels >1.3 ppm.
Determination of Pyrethrin and Pyrethroid Pesticides in Urine and Water Matrixes by Liquid Chromatography with Diode Array Detection
Authors: Loper Bobby L , Anderson Kim A
Published: February 2020

The following pyrethrin and pyrethroid pesticides were determined in urine and water matrixes by liquid chromatography with diode array detection (LC–DAD): pyrethrin I, pyrethrin II, tetramethrin, baythroid, bifenthrin, fenvalerate, phenothrin, allethrin, resmethrin, cis-permethrin, and trans-permethrin. In addition, 3-phenoxybenzyl alcohol, a metabolite of various pyrethroids, was also successfully determined by the analytical method. The matrix extraction was simple, inexpensive, and fast, using only sodium chloride and acetonitrile. The acetonitrile extract was filtered and analyzed by LC–DAD. The method detection limits for the pyrethrin pesticides in 5 mL urine were determined to range from 0.002 to 0.04 μg/mL, depending on the individual pyrethrin. Recoveries from spiked tap water ranged from 77 to 96%;recoveries from urine ranged from 80 to 117%. This method is especially well-suited to clinical investigations, in which rapid analysis of forensic samples is often required.
Determination of Ephedrine Alkaloids in Botanicals and Dietary Supplements by HPLC-UV: Collaborative Study
Authors: Roman Mark C ,   Collaborators:, Gray D , Luo G , McClanahan R , Perez R , Roper C , Roscoe V , Shevchuk C , Suen E , Sullivan D , Walther H J
Published: February 2020

An international collaborative study was conducted of a high-performance liquid chromatography (HPLC)-UV method for the determination of the major (ephedrine [EP] and pseudoephedrine [PS]) and minor (norephedrine [NE], norpseudoephedrine [NP], methylephedrine [ME], and methylpseudoephedrine [MP]) alkaloids in selected dietary supplements representative of the commercially available products. Ten collaborating laboratories determined the ephedrine-type alkaloid content in 8 blind replicate samples. Five products contained ephedra ground herb or ephedra extract. These 5 products included ground botanical raw material of Ephedra sinica, a common powdered extract of Ephedra sinica, a finished product containing only Ephedra sinica ground botanical raw material, a complex multicomponent dietary supplement containing Ma Huang, and a high-protein chocolate flavored drink mix containing Ma Huang extract. In addition, collaborating laboratories received a negative control and negative control spiked with ephedrine alkaloids at high and low levels for recovery studies. Test extracts were treated to solid-phase extraction using a strong-cation exchange column to help remove interferences. The HPLC analyses were performed on a polar-embedded phenyl column using UV detection at 210 nm. Repeatability relative standard deviations (RSD r) ranged from 0.64–3.0% for EP and 2.0–6.6% for PS, excluding the high protein drink mix. Reproducibility relative standard deviations (RSD R) ranged from 2.1–6.6% for EP and 9.0–11.4% for PS, excluding the high protein drink mix. Recoveries ranged from 84.7–87.2% for EP and 84.6–98.2% for PS. The data developed for the minor alkaloids are more variable with generally unsatisfactory HORRATS (i.e., >2). However, since these alkaloids generally add little to the total alkaloid content of the products, the method gives satisfactory results in measuring total alkaloid content (RSD r 0.85–3.13%; RSDR 2.03–10.97%, HORRAT 0.69–3.23, exclusive of the results from the high protein drink). On the basis of these results, the method is recommended for Official First Action for determination of EP and PS in dietary supplements exclusive of the high protein drinks.
Development and Single-Laboratory Validation of a Reversed-Phase Liquid Chromatography–Electrospray–Tandem Mass Spectrometry Method for Identification and Determination of Acrylamide in Foods
Authors: Calbiani Francesca , Careri Maria , Elviri Lisa , Mangia Alessandro , Zagnon Ingrid
Published: February 2020

A rapid and accurate method using reversed-phase liquid chromatography–tandem mass spectrometry interfaced with electrospray was developed for determination of acrylamide in cooked food samples. A simplified sample treatment procedure using an extraction step with acidified water without cleanup was developed. A C18 column with an aqueous formic acid–methanol mixture as the mobile phase was used under isocratic conditions. The method was validated in-house for robustness, limits of detection (LOD) and quantitation (LOQ), linearity, recovery, and accuracy both on standard and baked-product and potato flour matrixes. Good results in the low ppb level were obtained for LOD (<15 μg/kg) and LOQ (<25 μg/kg) of acrylamide in samples. Excellent linearity (r 2 = 0.999–1.000) was established over 2 orders of magnitude by performing statistical tests. The absence of both constant and proportional systematic errors demonstrated good method accuracy. Excellent results were obtained for intraday repeatability (RSD < 1.5%) and between-day precision (RSD < 5%). Extraction recoveries from food products were calculated in the 97 ± 3–99 ± 2% (n = 6) range with a labeled internal standard (13C3-acrylamide). The applicability of the method to determination of acrylamide in cooked food products was demonstrated.
Liquid Chromatographic Determination of Urea in Water-Soluble Urea-Formaldehyde Fertilizer Products and in Aqueous Urea Solutions: Collaborative Study
Authors: Hojjatie Michael M , Abrams Dean E , Parham Thomas M ,   Collaborators:, Balthrop J , Beine R , Dickinson V , Hartshorn J , Herald S , Latimer G , Padmore J , Pleasants S , Riter K , Roser R , Schmunck G , Sensmeier R , Smith V , Taylor L , Volgas G
Published: February 2020

