bluuebunny/crossref_metadata_2025 huggingface dataset:
Purity Assessment of Commercially Available Crystalline Deoxynivalenol
Authors: Krska Rudolf , Szente Elisabeth , Freudenschuss Martin , Hametner Christian , Zöllner Peter
Published: February 2020

Deoxynivalenol (DON) obtained from 2 commercial sources was characterized, and its purity was determined. The structural identity of DON was confirmed by 1 Hand 13C-nuclear magnetic resonance (NMR) spectroscopy, gas chromatography with mass spectrometric (GC/MS) detection, and infrared/attenuated total reflectance (IR/ATR) spectroscopy. NMR spectra showed shifts that varied from previously published data. However, we established a complete, unambiguous assignment for all signals. Chromatograms obtained by GC/MS were almost identical for both investigated samples and confirmed the structure of DON. Likewise, IR/ATR spectra verified the identity of DON. The degree of purity was determined by liquid chromatography (LC) with a variable wavelength detector, LC/MS/MS, GC with electron-capture detection (GC-ECD), and ultraviolet (UV) spectrophotometry. The purity check using LC showed a single peak in both chromatograms. With LC/MS/MS measurements, we could detect small amounts of impurities in the crystalline DON from both sources. In data obtained by GC-ECD, no differences in purity were observed. The UV measurements showed an absorption maximum at 217 nm. The mean εm of the extinction coefficients was calculated as 6727 (L/cm/mol) for DON (Sigma) and 6825 (L/cm/mol) for DON (Biopure). Finally, the purity of DON from the 2 commercial sources was calculated as >96 and >98%, respectively. Although the DON produced by both providers can be considered sufficiently pure for routine analysis of trichothecenes in food and feed, this work again demonstrated that the impurity of the solid mycotoxin constitutes the greatest contribution to the overall uncertainty of a mycotoxin calibrant.
Automatic Flow Procedure for the Determination of Ethanol in Wine Exploiting Multicommutation and Enzymatic Reaction with Detection by Chemiluminescence
Authors: Fernandes Elizabeth N , Reis Boaventura F
Published: February 2020

An automatic procedure for the determination of ethanol in wines using a flow system based on multicommutation and enzymatic reaction is described. Alcohol oxidase was immobilized on aminopropyl glass beads and packed in an acrylic column. The peroxide due to enzymatic reaction with ethanol reacted with luminol and generated the chemiluminescence radiation that was monitored by using a laboratory-made detector based on photodiodes. The system manifold comprised a set of 3-way solenoid valves controlled by a microcomputer furnished with electronic interfaces, which ran on software written in Quick BASIC 4.5 to provide facilities to perform on-line sample dilution, reagent addition, and data acquisition. After system parameters optimization, ethanol samples were processed without prior pretreatment. The following suitable features were achieved: linear response ranging from 2.5 to 25% (v/v) ethanol, relative standard deviation of 1.8% (n = 10), detection limit of 0.3% (v/v) ethanol, sampling rate of 23 determinations per hour, and low reagent consumption of 0.23 mg luminol and 7 mg hexacyanoferrate (III) per determination. When the results were compared with those obtained using the AOAC Official Method, no significant difference at the 90% confidence level was observed.
Liquid Chromatographic Determination of St. John's Wort Components in Functional Foods
Authors: Jager Lowri S De , Perfetti Gracia A , Diachenko Gregory W
Published: February 2020

A method was developed for determination of St. John's wort marker compounds hypericin, pseudohypericin, hyperforin, and adhyperforin in functional foods. Solid-phase extraction provided analyte extraction and significant sample cleanup prior to analysis using liquid chromatography (LC) with UV and fluorescence detection. In addition to quantification using LC-UV, confirmation was made with electrospray ionization LC mass spectrometry (LC/MS). Several commercially available tea and drink products claiming to contain St. John's wort were tested. Recoveries ranged from 51 to 98% for the liquid samples. Comparison of the concentrations in 4 St. John's wort teas showed a variation in analyte concentration (1044–10 ng/mL marker compounds in brewed tea) and composition. No marker compounds were found in the beverages, indicating possible decomposition of the marker compounds caused by low pH and/or exposure to light. A solvent extraction procedure was developed for analysis of the marker compounds from solid samples. Analytes were detected at low. parts per million, with an average recovery of 75% No St. John's wort components were found in the 2 solid functional food samples analyzed.
Simultaneous Quantification of Some Pharmaceutical Catharanthus roseus Leaf and Root Terpenoid Indole Alkaloids and Their Precursors in Single Runs by Reversed-Phase Liquid Chromatography
Authors: Digvijay Singh , Shashi Pandey-Rai , Suchi Srivastava , Kumar Rai Sanjay , Raghavendra Mishra , Sushil Kumar
Published: February 2020

