bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Determination of Moisture and Fat in Meats by Microwave and Nuclear Magnetic Resonance Analysis
Authors: Keeton Jimmy T , Hafley Brian S , Eddy Sarah M , Moser Cindy R , McManus Bobbie J , Leffler Timothy P
Published: February 2020

A peer-verified method is presented for the determination of percent moisture and fat in meat products by microwave drying and nuclear magnetic resonance (NMR) analysis. The method involves determining the moisture content of meat samples by microwave drying and using the dried sample to determine the fat content by NMR analysis. Both the submitting and peer laboratories analyzed 5 meat products by using the CEM SMART system (moisture) and the SMART Trac (fat). The samples, which represented a range of products that meat processors deal with daily in plant operations, included the following: 1) fresh ground beef, high-fat; 2) deboned chicken with skin; 3) fresh pork, low-fat; 4) all-beef hot dogs; and 5) National Institute of Standards and Technology Standard Reference Material. The results were compared with moisture and fat values derived from AOAC-approved methods, 950.46 (Forced Air Oven Drying) and 960.39 (Soxhlet Ether Extraction).
Optimized Simultaneous Determination of Several Elements in Human Intestinal Caco-2 TC7 Cells by Inductively Coupled Plasma-Mass Spectrometry after Closed Vessel Microwave Digestion
Authors: Noël Laurent , Guérin Thierry , Frémy Jean-Marc , Huet Hélène , Kolf-Clauw Martine
Published: February 2020

A rapid procedure, based on closed vessels microwave digestion and inductively coupled plasma-mass spectrometry (ICP-MS), was evaluated to ascertain the effect of chronic exposure to cadmium on intracellular accumulation of minor and essential trace elements in cultured epithelial cells (Caco-2 TC7). For all measurements, the method of external calibration was used and 3 elements (Be, Sc, In) were selected as internal standards. Optimization procedures are discussed and results are presented for the total determination of 9 key analytes (Na, Mg, Ca, Cr, Mn, Cu, Zn, Mo, and Cd) in certified reference materials (CRMs) and 20 samples of Caco-2 TC7 cells long-term exposed to Cd. The performance characteristics of the analytical system were evaluated by calibration and linearity, limits of detection and quantitation, accuracy with spiking, trueness and repeatability with available CRMs. As a complement to the ICP-MS determinations, both available CRMs and cell samples were analyzed either by electro thermal-or flame atomic absorption spectrometry. The results were in good agreement with the ICP-MS results.
Plasma Spectrometry for Elemental Speciation and Characterization in Beverages
Authors: Meija Juris , Mounicou Sandra , Caruso Joseph A
Published: February 2020

A review is presented on recent applications of plasma spectrometric techniques for speciation analysis in beverages. The 3 most common ways of characterizing beverages in addition to elemental speciation are also discussed: total element analysis, isotope ratio, and statistical characterization. To date, most of the elemental characterization in beverages with plasma techniques has been performed in the statistical evaluation of wines and in teas. However, despite the increasing interest in elemental speciation, most of the plasma-based techniques in beverage studies are used for total metal detection and the full capabilities of inductively coupled plasma techniques have yet to be realized.
Fractionation and Redox Speciation of Antimony in Agricultural Soils by Hydride Generation–Atomic Fluorescence Spectrometry and Stability of Sb(III) and Sb(V) During Extraction with Different Extractant Solutions
Authors: Fuentes Edwar , Pinochet Hugo , Potin-Gautier Martine , Gregori Ida De
Published: February 2020

This stability of Sb(III) and Sb(V) species was studied during single extraction from soils by water. EDTA, diluted H2SO4 and H3PO4, and oxalic acid/oxalate solutions, with and without ascorbic acid, were used as stabilizing reagent of both Sb species. Antimony redox speciation in soil extracts was performed by selective hydride generation–atomic fluorescence spectrometry. Simulated extraction procedures (without soil) showed that, except in oxalate medium, Sb(III) was oxidized to Sb(V), and this reaction was avoided with ascorbic acid. Recovery studies from a spiked agricultural soil showed that no oxidation but sorption of Sb(III) occurred during the extraction process in water and H2 SO4 medium, and quantitative oxidation in EDTA and oxalate medium. With ascorbic acid, this oxidation was totally avoided in EDTA and partially avoided in oxalate solution. A new sequential extraction procedure was proposed and applied to the fractionation and redox speciation of antimony in agricultural soils, using EDTA + ascorbic acid, pH 7 (available under complexing and moderately reducible conditions); oxalic acid /oxalate + ascorbic acid (extractable in reducible conditions) and HNO3 + HCl + HF (residual fraction). The proposed extraction scheme can provide information about the availability and mobility of antimony redox species in agricultural soils.
Kinetic Spectrophotometric Determination of Josamycin in Formulations and Spiked Human Plasma Using 3-Methylbenzothiazolin-2-one Hydrazone/Fe+3 System
Authors: Al-Majed Abdulrahman A , Belal Fathalla , Khalil Nasr Y , Ibrahim Kamal E E
Published: February 2020

