bluuebunny/crossref_metadata_2025 huggingface dataset:
What is Dietary Fiber?
Authors: Prosky Leon
Published: February 2020

Dietary fiber consists of the remnants of the edible plant cell, polysaccharides, lignin, and associated substances resistant to digestion (hydrolysis) by human alimentary enzymes. This physiological definition has been translated into a chemical method (AOAC Method 985.29), which has recently been shown to miss substances of 10, 11, and 12 degrees of polymerization. It also fails to precipitate some hydrolysis-resistant oligosaccharides which contain many physiological properties expected in dietary fiber, such as inulin and oligofructose, indigestible dextrin (Fibersol-2™), galactooligosaccharides and the synthetic polymer polydextrose. The Executive Board of the American Association of Cereal Chemists has appointed a committee to explore the possibility of expanding the definition or chemical methodology for dietary fiber to accommodate components that are not hydrolyzed by human alimentary enzymes, yet have the physiological attributes normally associated with dietary fiber. However, the present review suggests that the current definition is sufficient, along with new methodology, to detect recently discovered components of the dietary fiber complex.
Importance of Enzyme Purity and Activity in the Measurement of Total Dietary Fiber and Dietary Fiber Components
Authors: McCleary Barry V
Published: February 2020

A study was made of the effect of the activity and purity of enzymes in the assay of total dietary fiber (AOAC Method 985.29) and specific dietary fiber components: resistant starch, fructan, and β-glucan. In the measurement of total dietary fiber content of resistant starch samples, the concentration of α-amylase is critical; however, variations in the level of amyloglucosidase have little effect. Contamination of amyloglucosidase preparations with cellulase can result in significant underestimation of dietary fiber values for samples containing β-glucan. Pure β-glucan and cellulase purified from Aspergillus niger amyloglucosidase preparations were used to determine acceptable critical levels of contamination. Sucrose, which interferes with the measurement of inulin and fructooligosaccharides in plant materials and food products, must be removed by hydrolysis of the sucrose to glucose and fructose with a specific enzyme (sucrase) followed by borohydride reduction of the free sugars. Unlike invertase, sucrase has no action on low degree of polymerization (DP) fructooligosaccharides, such as kestose or kestotetraose. Fructan is hydrolyzed to fructose and glucose by the combined action of highly purified exo- and endo-inulinases, and these sugars are measured by the p-hydroxybenzoic acid hydrazide reducing sugar method. Specific measurement of β-glucan in cereal flour and food extracts requires the use of highly purified endo-1,3:1,4 β-glucanase and A. niger β-glucosidase. β-Glucosidase from almonds does not completely hydrolyze mixed linkage β-glucooligosaccharides from barley or oat β-glucan. Contamination of these enzymes with starch, maltosaccharide, or sucrose-hydrolyzing enzymes results in production of free glucose from a source other than β-glucan, and thus an overestimation of β-glucan content. The glucose oxidase and peroxidase used in the glucose determination reagent must be essentially devoid of catalase and α- and β-glucosidase.
Variability of Deoxynivalenol Measurements in Barley
Authors: Freese Larry , Friedrich Roger , Kendall Donald , Tanner Steven
Published: February 2020

Deoxynivalenol (DON), a toxin produced by Fusarium fungi, can occur in many cereal grains. If wet climatic conditions coincide with the flowering period of plant development, circumstances are favorable for the fungi infection. Because the presence of DON in barley can have significant economic consequences to barley producers, commercially available test kits are used to measure DON in shipments throughout marketing channels. The quantity of barley sampled from a lot and used to measure DON can vary widely, depending on where the test is conducted. The Grain Inspection, Packers and Stockyards Administration of the U.S. Department of Agriculture specifies that a minimum of 100 g of grain must be processed to measure DON. Other laboratories may use more or less grain. A study undertaken to measure the variability among measurements of different sample sizes found no detectable differences in variability attributable to sample size. It was concluded that the variability among DON concentrations in samples from the lot was small relative to that introduced by the measurement process (combined sample preparation and analysis). A separate experiment investigated variation among samples taken from a lot, variation among subsamples taken from ground samples, and variation among multiple replicated measurements of an extract. On 10 lots, all 3 sources were significant contributors to variation. Stratification of DON within lots was hypothesized as a source of variation of DON measurements. Tests indicated that some stratification may exist.
Testing Shelled Corn for Aflatoxin, Part I: Estimation of Variance Components
Authors: Johansson Anders S , Whitaker Thomas B , Hagler Winston M , Giesbrecht Francis G , Young James H , Bowman Daryl T
Published: February 2020

