bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection and molecular characterization of porcine enterovirus G15 and teschovirus from India
Authors: Sawant Pradeep Mahadev , Atre Nitin , Kulkarni Abhijeet , Gopalkrishna Varanasi
Published: July 2020

Porcine enterovirus G (EV-G) and teschovirus (PTV) generally cause asymptomatic infections. Although both viruses have been reported from various countries, they are rarely detected from India. To detect these viruses in Western India, fecal samples (n = 26) of diarrheic piglets aged below three months from private pig farms near Pune (Maharashtra) were collected. The samples were screened by reverse transcription-polymerase chain reaction using conserved enterovirus specific primers from 5′ untranslated region. For genetic characterization of detected EV-G strain, nearly complete genome, and for PTV, partial VP1 gene were sequenced. EV-G strain showed the highest identity in a VP1 gene at nucleotide (78.61%) and amino acid (88.65%) level with EV-G15, prototype strain. However, its complete genome was homologous with the nucleotide (78.38% identity) and amino acid (91.24% identity) level to Ishi-Ka2 strain (LC316832), unassigned EV-G genotype detected from Japan. The nearly complete genome of EV-G15 consisted of 7398 nucleotides excluding the poly(A) tail and has an open reading frame that encodes a 2170 amino acid polyprotein. Genetic analysis of the partial VP1 gene of teschovirus identified porcine teschovirus 4 (PTV-4) and putative PTV-17 genotype. To the best of our knowledge, this is the first report on nearly full genome characterization of EV-G15, and detection of PTV-4 and putative PTV-17 genotypes from India. Further, detection and characterization of porcine enteroviruses are needed for a comprehensive understanding of their genetic diversity and their association with symptomatic infections from other geographical regions of India.
Computers that Create Galaxies and See Gravitational Waves
Authors: Heck Lydia
Published: July 2020

Dr Lydia Heck of Durham University’s Institute for Computational Cosmology explains the research work at COSMA (aka the Cosmology Machine) and the national Distributed Research using Advanced Computing facility (DiRAC), and what has been achieved so far
Proficiency Testing of Eight French Laboratories in Using the AOAC Mouse Bioassay for Paralytic Shellfish Poisoning: Interlaboratory Collaborative Study
Authors: LeDoux Martial , Hall Sherwood ,   Collaborators:, Bohec Madeleine , Charron Bernard , Esnault Magali , Gleizes Elisabeth , LeBaut Claire , Le Gal Dominique , Raguin Christine , Rouaud Martine , Trotereau Sophie , Truhaut Martine , Turquetit Daniel
Published: July 2020

In an interlaboratory study, 8 French laboratories were tested for their proficiency in using the AOAC mouse bioassay for paralytic shellfish poisoning (PSP). Each laboratory received 1 saxitoxin (STX) standard solution, 1 STX acidified water solution for determination of the titer, 1 noncontaminated shellfish sample, 1 naturally contaminated shellfish sample, and 2 shellfish samples spiked, respectively, at low (152.8 μg STX/100 g meat) and moderate (334.7 μg STX/100 g meat) levels. All samples were analyzed in duplicate. Mean recoveries were 35.1% for the low level and 46.6% for the moderate level. Relative standard deviations (RSD) for within-laboratory variations (repeatability) ranged from 5.4 to 9.8%; RSD for between-laboratory variations (reproducibility) varied from 7.8 to 39.6%, depending on STX level. On the basis of overall performance, all 8 participating laboratories were proficient in their use of the AOAC mouse bioassay.
Method for Determination of Xanthene Dyes in Guava Fruits and Its Application in a Field Dissipation Study
Authors: Alcantara-Licudine Jocelyn P , Bui Ngoc Lan , Li Qing X , McQuate Grant T , Peck Steven L
Published: July 2020

Xanthene dyes, i.e., phloxine B and uranine or phloxine B alone, are phototoxic to tephritid fruit flies infesting guava fruits. An analytical method was developed for determination of residues of these dyes used in bait solutions for suppression of the tephritid fruit fly population in guava fruits. The procedure involved solvent extraction, anionexchange cleanup, and determination by liquid chromatography or capillary zone electrophoresis. The dyes were extracted from 50 g guava fruit at 45°C with 400 mL methanol–acetonitrile (1 + 1) and 5 g magnesium oxide added as an alkaline and clarifying agent. The guava extract was adjusted to pH 8.5 and subjected to an amino column cleanup. Average recoveries of xanthene dyes added to guava purees ranged from 77 to 99% for phloxine B and from 79 to 102% for uranine at spiking levels of 0.05–1.00 μg/g. The method was applied to the determination of phloxine B residues in guava fruits collected from a dye-sprayed orchard. After phloxine B was applied at a rate of 62.5 g/ha for 14 weekly sprayings, it was found on guava fruits at an average concentration of 111 ± 18 ng/g 4 h after the 11th spraying. The concentration of phloxine B was 426 ± 94 ng/g in selected fruits with high deposits of the dye 4 h after spraying. Average concentrations of phloxine B 5 days after the 7th and 14th sprayings were 29 ± 7 and 19 ± 8 ng/g, respectively.
Determination of Se4+ in Drinkable Water by Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry
Authors: Guidotti Maurizio
Published: July 2020