Water soluble urea-formaldehyde (UF) fertilizers, manufactured by complex reaction of urea and form-aldehyde, typically contain varying amounts of unreacted urea. A liquid chromatography method for the analysis of urea in these products, and in aqueous urea solutions, was collaboratively studied. An amine chromatography column was used to separate the unreacted urea from numerous UF reaction products present in these liquid fertilizers. Unreacted urea was determined by using external urea standards with UV detection at 195 nm. The standards and test samples were prepared in the mobile phase of 85% (v/v) acetonitrile in water. Ten laboratories analyzed 5 different UF-based commercial products containing unreacted urea in the range of 6 to 17% by weight, and 5 different concentrations of urea in water equivalent to commercial products of that nature. The aqueous urea solutions contained 2–20% urea (w/w). The range of sR values for the 5 UF-based commercial fertilizers was 0.49–1.02 and the %RSDR was 1.94–6.14. The sR range for the 5 urea solutions was 0.10 to 0.79 and the %RSDR range was 2.54 to 4.88. The average recovery of urea from the aqueous urea solutions was 96–103%. Therefore, this method is capable of monitoring urea nitrogen manufacturers' label claims and total nitrogen claims in those cases where urea is the sole source of plant food nitrogen. Based on the collaborative study data, the authors recommend this method be approved for AOAC Official First Action status.
Simultaneous Determination of Aflatoxins, Ochratoxin A, and Zearalenone in Grains by New Immunoaffinity Column/Liquid Chromatography
Authors: Göbel Roswitha , Lusky Klaus
Published: February 2020

The simultaneous determination of mycotoxins was performed in 3 steps: extraction, cleanup, and detection. For extraction, a mixture of acetonitrile–water (60 + 40, v/v) was proved appropriate. For cleanup, a new Afla-Ochra-Zea immunoaffinity column was used. After derivatization with trifluoroacetic acid, the mycotoxins aflatoxins, ochratoxin A (OTA), and zearalenone (ZEA) were determined simultaneously by liquid chromatography with fluorescence detection. The detection limits in different matrixes after cleanup with the new immunoaffinity column were very low: aflatoxins, 0.002–0.7 μg/kg; OTA, 0.07–0.25 μg/kg; ZEA, 1–3 μg/kg. The limits of determination were: aflatoxins, 0.25 μg/kg; OTA, 0.5 μg/kg; ZEA, 5 μg/kg. The recovery rates for aflatoxins, OTA, and ZEA for rye and rice were between 86 and 93% when a 0.5 g sample matter per immunoaffinity column was used.
Artifactual Oxidation of Cholesterol During the Analysis of Cholesterol Oxidation Products: Protective Effect of Antioxidants
Authors: Guardiola Francesc , Garcia-Cruset Sandra , Bou Ricard , Codony Rafael
Published: February 2020

To study the influence of the addition of various antioxidants and their combinations on the artifactual oxidation of cholesterol during analysis, 2 factorial experiments were performed in duplicate. In the first experiment, 2 amounts of the following antioxidants were assayed: ethylene-diaminetetraacetic acid (EDTA) disodium salt (0 and 1 mg), pyrogallol (0 and 600 μg), and butylated hydroxytoluene (BHT; 0 and 600 μg); in the second, EDTA disodium salt (0 and 1 mg), ascorbyl palmitate (0 and 600 μg), and BHT (0 and 600 μg). Under low oxidative conditions of dim light, evaporation of solvents at low temperatures, and cold saponification in darkness under nitrogen atmosphere, the addition of antioxidants showed no further protective effect. Furthermore, the presence of ascorbyl palmitate significantly increased the formation of cholesterol- 5β,6β-epoxide, and 7β-hydroxycholesterol.
Physiological Aspects of Resistant Starch and in vivo Measurements
Authors: Champ Martine M-J
Published: February 2020