A new, rapid, sensitive, and reproducible reversed-phase liquid chromatographic (LC) method with photodiode array detection is described. It allows, in a single run of 30 min, simultaneous separation of 6 pharmaceutically and biologically important Catharanthus roseus leaf and root terpenoid indole alkaloids (TIAs) and 3 of their precursors: TIA precursors tryptophan, tryptamine, and loganine; and TIAs serpentine, catharanthine, ajmalicine, vincristine, vinblastine, and vindoline. The method involves the use of a Phenomenex Luna 5 μm, C18 column (250 mm × 4.6 mm id) and a linear binary gradient mobile phase profile. Detection is performed at 220 and 254 nm, which provided good absorptivity for all of the roseus compounds listed above and gave a minimum detection limit of 0.02 μg/mL. The extraction efficiency, peak purity, and homogeneity parameters of the profiles could be validated using a photodiode array detector. The method was successfully used to quantify major components of leaf and root extracts of C. roseus accessions. The new method thus provides a reliable tool for rapid screening of C. roseus samples in large numbers, which is needed in breeding/genetic engineering and genetic mapping experiments and for monitoring the reaction products, in the in vitro/in vivo conversions of precursors into products, and vice versa.
Interlaboratory Verified Liquid Chromatographic Method for Analysis of Vitamins A and E in Soy-Based Infant Formula Powder
Authors: Chase G William , Ye Lin , Stoakes Vicky C , Eitenmiller Ronald R , Long Austin R
Published: February 2020

An interlaboratory verified, liquid chromatographic (LC) method is presented for the analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in soy-based infant formula. The extraction procedure uses sample dehydration with magnesium sulfate followed by extraction with isopropanol, hexane–ethyl acetate (85 + 15, v/v). After evaporation and filtration, the sample extract is injected directly onto a normal-phase LC system with fluorescence detection. All-rac-α-tocopheryl acetate and retinyl palmitate are quantitated isocratically with a mobile phase of hexane containing 0.50% (v/v) and 0.125% (v/v) isopropanol, respectively. A zero control reference material (ZRM) was spiked at 5 levels, with 5 replicate analyses of 1/2x, x, 2x, 4x, and 16x where “x” is the minimum level of 250 IU/100 kcal (vitamin A) and 0.7 IU/100 kcal (vitamin E) as specified in 21 Code of Federal Regulations 107.100. The following recoveries and RSD values represent an average (n = 25) of the 5 levels for each analyte: all-rac-α-tocopheryl acetate, 100% (RSD = 3.5%); retinyl palmitate, 97.2% (RSD = 2.1%). Two additional laboratories analyzed the fortified ZRM samples. Average recoveries (n = 24) of all-rac-α-tocopheryl acetate and retinyl palmitate at 4 levels were all-rac-α-tocopheryl acetate, 99.0% (RSD = 4.0%), and retinyl palmitate, 96.2% (RSD = 1.4%) at the second laboratory. Average recoveries (n = 24) of all-rac-α-tocopheryl acetate and retinyl palmitate at 4 levels were all-rac-α-tocopheryl acetate, 102% (RSD = 1.4%) and retinyl palmitate, 95.7% (RSD = 2.0%) at the third laboratory. In addition, 6 replicates of the same commercial soy-based infant formula powder were run by the 3 laboratories.
Determination of Processed Animal Proteins, Including Meat and Bone Meal, in Animal Feed
Authors: Gizzi Giséile , von Holst Christoph , Baeten Vincent , Berben Gilbert , van Raamsdonk Leo
Published: February 2020

An intercomparison study was conducted to determine the presence of processed animal proteins (PAPs), including meat and bone meal (MBM) from various species, in animal feed. The performances of different methods, such as microscopy, polymerase chain reaction (PCR), immunoassays, and a protocol based on iquid chromatography (LC), were compared. Laboratories were asked to analyze for PAPs from all terrestrial animals and fish (total PAPs); mammalian PAPs; ruminant PAPs; and porcine PAPs. They were free to use their method of choice. In addition, laboratories using microscopy were asked to determine the presence of PAPs from terrestrial animals, which is applicable only to microscopy. For total PAPs microscopy, LC and some immunoassays showed sufficient results at a concentration as low as 0.1% MBM in the feed. In contrast, PCR was not fit for purpose. In differentiating between MBM from terrestrial animals and fishmeal, microscopy detected 0.5% of terrestrial MBM in feed in the presence of 5% fishmeal, but was less successful when the concentration of MBM from terrestrial animals was 0.1%. The animal-specific determination of MBM from mammals or, more specifically from either ruminants or pigs, by PCR showed poor results, as indicated by a high number of false-positive and false-negative results. The only PCR method that scored quite well was applied by a member of the organizer team of the study. Immunoassays scored much better than PCR, showing sufficient sensitivity but some deficiency in terms of specificity. The results also demonstrated that the reliable determination of MBM from ruminants has not been resolved, especially for low concentrations of MBM (0.1%) in feed. Comparison of the results for mammalian MBM from all methods indicated that, for control purposes, the immunoassay method, especially when applied as dipsticks, could be used as a rapid screening method combined with microscopy to confirm the positive samples. However, implementation of such a system would require that the immunoassays were previously validated to demonstrate that this approach is fit for purpose. The determination of ruminant or porcine PAPs by immunoassays was more difficult, partly because the MBM in this study contained about 50% bovine and porcine material, thereby reducing the target concentration level to 0.05%.
Real-Time Polymerase Chain Reaction-Based Approach for Quantification of the pat Gene in the T25 Zea mays Event
Authors: Weighardt Florian , Barbati Cristina , Paoletti Claudia , Querci Maddalena , Kay Simon , De Beuckeleer Marc , Van den Eede Guy
Published: February 2020