A method was developed for the selective determination of Se4+ in drinkable water by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Se4+ was selectively derivatized to ethane, 1,1′-selenobis by reaction with sodium tetraethylborate, extracted by the SPME fiber, and determined by GC/MS. Both headspace (HS)–SPME and direct SPME were studied. The method requires only a few milliliters of sample and 20 min for completion. At 2.0 μg/L concentration, the relative standard deviation was 10.1% for HS–SPME and 9.1% for direct SPME. For HS–SPME, the theoretical detection limit was 81 ng/L and 166 ng/L for direct SPME. The recovery rate was 95%. The method was used to determine Se4+ in 10 tap water samples.
Evaluation of the Mixed Aggregate Method as an Alternative to the Bismuth Active Substances and Cobalt Thiocyanate Active Substances Procedures for the Determination of Nonionic Surfactants in Raw and Treated Sewage
Authors: Borrego Encarnación , Sicilia Dolores , Rubio Soledad , Pérez-Bendito Dolores
Published: July 2020

The mixed aggregate (MA) method was evaluated for the routine determination of total ethoxylated nonionic surfactants in municipal raw and treated sewage. Nonionics in wastewater samples were enriched with a C8 solid-phase extraction cartridge, eluted with ethyl acetate–methanol, and separated from interferences with stacked strong anionic (quaternary ammonium form) and cationic (benzenesulfonic acid form) exchange columns. Sample extracts were evaporated to dryness and redissolved in distilled water. The total amount of ethoxylates, on a weight basis, was determined by measuring the critical micelle concentration of a mixed micelle made up of ethoxylates and the anionic surfactant sodium dodecyl sulfate, used as the reagent. The dye Coomassie Brilliant Blue G was used as a photometric probe. The minimum amount of ethoxylate required for a single determination was 1 μg. For raw sewage samples, mean recoveries and standard deviations were 98 ± 6 and 98 ± 4% at fortification levels of 0.3 and 0.6 μg/mL, respectively. For treated sewage samples, mean recoveries and standard deviations were 95 ± 2 and 100 ± 2% at fortification levels of 0.03 and 0.06 μg/mL, respectively. The MA method and the classical bismuth active substances and cobalt thiocyanate active substances procedures were compared. The former offers some significant advantages over the classical procedures in terms of sensitivity, selectivity, precision, simplicity, and rapidity; the type of response is independent of both the molecular weight and the chain length of the surfactant.
Gas Chromatographic Analysis of Infant Formulas for Total Fatty Acids, Including trans Fatty Acids
Authors: Satchithanandam Subramaniam , Fritsche Jan , Rader Jeanne I
Published: July 2020

Twelve powdered and 13 liquid infant formulas were analyzed by using an extension of AOAC Official Method 996.01 for fat analysis in cereal products. Samples were hydrolyzed with 8N HCl and extracted with ethyl and petroleum ethers. Fatty acid methyl esters were prepared by refluxing the mixed ether extracts with methanolic sodium hydroxide in the presence of 14% boron trifluoride in methanol. The extracts were analyzed by gas chromatography. In powdered formulas, saturated fatty acid (SFA) content (mean ± SD; n = 12) was 41.05 ± 3.94%, monounsaturated fatty acid (MUFA) content was 36.97 ± 3.38% polyunsaturated fatty acid (PUFA) content was 20.07 ± 3.08%, and total trans fatty acid content was 1.30 ± 1.27%. In liquid formulas, SFA content (mean ± SD; n = 13) was 42.29 ± 2.98%, MUFA content was 36.05 ± 2.47%, PUFA content was 20.65 ± 2.40%, and total trans fatty acid content was 0.88 ± 0.54%. Total fat content in powdered formulas ranged from 4.4 to 5.5 g/100 kcal and linoleic acid content ranged from 868 to 1166 mg/100 kcal. In liquid formulas, total fat content ranged from 4.1 to 5.1 g/100 kcal and linoleic acid content ranged from 820 to 1100 mg/100 kcal. There were no significant differences between powdered and liquid infant formulas in concentrations of total fat, SFA, MUFA, PUFA, or trans fatty acids.
Interference-Free Biosensor Based on Screen-Printing Technology and Sol-Gel Immobilization for Determination of Acetaldehyde in Wine
Authors: Noguer Thierry , Tencaliec Anca , Calas-Blanchard Carole , Avramescu Alina , Marty Jean-Louis
Published: July 2020

A monoenzymatic amperometric biosensor was developed for the detection of acetaldehyde. The sensor is based on the association of screen-printed carbon electrodes and aldehyde dehydrogenase immobilized by a sol-gel entrapment method. Modification of screen-printed carbon electrodes with Reinecke salt of Meldola's Blue (MBRS) resulted in highly sensitive and interference- free nicotinamide-adenine dinucleotide (NADH) detectors. Based on MBRS-mediated oxidation of NADH at –150 mV versus pseudo Ag/AgCl, acetaldehyde was determined in the range 10–260 μM, compatible with wine quality monitoring. The method of immobilization based on sol-gel entrapment was optimized to obtain the best compromise between sensitivity and operational stability. The sensor response was stable for 40 consecutive assays with methyltrimethoxysilane used as alkoxide precursor, thus allowing a possible calibration of the sensor before each measurement. The biosensors were used to analyze French wines. The method was validated with a commercially available enzymatic kit based on a standard spectrophotometric method.
Determination of Semivolatile Organic Compounds in Environmental Samples by Gas Chromatography/Mass Spectrometry after Extraction by Cyclic Steam Distillation
Authors: Kawata Kuniaki , Tanabe Akiko , Yagoh Hiroaki , Ibaraki Tsuyoshi , Yasuhara Akio , Shibamoto Takayuki
Published: July 2020

