bluuebunny/crossref_metadata_2025 huggingface dataset:
Interlaboratory Validation of the Mehlich 3 Method as a Universal Extractant for Plant Nutrients
Authors: Schroder Jackie L , Zhang Hailin , Richards Jaben R , Payton Mark E
Published: February 2020

The Mehlich 3 (M3) method is widely used to extract plant-available phosphorus from soil over a wide range of pH values. The method is also used by many laboratories to determine multiple plant-available nutrients simultaneously. However, except for P, this method has not been statistically validated within and among laboratories. The objective of this study was to determine the repeatability (within-laboratory performance) and reproducibility (among-laboratories performance) of the M3 method for several different nutrients by using a wide variety of soils. An in-house homogeneity test was conducted for 11 soils. Three replicates of each of the 11 soils were sent to 23 domestic and international laboratories for analyses primarily for K, Ca, Mg, Zn, Mn, Fe, and Cu. Samples were scooped, weighed, or both scooped and weighed for extraction. The various nutrients in the extracts were quantified by the participating laboratories by using inductively coupled plasmaatomic emission spectrometry. Ranges (in parentheses) of the repeatability relative standard deviation (RSDr) values for the scooped samples were K (3.886.14), Ca (2.1910.6), Mg (2.275.73), Zn (4.1142.7), Mn (3.158.53), Fe (2.327.74), and Cu (3.6511.2). For the weighed samples, the ranges (in parentheses) of the RSDr values were K (1.654.65), Ca (1.4316.9), Mg (1.379.83), Zn (2.6033.0), Mn (1.614.90), Fe (1.564.47), and Cu (2.9517.9). Ranges (in parentheses) of the reproducibility relative standard deviation (RSDR) values for the scooped samples were K (7.4420.0), Ca (7.1033.5), Mg (7.6326.4), Zn (11.648.7), Mn (10.519.7), Fe (12.422.0), and Cu (8.8645.3). Ranges (in parentheses) of the RSDR values for the weighed samples were K (3.4712.7), Ca (7.6134.6), Mg (7.5329.0), Zn (10.649.2), Mn (6.5420.7), Fe (11.021.5), and Cu (9.7343.0). The Horwitz ratios (HorRat) were also used to evaluate the repeatability, HorRatr, and the reproducibility, HorRatR. Overall, the M3 method appears to be both repeatable and reproducible across the two categories for K, Mg, Zn, Mn, and Cu, and the vast majority of the HorRat values for both repeatability and reproducibility were within the acceptable range. However, a large number of soils in both the weighed and scooped categories displayed unacceptable HorRat values for the reproducibility of Ca and Fe, indicating that the M3 is not suitable for the extraction and quantitation of Ca and Fe in soils. The results of this study indicate that the M3 method for the determination of K, Mg, Zn, Mn, and Cu in soils is both accurate and precise when standardized procedures are used. The method has been proven to be suitable for use as a reference method for testing soil materials for extractable P, K, Mg, Zn, Mn, and Cu. Further study may be needed to confirm the suitability of the M3 method for Ca and Fe.
Trans Fat Labeling and Levels in U.S. Foods: Assessment of Gas Chromatographic and Infrared Spectroscopic Techniques for Regulatory Compliance
Authors: Mossoba Magdi M , Moss Julie , Kramer John K G
Published: February 2020

Trans fatty acids are found in a variety of foods like dairy and meat products, but the major dietary sources are products that contain commercially hydrogenated fats. There has been a renewed need for accurate analytical methods for the quantitation of total Trans fat since mandatory requirements to declare the amount of Trans fat present in food products and dietary supplements were issued in many countries. Official capillary GC and IR methodologies are the two most common validated methods used to identify and quantify Trans fatty acids for regulatory compliance. The present article provides a comprehensive discussion of the GC and IR techniques, including the latest attenuated total reflection (ATR)-FTIR methodology called the negative second derivative ATR-FTIR procedure, which is currently being validated in an international collaborative study. The identification and quantitation of Trans fatty acid isomers by GC is reviewed and an alternative GC method is proposed using two temperature programs and combining their results; this proposed method deals more effectively with the resolution of large numbers of geometric and positional monoene, diene, and triene fatty acid isomers present in ruminant fats. In addition, the different methylation procedures that affect quantitative conversion to fatty acid methyl esters are reviewed. There is also a lack of commercial chromatographic standards for many Trans fatty acid isomers. This review points to potential sources of interferences in the FTIR determination that may lead to inaccurate results, particularly at low Trans levels. The presence of high levels of saturated fats may lead to interferences in the FTIR spectra observed for Trans triacylglycerols (TAGs). TAGs require no derivatization, but have to be melted prior to IR measurement. While GC is currently the method of choice, ATR-FTIR spectroscopy is a viable, rapid alternative, and a complementary method to GC for a more rapid determination of total Trans fats for food labeling purposes.
Review of Methods for Preparation and Gas Chromatographic Separation of trans and cis Reference Fatty Acids
Authors: Delmonte Pierluigi , Kia Ali-Reza Fardin , Hu Qing , Rader Jeanne I
Published: February 2020