The variability associated with testing lots of shelled corn for aflatoxin was investigated. Eighteen lots of shelled corn were tested for aflatoxin contamination. The total variance associated with testing shelled corn was estimated and partitioned into sampling, sample preparation, and analytical variances. All variances increased as aflatoxin concentration increased. With the use of regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample preparation, and analytical variances. The expressions for these relationships were used to estimate the variance for any sample size, subsample size, and number of analyses for a specific aflatoxin concentration. Test results on a lot with 20 parts per billion aflatoxin using a 1.13 kg sample, a Romer mill, 50 g subsamples, and liquid chromatographic analysis showed that the total, sampling, sample preparation, and analytical variances were 274.9 (CV = 82.9%), 214.0 (CV = 73.1%), 56.3 (CV = 37.5%), and 4.6 (CV = 10.7%), respectively. The percentage of the total variance for sampling, sample preparation, and analytical was 77.8, 20.5, and 1.7, respectively.
Analysis of Ginkgo biloba for the Presence of Ginkgotoxin and Ginkgotoxin 5′-Glucoside
Authors: Scott Peter M , Lau Benjamin P-Y , Lawrence Guillaume A , Lewis David A
Published: February 2020

Hot water extracts of Ginkgo biloba seeds were analyzed for the presence of ginkgotoxin (4′-O-methylpyridoxine) by reversed-phase liquid chromatography (LC) using methanol–0.05M KH2PO4 (1 + 9, v/v) adjusted to pH 3 as mobile phase. Detection was by fluorescence (excitation 280 nm, emission 370 nm). A straight line calibration curve was obtained for the 10–100 ng injected. After addition of β-glucosidase (37°C/h), an earlier eluting peak disappeared and the ginkgotoxin peak increased. The identity of the ginkgotoxin was confirmed by LC/MS and LC/MS/MS. LC/MS/MS also confirmed the 5′-glucoside by comparison with the 3-glucoside. This is the first identification of a glucoside of ginkgotoxin in Ginkgo biloba. An unknown compound of MW 267 also observed in the Ginkgo biloba seed extract was shown not to be 3,5′-diacetylginkgotoxin by its different LC retention time. Extraction of ground Ginkgo biloba seeds with boiling water in a Soxhlet for 2 × 2 h yielded a total of 179 μg/g of free ginkgotoxin. The concentration in powder from Ginkgo biloba capsules was several times lower than this (17–64 μg/g) in 3 samples but higher in another (457 μg/g). Canned ginkgo seeds (white nuts) contained no detectable free ginkgotoxin but the glucoside was present. Different extraction times were studied: 0.5 h gave only 52 μg/g free ginkgotoxin in the ginkgo seeds. However, boiling an extract for 4 h showed about 15% loss of ginkgotoxin and its glucoside.
Liquid Chromatographic Method with Immunoaffinity Column Cleanup for Determination of Ochratoxin A in Barley: Collaborative Study
Authors: Entwisle A Catherine , Williams Alison C , Mann Peter J , Slack Philip T , Gilbert John
Published: February 2020

A collaborative study was conducted to evaluate a liquid chromatographic (LC) method with immunoaffinity column cleanup for determination of ochratoxin A. The method was tested at 3 concentration levels of ochratoxin A in barley, which represent possible future European regulatory limits. The test portion was extracted with acetonitrile–water by blending at high speed. The extract was filtered, diluted with phosphate-buffered saline (PBS), and applied to an ochratoxin A immunoaffinity column. The column was washed with water and the ochratoxin A eluted with methanol. The solvent was then evaporated and the residue redissolved in injection solvent. After injection of this solution onto reversed-phase LC column, ochratoxin A was measured by fluorescence detection. Eight samples of low level naturally contaminated barley and 2 samples of blank barley (ochratoxin A not found at the limit of detection of 0.2 μg/kg at the signal-to-noise ratio of 3 to 1) were sent, along with ampules of ochratoxin A, calibrant, and spiking solutions, to 15 laboratories in 13 different European countries. Test portions were spiked with ochratoxin A at levels of 4 ng/g, and recoveries ranged from 65 to 113%. Based on results for spiked samples (blind duplicates) and naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 4 to 24%, and the relative standard deviation for reproducibility (RSDR) ranged from 12 to 33%. The method showed acceptable within- and between-laboratory precision, as evidenced by HORRAT values, at the low level of determination for ochratoxin A in barley.
Deuterium Nuclear Magnetic Resonance Spectroscopy and Stable Carbon Isotope Ratio Analysis/Mass Spectrometry of Certain Monofloral Honeys
Authors: Giraudon Sylvie , Danzart Marc , Merle Marc H
Published: February 2020