A simple kinetic spectrophotometric method was developed for the determination of josamycin in its dosage forms and spiked human plasma. The method is based on reaction of the drug with 3-methylbenzothiazolin-2-one hydrazone/ferric chloride system for a fixed time of 20 min at 70°C and measuring the produced color at 665 nm. The absorbance-concentration plot is rectilinear over the range of 5.0–30.0 μg/mL with detection limit of 1.0 μg/mL (1.2 × 10−6M). The determination of josamycin by the fixed concentration and the rate-constant methods is also feasible with the calibration equations obtained, but the fixed-time method proved to be more applicable. The procedure was successfully applied to commercial tablets. The results obtained were favorably compared with those given by reference methods. The method was further extended to the in vitro determination of josamycin in spiked human plasma. The recovery (n = 8) was 100.76 ± 3.43%. The stoichiometry of the reaction between the drug and the reagent was studied by adopting the limiting logarithmic method, and a proposal of the reaction pathway was presented.
Preparation of Peanut Butter Suspension for Determination of Peanuts Using Enzyme-Linked Immunoassay Kits
Authors: Trucksess Mary W , Brewer Vickery A , Williams Kristina M , Westphal Carmen D , Heeres James T
Published: February 2020

Peanuts are one of the 8 most common allergenic foods and a large proportion of peanut-allergic individuals have severe reactions, some to minimal exposure. Specific protein constituents in the peanuts are the cause of the allergic reactions in sensitized individuals who ingest the peanuts. To avoid accidental ingestion of peanut-contaminated food, methods of analysis for the determination of the allergenic proteins in foods are important tools. Such methods could help identify foods inadvertently contaminated with peanuts, thereby reducing the incidence of allergic reactions to peanuts. Commercial immunoassay kits are available but need study for method performance, which requires reference materials for within- and between-laboratory validations. In this study, National Institute of Standards and Technology Standard Reference Material 2387 peanut butter was used. A polytron homogenizer was used to prepare a homogenous aqueous Peanut Butter suspension for the evaluation of method performance of some commercially available immunoassay kits such as Veratox for Peanut Allergen Test (Neogen Corp.), Ridascreen Peanut (R-Biopharm GmbH), and Bio-Kit Peanut Protein Assay Kit (Tepnel). Each gram of the aqueous peanut butter suspension contained 20 mg carboxymethylcellulose sodium salt, 643 μg peanut, 0.5 mg thimerosal, and 2.5 mg bovine serum albumin. The suspension was homogenous, stable, reproducible, and applicable for adding to ice cream, cookies, breakfast cereals, and chocolate for recovery studies at spike levels ranging from 12 to 90 μg/g.
Harmonization of Methods for Analysis of Cholesterol Oxides in Foods—The First Portion of a Long Road Toward Standardization: Interlaboratory Study
Authors: Appelqvist Lars-Åke ,   Collaborators:, Addis Paul , Björkhem Ingemar , Olivier Bosset Jacques , Fiorenza Caboni Maria , Dutta Paresh , Grandgirard Andre , Guardiola Fransesc , Hau Lung-Bin , Holm Nielsen Jacob , Hugget Antony , Sun Hwang Lucy , Kumpulainen Jorma , McCluskey Sinead , Ohshima Toshiaki , Przbylski Roman , Sevanian Alex , Yan Pearlly
Published: February 2020

A compilation of literature data on the content of cholesterol oxidation products (COP) in various food products and in blood demonstrates a large variation in content in products or tissues of very similar nature when analyzed in different laboratories according to a large number of methods. The lack of validated, internationally recognized methodology with published accuracy and precision has so far hindered such assessments. Hence an interlaboratory comparision of methodologies of COP analysis was undertaken on egg yolk powders (EYP), whole milk powders (WMP), skim milk powders (SMP), and lard (L). Each product type had one fresh sample (low) and one aged (high) in COP contents. A total of 17 sets of results on WMP, 15 on SMP and EYP, and 13 on L were compared. Overall results (mg/kg sample) varied extensively: Fresh EYP 0.72–265, aged EYP 2.51–361; fresh WMP 0.02–18.1, aged WMP 0.02–26.9; fresh SMP 0.02–6.51, aged SMP < 0.01–6.51; fresh L 0.18–97, aged L 4.15–452. Some results were questioned, viz., those from laboratories not indicating substantial differences between samples “low” and “high” in total COP. Others were excluded because of lack of verification of identity of gas chromato-graphic peaks by mass spectrometry. Then a more narrow range of core results (mg/kg sample) was observed: Fresh EYP 5.69–29.5 sample, aged EYP 11.8–79.0; fresh WMP 0.12–1.76, aged WMP 1.17–13.7; fresh SMP < 0.30–<1.21, aged SMP 0.30–2.26; fresh L 0.18–5.07, aged L 94.4–231. At a workshop discussing the results, numerous recommendations were made toward more reliable methodology for determination of COP in foods.
Improved Identification of Conjugated Linoleic Acid Isomers Using Silver-Ion HPLC Separations
Authors: Delmonte Pierluigi , Yurawecz Martin P , Mossoba Magdi M , Cruz-Hernandez Cristina , Kramer John K G
Published: February 2020