A method was developed for the multiple determination of semivolatile organic compounds found in groundwater, river water, seawater, sediment, and soil. Forty standard compounds were determined: n-alkenes, cycloalkanes, aromatic hydrocarbons, and polycyclic aromatic hydrocarbons. The compounds were isolated from water and soil samples by using an essential oil distillator (cyclic steam distillator) with hexane as a solvent. The extract was cleaned by using a silica gel cartridge with an acetone–hexane solution. The compounds were determined by using a gas chromatograph/mass spectrometer with 12 stable isotope-labeled compounds (surrogate compounds). The efficiencies of recoveries from water samples were 80.0–106% for groundwater, 80.1–106% for river water, and 81.2–103% for seawater. The relative standard deviation (RSD) values were 2.05–16.0% for groundwater, 3.22–16.6% for river water, and 4.45–16.0% for seawater. The efficiencies of recoveries from sediment and soil were 71.5–96.4% and 70.1–99.8%, respectively. RSD values ranged from 2.27 to 16.0% for sediment and from 2.12 to 15.1% for soil. Adjustment of recovery efficiencies of standard compounds by using surrogate compounds gave more accurate values. The present study proved that an essential oil distillator provides satisfactory results for multiple determinations of the semivolatile compounds in environmental waters, sediment, and soil.
Enumeration of Probiotic Bacilli Spores in Animal Feed: Interlaboratory Study
Authors: Leuschner Renata G K , Bew Jan , Cruz Armando ,   Collaborators:, Adler A , Auclair E , Bertin G , Braconnier M , Domig K , Jones P , Kneifel W , Krause M , Marmo S , Michard J , Mietke H , O’Briain A , Olofson A S , Ruppitsch W , Thalmann A , Voets A , Warmerdam C
Published: July 2020

Fourteen out of 17 laboratories completed an interlaboratory study comparing 2 pretreatment protocols of feed samples containing authorized probiotic bacilli spores. Both methods used tryptone soy agar for enumeration. Pretreatment A involved preparation of a suspension of the feed sample in 50% ethanol. For pretreatment B, the sample was suspended in peptone salt solution and heated at 80°C for 10 min. Each laboratory analyzed 12 samples (6 per pretreatment), which represented duplicates of a high (109 colony-forming units [CFU]/g) and low (105 CFU/g) level of bacilli spores or a blank that contained vegetative probiotic bacteria only. For pretreatment A, the re-peatability relative standard deviation (RSDr) was 2.9% for the low level and 2.5% for the high. The reproducibility relative standard deviation (RSDR) values were 7.8 and 5.9%, respectively. Pretreatment B revealed RSDr values of 1.1 and 1.0%, and RSDR values of 5.8 and 3.4%, respectively. The heat treatment (pretreatment B) of feed samples had better precision data, resulted in higher viable bacilli counts, and was more effective in deactivating vegetative background flora. It is therefore recommended for adoption for official control purposes and for CEN and ISO standards.
Multiresidue Method for the Determination of Pesticides in Korean Domestic Crops by Gas Chromatography/Mass Selective Detection
Authors: Chun Ock Kyoung , Kang Hee Gon , Kim Myung Hee
Published: July 2020

The multiresidue method used in this study allows the determination of 101 pesticides, including organophosphorus, organochlorine, and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector. Analysis was performed in the selected–ion monitoring mode, and the identities of the positive analytes were confirmed by retention time and the ratios of selected ions. The selected ion mode demonstrated an acceptable selectivity for most of the pesticides determined in 3 kinds of samples (Chrysanthemum coronarium; Perilla japonica, leaf; and Lactuca savita, which are very popular vegetables eaten raw in Korea), and very minor interferences were observed in the elution area of the pesticide analytes. Samples were spiked with pesticides at 0.1–1.0 mg/kg. The recoveries of 90% of the pesticides were between 70 and 110%; however, the recoveries of acephate and folpet were very poor, i.e., <50%. The limits of detection (LODs) for most pesticides were between 0.02 and 0.3 mg/kg, and the LODs for about half of the pesticeds studied were <0.05 mg/kg.
Determination of Ginsenosides (Ginseng Saponins) in Dry Root Powder from Panax ginseng, Panax quinquefolius, and Selected Commercial Products by Liquid Chromatography: Interlaboratory Study
Authors: Asafu-Adjaye Ebenezer B , Wong Siu Kay ,   Collaborators:, Arnason J , Betz J , Breakell K , Chen J X , Fitzloff J , Fong H H S , Kim C S , Kwan S Y , Leung H W , Li G Q , Lin R C , Luo G A , Nicolidakis H , Park H , Suen E , Wang X R , Wang Z T , Wen K C , Yeung H W
Published: July 2020

Twelve collaborating laboratories assayed 4 products, namely, Panax ginseng, Panax quinquefolius, and 2 ginseng products, for 6 ginsenosides: Rb1, Rb2, Rc, Rd, Re, andRg1. Collaborators also received a negative control for the recovery study. Pure ginsenosides were provided as reference standards for the liquid chromatography (LC) analysis and the system suitability tests. The LC analyses were performed on the methanol extract using UV detection at 203 nm. For P. ginseng, individual ginsenosides were consistent in their means; repeatability standard deviations (RSDr)rangedfrom4.17to5.09% and reproducibility standard deviations (RSDR) ranged from 7.27 to 11.3%. For P. quinquefolius, the Rb1 and Rb2 ginsenosides were higher and lower in concentration than P. ginseng, with RSDr values of 3.44 and 6.60% and RSDR values of 5.91 and 12.6% respectively, and other analytes at intermediate precisions. For ginseng commercial products, RSDr values ranged from 3.39 to 8.12%, andRSDR values ranged from 7.65 to 16.5%. A recovery study was also conducted for 3 ginsenosides: Rg1, Re, andRb1. The average recoveries were 99.9, 96.2, and 92.3%, respectively. The method is not applicable for the determination of Rg1 and Re in ginseng product at levels <300 mg/kg.
Determination of Nitrogen- and Phosphorus-Containing Pesticide Residues in Vegetables by Gas Chromatography with Nitrogen–Phosphorus and Flame Photometric Detection after Gel Permeation Chromatography and a Two-Step Minicolumn Cleanup
Authors: Ueno Eiji , Oshima Harumi , Saito Isao , Matsumoto Hiroshi
Published: July 2020