Quantitative deuterium nuclear magnetic resonance spectroscopy (NMR) has been used in conjunction with stable carbon isotope ratio analysis/mass spectrometry to refine the detection of sugars that have been added to monofloral honeys. The 13C content of sugars indicates the type of photosynthetic metabolism of the plant that synthesized them; the deuterium content is more characteristic of secondary metabolism and of environmental factors. Consequently, determination of the 13C content of honeys and of proteins extracted from the honeys can be used to detect the addition of C4 plant sugars (cane or corn), but it does not reveal the addition of C3 plant sugars such as beet sugar. Deuterium NMR gives useful information for some monofloral honeys. NMR measurement is performed on ethanol obtained from fermentation of the honey and extracted by distillation. The isotopic composition of the ethanol indicates the nature of the sugars from which it was derived. Various types of monofloral honeys were studied, and the results obtained with commercially available honeys demonstrate the usefulness of isotopic analysis and the need to compile a database of authentic honeys to validate or affirm certain results.
Evaluating Presence/Absence of Target Microbes in Microbiological Tests
Authors: Blodgett Robert J , Hitchins Anthony D
Published: February 2020

A typical qualitative microbiological method performance (collaborative) study gathers a data set of responses about a test for the presence or absence of a target microbe. We developed 2 models that estimate false-positive and false-negative rates. One model assumes a constant probability that the tests will indicate the target microbe is present for any positive concentration in the test portion. The other model assumes that this probability follows a logistic curve. Test results from several method performance studies illustrate these estimates.
Determination of α-Solanine and α-Chaconine in Potatoes by High-Performance Thin-Layer Chromatography/Densitometry
Authors: Bodart Patricia , Kabengera Charles , Noirfalise Alfred , Hubert Philippe , Angenot Luc
Published: February 2020

A high-performance thin-layer chromatographic (HPTLC) method was used to determine the glycoalkaloids α-solanine and α-chaconine in potatoes. α-Solanine and α-chaconine are extracted from dehydrated potatoes with boiling methanol–acetic acid (95 + 5, v/v). The analytes are separated on a Silica Gel 60 F254 HPTLC plate by a saturated mixture of dichloromethane–methanol–water–concentrated ammonium hydroxide (70 + 30 + 4 + 0.4, v/v), which is used for vertical development of the plate up to a distance of 85 mm. For visualization, the plate is dipped 3 times into a modified Carr-Price reagent, 20% (w/v) antimony(III) chloride in acetic acid–dichloromethane (1 + 3, v/v), and subsequently heated on a hot plate at 105°C for 5 min. The glycoalkaloids all appear as red chromatographic zones on a colorless background. Densitometric quantification is performed at 507 nm by reflectance scanning. After determination of the appropriate response function, the proposed method was validated. Good results with respect to linearity, accuracy, and precision were obtained in the concentration range studied.
Simultaneous Determination of Bergenin and Gallic Acid in Bergenia ligulata Wall by High-Performance Thin-Layer Chromatography
Authors: Chauhan Sateesh K , Singh Brijpal , Agrawal Sudhakar
Published: February 2020

A simple and reproducible high-performance thin-layer chromatographic method was developed for the simultaneous determination of bergenin and gallic acid in Bergenia ligulata. Water and methanol were used as the extracting solvents. The concentrations of bergenin and gallic acid in both of these solvents were found to be almost the same. The method involves separation of the components by thin-layer chromatography on a precoated Silica Gel 60 F254 plate with a solvent system of ethyl acetate–formic acid–acetic acid–water (100 + 11 + 11 + 27). The sensitivity of the method for bergenin was 0.30 μg, whereas for gallic acid it was 0.25 μg. The proposed method is precise and sensitive and can be used for the detection, monitoring, and simultaneous quantification of bergenin and gallic acid in B. ligulata.
Electroanalytical Determination of Cadmium and Lead in Deciduous Teeth after Microwave Oven Digestion
Authors: Bayo Javier , Moreno-Grau Stella , Martínez M José , Moreno José , Angosto José M , Moreno-Clavel Joaquín , Pérez José J Guillén , Marcos Luis García
Published: February 2020

A method using differential pulse anodic stripping voltammetry after microwave oven digestion was developed for the simultaneous determination of Cd(II) and Pb(II) in the deciduous teeth of children. Each tooth was weighed; deposited in a 120 mL capped Teflon vessel with 5 mL 65% nitric acid, Suprapur analytical grade; and digested in a 2-step microwave oven for 15 min. The detection limits for Cd(II) and Pb(II) in the final solution were 0.078 and 0.323 μg/L, and the quantitation limits 0.394 and 1.613 μg/L, respectively, with a linearity range of 2 μg/L for Cd(II) and 23.3 μg/L for Pb(II). The sensitivity was 2.51 nA/μg-L and 1.37 nA/μg-L, for Cd(II) and Pb(II). The main advantages of this technique are a complete and satisfactory dissolution of the tooth material with the proposed microwave oven digestion procedure, without sample pretreatments, such as drying, ashing, or powdering. The voltammetric procedure proved to be well designed because of significant goodness of fit to a linear model, and the accuracy of the method was established as compared with standard reference material. The methodology has enabled us to study Cd(II) and Pb(II) in 371 deciduous teeth from school children in Cartagena, Spain.
Polyclonal-Based ELISA for the Identification of Cyclohexanedione Analogs that Inhibit Maize Acetyl Coenzyme-A Carboxylase
Authors: Webb Steven R , Hall J Christopher
Published: February 2020