Silver-ion high-performance liquid chromatography (Ag+-HPLC) has been shown to be effective in the resolution of most of the isomers of conjugated octadecadienoic acids (18:2), also known as conjugated linoleic acid (CLA). The CLA isomers identified in natural fats from ruminants are a mixture of numerous positional and geometric isomers from 7,9- to 12,14–18:2. Ag+-HPLC separates both geometric (trans,trans < cis/trans < cis,cis) and positional CLA isomers using the mobile phase hexane/acetonitrile (99.9:0.1). The elution volumes for the CLA isomers were not only affected by the concentration of acetonitrile (in the prepared mobile phase) but also with successive runs during the day using a prepared mobile phase batch, due to the partial solubility of acetonitrile in hexane. However, this drift does not affect the relative resolution of the CLA isomers. The addition of diethyl ether to the mobile phase partly stabilizes the solvent mixture. In order to facilitate the interpretation of Ag-+HPLC chromatograms, the relative retention volumes (RRV) were calculated for each CLA isomer. Toluene was added to all the test portions and served as an estimator of dead volume, whereas the elution of the ubiquitous 9c,11t-CLA isomer was chosen as unity (1.00). Expressing the elution of all the CLA isomers as their RRV greatly helped to standardize each CLA isomer, resulting in relatively small coefficients of variation (% CV) for the trans,trans (<1.5%) and cis/trans (<0.5%) CLA isomers. The identification of the CLA isomers was further facilitated by synthesis of authentic CLA isomers. All the geometric CLA fatty acid methyl esters (FAME) from positions 6,8- to 13,15-CLA were commercially available or synthesized by a combination of partial hydrazine reduction of known polyunsaturated fatty acids followed by alkali isomerization, isolation of products, and further iodine-catalyzed geometric isomerization. Based on expressing the elution volume as RRV and the availability of the synthetic CLA isomers, a unique reversal of the elution order of the c/t CLA isomers was found. It is also proposed that the retention times of CLA isomers by gas chromatography (GC) should be expressed as their relative retention times (RRT) relative to methyl γ-linoleneate. The availability of CLA reference materials and the application of RRV and RRT to Ag+-HPLC and GC separations, respectively, will greatly improve in the identifications of CLA isomers.
Colorimetric Assay of Propranolol Tablets by Derivatization: Novel Application of Diazotized 4-Amino-3,5-Dinitrobenzoic Acid (ADBA)
Authors: Idowu Olakunle S , Adegoke Olajire A , Olaniyi Ajibola A
Published: February 2020

A novel colorimetric assay of propranolol tablets has been developed. The assay is based on chemical derivatization (aromatic ring derivatization technique) using diazotized 4-amino-3,5-dinitrobenzoic acid (ADBA) as the chromogenic derivatizing reagent and resultant formation of azo dyes. Optimization studies established an optimal reaction time of 5 min at 30°C after mixing on a Vortex mixer the drug/reagent mixture for 10 s. A new absorption maximum (λmax) was found at 470 nm, which was selected as the analytical wavelength. The assays were linear over 1–8 μg/mL propranolol, and the reaction occurred by a 1:1 reagent/drug stoichiometric ratio. The developed method has a low limit of detection of 0.76 μg/mL and is reproducible. It has been applied successfully to the assay of propranolol tablets and is of equivalent accuracy (p > 0.05) with the official (British Pharmacopoeia) ultraviolet spectrophotometric method. The new method has the main advantage of using more affordable instrumentation and could be applied to the in-process quality control of propranolol tablets.
Rapid Fluorescence Screening Assay for Tetracyclines in Chicken Muscle
Authors: Schneider Marilyn J , Lehotay Steven J
Published: February 2020

A simple, rapid fluorescence assay was developed for screening tetracyclines in chicken muscle at the U.S. tolerance level (2 mg/kg). The method requires only a homogenization of the tissue in acetonitrile–ammonium hydroxide, centrifugation, addition of Mg+2, and another centrifugation before fluorescence of the supernatant is measured at 505 nm (excitation at 385 nm). Comparison of the fluorescence of control chicken muscle extracts with extracts from muscle fortified with either 2 mg/kg tetracycline, oxytetracycline, or chlortetracycline showed no overlap. A threshold level set at the average fluorescence for a series of fortified 2 mg/kg samples minus 3σ minimized false-negative responses to provide a successful screening method. The method was tested with blinded samples as controls or samples fortified with tetracycline, oxytetracycline, or chlortetracycline in order to demonstrate its utility. This approach can provide an alternative to microbial screening assays.
Determination of the 13C/12C Ratio of Ethanol Derived from Fruit Juices and Maple Syrup by Isotope Ratio Mass Spectrometry: Collaborative Study
Authors: Jamin Eric , Martin Frédérique , Martin Gilles G ,   Collaborators:, Blanch-Cortés A-I , Christoph N , Ciambotti A , Giraudon S , Guérin R , Guillou C , Kelly; S , Lamoureux C , Mazac J , Naulet N , Pavanello F , Rétif M , Rossmann A , Versini G
Published: February 2020

A collaborative study of the carbon-13 isotope ratio mass spectrometry (13C-IRMS) method based on fermentation ethanol for detecting some sugar additions in fruit juices and maple syrup is reported. This method is complementary to the site-specific natural isotope fractionation by nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in the same products (AOAC Official Methods 995.17 and 2000.19), and uses the same initial steps to recover pure ethanol. The fruit juices or maple syrups are completely fermented with yeast, and the alcohol is distilled with a quantitative yield (>96%). The carbon-13 deviation (δ13C) of ethanol is then determined by IRMS. This parameter becomes less negative when exogenous sugar derived from plants exhibiting a C4 metabolism (e.g., corn or cane) is added to a juice obtained from plants exhibiting a C3 metabolism (most common fruits except pineapple) or to maple syrup. Conversely, the δ13C of ethanol becomes more negative when exogenous sugar derived from C3 plants (e.g., beet, wheat, rice) is added to pineapple products. Twelve laboratories analyzed 2 materials (orange juice and pure cane sugar) in blind duplicate and 4 sugar-adulterated materials (orange juice, maple syrup, pineapple juice, and apple juice) as Youden pairs. The precision of that method for measuring δ13C was similar to that of other methods applied to wine ethanol or extracted sugars in juices. The within-laboratory (sr) values ranged from 0.06 to 0.16‰ (r = 0.17 to 0.46‰), and the among-laboratories (sR) values ranged from 0.17 to 0.26‰ (R = 0.49 to 0.73‰). The Study Directors recommend that the method be adopted as First Action by AOAC INTERNATIONAL.
Estimation of the Measurement Uncertainty of the High-Performance Anion-Exchange Chromatographic Determination of Carbohydrates in Soluble (Instant) Coffee
Authors: Stöber Paul , Giller Véronique , Spack Lionel , Prodolliet Jacques
Published: February 2020