An efficient and reliable multiresidue method for determining pesticide residues in a large number of vegetable samples was studied. First, the important target compounds for monitoring, 52 nitrogen-and/or phosphorus-containing pesticides, were selected. The sample was extracted with acetonitrile, and the separated acetonitrile layer was cleaned up by a salting-out step. The acetonitrile extract was purified by gel permeation chromatography that divided the pesticide eluate into 2 fractions; the pesticide fractions were respectively purified by a 2-step minicolumn cleanup in which the second pesticide fraction was loaded on a silica-gel minicolumn. After a Florisil minicolumn was inserted on the silicagel minicolumn, the first pesticide fraction was loaded on the tandem minicolumn, which was eluted with acetone–petroleum ether (3 + 7). The combined eluate was subjected to dual-column gas chromatography (GC) with nitrogen–phosphorus and flame photometric detection. By application of the optimum cleanup conditions to the 52 pesticides selected, good resolution and low breakdown levels of the pesticides during GC were maintained. Recoveries of the 52 pesticides from fortified cabbage, lettuce, spring onion, and spinach ranged from 72 to 108% with relative standard deviations of 2–17%, except for the recoveries of methamidophos and chlorothalonil. The detection limits of the pesticides were satisfactory (0.001–0.009 mg/kg) for monitoring pesticide residues in vegetables.
Application of Derivative Spectrophotometry to Simultaneous Determination of Indomethacin and 5-Methoxy-2-methyl-3-indoleacetic Acid in Metindol Injections
Authors: Stolarczyk Mariusz , Krzek Jan , Rzeszutko Włodzimierz
Published: July 2020

Derivative spectrophotometry was employed to develop a rapid and accurate method for simultaneous determination of indomethacin and 5-methoxy-2-methyl-3-indoleacetic acid as its possible impurity in Metindol injections. At the selected wavelengths, 233.04 and 284.65 nm, no interference between the components determined was observed. Under the established experimental conditions, recoveries of the particular components were from 96.14 to 98.17%. Linearity was maintained over a broad range of concentrations, from 11.88 × 10−3 to 35.64 × 10−3 mg/mL for indomethacin and 0.4 to 1.2 mg/mL for 5-methoxy-2-methyl-3-indoleacetic acid. The limit of detection was found to be 6.0 × 10−3 mg/mL for indomethacin and 0.04 × 10−3 mg/mL for 5-methoxy-2-methyl-3-indoleacetic acid. The limits of quantitation were found to be 10.0 × 10−3 mg/mL and 0.20 × 10−3 mg/mL, respectively.
Multiresidue Analysis of Pesticides in Vegetables and Fruits by Gas Chromatography/Mass Spectrometry after Gel Permeation Chromatography and Graphitized Carbon Column Cleanup
Authors: Ueno Eiji , Oshima Harumi , Saito Isao , Matsumoto Hiroshi , Yoshimura Yoshihiro , Nakazawa Hiroyuki
Published: July 2020

A multiresidue method for pesticides that enables quantitative, sequential analysis of a large number of vegetable and fruit samples by gas chromatography/mass spectrometry has been developed. First, 89 important target compounds were selected for monitoring, and then the appropriate internal standards for these pesticides, 14 stable isotopically labeled pesticides (surrogates), were used. The sample was extracted with acetonitrile, and the extract was cleaned up by a salting-out step followed by redissolution in ethyl acetate. Coextractives were removed automatically by gel permeation chromatography with a graphitized carbon column, and then by use of a tandem silica-gel/PSA cartridge column. Recoveries of 82 of the 89 pesticides from fortified spinach, tomato, apple, and strawberry were within a range from 70 to 120%, and the relative standard deviation values of 80 of the 89 pesticides were <5%. The method was applied to 188 commercial vegetable and fruit samples to demonstrate its use in routine analysis.
One Internal Standard for Multiple Analytes: A Limit and Solution
Authors: Huang Li , Wu Mary
Published: July 2020

The use of a single internal standard (ephedrine-d5) as the basis for calculations of the concentrations of both the major and the minor alkaloids leads to incorrect results from variabilities in the solid-phase extraction (SPE) of the ephedra alkaloids. Because the SPE column is overloaded by ephedrine, the recovery of the internal standard, which is dependent on the dilution factor, is decreased. On the other hand, the recoveries of the minor alkaloids (methylephedrine, methylpseudoephedrine, norephedrine, and norpseudoephedrine) stay high because these compounds are less concentrated and do not overload the SPE column. Consequently, the recovery factors for the major and minor alkaloids are different, or the results are incorrect if the same recovery factor is used.
Thin-Layer Chromatography-Densitometry and Liquid Chromatography Analysis of Alkaloids in Leaves of Papaver somniferum Under Stress Conditions
Authors: Szabó Beata , Lakatos Ágnes , Kõszegi Tamás , Kátay György , Botz L
Published: July 2020