In recent years, several countries have implemented new regulations regarding the limitation or labeling of the trans fatty acid (TFA) content of foods and dietary supplements. GC methods for fatty acid (FA) analysis have been updated by improving the separation of TFAs from other FAs, especially trans- and cis-18:1, and by focusing more attention on the FAs contained in fats and oils in lower amounts. FA analysis is affected by the limited availability of reference materials. Identifications are frequently made simply by comparison with separations reported in the literature. This report describes the preparation of mixtures containing fatty acid methyl esters (FAMEs) that are not available as reference materials. These mixtures can be used for FAME identifications. The prepared mixtures are analyzed under the experimental conditions of the American Oil Chemists' Society (AOCS) Official Method Ce 1h-05 and AOCS Recommended Practice Ce 1j-07.
Comparative Validation Study to Demonstrate the Equivalence of a Minor Modification to AOAC Method 996.09 Visual Immunoprecipitate (VIP®) for E. coli O157:H7 Method to the Reference Culture Method
Authors: Feldsine Philip T , Kerr David E , Shen George , Lienau Andrew H
Published: February 2020

The Visual Immunoprecipitate (VIP®) for the Detection of Escherichia coli O157:H7 in Foods, AOAC Official Method 996.09, has been modified to change the color of the test and control lines of the device. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. Three foods were analyzed. In total, there were valid results from 225 samples and controls. Results showed that the VIP Gold® for E. coli O157:H7 is equivalent to the reference culture methods for the detection of E. coli O157:H7.
Evaluation of BD BBL CHROMagar Staph aureus Medium Using AOAC and ISO Culture Methods
Authors: Ritter Vicki , Kircher Susan , Sturm Krista , Warns Patty , Dick Nancy
Published: February 2020

BBL CHROMagar Staph aureus (CSA) medium was evaluated internally and externally for the isolation and enumeration of Staphylococcus aureus in cooked roast beef, smoked salmon, and shell eggs. All food matrixes were processed according to the AOAC Official Method 975.55 and ISO 6888-1:1999. Bacterial counts of S. aureus were compared on CSA to the reference media, Baird-Parker, at low, medium, and high contamination levels. Colony counts were converted to log10 for statistical analysis. Based on the paired t-test and one-way analysis of variance, no statistical difference was noted with the CSA method compared to the AOAC Official Method for the recovery of S. aureus for all food types and contamination levels. Compared to the ISO reference method, no statistical difference was found with the CSA method for any food type or contamination level, with the exception of low-level smoked salmon. A statistical difference was seen in the internal testing with the low-level contaminated smoked salmon where CSA recovered more colonies. The external testing showed no statistical difference with smoked salmon at the low level. The correlation coefficients ranged from 92.6 to 99.4, demonstrating good correlation for overall levels in all food types and methods. The sensitivity and specificity of the CSA method using known isolates was 100. The results of this study demonstrate that CSA is an effective medium for the isolation, enumeration, and presumptive identification of S. aureus in cooked roast beef, smoked salmon, and shell eggs in 24 h using ISO and AOAC official methods.
Simplex and Duplex Polymerase Chain Reaction Analysis of Herculex® RW (59122) Maize Based on One Reference Molecule Including Separated Fragments of 5 Integration Site and Endogenous Gene
Authors: Li Xiang , Yang Litao , Zhang Jianzhong , Wang Shu , Shen Kailin , Pan Liangwen , Zhang Dabing
Published: February 2020

Reference molecules, as positive controls and calibrators, have been recently developed in genetically modified organism analysis as a potential substitute for reference materials derived from plant raw materials. In this study, a novel reference molecule p59122, including the revealed 5 integration sequence of maize Herculex® RW (59122), was constructed that was suitable for simplex and duplex event-specific qualitative and quantitative PCR detections. The LOD values were 10 copies both for simplex and duplex qualitative PCR when p59122 was used as the calibrator. These values were comparable to those of using genomic DNA samples with 0.01 and 0.05, approximately 5 and 25 hyploid genomic DNA copies, respectively. The absolute LOD and LOQ values were confirmed to be as low as 10 and 25 copies of p59122 DNA both in simplex and duplex quantitative systems. Furthermore, ideal quantification data with low bias, SD and RSD values were obtained from the practical samples analyses in simplex and duplex real-time PCR systems using the reference molecule p59122 as a calibrator. All these results suggested that the developed reference molecule p59122 and the qualitative and quantitative PCR detection methods are suitable for identification and quantification of GM maize 59122 and its derived products.
Determination of the Insecticide Imidacloprid in Fruit Juices Using Micellar High-Performance Liquid Chromatography
Authors: Chin-Chen Mei-Liang , Esteve-Romero Josep , Carda-Broch Samuel
Published: February 2020

A simple and reliable HPLC method was developed to determine imidacloprid, a chloronicotinyl insecticide that has a highly specific affinity to the nicotinic acetylcholine receptor of insects, above its permissible limit of consumption in fruit juices (orange, apple, and a mixture of pineapple and pear). Samples were injected directly into a Kromasil C18 column, without any pretreatment step, using the micellar mobile phase 0.10 M sodium dodecyl sulfate and 2.5 (v/v) propanol buffered at pH 7 and UV detection at 210 nm. Under these conditions, imidacloprid was eluted in <4 min with no interference by the endogenous compounds of the juice fruits. The analytical parameters linearity (r > 0.9998) and intraday and interday precision (RSD 0.1 2.8 and 0.077, respectively) were obtained in the method validation. LOD and LOQ were calculated to be 0.4 and 1.5 ng/mL, respectively. Recoveries were in the 98103 range. The simplicity of the method makes it a good candidate for application in routine analysis in the area of food control and quality evaluation.
13C Nuclear Magnetic Resonance Spectroscopic Detection of the Adulteration of Extra Virgin Olive Oils Extracted from Different Cultivars with Cold-Pressed Hazelnut Oil
Authors: Vlahov Giovanna
Published: February 2020