The measurement uncertainty of the determination of free and total carbohydrates in soluble (instant) coffee using high-performance anion exchange chromatography with pulsed amperometric detection according to AOAC Method 995.13 and ISO standard 11292 was calculated. This method is important with regard to monitoring several carbohydrate concentrations and is used to assess the authenticity of soluble coffee. We followed the recommendations of the ISO, Eurachem, and Valid Analytical Measurement (VAM) guides: individual uncertainty contributions u(x) were identified, quantified, and expressed as relative standard deviations related to each specific source u(x)/x or RSD(x). Eventually, they were combined to yield the standard uncertainty and the relative standard uncertainty of a given carbohydrate concentration, c, that is respectively u(c) and u(c)/c. As a result of our study, we could demonstrate that the overall repeatability of the carbohydrate determination in duplicate, RSD(r); the repeatability of the integration of the peak area of the carbohydrate standards, RSD(rarea(ST)); and the uncertainty of the linear calibration model used in our laboratory, RSD (linST), are the most significant contributions to the total uncertainty. The u(c)/c values thus determined differ for each carbohydrate and depend on their concentrations. The least standard uncertainties that can be achieved are about 2.5%. The question of trueness in the total carbohydrate assay (determination of monosaccharides obtained upon hydrolysis of coffee oligo- and polysaccharides) was addressed. For this purpose, we analyzed the data of 2 different collaborative trials in which our laboratory took part.
A Novel Method for the Determination of Synthetic Colors in Ice Cream Samples
Authors: Tripathi Meenakshi , Khanna Subhash K , Das Mukul
Published: February 2020

A simple method has been developed for the extraction, separation, and determination of synthetic colors in ice cream samples. The process involves the breakdown of emulsion by neutral detergents (Triton X-100 and Tween 20) followed by extraction with petroleum ether for removal of fat. The aqueous colored solution obtained is treated with 5% acetic acid, and the uptake of color is carried out by a wool-dyeing technique. The color is eluted from the wool with 5% ammonia solution, the solution is evaporated to dryness, and the residue is dissolved in 60% ethanol for paper chromatography using trisodium citrate–ammonia–water (2 + 5 + 95, w/v/v) as the mobile phase. The colored spots from the paper chromatogram are cut and eluted with 60% ethanol, and the absorbance is measured at the respective λ maximum corresponding to the Rf value of the appropriate standard. The recoveries of 6 colors, including sunset yellow FCF (SSYFCF), tartrazine, carmoisine, ponceau 4R, brilliant blue FCF (BBFCF), and fast green FCF from spiked samples with either detergent were found to be >90%. However, recoveries of erythrosine were 21 and 65% with Triton X-100 and Tween 20, respectively. Indigo carmine could not be recovered at all because of its fugitive property in 5% ammonia solution, which is used to strip the color from the wool. The sensitivity of the method with the use of Tween 20 is 1 ppm (1 μg/g) for the colors in spiked ice cream samples. With this method, we analyzed samples of 20 branded colored ice cream. The results showed the presence of tartrazine (8.4–43.3 ppm), SSYFCF (23.5–117.6 ppm), carmoisine (traces–53.2 ppm), erythrosine (3.5 ppm), and BBFCF (4.1 ppm) in the ice cream samples. Apart from 2 samples of tuttifruity, all of the ice cream samples showed the presence of permitted synthetic colors below the permissible level of 100 ppm established by the Prevention of Food Adulteration Act of India.
Physiological Functions of Resistant Proteins: Proteins and Peptides Regulating Large Bowel Fermentation of Indigestible Polysaccharide
Authors: Morita Tatsuya , Kasaoka Seiichi , Kiriyama Shuhachi
Published: February 2020

Animal studies have shown conclusively that feeding of resistant starch (RS) increases production of large bowel total short-chain fatty acids (SCFAs). However, fermentation products of RS may be affected considerably by other dietary ingredients. In rats fed a 20% high-amylose cornstarch (HAS) with casein as the sole protein source, greater cecal SCFAs production was observed compared with that in rats fed a regular cornstarch diet. However, with this diet, the cecal succinate production was also very high. In contrast, when rice or potato protein with lower digestibility was used in place of casein, cecal succinate production decreased with a concomitant increase in butyrate. These observations suggest that nondigested protein, namely resistant protein, might play a role in correcting an imbalance in the ratio of carbohydrate and nitrogen as fermentative substrates for cecal bacteria and in promoting butyrate production. Epidemiological and biochemical data indicate a possible linkage between the fermentation products of starch (butyrate in particular) and the prevention of colorectal cancer as well as ulcerative colits. Accordingly, a fermentation strategy of RS favoring SCFA production should be established to elucidate the potentially beneficial effects of SCFAs on large bowel physiology.
A Simple and Rapid Spectrophotometric Method for Determination of Thiophanate-Methyl in Commercial Formulations and Its Residues in Foodstuffs
Authors: Verma Balbir C , Sood Sumita , Chauhan Chetan , Sharma Devender K
Published: February 2020