In Europe, a growing interest for reliable techniques for the quantification of genetically modified component(s) of food matrixes is arising from the need to comply with the European legislative framework on novel food products. Real-time polymerase chain reaction (PCR) is currently the most powerful technique for the quantification of specific nucleic acid sequences. Several real-time PCR methodologies based on different molecular principles have been developed for this purpose. The most frequently used approach in the field of genetically modified organism (GMO) quantification in food or feed samples is based on the 5′-3′-exonuclease activity of Taq DNA polymerase on specific degradation probes (TaqMan® principle). A novel approach was developed for the establishment of a TaqMan quantification system assessing GMO contents around the 1% threshold stipulated under European Union (EU) legislation for the labeling of food products. The Zea mays T25eliteeventwas chosen as a model for the development of the novel GMO quantification approach. The most innovative aspect of the system is represented by the use of sequences cloned in plasmids as reference standards. In the field of GMO quantification, plasmids are an easy to use, cheap, and reliable alternative to Certified Reference Materials (CRMs), which are only available for a few of the GMOs authorized in Europe, have a relatively high production cost, and require further processing to be suitable for analysis. Strengths and weaknesses of the use of novel plasmid-based standards are addressed in detail. In addition, the quantification system was designed to avoid the use of a reference gene (e.g., a single copy, species-specific gene) as normalizer, i.e., to perform a GMO quantification based on an absolute instead of a relative measurement. In fact, experimental evidences show that the use of reference genes adds variability to the measurement system because a second independent real-time PCR-based measurement must be performed. Moreover, for some reference genes no sufficient information on copy number in and among genomes of different lines is available, making adequate quantification difficult. Once developed, the method was subsequently validated according to IUPAC and ISO 5725 guidelines. Thirteen laboratories from 8 EU countries participated in the trial. Eleven laboratories provided results complying with the predefined study requirements. Repeatability (RSDr)values ranged from 8.7 to 15.9%, with a mean value of 12%. Reproducibility (RSDR) values ranged from 16.3 to 25.5%, with a mean value of 21%. Following Codex Alimentarius Committee guidelines, both the limits of detection and quantitation were determined to be <0.1%.
Regulatory and Compliance Activities to Protect Food-Allergic Consumers in Canada: Research in Support of Standard Setting and Consumer Protection
Authors: Ben Rejeb Samuel , Lauer Bruce , Salminen John , Roberts Irene , Wadhera Ashwani , Abbott Michael , Davies David , Cléroux Chantal , Weber Dorcas , Lau Benjamin , Bacler Stan , Langlois Daniel , Kurz Karl
Published: February 2020

An overview is presented of the activities of Health Canada and the Canadian Food InspectionAgency (CFIA) in the area of food allergens. Since the 1990s, changes were made in the Food and Drug Regulations in order to better protect allergic consumers by imposing labeling requirements to clearly identify sources of priority food allergens in prepackaged foods. Policies of application as well as risk management strategies are discussed with some statistics on allergen-related food recalls in Canada for the years 1997–2001. Health Canada's allergen method development program is a pioneering research initiative that was developed in the early 1990s in support of the changing Canadian regulatory environment. The objectives and some of the accomplishments of this program are presented. The development of the CanadianCompendium of Allergen Methodologies under aWeb-based application to compile data on evaluated allergen detection methods will provide further support to compliance activities nationally, as well as to the international analytical community in both government and the food industry. Some emerging techniques for the confirmation of results generated by enzyme-linked immunosorbent assays are also discussed.
Immunochemical Analytical Methods for the Determination of Peanut Proteins in Foods
Authors: Whitaker Thomas B , Williams Kristina M , Trucksess Mary W , Slate Andrew B
Published: February 2020

Peanut proteins can cause allergenic reactions that can result in respiratory and circulatory effects in the body sometimes leading to shock and death. The determination of peanut proteins in foods by analytical methods can reduce the risk of serious reactions in the highly sensitized individual by allowing for the detection of these proteins in a food at various stages of the manufacturing process. The method performance of 4 commercially available enzyme-linked immunosorbent assay (ELISA) kits was evaluated for the detection of peanut proteins in milk chocolate, ice cream, cookies, and breakfast cereals: ELISA-TEK Peanut Protein Assay, now known as “Bio-Kit” for peanut proteins, from ELISA Technologies Inc.; Veratox for Peanut Allergens from Neogen Corp.; RIDASCREEN Peanut Kit from R-Biopharm GmbH; and ProLisa from Canadian Food Technology Ltd. The 4 test kits were evaluated for accuracy (recovery) and precision using known concentrations of peanut or peanut proteins in the 4 food matrixes. Two different techniques, incurred and spiked, were used to prepare samples with 4 known concentrations of peanut protein. Defatted peanut flour was added in the incurred samples, and water-soluble peanut proteins were added in the spiked samples. The incurred levels were 0.0, 10, 20, and 100 μg whole peanut per g peanut protein per g food; the spiked levels were 0.0, 5, 10, and 20 μg peanut protein per g food. Performance varied by test kit, protein concentration, and food matrix. The Veratox kit had the best accuracy or lowest percent difference between measured and incurred levels of 15.7% when averaged across all incurred levels and food matrixes. Recoveries associated with the Veratox kit varied from 93 to 115% for all food matrixes except cookies. Recoveries for all kits were about 50% for cookies. The analytical precision, as measured by the variance, increased with an increase in protein concentration. However, the coefficient of variation (CV) was stable across the 4 incurred protein levels and was 7.0% when averaged across the 4 food matrixes and analytical kits. The R-Biopharm test kit had the best precision or a CV of 4.2% when averaged across all incurred levels and food matrixes. Because measured protein values varied by test kit and food matrix, a method was developed to normalize or transform measured protein concentrations to an adjusted protein value that was equal to the known protein concentration. The normalization method adjusts measured protein values to equal the true protein value regardless of the type test kit or type food matrix.
Results from Two Interlaboratory Comparison Tests Organized in Germany and at the EU Level for Analysis of Acrylamide in Food
Authors: Klaffke Horst , Fauhl Carsten , Mathar Wolfgang , Palavinskas Richard , Wittkowski Reiner , Wenzl Thomas , Anklam Elke
Published: February 2020