13C NMR spectroscopy was applied to detect the adulteration of olive oils with hazelnut oil. Considering that the linolenate chain and the squalene hydrocarbon were absent in hazelnut oil, unlike olive oil, a 13C NMR spectroscopy method was developed to measure in addition to the triglyceride normal chains (i.e., saturated, oleate, and linoleate chains), the resonances of the linolenate chain and of squalene hydrocarbon. Acyl chain and squalene resonances highly discriminated olive oil samples by cultivars. Nevertheless, the hazelnut oil percentage factor prevailed over the cultivar factor, thus correctly classifying 86 of the authentic and adulterated olive oil samples according to the hazelnut oil percentages. In particular, 85.7, 73.7, and 100.0 of the authentic olive oil samples, and the samples adulterated with 5 and 20 of hazelnut oil, were correctly classified through cross-validation.
Toward a Quality Guide to Facilitate the Transference of Analytical Methods from Research to Testing Laboratories: A Case Study
Authors: Bisetty Krisnha , Gumede Njabulo Joyfull , Escuder-Gilabert Laura , Sagrado Salvador
Published: February 2020

At present, there is no single viewpoint that defines QA strategies in analytical chemistry. On the other hand, there are no unique protocols defining a set of analytical tasks and decision criteria to be performed during the method development phase (e.g., by a single research laboratory) in order to facilitate the transference to the testing laboratories intending to adapt, validate, and routinely use this method. This study proposes general criteria, a priori valid for any developed method, recommended as a provisional quality guide containing the minimum internal tasks necessary to publish new analytical method results. As an application, the selection of some basic internal quality tasks and the corresponding accepted criteria are adapted to a concrete case study: indirect differential pulse polarographic determination of nitrate in water samples according to European Commission requisites. Extra tasks to be performed by testing laboratories are also outlined.
Optimization and Validation of an RP-HPLC Method for Analysis of Hydrocortisone Acetate and Lidocaine in Suppositories
Authors: Jancic-Stojanović Biljana , Malenović Andjelija , Marković Slavko , Ivanović Darko , Medenica Mirjana
Published: February 2020

An RP-HPLC method has been optimized and validated for the simultaneous determination of hydrocortisone acetate and of lidocaine in suppositories. For the method optimization, response surface methodology was applied, and the obtained model was tested using analysis of variance. The optimal separations were conducted on a Beckman-Coulter 150 4.6 mm, 5 µm particle-size column at 20C. The mobile phase was methanolwater (65 + 35, v/v), pH adjusted to 2.5 with 85% orthophosphoric acid, with a flow rate of 1.0 mL/min. UV detection was performed at 250 nm. Phenobarbital was used as an internal standard. The method was validated for selectivity, linearity, precision, and robustness.
Development and Validation of a Stability-Indicating Assay Method for Simultaneous Determination of Perindopril and Indapamide in Combined Dosage Form by Reversed-Phase High-Performance Liquid Chromatography
Authors: Jogia Hitesh , Khandelwal Umesh , Gandhi Tripti , Singh Sukhdev , Modi Darshana
Published: February 2020

An approach of forced degradation study was successfully applied for the development of a stability-indicating assay method for simultaneous determination of perindopril and indapamide in a formulation in the presence of its degradation products. The method showed adequate separation of perindopril and indapamide from their associated main impurities and degradation products. Separation was achieved on an XTerra RP18, 5 µm, 150 4.6 mm id column at 55°C by using the mobile phase NaH2PO4 buffer (pH 2.0; 0.005 M)acetonitrile (75 + 25, v/v ) at a flow rate of 1 mL/min and UV detection at 215 nm. Comprehensive stress testing of perindopril and indapamide was carried out according to the International Conference on Harmonization (ICH) guideline Q1A (R2). The specificity of the method was determined by assessing interference from the placebo and by stress testing of the drug (forced degradation). The drug was subjected to acid hydrolysis, base hydrolysis, oxidation, dry heat, and photolysis to apply stress conditions. There were no other coeluting, interfering peaks from excipients, impurities, or degradation products due to variable stress conditions, and the method was specific for determination of perindopril and indapamide in the presence of degradation products. The method was validated in terms of linearity, precision, accuracy, specificity, robustness, and solution stability. The linearity of the proposed method was investigated in the range of 2456 µg/mL (r2 = 0.9993) for perindopril and 7.517.5 µg/mL (r2 = 0.9992) for indapamide. Degradation products produced as a result of stress studies did not interfere with the detection of perindopril and indapamide, and the assay can thus be considered stability indicating.
Determination of Aflatoxins in Botanical Roots by a Modification of AOAC Official MethodSM 991.31: Single-Laboratory Validation
Authors: Weaver Carol M , Trucksess Mary W
Published: February 2020