Cyclohexanedione herbicides inhibit monocotyledonous acetyl coenzyme-A carboxylase (ACCase; E.C. 6.4.1.2.), which catalyzes the first committed step in fatty acid biosynthesis. Although the target site has been identified, little is known about the mechanisms involved in herbicide binding. An immunological study was undertaken to create a model to better characterize the herbicide–enzyme interaction. Cyclohexanedione-specific antiserum was raised in New Zealand white rabbits by immunizing them with a cyclohexanedione analog–bovine serum albumin conjugate. Two indirect enzyme-linked immunosorbent assays (ELISA) were developed using 2 different cyclohexanedione analogs conjugated to ovalbumin as coating conjugates. Nineteen cyclohexanedione analogs, 13 active ACCase inhibitors, and 6 inactive analogs were tested for their ability to compete with both coating conjugates for antiserum binding. All active ACCase inhibitors were observed to compete with both coating conjugates, whereas all inactive analogs failed to compete with at least one coating conjugate. On the basis of these results, the immunological model could be used to distinguish all active ACCase inhibitors from inactive analogs using the 2 ELISAs sequentially.
Analytical Study of Comprehensive and Targeted Multidimensional Gas Chromatography Incorporating Modulated Cryogenic Trapping
Authors: Truong Thy T , Marriott Philip J , Porter Nichola A
Published: February 2020

This paper reports the results of an analytical study comparing capillary gas chromatography (GC) operated in the normal mode with 2 new GC techniques, comprehensive GC (GC × GC) and targeted (or selective) multidimensional GC, which use a longitudinally modulated cryogenic system (LMCS), recently developed in our laboratory. A high-temperature application of derivatized sterols, of interest in fecal pollution monitoring, was chosen for this work. A directly connected coupled-column ensemble was used, comprising a nonpolar column and a moderately polar column. With LMCS, effluent from the first column is zone-compressed in a cryogenic trap and then pulsed to a short second column, producing narrower peaks with sharp, tall peak responses at the detector. The modulator is operated at a constant frequency, e.g., 0.25 s−1, to produce the GC × GC result, or is moved in a predefined manner so that whole peaks are selectively trapped and subsequently pulsed through to the second column in the targeted mode. Standard solutions containing a mixture of 7 sterols and 5-α-cholestane internal standard were used. Detection sensitivity is increased by a factor of ≥25 with the use of LMCS. The estimated limit of detection was about 0.1 μg/mL when normal GC with flame ionization detection (GC/FID) and a 1.0 μL splitless injection volume were used, compared with 0.02 and 0.004 μg/mL for the LMCS operated in GC × GC and selective modes, respectively. Calibration curves for GC/FID were linear over the 0.1–2.0 μg/mL range tested. Reproducibilities for the GC × GC and normal GC modes were comparable; generally, relative standard deviations (RSD) were on the order of 3–4%, based on raw peak responses. Improved reproducibility was found for selective LMCS operation, at an RSD of around 2%; with internal standardization, better results were achieved. The coupled-column arrangement allowed complete separation of sterol peaks from overlapping impurity peaks in a number of instances with LMCS modes, and its use should improve data quality over that of normal GC operation, in which the overlapping peaks interfere with measurement of peak response in the normal mode.
Determination of Phthalates in Crude Extracts of Sewage Sludges by High-Resolution Capillary Gas Chromatography with Mass Spectrometric Detection
Authors: Berset Jean-Daniel , Etter-Holzer Ruth
Published: February 2020

A simple solvent extraction by ethyl acetate without subsequent cleanup was used to determine 16 phthalic acid esters (PAEs), including bis(2-ethylhexyl) phthalate (DEHP), in sewage sludge samples from different catchment areas. The compounds were separated on a gas chromatographic capillary column with a nonpolar HT-8 stationary phase. For most of the PAEs, internal standard quantification with deuterated dibutyl phthalate (DBP) and deuterated DEHP was best achieved by using electron ionization mass spectrometry in the selected-ion monitoring mode. Because of its high concentrations in the sludges, DEHP was quantified in the full-scan acquisition mode. Molecular weight and ester-type information for the PAEs was obtained in the positive chemical ionization mode with methane as the reagent gas. Finally, selected sewage sludges containing different amounts of industrial wastewater were analyzed by the proposed method. DEHP was the most abundant compound found at 21–114 mg/kg·dm, followed by the lower-molecular weight PAEs diethyl phthalate, diisobutyl phthalate, and DBP and the higher-molecular weight compounds butylbenzyl phthalate, dicyclohexyl phthalate, di-n-octyl phthalate, and dinonyl phthalate, which were present mostly at <1 mg/kg·dm.
Solid-Phase Microextraction for the Enantiomeric Analysis of Flavors in Beverages
Authors: Ebeler Susan E , Sun Gay M , Datta Meera , Stremple Phil , Vickers Allen K
Published: February 2020