After the publication of high levels of acrylamide (AA) in food, many research activities started all over the world in order to determine the occurrence and the concentration of this substance in various types of food. As no validated methods were available at that time, interlaboratory studies on the determination of AA in food were of the highest priority. Under the boundary conditions of applying well-established evaluation schemes, the results of 2 studies conducted by the Federal Institute for Risk Assessment (BfR) in Germany and by the European Commission's Directorate General Joint Research Center (JRC) exhibited an overall acceptable performance of the participants in these studies. Nevertheless, many laboratories showed problems in determining AA in food with a complex matrix such as cocoa. The results of analysis also showed a broader variation of AA for samples with low AA concentrations and indicated a bias of the results obtained by gas chromatography–mass spectrometry without derivatization. Improvements of the performance of some laboratories appeared to be necessary.
Validation of a Method for the Determination of Narasin in the Edible Tissues of Chickens by Liquid Chromatography
Authors: Ward Tracey L Cash , Moran John W , Turner James M , Coleman Mark R
Published: February 2020

Maxiban® and Monteban® are 2 products marketed by Elanco Animal Health. They contain narasin and are used for the prevention of coccidiosis in chickens. Products used in the European market must be regularly re-registered with new data to support label claims. This study was undertaken as part of such a re-registration effort. A method for the determination of narasin in poultry tissue was previously registered with the authorities; however, a method with more environmentally friendly solvents was desired. The Canadian Food Inspection Agency accomplished this goal and published an improved method. In order to register the method with European authorities as the official Elanco method for determination of narasin, Elanco scientists were required to provide validation data for all edible poultry tissues. This paper shows the validation of the method to detect residues of narasin using solid-phase extraction followed by liquid chromatographic analysis utilizing post-column derivatization.
Precolumn Derivatization Liquid Chromatography Method for Analysis of Dietary Supplements for Glucosamine: Single Laboratory Validation Study
Authors: Ji David , Zhang Lingjun , Chen Jianhai , Peng Emily
Published: February 2020

A precolumn derivatization liquid chromatography (LC) method was developed for the analysis of various dietary supplement formulations and raw materials for glucosamine. A 1 mL sample or standard water solution (containing about 0.05 mg glucosamine) was mixed with 1 mL pH 8.3 buffer, 1 mL 5% phenylisothiocyanate methanolic solution, and derivatized at 80°C in a water bath for 30 min. After derivatization, the solution was cooled in a cold water bath and centrifuged at 3000–5000 rpm. The clear upper layer was ready for injection. The LC system was equipped with a C18 reversed-phase column and an ultraviolet detector set at 240 nm. The column was developed with a linear gradient composed of 0.1% phosphoric acid in deionized water and 0.1% phosphoric acid in methanol. The method was subjected to Single Laboratory Validation. The method precision was 0.50% relative standard deviation, accuracy was less than ±1.5%, method linearity in the range 0–2 mg glucosamine/mL was 1.00, the detection limit was 0.0705 μg/mL, and the quantitation limit was 0.235 μg/mL. Chondroitin sulfate, amino acids, and excipients did not interfere with glucosamine testing. After derivatization, both standard and sample preparations were stable for at least 48 h. Due to its high sensitivity, this method can be used to assay glucosamine in functional foods and pet foods. The validation data will be published separately.
Validation of a Fast and Easy Method for the Determination of Residues from 229 Pesticides in Fruits and Vegetables Using Gas and Liquid Chromatography and Mass Spectrometric Detection
Authors: Lehotay Steven J , Kok André de , Hiemstra Maurice , Bodegraven Peter van
Published: February 2020

Validation experiments were conducted of a simple, fast, and inexpensive method for the determination of 229 pesticides fortified at 10–100 ng/g in lettuce and orange matrixes. The method is known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods. The procedure involved the extraction of a 15 g sample with 15 mL acetonitrile, followed by a liquid–liquid partitioning step performed by adding 6 g anhydrous MgSO4 plus 1.5 g NaCl. After centrifugation, the extract was decanted into a tube containing 300 mg primary secondary amine (PSA) sorbent plus 1.8 g anhydrous MgSO4, which constituted a cleanup procedure called dispersive solid-phase extraction (dispersive SPE). After a second shaking and centrifugation step, the acetonitrile extract was transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry with an ion trap instrument and liquid chromatography/tandem mass spectrometry with a triple quadrupole instrument using electrospray ionization. Each analytical method was designed to analyze 144 pesticides, with 59 targeted by both instruments. Recoveries for all but 11 of the analytes in at least one of the matrixes were between 70–120% (90–110% for 206 pesticides), and repeatabilities typically <10% were achieved for a wide range of fortified pesticides, including methamidophos, spinosad, imidacloprid, and imazalil. Dispersive SPE with PSA retained carboxylic acids (e.g., daminozide), and <50% recoveries were obtained for asulam, pyridate, dicofol, thiram, and chlorothalonil. Many actual samples and proficiency test samples were analyzed by the method, and the results compared favorably with those from traditional methods.
Determination of Chloramphenicol Residues in Milk, Eggs, and Tissues by Liquid Chromatography/Mass Spectrometry
Authors: Penney Lisa , Smith Anderson , Coates Brent , Wijewickreme Arosha
Published: February 2020