AOAC Official MethodSM 991.31 for the determination of aflatoxins (AFs; sum of aflatoxins B1, B2, G1, and G2) in corn, raw peanuts, and peanut butter by using immunoaffinity column cleanup with LC has been modified and applied to the determination of AFs in botanical roots. The modifications were necessary to improve the performance of the method for matrixes beyond corn and peanuts. The extraction solvent was changed from a mixture of methanol and water to acetonitrile and water. The accuracy, repeatability, and reproducibility characteristics of this method were determined. Replicates of 10 test portions of each powdered root (black cohosh, echinacea, ginger, ginseng, kava kava, and valerian) at each spiking level (AFs at 0, 2, 4, 8, and 16 ng/g) were analyzed on 3 separate days. Test portions were extracted with acetonitrilewater (84 + 16, v/v), and the extracts were centrifuged, diluted with phosphate-buffered saline, filtered, and applied to an immunoaffinity column containing antibodies specific for AFs. After the column was washed with water, the toxins were eluted from the column with methanol and quantified by HPLC with fluorescence detection. All test materials except kava kava were found to contain AF at <0.1 ng/g. Kava kava was naturally contaminated with AFs at 0.5 ng/g. Average within-day and between-days recoveries of AFs from botanical roots ranged from 88 to 112 and from 86 to 118, respectively. Total RSD values for within-day and between-days repeatability ranged from 1.4 to 15.9. HorRat values were <0.4 for all of the matrixes examined. The modified AOAC Official Method 991.31 was found to be applicable to an analysis of the six botanical roots.
Determination of Total Dietary Fiber (CODEX Definition) by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study
Authors: McCleary Barry V , De Vries Jonathan W , Rader Jeanne I , Cohen Gerald , Prosky Leon , Mugford David C , Champ Martine , Okuma Kazuhiro ,   Collaborators:, Abercrombie L , Ames N , Bajoras T , Bhandari S , Burkhardt G , Camire M , Cohen G , Cui S , Dougherty M P , Erhardt S , Evans A , Grutters M , Hutton-Okpalaeke M , Illaens S , Kanaya K , Kohn A , Konings E , Lai G , Lee T , Marshak M , Neese U , Nishibata T , Santi A , Saylor D , Steegmans M , Themeier H , Thomsen A , Tervila-Wilo A , Walker R , Wang C
Published: February 2020

A method for the determination of total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC Official MethodsSM 985.29, 991.43, 2001.03, and 2002.02, the method quantitates high- and low-molecular-weight dietary fiber (HMWDF and LMWDF, respectively). In 2007, McCleary described a method of extended enzymatic digestion at 37C to simulate human intestinal digestion followed by gravimetric isolation and quantitation of HMWDF and the use of LC to quantitate low-molecular-weight soluble dietary fiber (LMWSDF). The method thus quantitates the complete range of dietary fiber components from resistant starch (by utilizing the digestion conditions of AOAC Method 2002.02) to digestion resistant oligosaccharides (by incorporating the deionization and LC procedures of AOAC Method 2001.03). The method was evaluated through an AOAC collaborative study. Eighteen laboratories participated with 16 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of traditional dietary fiber, resistant starch, and nondigestible oligosaccharides. The dietary fiber content of the eight test pairs ranged from 11.57 to 47.83. Digestion of samples under the conditions of AOAC Method 2002.02 followed by the isolation and gravimetric procedures of AOAC Methods 985.29 and 991.43 results in quantitation of HMWDF. The filtrate from the quantitation of HMWDF is concentrated, deionized, concentrated again, and analyzed by LC to determine the LMWSDF, i.e., all nondigestible oligosaccharides of degree of polymerization 3. TDF is calculated as the sum of HMWDF and LMWSDF. Repeatability standard deviations (sr) ranged from 0.41 to 1.43, and reproducibility standard deviations (sR) ranged from 1.18 to 5.44. These results are comparable to other official dietary fiber methods, and the method is recommended for adoption as Official First Action.
Enzyme-Linked Immunosorbent Assay Kit for the Determination of Soybean Protein in Processed Foods: Interlaboratory Evaluation
Authors: Sakai Shinobu , Adachi Reiko , Akiyama Hiroshi , Teshima Reiko , Morishita Naoki , Matsumoto Takashi , Urisu Atsuo ,   Collaborators:, Arakawa F , Endo Y , Haraguchi H , Hirose Y , Hirota M , Iidzuka T , Kojima K , Minegishi Y , Mishima T , Nishihara R , Seki T , Yamakawa H , Yano T , Yasuda K
Published: February 2020

The labeling of foods containing ingredients derived from soybean is recommended in Japan because of an increasing number of patients who are allergic to soybeans. To ensure proper labeling, a novel sandwich ELISA kit for the determination of soybean protein in processed foods (FASTKIT Ver. II, Soybean, Nippon Meat Packers, Inc.; soy kit) has been developed. Five types of incurred samples (model processed foods: rice gruel, sausage, sweet adzuki bean soup, sweet potato cake, and tomato sauce) containing 10 g soybean soluble protein/g food were prepared for use in interlaboratory evaluations of the soy kit. The soy kit displayed a sufficient RSDR value (interlaboratory precision: 9.313.4 RSDR) and a high level of recovery (97114) for all the incurred samples. The RSDr value for the incurred samples was mostly <4.8. The results of this interlaboratory evaluation suggest that the soy kit can be used as a precise and reliable tool for the determination of soybean proteins in processed foods.
A Practical and Nontarnishing Method for the Analysis of Trace Nickel in Hydrogenated Cottonseed Oil by Inductively Coupled Plasma/Mass Spectrometry with Pressurized PTFE Vessel Acid Digestion
Authors: Zhang Ni , Ding Zhiying , Li Hao , Wang Xin , Shao Xiaodong
Published: February 2020