Solid-phase microextraction combined with gas chromatographic/mass spectrometric analysis and separation on a chiral cyclodextrin stationary phase was a rapid, reliable technique for profiling chiral aroma compounds in flavored alcoholic beverages. Several enantiomeric terpenes, esters, alcohols, norisoprenoids, and lactones were identified in berry-, peach-, strawberry-, and citrus-flavored wine and malt beverages (wine coolers). Using this technique, we were able to confirm the addition of synthetic flavoring to several beverages, consistent with label designations.
Complexation Equilibria and Spectrophotometric Determination of Iron(III) with Resorcylic Acid
Authors: Hashem Elham Y
Published: February 2020

The complexation equilibria of Fe(III) with resorcylic acid (2,4-dihydroxybenzoic acid, DHB) were studied spectrophotometrically in ethanol–water (4 + 6, v/v) at an ionic strength of 0.1M NaClO4. The complexation reactions were demonstrated and characterized. A simple, rapid, and sensitive method based on the formation of the Fe(III)–DHB complex at pH 2.5 (λmax = 520 nm, ε = 0.8 × 104 L/mol·cm) was developed for the spectrophotometric determination of Fe(III). The effect of diverse ions on the sensitivity of the proposed method was studied. The Fe–DHB complex was isolated and characterized by both elemental analysis and infrared spectroscopy. The thermal behavior of the complex in dynamic nitrogen gas was studied by thermogravimetric and differential thermogravimetric analysis. Thermal events encountered throughout the course of decomposition were monitored. A computer program was used for regression analysis and for determination of kinetic and thermodynamic parameters from experimental nonisothermal thermogravimetric data. The proposed method was tested by determinations of iron in various synthetic samples and Portland cement materials.
Variations of Moisture Measurements in Cheese
Authors: Emmons Douglas B , Bradley Robert L , Sauvé J Paul , Campbell Carol , Lacroix Christophe , Jimenez-Marquez Sergio A
Published: February 2020

Data were accumulated during interlaboratory trials for cheese moisture determination from laboratories using officially recognized methods: AOAC; International Dairy Federation, and Standard Methods for the Examination of Dairy Products (SM). In one trial, ranges of means of 5 cheeses were 0.67, 0.56, and 0.19% for 5, 9, and 8 laboratories, respectively. The lower ranges for the SM method were typical of 3 other interlaboratory trials, with ranges of 0.27, 0.34, and 0.34% for 6, 7, and 5 laboratories, respectively. Within one laboratory, there were no significant differences among the 3 methods, but they all gave about 0.2% lower results than 2 other methods, one using freeze-drying, followed by drying in a vacuum, the other using cheese that was spread on sand and dried in a vacuum oven for 24 h. This finding indicated that none of the officially recognized methods removed all the moisture. Data showed that many laboratories tended to give either higher or lower results than the mean of all of them in a series of 7 interlaboratory trials. Constant results, free of biases or systematic errors, are important in application of formulas for prediction of yield of cheese for purposes of yield control, but are difficult to obtain. It is proposed that results by a laboratory in interlaboratory trials be compared with those obtained by one or more reference laboratories using a method that removes all the moisture from cheese. The difference would be applied as a constant in the predictive yield formula. That difference would likely be best as a running mean of differences in an ongoing series of trials. The reference laboratories would use frozen samples for quality control to ensure uniformity of results among trials. Mean moistures of 36.10 and 36.11% were obtained on subsamples before and after freezing for 7 months.
Reveal 8-Hour Test System for Detection of Escherichia coli O157:H7 in Raw Ground Beef, Raw Beef Cubes, and Iceberg Lettuce Rinse: Collaborative Study
Authors: Bird Charles B , Hoerner Rebecca J , Restaino Lawrence ,   Collaborators:, Anderson G , Birbari W , Bodra L , Brookman D , Bryant D , Campbell C , Degraft-Hanson J , Fetviet D , Forde R , Goins D , Hajkowski S , Haley E , Holland R , Jones J , Joseph J M , Kallewaard N , Keckeissen J , Kirkbride T , Kusch S , Noel D , Nutsch A , Okolo C , Parks K , Raines D , Remes A , Roach V , Robbins R , Rodrick G , Shelef L , Theissen H , Vasavada P C , Wang T
Published: February 2020