A new liquid chromatography/mass spectrometry (LC/MS) method is presented for the determination of chloramphenicol (CAP) residues in milk, eggs, chicken muscle and liver, and beef muscle and kidney. CAP is extracted from the samples with acetonitrile and defatted with hexane. The acetonitrile extracts are then evaporated, and residues are reconstituted in 10mM ammonium acetate–acetonitrile mobile phase and injected into the LC system. CAP is determined by reversed-phase chromatography using an Inertsil ODS-2 column and MS detection with negative ion electrospray ionization. Calibration curves were linear between 0.5–5.0 ng/g for all matrixes studied. The relative standard deviations for measurements by this method were generally <12%, and average recoveries ranged from 80 to 120%, depending on the matrix involved. The method detection limits of CAP ranged from 0.2 to 0.6 ng/g, which are comparable to previously reported results. The proposed method is rapid, simple, and specific, allowing a single analyst to easily prepare over 40 samples in a regular working day.
Isoelectric Focusing Identification of Four Freshwater Fish Commercially Labeled “Perch”
Authors: Berrini Anna , Tepedino Valentina , Borromeo Vitaliano , Secchi Camillo
Published: February 2020

Isoelectric focusing (IEF) was used to distinguish 4 freshwater fish species that are sold in the European Union under the generic label of “perch”: Perca fluviatilis (European perch), Lates niloticus (Nile perch), Stizostedion lucioperca (European pikeperch), and Morone chrysops x saxatilis (Sunshine bass). These species have different commercial values but are easily interchangeable because they are sold already filleted, in view of the numerous bones of the whole fish. IEF of the water-soluble proteins extracted from fish muscle resulted in species-specific patterns. None of the bands was common to all 4 species. Intraspecies polymorphism was low and did not concern the bands identified as characteristic of the species.
Determination of Ochratoxin A in Green Coffee by Immunoaffinity Column Cleanup and Liquid Chomatography: Collaborative Study
Authors: Vargas Eugênia Azevedo , dos Santos Eliene Alves , Pittet Alain ,   Collaborators:, Corrêa T B S , da Rocha A P P , Diaz G J , Gorni R , Koch P , Lombaert G A , MacDonald S , Mallmann C A , Meier P , Nakajima M , Neil R J , Patel S , Petracco M , Prado G , Sabino M , Steiner W , Stroka J , Taniwaki M H , Wee S M
Published: February 2020

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol–3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of <0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (<0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of ≤0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.
Chromatographic Determination of Amino Acids in Foods
Authors: Peace Robert W , Gilani G Sarwar
Published: February 2020

Amino acids in foods exist in a free form or bound in peptides, proteins, or nonpeptide bonded polymers. Naturally occurring L-amino acids are required for protein synthesis and are precursors for essential molecules, such as co-enzymes and nucleic acids. Nonprotein amino acids may also occur in animal tissues as metabolic intermediates or have other important functions. The development of bacterially derived food proteins, genetically modified foods, and new methods of food processing; the production of amino acids for food fortification; and the introduction of new plant food sources have meant that protein amino acids and amino acid enantiomers in foods can have both nutritional and safety implications for humans. There is, therefore, a need for the rapid and accurate determination of amino acids in foods. Determination of the total amino acid content of foods requires protein hydrolysis by various means that must take into account variations in stability of individual amino acids and resistance of different peptide bonds to the hydrolysis procedures. Modern methods for separation and quantitation of free amino acids either before or after protein hydrolysis include ion exchange chromatography, high performance liquid chromatography (LC), gas chromatography, and capillary electrophoresis. Chemical derivatization of amino acids may be required to change them into forms amenable to separation by the various chromatographic methods or to create derivatives with properties, such as fluorescence, that improve their detection. Official methods for hydrolysis and analysis of amino acids in foods for nutritional purposes have been established. LC is currently the most widely used analytical technique, although there is a need for collaborative testing of methods available. Newer developments in chromatographic methodology and detector technology have reduced sample and reagent requirements and improved identification, resolution, and sensitivity of amino acid analyses of food samples.
The Protein Digestibility-Corrected Amino Acid Score (PDCAAS)—A Concept for Describing Protein Quality in Foods and Food Ingredients: A Critical Review
Authors: Schaafsma Gertjan
Published: February 2020