A practical and nontarnishing method for the determination of trace nickel (Ni) in hydrogenated cottonseed oil by inductively coupled plasma/mass spectrometry (ICP/MS) was developed. In order to avoid tarnishing in the pretreatment of samples, the technology of pressurized PTFE vessel acid digestion was applied. The temperature and acid content in the digestion were optimized. The results showed that hydrogenated cottonseed oil could be digested completely by the proposed method. Compared with the U.S. Pharmacopeia 28 and British Pharmacopoeia 2003 methods, the developed method avoided the risk of using platinum and the tarnish from silica crucibles. In addition, the analytical cycle of the test solution was shortened by the use of ICP/MS instead of graphite furnace atomic absorption spectrophotometry.
An Expression System for the E. coli Fermentation of Recombinant Antibody Fab Fragments from Mice and Rabbits
Authors: Wiebe Julia C , Schüller Carolin , Reiche Jana A , Kramer Karl , Skerra Arne , Hock Bertold
Published: February 2020

A mutually compatible vector system was developed for the bench-top fermenter production of mouse and rabbit Fab fragments comprising pASK85-pro-K411B and pASK85Rab-pro-WR13. These vectors provide a mouse- and rabbit-specific cloning site, respectively, the tetA promoter/operator and the proBA operon that complements the Pro biosynthetic deficiency of the Escherichia coli strain JM83 and can serve as an additional selection marker. Fermentation at elevated cell density (OD600 = 2040) of the atrazine-specific mouse Fab fragment K411B using JM83 harboring pASK85-pro-K411B in a 2 L bench-top vessel resulted in a yield of 240 g/L OD600 affinity-purified protein (13.8 mg). In contrast, expression of leporid Fab fragments using pASK85Rab-pro-WR13 was unsuccessful due to the aggregation of rabbit light chains, which probably relates to a general problem of this specific class of immunoglobulins with their additional Cys residues. Coexpression of rabbit Fab fragments together with four periplasmic folding-helper proteins encoded on pTUM4 led to a significantly improved folding efficiency, resulting in a yield of 50 µg/L OD600 affinity-purified rabbit Fab fragment (3.3 mg) from the 2 L bench-top fermenter.
High-Performance Liquid Chromatographic Determination of Dihydroergocristine in a Pharmaceutical Formulation with Fluorescence Detection
Authors: Douša Michal , Dubovská Michaela
Published: February 2020

A rapid procedure based on a direct extraction and HPLC determination of dihydroergocristine in a pharmaceutical preparation with fluorescence detection has been developed and validated. The optimized chromatographic conditions included a Purospher RP18e column, 5 µm particle size, 250 4.0 mm, and 25 mM potassium dihydrogen phosphate buffer (pH 2.8)acetonitrile (60 + 40, v/v) mobile phase at a flow rate of 1 mL/min. The separation was carried out at 50C, and the injection volume was 5 L. Fluorescence detection was performed at an excitation and emission wavelength of 224 and 344 nm, respectively. The mobile phase parameters such as organic solvent composition, temperature, and pH were studied. The proposed method has the advantages of a very simple sample pretreatment and fast HPLC determination.
Multi-Analyst, Multi-Matrix Performance of the QuEChERS Approach for Pesticide Residues in Foods and Feeds Using HPLC/MS/MS Analysis with Different Calibration Techniques
Authors: Lehotay Steven J , Mastovska Katerina , Lightfield Alan R , Gates Robert A
Published: February 2020

Three different calibration approaches were applied in HPLC/MS/MS using electrospray ionization for the determination of 14 diverse pesticide residues at different levels in a variety of food matrixes. This study was conducted as part of a 4 day training course for 17 chemists to learn the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach to pesticide residue analysis in foods. The analysts were divided into four different teams for the analysis of 12 different matrixes (strawberries, plums, carrots, green peppers, milk, molasses, alfalfa oats, corn silage, dry pet food, soybean, almonds, and foliage). The acetate-buffered QuEChERS protocol gave excellent results in the spiked samples for all matrixes tested. The HPLC/MS/MS calibration techniques consisted of external standardization in solvent solutions, matrix-matching, and the echo-peak technique. Peak areas were normalized to an internal standard in all three approaches. Matrix effects were observed with the corn silage, carrot, and foliage extracts, but they were minimal or nonexistent in the other matrixes. Matrix-matching best compensated for matrix effects, but has logistical difficulties in real-world application and required extra sample preparation compared to the other approaches. The echo-peak technique reduced matrix effects but did not eliminate them.
Multiresidue Analysis of Synthetic Pyrethroid Pesticides in Grapes by Gas Chromatography with Programmed Temperature VaporizingLarge Volume Injection Coupled with Ion Trap Mass Spectrometry
Authors: Banerjee Kaushik , Savant Rahul H , Dasgupta Soma , Patil Sangram H , Oulkar Dasharath P , Adsule Pandurang G
Published: February 2020

A multiresidue analysis method was optimized and validated for simultaneous estimation of 21 synthetic pyrethroid pesticides and their isomers in grape matrix at 10 ng/g and higher levels. The method involves extraction of a 10 g sample with 10 mL ethyl acetate, cleanup by dispersive SPE with primary-secondary amine (25 mg) sorbent, and estimation by GC/MS/MS large volume injection (LVI) through a programmed temperature vaporizer (PTV) injector. The PTV-LVI parameters of the gas chromatograph and the multiple reaction monitoring (MRM) parameters of the ion trap mass spectrometer were optimized for each compound to achieve the highest S/N. For each analyte, the unique and most abundant MRM transition was used for quantification, along with the next most abundant MRM transition for confirmatory identification. The abundance ratio of the confirmatory to quantifier MRMs was used to ensure unambiguous residue monitoring in unknown samples within a 20 tolerance range at the 10 ng/g level. The analytes were separated on a TR-5MS capillary column within a 22 min run time. The method was selective and sensitive and ensured separation of the synthetic pyrethroids from high-boiling matrix components. The LOD and LOQ of the analytes ranged between 0.5 to 3.1 and 2.5 to 10 ng/g, respectively. Linearity of solvent and matrix-matched calibrations between 2.0 and 250 ng/g was established for each compound with r2 > 0.99. Recovery at 10, 25, and 50 ng/g levels of fortification in grapes ranged within 77115 with associated RSD values (n 8) up to 20.
Analytical Testing as a Tool for the Enforcement of Future Regulatory Thresholds for Food Allergens
Authors: Diaz-Amigo Carmen , Popping Bert
Published: February 2020