A new, simple, rapid, and sensitive spectrophotometric method for the determination of thiophanate-methyl, based on its reaction with cobalt(II) in the presence of triethylamine, has been developed. The yellowish green color that develops instantaneously on mixing the fungicide with the reagents in dimethylformamide is stable for at least 2 h and has maximum absorbance at 360 nm. The method has been successfully applied to the determination of thiophanate-methyl in its commercial formulations and residues on grains and apples. A photometric titration procedure for formulation analysis of the fungicide has also been developed.
Toward an International Standard for PCR-Based Detection of Foodborne Escherichia coli O157: Validation of the PCR-Based Method in a Multicenter Interlaboratory Trial
Authors: Abdulmawjood Amir , Bülte Michael , Roth Stefanie , Schönenbrücher Hahn , Cook Nigel , D’Agostino Martin , Malorny Burkhard , Jordan Kieran , Pelkonen Sinikka , Hoorfar Jeffrey
Published: February 2020

The performance of a polymerase chain reaction (PCR) method for detection of Escherichia coli O157, previously validated on DNA extracted from pure cultures, was evaluated on spiked cattle swabs through an interlaboratory trial, including 12 participating laboratories from 11 European countries. Twelve cattle swab samples, spiked at 4 levels (0, 1–10, 10–100, and 100–1000 colony-forming units, in triplicate) with E. coli O157 were prepared centrally in the originating laboratory; the receiving laboratories performed pre-PCR treatment followed by PCR. The results were reported as positive when the correct amplicons were present after gel electrophoresis. The statistical analysis, performed on 10 sets of reported results, determined the diagnostic sensitivity to be 92.2%. The diagnostic specificity was 100%. The accordance (repeatability) was 90.0%, calculated from all positive inoculation levels. The concordance (reproducibility) was 85.0%, calculated from all positive inoculation levels. The concordance odds ratio (degree of interlaboratory variation calculated from all positive inoculation levels) was 1.58, indicating the robustness of the PCR method. Thus, the interlaboratory variation due to personnel, reagents, minor temperature or pH fluctuations and, not least, thermal cyclers, did not affect the performance of the method, which is currently being considered as part of an international PCR standard.
Model Proficiency Testing Scheme for Serological Diagnosis of Brucellosis: Interlaboratory Study
Authors: Nannini Donatella , Tittarelli Manuela , Ricci Lucilla , Conte Annamaria , Emidio Bernardo Di , Giovannini Armando , Caporale Vincenzo
Published: February 2020

A model interlaboratory testing scheme was developed by the Italian National Reference Laboratory for Brucellosis. This scheme was planned for both qualitative (Rose Bengal Plate Test; RBPT) and quantitative (Complement Fixation Test; CFT) serological tests and involved a total of 42 laboratories. In the preparation of this scheme, reference was made to general protocols and guidelines and to methods reported in the literature, which were applicable to analytical chemistry laboratories. Six field sera from naturally infected animals, one positive serum at a titer below the European Union (EU) positivity threshold, and 5 sera positive at titers between 20 and 851 International Units of Complement Fixation Test (IUCFT)/mL plus one negative serum were used to produce a panel of test sera. To evaluate laboratory performances in the quantitative test for each tested sample examined, z-scores based on robust summary statistics (the median and normalized interquartile range) were used. To evaluate overall laboratory performance, 2 types of combined z-scores were used: Rescaled Sum of Scores and Sum of Squared Scores. In the case of the qualitative test (RBPT), results were analyzed by a Bayesian approach. A Beta distribution, based on the result of each laboratory, was calculated and used to estimate the probability of each laboratory giving a correct result and its uncertainty.
Determination of Lipid Oxidation Level in Broiler Meat by Liquid Chromatography
Authors: Marcinčák Slavomír , Sokol Jozef , Bystrický Pavel , Popelka Peter , Turek Peter , Bhide Mangesh , Máté Dionýz
Published: February 2020

An assay was conducted for the determination of malondialdehyde (MDA) levels in broiler meat. The method involves extraction of tissues with trichloroacetic acid (TCA) and reaction of the TCA extract with 2,4-dinitrophenylhydrazine (DNPH). After separation of the MDA-DNPH complex using a solid-phase extraction C18 column, samples were eluted with 1 mL acetonitrile. Aliquots of 20 μL acetonitrile were analyzed by liquid chromatography on reversed-phase C18 column (3 μm) with UV detection. The products were eluted isocratically with the mobile phase containing acetonitrile–water–acetic acid (39 + 61 + 0.2, v/v/v). The retention time was for MDA-DNPH was 6.5 min, and the detection limit was 3.5 μg/kg. Two extraction methods (cold and hot) were also used in the study. The results showed that hot extraction increased results about 55.8% and recovery from samples spiked with 116.6 μg/kg was lower (74.6%) in comparison with cold extraction (94.7%).
Application of Rapid, Electrochemical Flash Titration™ to Total Acidity and Alkalinity Determinations in Buffers, Foods, and Beverages
Authors: Wen Xiaowen , Herdan Janet , West Steven , Kinkade Denise , Vilissova Nadejda , Anderson Matthew
Published: February 2020