Protein Digestibility-Corrected Amino Score (PDCAAS) is discussed. PDCAAS is now widely used as a routine assay for protein quality evaluation, replacing the more traditional biological methods [e.g., measurement of the Protein Efficiency Ratio (PER) in rats]. PDCAAS is based on comparison of the essential amino acid content of a test protein with that of a reference essential amino acid pattern and a correction for differences in protein digestibility as determined using a rat assay. Although PDCAAS is a rapid and useful method, it often shows discrepancies when compared to PER values. These discrepancies relate to the following issues: uncertainty about the validity of reference patterns, invalidity of correction for fecal (versus ileal) digestibility, truncation of PDCAAS values to 100%, failure to obtain full biological response after supplementation of the limiting essential amino acid, discrepancies between protein and amino acid digestibility, effects of processing on protein quality, and effects of the presence of antinutritional factors in the matrix containing the protein. Part of the discrepancy between PDCAAS and PER can be overcome by modifications of PDCAAS. This article describes some proposed modifications and puts forward the suggestion that the rat protein fecal digestibility assay be replaced by an in vitro ileal amino acid digestibility assay based on a computer-controlled gastrointestinal model.
Biological Assay and Liquid Chromatographic Method for Analysis of Moxifloxacin in Tablets
Authors: Guerra Fanny L B , Paim Clesio S , Steppe Martin , Schapoval Elfrides E S
Published: February 2020

A microbiological assay and a liquid chromatographic method were validated for quantitation of moxifloxacin in tablets. The microbiological method consisted of a cylinder-plate agar diffusion assay using Micrococcus luteus ATCC 9341 as the test microorganism and phosphate buffer (0.1M, pH 8.0) as the diluent solution. The response graphs for standard and sample solutions were linear (r = 0.9479), and no parallelism deviations were detected in the tested levels of concentration (4.0, 8.0, and 16.0 μg/mL). The interday precision was 2.73%. Recovery values were between 96.25 and 100.5%. The chromatographic analyses were performed using a Shim-pack CLC-ODS column (250 × 4.6 mm, 5 μm) with a mobile phase consisting of (A) a mixture of phosphoric acid (0.17%, v/v) with tetramethylammonium hydroxide (0.05M) and acetonitrile (95 + 5, v/v) and (B) methanol (55 + 45, v/v) adjusted to pH 3.0. The flow rate was 1.0 mL/min, and detection was made at 294 nm. The method was linear in a range from 12.0 to 42 μg/mL (r = 0.9999), and the interday precision was 1.39%. Recovery ranged between 101.9 and 103. 81%. Both validated methods were used to quantify the moxifloxacin content in tablets exposed to ultraviolet radiation, and similar results were obtained.
Kinetics of Thermal Decomposition of 4-Carboxyl-2,6-Dinitrobenzenediazonium Ion (CDNBD)
Authors: Idowu Olakunle S , Kolawole Abiola O , Adegoke Olajire A , Kolade Yetunde T , Fasanmade Adedigbo A , Olaniyi Ajibola A
Published: February 2020

The kinetics of thermal decomposition of 4-carboxyl-2,6-dinitrobenzenediazonium ion (CDNBD), an arenediazonium ion newly developed as a derivatizing reagent for drug analysis, are described. The arenediazonium ion, in an optimized concentrated sulfuric acid/orthophosphoric acid medium, was incubated for various time intervals at 30°, 45°, 55°, 65°, 75°, and 85°C. The amount of ion left after each time interval was quantified selectively by colorimetric assay at 490 nm, using mefenamic acid as a model diazo-coupling component. The rate constants for the decomposition were determined graphically. An Arrhenius plot was used to delineate the dependence of the rate constant on temperature and to predict the half-life at 25°C and lower temperatures. The diazonium ion decomposed by first-order kinetics. The rate constants of decomposition, which increased progressively with temperature, were 3.18 ± 0.41 × 10−5, 1.19 ± 0.07 × 10−4, 4.87 ± 0.15 × 10−4, 12.88 ± 0.73 × 10−4, and 21.32 ± 2.74 × 10−4 (s−1) with corresponding half-lives of 363, 97.06, 23.72, 8.97, and 5.42 min at 30°, 45°, 55°, 65°, and 75°C, respectively. CDNBD is highly stable in concentrated acid medium, with half-life values of about 10 h, 10 days, and 7.3 months at 25°, 0°, and −20°C, respectively. The reagent stability profile shows that it could be readily adapted for routine applications in instrumental chemical analysis.
Simultaneous Determination of Caffeine, 8-Chlorotheophylline, and Chlorphenoxamine Hydrochloride in Ternary Mixtures by Ratio-Spectra Zero-Crossing First-Derivative Spectrophotometric and Chemometric Methods
Authors: Kelani Khadiga M
Published: February 2020

A ratio-spectra zero-crossing first-derivative spectrophotometric method and 2 chemometric methods have been used for the simultaneous determination of ternary mixtures of caffeine (A), 8-chlorotheophylline (B), and chlorphenoxamine hydrochloride (C) in bulk powder and dosage forms. In the ratio-spectra zero-crossing first-derivative spectrophotometric technique (1DD), calibration curves were linear in the range of 4–20 μg/mL for A, B, and C (r = 0.9992, 0.9994, and 0.9976, respectively). The measurements were carried out at 212, 209.2, and 231.4 nm for A, B, and C, respectively. The detection limits for A, B, and C were calculated to be 0.24, 0.34, and 0.13 μg/mL, and the percentage recoveries were 99.1 ± 0.89, 100.1 ± 0.95, and 100.1 ± 1.0, respectively. Two chemometric methods, namely, the partial least-squares (PLS) model and the principal component regression (PCR) model, were also used for the simultaneous determination of the 3 drugs in the ternary mixture. A training set consisting of 15 mixtures containing different ratios of A, B, and C was used. The concentration used for the construction of the PLS and PCR models varied between 4 and 25 μg/mL for each drug. These models were used after their validation for the prediction of the concentrations of A, B, and C in mixtures. The detection limits for A, B, and C were calculated to be 0.13, 0.15, and 0.14 μg/mL, respectively, and the percent recoveries were found to be 99.8 ± 0.96, 99.9 ± 0.94, and 99.9 ± 1.18, respectively, for both methods. The 3 proposed procedures are rapid, simple, sensitive, and accurate. No preliminary separation steps or resolution equations are required; thus, they can be applied to the simultaneous determination of the 3 drugs in commercial tablets and suppositories or in quality-control laboratories.
Voltammetric Behavior of Zaleplon and Its Differential Pulse Polarographic Determination in Capsules
Authors: Larenas Gipsy , Bollo Soledad , Rodriguez Marcelo , Lemus Igor , Nuñez-Vergara Luis J , Squella Juan A , Álvarez-Lueje Alejandro
Published: February 2020