Food allergen labeling regulations have been implemented in several countries since 2006. Currently, experts are still discussing the introduction of thresholds or action levels, which should lead to the reduction of the widespread use of advisory statements (e.g., may contain) for the benefit of the allergic consumer. However, the establishment of threshold requires supporting analytical methodologies to enforce and comply with the regulations. This article discusses the possibilities and limitations of existing and emerging methodologies for the purpose of enabling compliance with and enforcement of allergen action levels.
Voltammetric Determination of Candesartan Cilexetil in Its Cu(II) Complex and Application to Pharmaceutical Formulations
Authors: Süslü İncilay , Özaltin Nuran , Altinöz Sacide
Published: February 2020

The aim of this study was to develop a new, simple, rapid, and sensitive square-wave adsorptive stripping voltammetric method for the determination of candesartan cilexetil in bulk form and pharmaceutical formulations by complex formation with Cu(II). The experimental and instrumental parameters affecting the response of the candesartan cilexetilCu(II) complex were investigated and optimized. This method was based on electrochemical reduction of candesartan cilexetilCu(II) complex at a hanging mercury drop electrode in phosphate buffer at pH 3.0 containing CuCl22H2O. A well-defined reduction peak was observed at 325 mV with 30 s accumulation time and 150 mV accumulation potential versus an Ag/AgCl reference electrode in the proposed method. The developed voltammetric method was validated in terms of linearity, sensitivity, precision, accuracy, recovery, selectivity, robustness, and ruggedness. The linear calibration range was 0.501.77 g/mL (r 0.9972). The LOD and LOQ of this method were 0.10 and 0.50 g/mL (n 7), respectively. The developed method was fully validated and applied to the pharmaceutical formulations, including candesartan cilexetil.
Validation Study of a Rapid ELISA for Detection of Deoxynivalenol in Wheat, Barley, Malted Barley, Corn, Oats, and Rice
Authors: Lupo Anthony , Roebuck Chris , Settimo Ken , Quain Anna , Kennedy Justina , Abouzied Mohamed
Published: February 2020

Neogen Corp. developed the Veratox DON test kit for the detection of deoxynivalenol (DON). The purpose of this study was to validate the method under the requirements of the AOAC Research Institute Performance Tested MethodsSM (PTM) program. There are two AOAC Official MethodsSM for DON detection: 986.17 and 986.18, the first of which is a TLC method and the second a GC method. A rapid method (PTM 000701) has also been performance tested by the AOAC Research Institute. One of the most widely used reference methods; however, is a GC method with electron capture detection that is referred to as the reference method in this paper. Although considered the reference method, the GC procedure is complicated and requires the investment of both expensive equipment and a highly skilled technician. A rapid (e.g., ELISA) test kit needs to be validated by the AOAC Research Institute. The Veratox 2/3 method is highly reproducible with average CV values <10, and is very accurate, showing >97 correlation to reference methods.
Assessing Analytical Variability of Measurement of Vitamin A in Corn-Soy Blend
Authors: Moore Wayne R , DeVries Jonathan , MacDonald John , Hare Lynne ,   Collaborators:, Carson J , Chaudhari P , DeVries J , Fontana J , Golz P , King J , MacDonald J , McCullough C , Noggle, S , Rasgorshek E , Schorn S , Skogerson L , Sullins D , Sullivan D , Sussman M , Weibel M
Published: February 2020

Two multilaboratory investigations were conducted by SUSTAIN to assess variability in the measurement of vitamin A, the marker used to verify levels of vitamin premix addition to enriched/fortified food aid products, including the widely distributed corn-soy blend (CSB). CSB specifications identify AACC Approved Method 86-06 or equivalent methods for vitamin A analysis, however there is no requirement to demonstrate equivalency. CSB samples with known and blinded levels of vitamin A and a reference standard were analyzed by 16 laboratories using their respective methods. Calculated coefficients of variation across all laboratories and methods for unknown samples and reference standard were 35 and 7.1, respectively, suggesting the largest source of variation is the vitamin extraction procedure. Laboratories generally overestimated low levels and underestimated high levels of vitamin A within the range of 6000 and 16 000 IU/lb. Only two laboratories demonstrated excellent internal precision (300 IU vitamin A/lb) and reported values within 95 confidence interval for all blinded samples. Results of this study have implications both for quality control in food aid products (due to the use of vitamin A as a marker) and for regulatory oversight of vitamin A content in commercial food products.
Determination of New Antidepressants in Pharmaceuticals by Thin-Layer Chromatography with Densitometry
Authors: Gondová Tatána , Petríková Iveta
Published: February 2020