Five different food types were analyzed by the Reveal for E. coli O157:H7 8-Hour Test System (Reveal 8) and either the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) culture method or the U.S. Department of Agriculture Food Safety Inspection Service (FSIS) culture method for the presence of E. coli O157:H7. A total of 27 laboratories representing academia and private industry in the United States and Canada participated. Food types were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. During this study, 1110 samples and controls were analyzed by both the Reveal 8 and by BAM or FSIS by each of the collaborators (2220 samples in total). For each set of samples, 740 were artificially inoculated with E. coli O157:H7, and 370 were uninoculated controls. The Reveal 8 detected 528 presumptive positives of which 487 were confirmed positive by the BAM culture method. In comparison, BAM and FSIS detected 489 of the 740 artificially contaminated samples as positive. In an additional in-house study performed only on chilled and frozen raw ground beef, 240 artificially inoculated samples were analyzed by both the Reveal 8 and by FSIS. The Reveal 8 detected and confirmed 104 samples as positive compared to 79 confirmed positive by FSIS.
Determination of Ephedrine-Type Alkaloids in Dietary Supplements by LC/MS Using a Stable-Isotope Labeled Internal Standard
Authors: Gay Martha L , White Kevin D , Obermeyer William R , Betz Joseph M , Musser Steven M
Published: February 2020

Arapid, isocratic method for the separation of 6 ephedrine-type alkaloids which may occur in dietary supplements was modified to permit quantitation and confirmation by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization. Several columns and sets of conditions were examined for suitability and the results compared. The use of ion-pairing reagents to enhance resolution is also reported. Mass spectrometric conditions were adjusted to provide sufficient fragmentation for qualitative identification of the analytes. Stable-isotope labeled ephedrine was used as an internal standard for quantitation.
Gas Chromatography with Pulsed Flame Photometric Detection Multiresidue Method for Organophosphate Pesticide and Metabolite Residues at the Parts-Per-Billion Level in Representative Commodities of Fruit and Vegetable Crop Groups
Authors: Podhorniak Lynda V , Negron Juan F , Griffith Francis D
Published: February 2020

A gas chromatographic method with a pulsed flame photometric detector (P–FPD) is presented for the analysis of 28 parent organophosphate (OP) pesticides and their OP metabolites. A total of 57 organophosphates were analyzed in 10 representative fruit and vegetable crop groups. The method is based on a judicious selection of known procedures from FDA sources such as the Pesticide Analytical Manual and Laboratory Information Bulletins, combined in a manner to recover the OPs and their metabolite(s) at the part-per-billion (ppb) level. The method uses an acetone extraction with either miniaturized Hydromatrix column partitioning or alternately a miniaturized methylene dichloride liquid–liquid partitioning, followed by solid-phase extraction (SPE) cleanup with graphitized carbon black (GCB) and PSA cartridges. Determination of residues is by programmed temperature capillary column gas chromatography fitted with a P–FPD set in the phosphorus mode. The method is designed so that a set of samples can be prepared in 1 working day for overnight instrumental analysis. The recovery data indicates that a daily column-cutting procedure used in combination with the SPE extract cleanup effectively reduces matrix enhancement at the ppb level for many organophosphates. The OPs most susceptible to elevated recoveries around or greater than 150%, based on peak area calculations, were trichlorfon, phosmet, and the metabolites of dimethoate, fenamiphos, fenthion, and phorate.
Determination of Pesticides in Composite Dietary Samples by Gas Chromatography/Mass Spectrometry in the Selected Ion Monitoring Mode by Using a Temperature-Programmable Large Volume Injector with Preseparation Column
Authors: Rosenblum Laura , Hieber Thomas , Morgan Jeffrey
Published: February 2020

Use of a temperature-programmable preseparation column in the gas chromatographic (GC) injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reducing sample preparation time and solvent consumption. Dietary samples are mixed with diatomaceous earth and are Soxhlet-extracted with an azeotropic solution of hexane and acetone. Sample preparation uses liquid–liquid partitioning over diatomaceous earth followed by normal phase chromatography over partially deactivated alumina. The final cleanup step occurs in a preseparation column in the GC injector, which is able to perform splitless transfer of the analytes to the analytical column and purge 99% of the high molecular weight residue. Detection is performed by GC/mass spectrometry (MS) in the selected ion monitoring mode. Method detection limits were at or below 2 ng/g for 24 of 35 pesticides studied, with recovery between 70 and 125% for 27 pesticides in samples fortified at 10 ng/g. Recovery was not dependent on fat content when measured in laboratory fortified samples containing 1, 5, and 10% fat by weight. Precision over multiple injections was acceptable, with a relative standard deviation of 2.6–15% for 25 analytes.
Determination of Azadirachtin in Agricultural Matrixes and Commercial Formulations by Enzyme-Linked Immunosorbent Assay
Authors: Hemalatha Kalidindi , Venugopal Namburi B K , Venugopal Namburi B K , Rao Beedu S
Published: February 2020