In this work both the electrochemical behavior and the analysis of the hypnotic pyrazolopyrimidine derivative zaleplon were studied. Zaleplon in ethanol–0.1M Britton Robinson buffer solution (30–70) showed 2 irreversible, well-defined cathodic responses in the pH range of 2–12 using differential pulse polarography (DPP), tast polarography, and cyclic voltammetry. From chronocoulometric studies, it was possible to conclude that one electron was transferred in each reduction peak or wave. For analytical purposes, the DPP technique working at pH 4.5 for peak I was selected, which exhibited adequate repeatability, reproducibility, and selectivity. The recovery was 99.97 ± 1.52%, and the detection and quantitation limits were 5.13 × 10−7M and 1.11 × 10−6M, respectively. The DPP method was applied successfully to the individual assay of capsules in order to verify the content uniformity of zaleplon. Treatment of the sample is not required because the excipients do not interfere, the method is not time consuming, and it is less expensive than column liquid chromatography.
Quantitative Determination of Usnic Acid in Usnea lichen and Its Products by Reversed-Phase Liquid Chromatography with Photodiode Array Detector
Authors: Ji Xiuhong , Khan Ikhlas A
Published: February 2020

Usnic acid, a lichen substance, has a wide range of pharmaceutical applications, including antibiotic, antimycotic, antifeedant, antitubercular, antitumor, and analgesic activities. Some products containing usnic acid are marketed as weight control supplements; however, hepatotoxicity and acute liver failures were reported as severe side effects. The usnic acid content present in the plant materials and market products was analyzed by reversed-phase high-pressure liquid chromatography with a photodiode array detector at 233 nm. A Waters XTerra RP18 (150 × 4.6 mm; 5 μm particle size) column was the stationary phase; mobile phase was aqueous 0.1% acetic acid and acetonitrile gradient at flow rate of 1.0 mL/min. The temperature was held constant at 30°C. The retention time of usnic acid was approximately 13.3 min. Acetone extraction of the samples took place with sonication. The precision of the method was confirmed by a standard deviation below 3.0% (n = 3) and usnic acid recovery was 99.0%. Limit of detection was 0.4 μg/mL and the response was linear from 1.4 to 570.0 μg/mL with a correlation coefficient (R2) of 0.9991. The content of usnic acid in 4 raw materials and 22 finished products was analyzed.
Real-Time Polymerase Chain Reaction Approach for Quantitation of Ruminant-Specific DNA to Indicate a Correlation Between DNA Amount and Meat and Bone Meal Heat Treatments
Authors: Chiappini Barbara , Brambilla Gianfranco , Agrimi Umberto , Vaccari Gabriele , Aarts Henk J M , Berben Gilbert , Frezza Domenico , Giambra Vincenzo
Published: February 2020

The use of ruminant-derived proteins in ruminant feeds has been banned in both the European Union and the United States to prevent further spread of bovine spongiform encephalopathy. Enforcement of these regulations relies on the ability to identify the presence of prohibited proteins in feed. We developed a quantitative real-time polymerase chain reaction assay for the quantification of ruminant-specific DNA as index of protein content. The assay is based on the amplification of a 117 base pair mitochondrial 16S rRNA DNA gene fragment and an internal positive control (IPC). The use of an IPC permits compensation for differences in DNA extraction efficiency and avoids the occurrence of false-negative results. We demonstrated a decrease in target DNA amount with a difference of 2 logs between meat and bone meal (MBM) treated at 133° and 145°C. Such a difference indicates that bias could occur when DNA-based methods are used for quantitation purposes. Risk management could benefit from future efforts concerning validation of the method for MBM detection in feedstuff and safety evaluation of the use of animal-derived proteins in animal nutrition.
Analytical Method for Dimethenamid-P in Selected Raw Agricultural Commodities by Gas Chromatography with Electron Capture Detection
Authors: Anderson Kim A , Basile Jennifer L , Johnson Eugene R
Published: February 2020