A new and simple TLC-densitometry method has been developed for the simultaneous separation of the two noradrenergic and specific serotonergic antidepressants mirtazapine and mianserine and validated for their determination in commercially available tablets. The method used TLC plates precoated with silica gel 60F254 as the stationary phase, and the mobile phase consisted of hexaneisopropanol25 ammonia (70 + 25 + 5, v/v/v). Densitometric analysis was carried out in the absorbance mode at 280 nm. The method was validated in accordance with International Conference on Harmonization guidelines in terms of linearity, LOD, LOQ, precision, and accuracy. Calibration curves were linear (R2 > 0.9970) with respect to peak area in the concentration range of 5002500 and 5005000 ng/spot for mirtazapine and mianserine, respectively. The LODs were 20 and 35 ng/spot for mirtazapine and mianserine, respectively. The described method was successfully applied to the determination of mirtazapine and mianserine in their pharmaceutical formulations with recovery ranging from 99.83 to 101.20 of the labeled amount of the compounds. The proposed method can be used in routine QC of these drugs in pharmaceutical formulations.
A Liquid Chromatographic Method for Routine Analysis of 5-Mononucleotides in Pediatric Formulas
Authors: Gill Brendon D , Indyk Harvey E , Kumar Maureen C , Sievwright Nathan K , Manley-Harris Merilyn
Published: February 2020

An RP-HPLC method for the routine determination of supplemented 5-mononucleotides (uridine 5-monophosphate, inosine 5-monophosphate, adenosine 5-monophosphate, guanosine 5-monophosphate, and cytidine 5-monophosphate) in pediatric formulas and milk products is described. Following sample dissolution, potential interferences were removed by anion-exchange SPE. Chromatographic analyses were performed using a C18 stationary phase with gradient elution, UV detection, and quantitation by an internal standard technique. A single-laboratory validation was performed, with recoveries of 92101 and repeatability RSDs of 1.02.3. The method was optimized for the rapid, routine analysis of nucleotide-supplemented bovine milk-based infant and follow-on formulas.
Strain Typing and the Ecological Structure of Escherichia coli
Authors: Gordon David M
Published: February 2020

Escherichia coli is a commonly encountered commensal of the lower intestinal tract of humans and other mammals. Strains of the species are responsible for a significant amount of human morbidity and mortality each year. Consequently, numerous efforts attempt to track the movement of hospital-acquired infections, determine the source of a foodborne disease outbreak, or investigate the seasonal patterns of pathogen abundance in domestic animals. All of these endeavors require that the isolates acquired be differentiated from each other in some manner. This review briefly describes some of the commonly used molecular typing methods for E. coli. However, the main aim of the review is to describe the many levels, from the species to individual strains, at which E. coli can be considered, and to contend that a hierarchical approach to strain typing may often reveal patterns that are not obvious when a typing scheme is simply designed to differentiate isolates.
Sample Preparation Based on Matrix Solid-Phase Dispersion and Solid-Phase Extraction Cleanup for the Determination of Organochlorine Pesticides in Fish
Authors: Barriada-Pereira Mercedes , Gonzlez-Castro María José , Muniategui-Lorenzo Soledad , López-Maha Purificíon , Prada-Rodrguez Daro
Published: February 2020

A method based on matrix solid-phase dispersion (MSPD) and SPE to determine 20 organochlorine pesticides (OCPs) in fish tissues (muscle and liver) was optimized in terms of the sorbents and elution solvents used for the analysis. The following analytical components were evaluated: ENVI-Carb and ENVI-18 as dispersing agents, Florisil and Florisil over alumina as cleanup adsorbents, and hexane and hexaneethyl acetate (80 + 20) as elution solvents. The pesticides were determined by GC with electron capture detection. The best results were obtained with ENVI-Carb as a dispersing agent and an ENVI-Florisil co-column using 40 mL hexaneethyl acetate (80 + 20) as the elution solvent. Analytical recoveries ranged between 75 and 130 except for -HCH in fish liver, and the RSD values were <15 for most of the pesticides studied. Furthermore, sensitivity was sufficient (LOD of <300 g/kg) for all OCPs under study, in compliance with the tolerance limits of the U.S. Food and Drug Administration for OCPs in fish. The results were compared with those obtained by microwave-assisted extraction (MAE) and pressurized liquid extraction (PLE) in order to evaluate the performance of the MSPD procedure. The MPSD methodology was shown to be easy to use and fast, with a clear advantage relative to cost, because it does not need the expensive equipment required for MAE and PLE.
Development and Validation of a Stability-Indicating RP-HPLC Method for Determination of Atomoxetine Hydrochloride in Tablets
Authors: Patel Sejal K , Patel Natvarlal J
Published: February 2020

This paper describes the development of a stability-indicating RP-HPLC method for the determination of atomoxetine hydrochloride (ATX) in the presence of its degradation products generated from forced decomposition studies. The drug substance was subjected to stress conditions of acid, base, oxidation, wet heat, dry heat, and photodegradation. In stability tests, the drug was susceptible to acid, base, oxidation, and dry and wet heat degradation. It was found to be stable under the photolytic conditions tested. The drug was successfully separated from the degradation products formed under stress conditions on a Phenomenex C18 column (250 4.6 mm id, 5 m particle size) by using acetonitrilemethanol0.032 M ammonium acetate (55 + 05 + 40, v/v/v) as the mobile phase at 1.0 mL/min and 40C. Photodiode array detection at 275 nm was used for quantitation after RP-HPLC over the concentration range of 0.55 g/mL with a mean recovery of 100.8 0.4 for ATX. Statistical analysis demonstrated that the method is repeatable, specific, and accurate for the estimation of ATX. Because the method effectively separates the drug from its degradation products, it can be used as a stability-indicating method.
Determination of Rosuvastatin and Ezetimibe in a Combined Tablet Dosage Form Using High-Performance Column Liquid Chromatography and High-Performance Thin-Layer Chromatography
Authors: Varghese Susheel John , Ravi Thengungal Kochupappy
Published: February 2020