The effect of stress conditions on the concentrations of secondary metabolites were examined during various developmental stages of Papaver somniferum plants. P. somniferum plants were grown in laboratory conditions (Budakalász). The experiment consisted of 22 treatments. Significantly different alkaloid contents can be observed under different stress conditions. In general, the alkaloid contents of plants are very low; therefore, a highly sensitive and reliable method has to be developed for analysis. The amount of alkaloids was measured by 2 separation and detection techniques. Accuracy of the thin-layer chromatography method for quantitative analysis is limited. Without purification of samples the background is too noisy. Column liquid chromatography is a sensitive and relatively inexpensive method that allows precise quantitative determination of the alkaloid content.
Flow-Injection Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Cadmium in Solid and Semisolid Milk Products Coupling a Continuous Ultrasound-Assisted Extraction System with the Online Preconcentration on a Chelating Aminomethylphosphoric Acid Resin
Authors: Cancela Sheila , Yebra M Carmen
Published: July 2020

A new sensitive and low-cost method that combines continuous acid extraction, online preconcentration, and flame atomic absorption spectrometry for cadmium determination at g levels in solid and semisolid milk products is described. A continuous ultrasound-assisted extraction system is used to carry out the dynamic acid extraction step. The acid extract is preconcentrated online on a minicolumn packedwith a chelating resin (Chelite P,with aminomethylphosphoric acid groups), and the retained cadmium is elutedwith hydrochloric acid and continuously monitored by flame atomic absorption spectrometry. An experimental design (Plackett-Burman 263/16) is used to optimize the continuous extraction and the preconcentration step. The method allowed a total sampling frequency of 28 samples/h. A good precision of the whole procedure (3.0% relative standard deviation) for a cheese sample containing 0.103 0.004 g/g Cd (dry mass), a high enrichment factor (20.5), and detection and quantification limits of 0.014 and 0.067 g/g, respectively, for a 60 mg of sample were obtained with this methodology. The method was successfully applied to the determination of trace amounts of cadmium in solid and semisolid milk products, such as cheese and yogurt samples.
Clonal Structure and Variation in Virulence of Salmonella Enteritidis Isolated from Mice, Chickens, and Humans
Authors: Saeed A Mahdi , Walk Seth T , Arshad Mokhtar , Whittam Thomas S
Published: July 2020

The clonal analysis of a diverse collection of Salmonella Enteritidis indicates that most strains belong to a single multilocus genotype (i.e., ET-3) regardless of phage type, geographic origin, or time of isolation that spanned over 2 decades (1978 to 2004). Attachment and invasion assays, however, indicate that, among ET-3 isolates, there is a distinct invasive bacterial subpopulation that is more readily recovered from eggs and clinical cases in humans than from chicken cecal samples. These observations support the hypothesis that the specialized ability of S. Enteritidis to infect the avian reproductive tract and contaminate eggs has been critical in its emergence as a frequent cause of human illness.
Testing Green Coffee for Ochratoxin A, Part III: Performance of Ochratoxin A Sampling Plan
Authors: Vargas Eugenia A , Whitaker Thomas B , Santos Eliene A , Slate Andrew B , Lima Francisco B , Franca Regina C A
Published: July 2020

Green coffee shipments are often inspected for ochratoxin A (OTA) and classified into good or bad categories depending on whether the OTA estimates are above or below a defined regulatory limit. Because of the uncertainty associated with the sampling, sample preparation, and analytical steps of an OTA test procedure, some shipments of green coffee will be misclassified. The misclassification of lots leads to some good lots being rejected (sellers' risk) and some bad lots being accepted (buyers' risk) by an OTA sampling plan. Reducing the uncertainty of an OTA test procedure and using an accept/reject limit less than the regulatory limit can reduce the magnitude of one or both risks. The uncertainty of the OTA test procedure is most effectively reduced by increasing sample size (or increasing the number of samples analyzed), because the sampling step is the largest source of uncertainty in the OTA test procedure. The effects of increasing sample size and changing the sample accept/reject limit relative to the regulatory limit on the performance of OTA sampling plans for green coffee were investigated. For a given accept/reject limit of 5 μg/kg, increasing sample size increased the percentage of lots accepted at concentrations below the regulatory limit and increased the percentage of lots rejected at concentrations above the regulatory limit. As a result, increasing sample size reduced both the number of good lots rejected (sellers' risk) and the number of bad lots accepted (buyers' risk). For a given sample size (1 kg), decreasing the sample accept/reject limit from 5 to 2 μg/kg relative to a fixed regulatory limit of 5 μg/kg decreased the percentage of lots accepted and increased the percentage of lots rejected at all OTA concentrations. As a result, decreasing the accept/reject limit below the regulatory limit increased the number of good lots rejected (sellers' risk), but decreased the number of bad lots accepted (buyers' risk).
The Horwitz Ratio (HorRat): A Useful Index of Method Performance with Respect to Precision
Authors: Horwitz William , Albert Richard
Published: July 2020

The Horwitz ratio (HorRat) is a normalized performance parameter indicating the acceptability of methods of analysis with respect to among-laboratory precision (reproducibility). It is the ratio of the observed relative standard deviation among laboratories calculated from the actual performance data, RSDR (%), to the corresponding predicted relative standard deviation calculated from the Horwitz equation PRSDR (%) = 2C0.15, where C is the concentration found or added, expressed as a mass fraction. It is more or less independent of analyte, matrix, method, and time of publication (as a surrogate for the state of the art of analytical chemistry). It is now one of the acceptability criteria for many of the recently adopted chemical methods of analysis of AOAC INTERNATIONAL, the European Union, and other European organizations dealing with food analysis (e.g., European Committee for Standardization and Nordic Analytical Committee). The origin and applications of the formula are described. Consistent deviations from the ratio on the low side (values <0.5) may indicate unreported averaging or excellent training and experience; consistent deviations on the high side (values >2) may indicate inhomogeneity of the test samples, need for further method optimization or training, operating below the limit of determination, or an unsatisfactory method.
Determination of Fat,Moisture, and Protein in Meat and Meat Products by Using the FOSS FoodScan Near-Infrared Spectrophotometer with FOSS Artificial Neural Network Calibration Model and Associated Database: Collaborative Study
Authors: Anderson Shirley ,   Collaborators:, Aldana S , Beggs M , Birkey J , Conquest A , Conway R , Hemminger T , Herrick J , Hurley C , Ionita C , Longbind J , McMaignal S , Milu A , Mitchell T , Nanke K , Perez A , Phelps M , Reitz J , Salazar A , Shinkle T , Strampe M , Van Horn K , Williams J , Wipperfurth C , Zelten S , Zerr S
Published: July 2020