A sensitive and simple method for the extraction and quantification of the herbicide dimethenamid-P from several raw agricultural commodities (RAC) is presented. The method provides sensitive and well-defined chromatography with baseline resolution in all matrixes tested. Homogenized samples were extracted with methanol–water, filtered, and then extracted with hexanes. A Florisil solid-phase extraction was then applied for the final cleanup. Sample separation and quantification were performed by gas chromatography with an electron capture detector. The instrument detection limit was 0.007 μg/mL, and the practical quantification limit was 0.003 μg/g (w/w) based on a 25 g sample. Recoveries for a series of fortified plant tissues ranged from 69 to 103%. The study demonstrated selective and sensitive recovery of dimethenamid-P from the RAC tested.
Authentication of Valeriana procera Kunth and Comparative Account of Five Valeriana Species
Authors: Joshi Vaishali C , Navarrete Andres , Khan Ikhlas A
Published: February 2020

Valeriana procera Kunth (Mexican Valerian) is a commercially important species, sometimes used as a substitute for Valeriana officinalis L., an important sedative in herbal medicine. A detailed macroscopic and microscopic account was provided for V. procera Kunth and a comparison was made between the wild and cultivated samples of V. procera Kunth. Macroand microscopic comparative analyses were performed to differentiate V. procera Kunth from V. officinalis L. and other commercially important Valerian species such as V. jatamansi Jones, Valeriana edulis Nutt, and V. sitchensis Bong.
Stability Study of Simvastatin under Hydrolytic Conditions Assessed by Liquid Chromatography
Authors: Álvarez-Lueje Alejandro , Valenzuela Christian , Squella Juan Arturo , Núñez-Vergara Luis Joaquín
Published: February 2020

In this work, a liquid chromatography stability-indicating method was developed and applied to study the hydrolytic behavior of simvastatin in different pH values and temperatures. The selected chromatographic conditions were a C18 column; acetonitrile–28 mM phosphate buffer solution, pH 4 (65 + 35) as the mobile phase; 251°C column temperature; and flow rate 1 mL/min. The developed method exhibited an adequate repeatability and reproducibility (coefficient of variation 0.54 and 0.74%, respectively) and a recovery higher than 98%. Furthermore, the detection and quantification limits were 9.1 × 10−7 and 2.8 × 10−6 M, respectively. The degradation of simvastatin fitted to pseudo-first order kinetics. The degradation was pH dependent, being much higher at alkaline pH than at acid pH. Activation energy, kinetic rate constants (k) at different temperatures, the half life (t1/2) and the time for 10% degradation to occur (t90) values are also reported.
Development and Validation of Routine Analysis Methods for the Determination of Essential, Nonessential, and Toxic Minor and Trace Elements in Cereal and Cereal Flour Samples by Inductively Coupled Plasma–Atomic Emission Spectrometry
Authors: Momen Awad A , Zachariadis George A , Anthemidis Aristidis N , Stratis John A
Published: February 2020

Various digestion procedures were carefully investigated and accurately evaluated with respect to their effect on the analysis of cereals and cereal flours. Multielement methods were selected and well developed for the determination of essential (Cr, Cu, Fe, Mg, Mn, and Zn), nonessential (Ag, Al, Ba, Bi, In, and Ga), and toxic (Cd and Pb) minor and trace elements by inductively coupled plasma–atomic emission spectrometry. Only Ag could be determined, either with aqueous standard or standard addition calibration methods, while the standard addition methods were more accurate for the determination of other elements. The recoveries were mostly within the range of 84.1–113% for the expected values of all analytes with respect to certified reference material NIST SRM 1586a (rice flour). The results proved that, for cereals and cereal flours, the use of H2O2 for wet digestion and HNO3 for dry ashing were not necessary. Linear regression analysis and Student's paired t-test were applied to evaluate the significant differences between different procedures and type of samples.
Youden Analysis of Karl Fischer Titration Data from an Interlaboratory Study Determining Water in Animal Feed, Grain, and Forage
Authors: Jones Frank E
Published: February 2020

Data from a recent interlaboratory study of the determination of water (moisture) in animal feed, grain, and forage (plant tissue) by Karl Fischer titration were re-analyzed using Youden plots. The purpose was to show the unique ability these plots possess of separating random and systematic errors visually while providing numerical estimates of the precision and the systematic error of the method. Furthermore, the usefulness of the technique is underscored because AOAC INTERNATIONAL allows the use of matched pairs in collaborative studies to obtain estimates of repeatability and reproducibility.
Comparison of the Compact Dry CF with the Most Probable Number Method (AOAC Official Method 966.24) for Enumeration of Coliform Bacteria in Raw Meats: Performance-Tested MethodSM 110401
Authors: Kodaka Hidemasa , Teramura Hajime , Nirazuka Tadanobu , Mizuochi Shingo , Goins David , Odumeru Joseph , Kokubo Yataro
Published: February 2020

Compact Dry CF is a ready-to-use test method for the enumeration of coliform bacteria in food. The plates are presterilized and contain culture medium and a cold water-soluble gelling agent. The medium should be rehydrated with 1 mL diluted sample inoculated into the center of the self-diffusible medium, allowing the solution to diffuse by capillary action. The plate can be incubated at 35C for 2024 h and the colonies counted without any further working steps. The Compact Dry CF medium plates were validated with 5 different raw meats. The performance tests were conducted at 35C. In all studies performed, no apparent differences were observed between the Compact Dry CF method and the AOAC Official Method 966.24 results. For the accuracy claim (n = 75), a correlation factor of r2 = 0.91 (coliform) could be assigned, as stated in the application for Performance-Tested MethodSM. No significant variations in coliform bacterial counts were observed with different production lots or plates of diverse storage age by the quality consistency and storage robustness studies.