This paper describes validated HPLC and HPTLC methods for the simultaneous determination of rosuvastatin (ROS) and ezetimibe (EZE) in a combined tablet dosage form. The isocratic RP-HPLC analysis was performed on a Chromolith C18 column (100 6 mm id) using 0.1 (v/v) orthophosphoric acid solution (pH 3.5)acetonitrile (63 + 37, v/v) mobile phase at a flow rate of 1 mL/min at ambient temperature. Quantification was carried out using a photodiode array UV detector at 245 nm over the concentration range of 0.510 g/mL for ROS and EZE. The HPTLC separation was carried out on an aluminum-backed sheet of silica gel 60F254 layers using n-butyl acetatechloroformglacial acetic acid (1 + 8 + 1, v/v/v) mobile phase. Quantification was achieved with UV densitometry at 245 nm over a concentration range of 0.10.9 g/spot for ROS and EZE. The analytical methods were validated according to International Conference on Harmonization guidelines. Low RSD values indicated good precision. Both methods were successfully applied for the analysis of the drugs in laboratory-prepared mixtures and commercial tablets. No chromatographic interference from the tablet excipients was found. These methods are simple, precise, and sensitive, and are applicable for simultaneous determination of ROS and EZE in pure powder and tablets.
Determination of Walnut Protein in Processed Foods by Enzyme-Linked Immunosorbent Assay: Interlaboratory Study
Authors: Sakai Shinobu , Adachi Reiko , Akiyama Hiroshi , Teshima Reiko , Doi Hirotoshi , Shibata Haruki , Urisu Atsuo ,   Collaborators:, Arakawa F , Haraguchi H , Hirose Y , Hirota M , Iidzuka T , Ikeno K , Kojima K , Maeda S , Minegishi Y , Mishima T , Oguchi K , Seki T , Yamakawa H , Yano T , Yasuda K
Published: February 2020

Because food allergens from tree nuts, including walnuts, are a frequent cause of adverse food reactions for allergic patients, the labeling of foods containing ingredients derived from tree nuts is required in numerous countries. According to Japanese regulations, the labeling of food products containing walnuts is recommended. To ensure proper labeling, a novel sandwich ELISA kit for the determination of walnut protein in processed foods (Walnut Protein [2S-Albumin] Kit; Morinaga Institute of Biological Science, Inc.; walnut kit) has been developed. We prepared seven types of incurred samples (model processed foods: biscuits, bread, sponge cake, orange juice, jelly, chicken meatballs, and rice gruel) containing 10 g walnut soluble protein/g of food for use in interlaboratory evaluations of the walnut kit. The walnut kit displayed sufficient reproducibility relative standard deviations (interlaboratory precision: 5.89.9 RSDR) and a high level of recovery (81119) for all the incurred samples. All the repeatability relative standard deviation (RSDr) values for the incurred samples that were examined were less than 6.0. The results of this interlaboratory evaluation suggested that the walnut kit could be used as a precise and reliable tool for determination of walnut protein in processed foods.
Method Development and Validation for the Simultaneous Determination of Four Coumarins in Saussurea superba by Capillary Zone Electrophoresis
Authors: Chen Juan , Chen Li , Zhang Hong-Li , Shi Yan-Ping
Published: February 2020

A capillary zone electrophoretic method has been developed for the determination of four coumarinsskimmin, scopolin, scopoletin, and umbelliferonein Saussurea superba with UV detection at 254 nm. The capillary temperature was kept constant at 25°C. Effects of buffer pH, electrolyte concentration, organic modifier, and applied voltage on migration behavior were studied systematically. The optimum conditions for separation were achieved by using 30 mM borate buffer at pH 9.02 containing 15% (v/v) methanol as the electrolyte and 25 kV as the applied voltage. For all analytes a good linear regression relationship (r >0.999) was obtained between peak area and concentration over a relatively wide range. The method was validated for repeatability, precision, and accuracy. The validated method was successfully applied to the simultaneous determination of the four analytes in S. superba.
Validated HPTLC Method for Quantitative Determination of Gallic Acid in Stem Bark of Myrica esculenta Buch.-Ham. Ex D. Don, Myricaceae
Authors: Patel Kalpana G , Patel Vandana G , Patel Kirti V , Gandhi Tejal R
Published: February 2020

A simple, rapid, and precise HPTLC method was developed for quantitative estimation of gallic acid in stem bark of Myrica esculenta, family Myricaceae. Separation was performed on silica gel 60F254 HPTLC plates using tolueneethyl acetateformic acidmethanol (3 + 3 + 0.6 + 0.4, v/v/v/v) mobile phase for separation of the extracted components. The determination was carried out in the UV densitometric absorbance-reflection mode at 280 nm. The amount of gallic acid in free and combined form in the stem bark powder was found to be 0.276 and 0.541%, respectively, on a dry weight basis. The method was validated in terms of linearity, accuracy, precision, and specificity according to International Conference on Harmonization guidelines. Gallic acid response was found to be linear over a broad concentration range of 0.42.0 µg/band. LOD and LOQ were 0.103 and 0.312 µg/spot, respectively. The developed method is capable of quantifying amounts of gallic acid in stem bark powder of M. esculenta.