Resistant starch (RS) is the sum of starch and products of starch degradation not absorbed in the small intestine of healthy individuals. There are a number of RS with different characteristics which may have a different fate in the colon. As a consequence, all RS should not be considered equivalent as far as physiological properties are concerned; indeed, they may have a different impact on colonic health. This statement may explain part of the apparent contradictions in the literature on RS and cancer or inflammatory disease prevention. RS is fermented in the large intestine into short-chain fatty acids and, among those, butyrate, which is recognized as the main nutrient of the colonocyte. This fermentation pattern seems to be responsible for most of the effects of RS on colonic health. Another important property is linked to its ability to lower colonic pH, which is usually considered as beneficial for mineral biovailability in the colon or cancer prevention. Due to their fate in the digestive tract, RS materials do not seem to have any significant impact on glucose absorption or metabolism. On the contrary, they may have a hypocholesterolemic effect, but available information is contradictory.
Resistant Starch and Colorectal Neoplasia
Authors: Young Graeme P , Le Leu Richard K
Published: February 2020

There are several approaches to examining the relationship between resistant starch (RS) and development of colorectal cancer (CRC). These include examination of epidemiological relationships, objective testing of effects of RS given to humans on biological events of relevance to CRC, and studies in animal models where protection and mechanisms of protection can be directly tested. Nine epidemiological studies have examined the relationship between starch and CRC and/or adenomas. Most show a significant protective effect. However, epidemiological tools for measuring consumption of RS are poorly developed and so a benefit for RS can only be inferred. On balance, the magnitude of protection by starch appears to be in the order of 25–50%. Human intervention studies have examined the effect of various types and amounts of RS consumption on colonic biology. To generalize from these studies, RS softens stools and increases stool bulk, decreases pH, increases short-chain fatty acids (SCFAs) including butyrate, reduces products of protein fermentation, and decreases bile salts in fecal water. Such changes seem to be achieved within about 4 weeks of commencing consumption. The greatest effects are seen with the highest doses where increased fecal starch recovery is observed. A modest number of animal studies have been undertaken. Those examining effects of RS on colonic biology and biomarkers for CRC confirm and extend the results in humans. RS modifies the lumenal environment, largely through altered fermentation of polysaccharides and proteins. RS also affects epithelial biology in that it increases apoptotic deletion of genetically damaged cells. More work is needed to define what types and combinations of RS, perhaps with probiotics, exert the greatest effects on colonic environment and epithelial biology, and then to test these in the cancer models for their protective effect. A few studies have examined effect of RS on cancer as an end point in several rodent models, but the results are not clear cut. In conclusion, consumption of RS dramatically affects the colonic lumenal environment and facilitates apoptotic deletion of genetically damaged cells in the colon, several of which are considered to be biomarkers associated with risk for CRC. These effects can be interpreted as reflecting improved colonic health, which might be of benefit in protection against CRC. Direct evidence for protection is still not available.
New Liquid Chromatographic Method for Determination of Rabeprazole Sodium in Coated Tablets
Authors: Garcia Cássia V , Paim Clésio S , Steppe Martin
Published: February 2020

Rabeprazole sodium is a proton pump inhibitor that covalently binds and inactivates the gastric parietal cell proton pump (H+/K+ ATPase). Little has been published about the quantitative determination of this drug. The aim of this research was to develop a new liquid chromatographic method for quantitative determination of rabeprazole in coated tablets. The system consisted of a Hypersil Keystone Betabasic C8 column (250 × 4.6 mm, 5 μm particle size), an isocratic acetonitrile–water (35 + 65) mobile phase at a flow rate of 1.0 mL/min, and a diode array detector set at 282 nm. The following validation parameters were evaluated: linearity, precision, accuracy, specificity, detection and quantitation limits, and robustness. The method showed good linearity in the concentration range of 10–70 μg/mL. The quantitation limit was 2.43 μg/mL, and the detection limit was 0.80 μg/mL. The intra- and interday precision data showed that the method has good reproducibility (relative standard deviation = 1.03). Accuracy and robustness were also evaluated, and the results were satisfactory. The mean recovery was 101.61%. The analysis of a placebo mixture demonstrated the method is also specific.
A Sensitive Extracto-Photometric Method for Determination of Residual Chlorine in Greywater
Authors: March Juan G , Gual Mateu , Simonet Bartolomé M
Published: February 2020

A new photometric method for chlorine determination based on the oxidative transformation of iodide to iodine and subsequent extraction in ethyl acetate has been developed. The effects of several chemical variables (pH, ionic strength, and iodide concentration) have been studied. Characteristics of the method were linear range 0–0.6 mg Cl2/L, limit of detection 5 μg Cl2/L, and coefficient of variation 0.6%. The method has been applied to greywater without previous sample treatment.