An enzyme-linked immunosorbent assay (ELISA) was developed for azadirachtin (aza), a biopesticide from the neem tree (Azadirachta indica A. Juss). The immunogen was synthesized by epoxidation using the furan ring in the aza molecule. Rabbits were immunized with either bovine serum albumin (BSA)-azadirachtin or ovalbumin (OA)-azadirachtin conjugate. Evaluation of the antisera by antibody capture assay showed that the antibody titer of antisera raised against OA-aza was 1:30 000. An indirect competitive ELISA was developed with BSA-azadirachtin as coating antigen and aza-specific antibodies raised against OA-aza immunogen. The immunoassay showed an inhibitory concentration (IC50) value of 75 ppb, with a range of detection from 0.5 to 1000 ppb for azadirachtin [based on regression analysis, y = 85.87 (−18.89x); r2 = −0.97]. Cross-reactivity of the antibodies with 2 aza- derivatives (22,23-dihydro-23β-methoxy azadirachtin and 3-tigloylazadirachtol) was 33 and 29%, respectively. The indirect competitive ELISA was validated and evaluated by quantitating aza in spiked agricultural commodities and from neem formulations. Azadirachtin was spiked into 5 different agricultural commodities: tomato, brinjal, coffee, tea, and cotton seed at 500 and 1000 ppb and recovered at 62–100%. In samples drawn from 6 lots, the aza content in neem-seed kernels ranged from 0.1 to 0.15%; in commercial neem formulations the content ranged from 200 to 2000 ppm. The method developed may be applied to environmental monitoring of aza and quality assurance studies of aza-based commercial formulations.
Spectrofluorimetric Determination of Vigabatrin and Gabapentin in Dosage Forms and Spiked Plasma Samples Through Derivatization with 4-Chloro-7-Nitrobenzo-2-Oxa-1,3-Diazole
Authors: Hassan Ekram M , Belal Fathalla , Al-Deeb Omar A , Khalil Nasr Y
Published: February 2020

A highly sensitive and specific method is proposed for the determination of vigabatrin (I) and gabapentin (II) in their dosage forms and spiked human plasma. The method is based on coupling the drugs with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole in borate buffer at pH 7.1 and measuring the resulting fluorescence at 532 nm after excitation at 465 nm. The fluorescence intensity was a linear function of the concentration of the drugs over the ranges of 1.3–6.5 and 1.7–8.5 μg/mL for I and II, respectively. Minimum detectability values were 0.54 μg/mL (4.2 × 10−6M) and 0.97 μg/mL (5.7 × 10−6M) for I and II, respectively, under the described conditions. The proposed method was successfully applied to the determination of the 2 drugs in their dosage forms, and the percent recoveries ± standard deviation (SD) were 104.53 ± 1.2 and 100.00 ± 1.32 of the label claim for I and II, respectively. The method was further applied to the determination of vigabatrin in spiked plasma samples. The percent recovery ± SD was 101.58 ± 2.68. Interference from endogenous α-amino acids was overcome through selective complexation with freshly prepared Cu(OH)2. The interference likely to be encountered from co-administered drugs, such as carbamazepine, cimetidine, clonazepam, clopazam, phenobarbital, valproic acid, and lamotrigine, was also studied. A reaction pathway is suggested.
Characterization of Partially Transesterified Poly(β-Hydroxyalkanoate)s by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry
Authors: Saeed Kamal A , Ayorinde Folahan O , Eribo Broderick E , Gordon Michael , Collier Ledelle
Published: February 2020

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used for the characterization of a partially transesterified poly(β-hydroxyalkanoate) (PHA), a polymer produced by the bacterial strain Alcaligenes eutrophus with saponified vegetable oils as the sole carbon sources. The transesterification was carried out separately under acidic and basic conditions to obtain PHA oligomers weighing <10 kDa. The intact oligomers were detected in their cationized forms, [M + Na]+ and and [M + K]+, by MALDI–TOFMS. A composition analysis, using the MALDI-TOF spectra, indicated that the oligomers obtained via acid catalysis contained a methyl 3-hydroxybutyrate end group, and those obtained by base catalysis had a methyl crotonate (olefinic) end group. In addition to hydroxybutyrate (HB), the oligomers were found to contain a small percentage of hydroxyvalerate, which was independently confirmed by gas chromatography/mass spectrometry. In comparison, analysis of a commercial PHA polymer, transesterified under identical conditions, showed only the presence of HB, i.e., a pure poly(HB) homopolymer.
Quantitation of Volatile Oils in Ground Cumin by Supercritical Fluid Extraction and Gas Chromatography with Flame Ionization Detection
Authors: Heikes David L , Scott Brendan , Gorzovalitis Nick A
Published: February 2020