A collaborative study was conducted to evaluate the repeatability and reproducibility of the FOSS FoodScan near-infrared spectrophotometer with artificial neural network calibration model and database for the determination of fat, moisture, and protein in meat and meat products. Representative samples were homogenized by grinding according to AOAC Official Method 983.18. Approximately 180 g ground sample was placed in a 140 mm round sample dish, and the dish was placed in the FoodScan. The operator ID was entered, the meat product profile within the software was selected, and the scanning process was initiated by pressing the start button. Results were displayed for percent (g/100 g) fat, moisture, and protein. Ten blind duplicate samples were sent to 15 collaborators in the United States. The within-laboratory (repeatability) relative standard deviation (RSDr) ranged from 0.22 to 2.67% for fat, 0.23 to 0.92% for moisture, and 0.35 to 2.13% for protein. The between-laboratories (reproducibility) relative standard deviation (RSDR) ranged from 0.52 to 6.89% for fat, 0.39 to 1.55% for moisture, and 0.54 to 5.23% for protein. The method is recommended for Official First Action.
Validation of the SL3 -Lactam Test for Screening Milk in Compliance with U.S. Pasteurized Milk Ordinance: Performance-Tested MethodSM 040701
Authors: Salter Robert S , Conaway David , Markovsky Robert
Published: July 2020

The SL3 -Lactam Test is a 3 min, receptor-based lateral flow Rapid One Step Assay (ROSA) that detects 5 of 6 -lactam drugs approved for dairy cattle in the United States. The method was evaluated through the AOAC Research Institute Performance-Tested Method program following a U.S. Food and Drug Administration protocol. Three combined lots detected penicillin G 4.2 parts per billion (ppb), ampicillin 8.7 ppb, amoxicillin 7.8 ppb, cephapirin 16.0 ppb, and ceftiofur (total metabolites) 51 ppb at least 90 of the time, with 95 confidence as determined by dose response probit analysis. These detection levels are less than safe level/tolerances but not more than 50less. Lot repeatability was within 20. Incurred residues were detected comparably or more sensitively to fortified samples due to the cumulative effect of biologically active metabolites. There were no interferences from somatic cells at 1 M/mL, bacterial cells 500 000 colony-forming units/mL, or 30 other non--lactam drugs. These performances met approval conditions of the National Conference on Interstate Milk Shipments. Ruggedness conditions were incorporated into public health procedures for annual laboratory proficiency and certification.
Simultaneous Quantification of Withanolides in Withania somnifera by a Validated High-Performance Thin-Layer Chromatographic Method
Authors: Srivastava Pooja , Tiwari Neerja , Yadav Akhilesh K , Kumar Vijendra , Shanker Karuna , Verma Ram K , Gupt Madan M , Gupta Anil K , Khanuja Suman P S
Published: July 2020

This paper describes a sensitive, selective, specific, robust, and validated densitometric high-performance thin-layer chromatographic (HPTLC) method for the simultaneous determination of 3 key withanolides, namely, withaferin-A, 12-deoxywithastramonolide, and withanolide-A, in Ashwagandha (Withania somnifera) plant samples. The separation was performed on aluminum-backed silica gel 60F254 HPTLC plates using dichloromethanemethanolacetonediethyl ether (15 + 1 + 1 + 1, v/v/v/v) as the mobile phase. The withanolides were quantified by densitometry in the reflection/absorption mode at 230 nm. Precise and accurate quantification could be performed in the linear working concentration range of 66330 ng/band with good correlation (r2 0.997, 0.999, and 0.996, respectively). The method was validated for recovery, precision, accuracy, robustness, limit of detection, limit of quantitation, and specificity according to International Conference on Harmonization guidelines. Specificity of quantification was confirmed using retention factor (Rf) values, UV-Vis spectral correlation, and electrospray ionization mass spectra of marker compounds in sample tracks.
Simultaneous Determination of Phenolic Acids and Phthalide Compounds by Liquid Chromatography for Quality Assessment of Rhizoma Cnidii
Authors: Islam M Nurul , Yoo Hye Hyun , Sung Chung-Ki , Dong Mi-Sook , Park Young In , Jin Changbae , Kim Dong-Hyun
Published: July 2020

This paper describes a simple, rapid, and validated reversed-phase high-performance liquid chromatographic method developed for the determination of 4 major bioactive constituents, namely, chlorogenic acid, ferulic acid, senkyunolide A, and Z-ligustilide in Rhizoma Cnidii extract. A Capcell Pak C18 chromatographic column (150 4.6 mm, 3 m) was used with mobile phases consisting of 0.1 formic acid, acetonitrile, and methanol at a flow rate of 0.8 mL/min and UV detection at 285 nm. Comprehensive validation of the method included evaluation of linearity, repeatability, recovery, and stability. Excellent linear behavior (r2 >0.99) was observed over the concentration range of 2100 g/mL for the compounds under investigation. Repeatability and accuracy were evaluated by intra- and interday assays; the relative standard deviation (RSD) values were 5.37 and accuracies ranged from 97.1 to 104.9. Recoveries of the compounds ranged from 94.2 to 104.2 with RSD values of 9.50. The developed method was successfully applied to the analysis of ethanolic extracts of Rhizoma Cnidii samples. As a result, the concentrations of chlorogenic acid, ferulic acid, Z-ligustilide, and senkyunolide A were determined to be 0.845.35, 0.451.65, 0.744.39, and 0.321.14 mg/g herb, respectively. Thus, the developed method was found to be accurate and reproducible and is considered suitable for the qualitative and quantitative analysis of Rhizoma Cnidii for bioactive compounds.
Stability-Indicating Simultaneous Determination of Paracetamol and Three of Its Related Substances Using a Direct GC/MS Method
Authors: Belal Tarek , Awad Tamer , Clark C Randall
Published: July 2020