A new technique (Flash Titration™) for the determination of total acidity and total alkalinity was applied to food and beverage analysis. Requiring no liquid titrants, Flash Titration is a technique made possible through microfabrication of electrochemical components on a silicon chip. Acidic or basic titrant was generated electrochemically at a noble-metal electrode that intimately surrounded an ion-selective, field-effect transistor pH sensor. As acid or base was generated through electrolysis, sample alkalinity or acidity, respectively, was neutralized in the immediate vicinity of the electrode. Through diffusion, a zone comprising a gradient of partially to totally neutralized sample expanded from the generating electrode into the volume element sensed by the nearby pH sensor. An analysis of the pH signal versus time revealed an end point inflection at an elapsed time related to the total alkalinity or acidity of the sample. End point times were typically a few seconds. In this paper, Flash Titration was applied to the analysis of a variety of samples, including juices, soft drinks, wines, and food products. The differences between the results obtained by the Flash Titration method and a commonly used conventional volumetric method were less than 2% in most food products tested. Analysis costs were reduced both through time saving and reduction or elimination of hazardous liquid titrant disposal, by the use of the Flash Titration method.
Inductively Coupled Plasma Compared with Direct Current Arc Spectrometry for Analysis of Minor Elements in Aluminium Baths
Authors: Antolín Raquel , Borge Gregorio , Posada Tomás , Raposo Juan C , Seara Iker , Etxebarria Néstor
Published: February 2020

A validation study was carried out in order to evaluate the efficiency of inductively coupled plasma-optical emission spectrometry (ICP-OES) for the analysis of minor elements (manganese, chromium, copper, iron, and titanium) in aluminium alloys. Aluminium casting samples were obtained by adding compressed powder compacts of each alloying element and aluminium (minitablets) to aluminum baths in a laboratory crucible furnace. Digestion of solid samples was performed using concentrated HCl and H2O2 35% (v/v) previous to analysis by ICP-OES without any matrix separation. This solution-based method was validated considering direct current arc spectrometry as the reference method based on direct analysis without any pretreatment of the solid samples considered. Univariate statistical procedures were carried out, for which precision <3% and trueness of the analytical results were taken into account.
Multiresidue Method for N-Methyl Carbamates and Metabolite Pesticide Residues at the Parts-per-Billion Level in Selected Representative Commodities of Fruit and Vegetable Crop Groups
Authors: Podhorniak Lynda V , Schenck Frank J , Krynitsky Alexander , Griffith Francis , Griffith Francis
Published: February 2020

A reversed-phase liquid chromatographic method with both fluorescence and mass spectrometric detection is presented for the determination of 13 parent N-methyl carbamate pesticides and their metabolites, as well as piperonyl butoxide, for a total of 24 compounds in selected fruits and vegetables. The commodities chosen were of special concern to the U.S. Environmental Protection Agency (EPA) because they had the least amount of monitoring data for dietary exposure estimates used in risk assessment. The method is based on a judicious selection of procedures from U.S. Food and Drug Administration sources such as the Pesticide Analytical Manual (Volume I), and Laboratory Information Bulletins, plus additional material from the chemical literature combined in a manner to recover the N-methyl carbamates and their metabolites at the 1 μg/kg or 1 part-per-billion level. The method uses an acetone extraction, followed by an aminopropyl solid-phase extraction cleanup. Determination of residues is by RP-LC, in which the liquid chromatograph is interfaced with either a fluorescence or a mass spectrometric detector. The method is designed so that a set of 6 samples can be prepared in 1 working day for overnight instrumental analysis. Recovery data are presented from analyses of selected commodities in some of EPA's fruit and vegetable crop groupings. A table listing relative retention times is presented for the N-methyl carbamates and their metabolites.
Determination of the Residues of Eleven Organophosphorus Insecticides in Job's-tears by Gas Chromatography with a Nitrogen-Phosphorus Detector
Authors: Wu Jialun , Li Liqing
Published: February 2020

A simplified method for determining 11 organophosphorus insecticides (dichlorvos, methamidophos, acephate, diazinon, dimethoate, chlorpyrifos, malathion, parathion, quinalphos, methidathion, and ethion) in the Chinese herbal medicine Job's-tears is described. Standards were fortified into Job's-tears (5 g) at 4 levels. The organophosphorus insecticides were extracted with dichloromethane and cleaned up with a mixture of Celite 545–activated carbon (4 + 1). The extracts were analyzed by gas chromatography using a nitrogen-phosphorus detector. Analysis of fortified Job's-tears shows average recoveries ranged from 73.90–98.70%, 86.31–93.15%, 84.92–96.22%, and 83.29–104.23% at 0.05, 0.1, 0.5, and 1.0 mg/kg levels, respectively. The minimum detectable amount ranged from 1.0 × 10−10 to 5.0 × 10−10 g, and the limit of quantitation for the method was 0.05 mg/kg. The method is rapid, simple, sensitive, reproducible, and applicable to the determination of these 11 organophosphorus insecticides in Job's-tears.
Multiresidue Determination of Pesticides in Agricultural Products by Gas Chromatography/Mass Spectrometry with Large Volume Injection
Authors: Saito Yukio , Kodama Shuji , Kodama Shuji , Kodama Shuji , Kodama Shuji , Matsunaga Akinobu , Yamamoto Atsushi
Published: February 2020

A method is described for the rapid determination of pesticide residues in agricultural products. Pesticides were extracted from samples with acetonitrile. To remove pigments and fatty acids, an aliquot of the extract was cleaned up by a minicolumn that was packed both with graphitize carbon black and primary secondary amine. Analysis was performed by gas chromatography/ mass spectrometry with programmable temperature vaporizer-based large volume injection using a liner packed with phenylmethylsilicone chemically bonded silica. The method was evaluated for 114 pesticides by spiking into tomato, spinach, Japanese pear, grape, and brown rice at various concentrations of each pesticide (0.02–0.4 μg/g). The method, which gave good recovery (>60%) for 108 pesticides, is characterized by high cleanup efficiency and short cleanup time, and is useful as a rapid screening analysis.
Polymerase Chain Reaction Techniques for Food Allergen Detection
Authors: Poms Roland Ernest , Anklam Elke , Kuhn Matthias
Published: February 2020

Food allergies represent an important health problem in industrialized countries. Undeclared allergenic foods as contaminants in food products pose a major risk for sensitized persons. Reliable detection and quantification methods for food allergens are necessary to ensure compliance with food labeling and improve consumer protection. The methods currently used for the detection of potential allergens in foods are to target either the allergen itself or a marker that indicates the presence of the offending food. As markers for the presence of potentially allergenic foods or ingredients, specific proteins or DNA fragments are targeted. In routine food analysis, the enzyme-linked immunosorbent assay (ELISA) and the polymerase chain reaction (PCR) in the form of a real-time PCR or in combination with an ELISA have been used. The availability, the characteristics, and some future aspects ofDNA-based methods in the rapid and sensitive detection of potentially allergenic food constituents or contaminations are discussed in this review.
Potential Allergenicity of Novel Proteins in Murine Models
Authors: Westphal Carmen D , Raybourne Richard B
Published: February 2020

Bioengineered crops represent an important advancement for farmers who want to avoid losses caused by insect infestations or adverse environmental conditions. However, the use of modern biotechnology has raised questions regarding the safety of bioengineered foods because of the potential allergenicity of proteins expressed by the newly introduced genes. Standard approaches for safety assessment of these foods are still evolving. Animal models have been suggested as a tool that could help evaluate the potential allergenicity of such compounds. Several investigators are developing animal models to evaluate novel proteins, but none of these have yet been validated. This article reviews the published murine models, rat and mouse in particular, and the different methods used to evaluate parameters related to allergy. It also addresses the factors involved in the development of a model. Finally, it raises some questions that should be considered by the international community so that financial and intellectual efforts can be addressed in a unified manner.
Sensitization and Allergic Response and Intervention Therapy in Animal Models
Authors: Helm Ricki M , Burks A Wesley
Published: February 2020

A review is presented of 3 murine models and a swine neonatal model used to investigate immunotherapeutic options. In Model 1, mutation of linear IgE-binding epitopes of Ara h 1 for the preparation of a hypoallergenic Ara h 1 is discussed with respect to expression in transgenic tobacco plants and correct folding following expression in the pET16b construct. In Model 2, the mutations of Ara h 1 were assessed for use as an immunotherapeutic agent. Although some protective benefit was observed with the modified Ara h 1 protein, animals desensitized with heat-killed E. coli preparations showed increased protection to challenge. In Model 3, soybean homologs to peanut proteins were investigated to determine if soybean immunotherapy can potentially provide benefit to peanut-allergic subjects. Although some protection was provided, additional experimentation with respect to optimal doses for sensitization and challenge will need to be investigated. In Model 4, the neonatal swine model was used to profile different foods (low to moderate to high sensitizing) similar to food allergies in humans. Evidence suggests such feasiblity; however, threshold levels for sensitization and allergic responses will need additional study. In summary, murine and swine animal models are being used to address immunotherapeutic avenues and investigation into the mechanisms of food-allergic sensitization.
Evaluation of Extraction Buffers Using the Current Approach of Detecting Multiple Allergenic and Nonallergenic Proteins in Food
Authors: Westphal Carmen D , Pereira Marion R , Raybourne Richard B , Williams Kristina M
Published: February 2020

The detection of food allergens has been a challenge because of the increasing need to ensure the absence of undeclared allergens in foods. The current trend in the detection of some food allergens, like peanuts, is based on the detection of multiple allergenic and nonallergenic proteins, and this is the approach that kit manufacturers have adopted. Because commercial kits differ in their ability to detect allergens, regulatory agencies, the food industry, and kit manufacturers are working together to standardize the detection methods. Three kits for the detection of peanuts have been evaluated for performance by the AOAC Research Institute. For this evaluation, a peanut butter suspension was used as a reference material. Several kit components contribute to between-kit analytical variation, even when the same sample is used. One component of commercial kits, which may be contributing to this variability, is the sample extraction buffer. In this study, differences in extractability of 3 allergenic foods were evaluated by using 4 different extraction buffers. The conclusion is that optimum allergen extractability was buffer-dependent, and no single buffer is appropriate for use as a universal extraction solution for all allergenic foods. Therefore, a thorough evaluation of sample preparation buffers needs to be performed for every individual allergenic food. In light of the results obtained, the current approach used for detection of peanut allergens based on the detection of multiple allergenic and nonallergenic proteins is being analyzed.
Effects of Chemical, Physical, and Technological Processes on the Nature of Food Allergens
Authors: Poms Roland E , Anklam Elke
Published: February 2020

A review is presented of studies of different processing techniques and their effect on the allergenicity and antigenicity of certain allergenic foods. An overview of investigated technologies is givenwithregardtotheirimpactontheprotein structure and their potential application in the production of hypoallergenic foods. The use of physical processes (such as heating, high pressure, microparticulation, ultrafiltration, and irradiation), chemical processes (such as proteolysis, fermentation, and refining by extraction), and biotechnological approaches, as well as the effects of these processes on individual allergenic foods, are included. Additionally, the implications of food processing for food allergen analysis with respect to food safety assessment and industrial quality control are briefly discussed.
Determination of Six Kavalactones in Dietary Supplements and Selected Functional Foods Containing Piper methysticum by Isocratic Liquid Chromatography with Internal Standard
Authors: Hu Lihong , Jhoo Jin-Woo , Ang Catharina Y W , Dinovi Michael , Mattia Antonia
Published: February 2020