A simple, direct, and selective stability-indicating GC/MS procedure was developed for the simultaneous determination of paracetamol (PR) and three of its related substances: 4-aminophenol (4-AP), acetanilide (AD), and 4-chloroacetanilide (4-CA). The method involved resolution of the underivatized compounds using a 100 dimethylpolysiloxane (Rtx-1) column, and MS detection was carried out in the electron-impact mode. The four compounds were completely resolved in less than 11 min. The fragmentation pathways for the four compounds were described, and the structures of the major fragment ions peaks were proposed. Quantification of the analytes was based on measuring their peak areas. The reliability and analytical performance of the proposed method including linearity, range, precision, accuracy, and detection and quantification limits were statistically validated. Calibration curves were linear over the ranges 75500, 25350, 25350, and 25350 g/mL for PR, 4-AP, AD, and 4-CA, respectively. The proposed method was successfully applied for the determination of PR and its related substances in laboratory-prepared mixtures of different proportions. Also, it was applied for the assay of PR in several commercially available pharmaceutical formulations with recoveries of 98.95100.76.
Assessment of Suitability of Magnetic Beads for Purification of Rat Plasma in Proteomic Analyses by Matrix-Assisted Laser Desorption IonizationTime-of-Flight MS
Authors: Mohottalage Susantha , Vincent Renaud , Kumarathasan Prem
Published: July 2020

Plasma is a complex matrix and has to be clarified or fractionated to obtain informative MS data. Although there are a number of prefractionation methods to clean up complex biological matrixes before proteomic analysis, these methods require large sample volumes and are costly and time-consuming. Alternatively, recently introduced magnetic beads (MB) appear to be attractive in overcoming these difficulties. Therefore, we were interested in investigating the applicability of MB in the clarification of rat plasma samples for proteome analyses. For this purpose, we used complementary supports, such as hydrophobic interaction chromatography-based MB (MB-C18) and weak cation-exchange chromatography-based MB (MB-WCX). MB-based fractionated samples were either spotted directly or underwent tryptic digestion before matrix-assisted laser desorption ionization (MALDI) spotting. Samples from both MB separation techniques gave clean and well-resolved MALDI-time-of-flight MS spectra in the low molecular mass range of 110 kDa with -cyano-4-hydroxycinnamic acid as the matrix. Both techniques gave approximately 300 analyte peaks in this mass range. Our results showed that both MB-based separation procedures gave complementary mass spectral information. This approach provided information on the identity of a number of less-abundant and more-abundant proteins in plasma. Our findings suggest that this MB-based proteomic approach can be valuable in conducting faster screening of plasma samples for protein profiling.
Second-Derivative Spectrometric Determination of Urea in Milk Using the Diacetyl Monoxime Reagent
Authors: Nyanzi Steven A , Isiko Maureen , Kateregga Francis , Schwack Wolfgang
Published: July 2020

The application of derivative spectrometry to resolve overlapping spectra and improve the sensitivity and selectivity of the colorimetric determination of urea in milk using diacetyl monoxime is presented. With first-derivative (1D) spectrometry, the max of the colored complex was established to be 525 nm. The absorption band at max 525 nm in normal absorption (0D) spectrometry was resolved into three clearly distinct spectral bands with minima at 497, 530, and 566 nm with second-derivative (2D) spectrometry. With the second-derivative (2D530) technique, the depth of the trough of the strongest signal at 530 nm was used to determine urea in milk samples. Linear calibration curves for urea were obtained over a concentration range of 0.21.4 mg/L, with correlation coefficients greater than 0.999. The LOD and LOQ of the method were 0.01 and 0.03 mg/L, respectively. Recoveries of 99100 of spiked urea in milk with RSD values below 2.0 were obtained. The second-derivative method is simple, affordable, sensitive, and selective for the determination of urea in milk.
Determination of Aflatoxins B1, B2, G1, and G2 in Olive Oil, Peanut Oil, and Sesame Oil
Authors: Bao Lei , Trucksess Mary W , White Kevin D
Published: July 2020

Edible oils are consumed directly, and used as ingredients in food, soaps, and skin products. However, oils such as olive oil, peanut oil, and sesame oil could be contaminated with aflatoxins, which are detrimental to human and animal health. A method using immunoaffinity column cleanup with RPLC separation and fluorescence detection (FLD) for determination of aflatoxins (AF) B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil was developed and validated. Test samples were extracted with methanolwater (55 + 45, v/v). After shaking and centrifuging, the lower layer was filtered, diluted with water, and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column, and the toxins were eluted with methanol. The toxins were then subjected to RPLC/FLD analysis after postcolumn UV photochemical derivatization. The accuracy and repeatability characteristics of the method were determined. Recoveries of AFB1 spiked at levels from 1.0 to 10.0 g/kg in olive oil, peanut oil, and sesame oil ranged from 82.9 to 98.6. RSDs ranged from 0.6 to 8.9. HorRat values were <0.2 for all of the matrixes tested. Recoveries of AF spiked at levels from 2.0 to 20.0 g/kg ranged from 87.7 to 102.2. RSDs ranged from 1.3 to 12.6. HorRat values were <0.4 for all of the matrixes tested. LC/MS/MS with multiple-reaction monitoring was used to confirm the identities of aflatoxins in a naturally contaminated peanut oil.
Liquid Chromatographic and Spectrophotometric Determination of Diflucortolone Valerate and Isoconazole Nitrate in Creams
Authors: Karacan Elif , Çaġlayan Mehmet Gokhan , Palabiyik İsmail Murat , Onur Feyyaz
Published: July 2020