Kava (Piper methysticum) dietary products have been sold worldwide for treatment of nervous anxiety, tension, and restlessness. Recent reports showed potential association of kava usage and liver injuries. This study was conducted to develop simple and reliable methodologies for the extraction and determination of 6 major kavalactones: (+)-methysticin, (+)-dihydromethysticin, (+)-kavain, (+)-dihydrokavain, yangonin, and desmethoxyyangonin. Ultrasonic extraction techniques and isocratic reversed-phase liquid chromatography (LC) were optimized for different types of samples, including capsules containing kava root extract or root powder, raw root material, tea bags, and snack bar. A suitable internal standard, 5,7-dihydroxyflavone, was used for LC calibration. Kavalactones were completely separated in 30 min using a Luna C18-2 column at 60°C with an isocratic mobile phase consisting of 2-propanol–acetonitrile–water–acetic acid (16 + 16 + 68 + 0.1, v/v/v/v). Within-laboratory, intraday, and interday method variation (% relative standard deviation) for most samples extracted by methanol or methanol–water mixture were <5%. Lower levels of kavalactone contents and higher variations were observed for tea bags from water extraction or infusion as compared to methanol extraction. Labeling information of tea bags based on methanol extraction could be misleading to consumers. Analytical recoveries of snack bar fortified at 10 and 20 μg/g were >84% with RSD values <8%. Methods developed in this study offer a simple and reproducible means for analysis of kavalactones in various matrixes of dietary products.
Improved Extraction of Ginkgotoxin (4′-O-methylpyridoxine) from Ginkgo biloba Products
Authors: Lawrence Guillaume A , Scott Peter M
Published: February 2020

A simple extraction procedure was applied to the analysis of canned/packaged white nuts and Ginkgo biloba extracts. Extraction by shaking with water at room temperature was more convenient to use than a previously published Soxhlet procedure for analysis of packaged Ginkgo biloba seeds (white nuts) for ginkgotoxin; recoveries from spiked dried seeds by the simple extraction procedure averaged 76%. Determination was by liquid chromatography with UV or fluorescence detection. Recoveries of ginkgotoxin from a spiked and unspiked natural health product (powder from Ginkgo biloba capsules) were equivalent by both procedures; recovery from spiked powder by the simple extraction procedure was 81%. Application of this extraction procedure in the analysis of 6 samples of white nuts (vacuum packaged and canned products) showed that free ginkgotoxin was present in 5 samples at concentrations up to 25 μg/g dry weight. Total ginkgotoxin was determined after hydrolysis with β-glucosidase of sample extracts in which a peak corresponding to the 5′-O-glucoside was detected. Ginkgotoxin was determined in 10 Ginkgo biloba natural health products by the same method at levels up to 181 μg/g.
Liquid Chromatographic Determination of Cetirizine in Oral Formulations
Authors: Bajerski Lisiane , Cardoso Simone G , Diefenbach Isabel Fraçao , Malesuik Marcelo Donadel , Borgmann Silvia Helena Miollo
Published: February 2020

The development and validation of a reversed-phase liquid chromatographic (LC) method for the determination of cetirizine dihydrochloride in oral formulations are described. An isocratic LC analysis was performed on a reversed-phase C18 column (250 × 4.6 mm id, 5 μm particle size). The mobile phase was 1% orthophosphoric acid solution, pH 3.0–acetonitrile (60 + 40, v/v), pumped at a constant flow rate of 1.0 mL/min. Measurements were made at a wavelength of 232 nm. The calibration curves were linear over the range of 10–30 μg/mL (r2 = 0.9999). The relative standard deviation (RSD) values for intraday precision were 0.94 and 1.43% for tablets and compounded capsules, respectively. The RSD values for interday precision were 0.13 and 0.82% for tablets and compounded capsules, respectively. Recoveries ranged from 97.7 to 101.8% for tablets and from 98.4 to 102% for compounded capsules. No interferences from the excipients were observed. Because of its simplicity and accuracy, the method is suitable for routine quality-control analysis for cetirizine in tablets and compounded capsules.
Determination of Ceftriaxone in Cerebrospinal Fluid by Ion-Pair Liquid Chromatography
Authors: Glaría Marta de Diego , Moscciati Gloria Godoy , Ramos Ricardo Godoy
Published: February 2020

An ion-pair liquid chromatographic assay was developed and validated for the determination of ceftriaxone in cerebrospinal fluid. Chromatographic separation was achieved on a C18 column (125 × 4 mm, 5 μm) with detection at 270 nm, a 1 mL/min flow rate and a 50 μL loop. The mobile phase consisted of 300 mL acetonitrile, 50 mL 0.1M phosphate buffer (pH 7.4), 3.2 g tetrabutylammonium bromide as the ion-pairing agent, and dilution with distilled deionized water to 1 L. Cephradine was used as the internal standard. The assay was linear for ceftriaxone concentrations of 0.5–50 μg/mL. The coefficients of variation for precision were <4.61%. The accuracy ranged from 96.07 to 102.42%. The detection and quantitation limits were 0.019 and 0.065 μg/mL, respectively. This method was used to quantify ceftriaxone in the cerebrospinal fluid of children with meningitis. The results showed that the method described here is useful for the determination of ceftriaxone in cerebrospinal fluid.