A new RP-LC method and two new spectrophotometric methods, principal component regression (PCR) and first derivative spectrophotometry, are proposed for simultaneous determination of diflucortolone valerate (DIF) and isoconazole nitrate (ISO) in cream formulations. An isocratic system consisting of an ACE® C18 column and a mobile phase composed of methanol–water (95+5, v/v) was used for the optimal chromatographic separation. In PCR, the concentration data matrix was prepared by using synthetic mixtures containing these drugs in methanol–water (3+1, v/v). The absorbance data matrix corresponding to the concentration data matrix was obtained by measuring the absorbances at 29 wavelengths in the range of 242–298 nm for DIF and ISO in the zero-order spectra of their combinations. In first derivative spectrophotometry, dA/dλ values were measured at 247.8 nm for DIF and at 240.2 nm for ISO in first derivative spectra of the solution of DIF and ISO in methanol–water (3+1, v/v). The linear ranges were 4.00–48.0 μg/mL for DIF and 50.0–400 μg/mL for ISO in the LC method, and 2.40–40.0 μg/mL for DIF and 60.0–260 μg/mL for ISO in the PCR and first derivative spectrophotometric methods. These methods were validated by analyzing synthetic mixtures. These three methods were successfully applied to two pharmaceutical cream preparations.
124 Impact of heat stress and antioxidant supplements in feed or drinking water on growth, intestinal morphology, and oxidative and immune status in growing pigs
Authors: Silva-Guillen Ysenia Victoria , Martinez Padilla Gabriela E , Wiegert Jeffrey , Arellano Consuelo , Dean Boyd R , van Heugten Eric
Published: July 2020

The objective of this study was to evaluate the impact of vitamin E (vitE) or polyphenols supplemented in feed or drinking water as a heat abatement strategy in growing pigs. Individually housed pigs (n = 128, 47.3 ± 5.0 kg BW) were assigned within weight blocks and sex to a 2x4 factorial arrangement consisting of 2 environments (thermo-neutral [21.2°C] or heat-stressed [30.9°C]) and 4 supplementation treatments (control diet [25 IU/kg dl-α-tocopherol acetate]; control+100 IU/L vitE [d-α-tocopherol] in water; control+200 IU/kg vitE [dl-α-tocopherol acetate] in feed; or control+400 mg/kg polyphenols in feed). Supplementation was started 7 d prior to temperature treatments applied for 28 d. Heat stress reduced (P ≤ 0.001) final BW, ADG, and ADFI (-7.4 kg, -26.7%, and -25.4%, respectively) and increased (P < 0.001) respiration rate and rectal temperature, but no effects of supplementation were detected. Serum vitamin E concentration increased (P < 0.001) with vitE supplementation (1.64, 3.59, 3.24, and 1.67 mg/kg for control, vitE in water, vitE in feed, and polyphenols, respectively) and was greater when supplemented in water vs. feed (P = 0.002), especially when measured on d 28 (chronic) vs. d 2 (acute) of heat stress. Liver vitamin E increased (P < 0.001) with vitE supplementation, especially in water, but not polyphenols (3.9, 31.8, 18.0, 4.9 ppm for control, vitE in water, vitE in feed, and polyphenols, respectively). Serum malondialdehyde (MDA) was greater (P < 0.05) for supplemented pigs compared to control, and heat stress reduced (P = 0.014) serum MDA on d 2, but not d 28. No differences were detected for intestinal morphology or MDA in mucosa of jejunum or ileum. Heat stress decreased (P < 0.03) TNF-α in mucosa of ileum and jejunum, and supplementation reduced (P < 0.05) TNF-α in mucosa of the ileum, but not jejunum. Heat stress markedly reduced performance of growing pigs, and supplementing antioxidants in feed or water was not effective in alleviating the impact of heat stress.
Studies on the gene regulation involved in the lytic–lysogenic switch in Staphylococcus aureus temperate bacteriophage Phi11
Authors: Das Avijit , Mandal Sukhendu , Hemmadi Vijay , Ratre Vivek , Biswas Malabika
Published: July 2020

Antirepressor proteins of bacteriophages are chiefly involved in interfering with the function of the repressor protein and forcing the bacteriophage to adopt the lytic cycle. The genome of Staphylococcus aureus phage, Phi11 has already been sequenced; from the genome sequence, we amplified gp07 gene and analysed its involvement in the developmental pathway of Phi11. Our results indicate that Gp07 functions as a novel antirepressor and regulates the developmental pathway of Phi11 by enhancing the binding of the Cro repressor protein to its cognate operator. We also report our finding that the CI repressor protein of Phi11 binds to the putative operator of Gp07 and regulates its expression. We further report that S.aureus transcriptional repressor LexA and coprotease RecA play a crucial role in the lytic–lysogenic switching in Phi11. We also identified that the N-terminal domain (Bro-N) of Gp07 is actually responsible for enhancing the binding of Cro repressor to its cognate operator. Our results suggest that Phi11 prophage induction is different from other bacteriophages. This study furnishes a first-hand report regarding the regulation involved in the developmental pathway of Phi11.