Ground cumin is used as a flavoring agent in a number of ethnic cuisines. The chemical entities, which primarily establish its characteristically pungent flavor, are found in the volatile oil of cumin. Fixed oils and carbohydrates tend to round out the harshness of the volatile oil components. However, the quantity of volatile oil is commonly the measure of the quality of this spice. For several decades, the spice industry has used a classical distillation procedure for the determination of volatile oil in cumin and other spices. However, the method is cumbersome and requires nearly 8 h to complete. Supercritical fluid extraction with capillary gas chromatography–flame ionization detection is utilized in the formulation of a rapid, accurate, and specific method for the determination of volatile oil in ground cumin. Samples are extracted in a static-dynamic mode with CO2 at 550 bar and 100°C. Toluene is used as a static modifier addition. The extracted volatile oil, collected in toluene, is analyzed directly using tetradecane as the internal standard. Integration is performed as grouped peaks to include all chemical entities found in cumin volatile oil recovered from the official distillation procedure. Results from this procedure compare favorably with those obtained by the official procedure (coefficient of correlation = 0.995, 24 samples).
Validation and Quality Assurance of Planar Chromatographic Procedures in Pharmaceutical Analysis
Authors: Ferenczi-Fodor Katalin , Végh Zoltán , Nagy-Turák Anikó , Renger Bernd , Zeller Marco
Published: February 2020

Within the process of the International Conference on Harmonization (ICH), 2 guidelines were released containing a standardized terminology, a verified model of requirements for the validation of analytical procedures, and some guidance in the practical aspects of conducting validation studies in pharmaceutical analysis. For planar chromatographic procedures, which may be used at different levels either in qualitative identity testing, assays, semiquantitative limit tests, or quantitative determination of impurities, this paper tries to transfer these formal requirements into practical approaches for validation. Basic acceptance criteria for evaluation of validation experiments based on practical experience are proposed. In addition, selected parameters for robustness testing of given procedures and quality assurance of quantitative planar chromatographic testing by control charts is described.
Validation of a UV Spectrophotometric Method for the Determination of Melatonine in Solid Dosage Forms
Authors: Pérez Renato F , Lemus Igor G , Bocic Rony V , Pérez Mauricio V , García-Madrid Rubén
Published: February 2020

The aim of the work described in this paper was to provide a fast, easy, inexpensive, precise, and accurate method for the determination of melatonine in solid pharmaceutical dosage forms. The developed method is based on a UV first-derivative spectrophotometric determination, which exhibits excellent linearity in aqueous solutions (r2 = 0.996) for analyte concentrations of 1.5–4.5 mg/dL within a pH range of 5–9. Neither excipients present in the formulation nor indole adulterants, such as tryptophan (up to 5%), interfere with the assay. A study of variation parameters showed that sonication temperature was the main factor for successful determination. At temperatures of <45°C, the sample dissolved completely, and accurate spectrophotometric measurements were obtained. A study was conducted of all the parameters established by the United States Pharmacopeia, 23rd Rev., to validate an analytical method for a solid pharmaceutical form, i.e., linearity, range, accuracy, precision, and specificity. All the parameters were in accordance with the acceptance criteria of the Comité de Guías Oficiales de Validación de la Dirección General de Control de Insumos para la Salud de Méjico. In addition, robustness and content uniformity tests were performed to substantiate the usefulness of the method.
Petrifilm™ Rapid S. aureus Count Plate Method for Rapid Enumeration of Staphylococcus aureus in Selected Foods: Collaborative Study
Authors: Silbernagel Karen M , Lindberg Kathryn G ,   Collaborators:, Ary M , Bannach B , Barbour M , Battista K , Bauten H , Beatty S , Bogar S , Buczek L , Bulthau M , Burnett T , Carver C , Cha K , Cooper L , D’Andrea L , Davis B , Fain A , Feiler B , Fender M , Hirt W , Iannucci M , Jackson J K , Jensen D , Johnson K , Julien-Davis G , Kempf A , Krone P , Kusch S , LaPointe A , Leiva B R , Lewandowski V , Lewis J , Maycock L , Mebs D , McCann T , Moulsoff M , Newcomer C , Ooya M , O’Shea P , Otten N , Reed J , Remes A , Resutek J , Rukamp B , Rukamp S , Saito A , Shafie A , Smith A , Tabatt J , Tanaka H , Torrance H , VandeVoort M , Wang D , Windsor S , Xiong Y , Zebchuck A
Published: February 2020

A rehydratable dry-film plating method for Staphylococcus aureusin foods, the 3M™ Petrifilm™ Rapid S. aureus Count Plate method, was compared with AOAC® Official MethodSM 975.55 (Staphylococcus aureus in Foods). Nine foods—instant nonfat dried milk, dry seasoned vegetable coating, frozen hash browns, frozen cooked chicken patty, frozen ground raw pork, shredded cheddar cheese, fresh green beans, pasta filled with beef and cheese, and egg custard—were analyzed for S. aureus by 13 collaborating laboratories. For each food tested, the collaborators received 8 blind test samples consisting of a control sample and 3 levels of inoculated test sample, each in duplicate. The mean log counts for the methods were comparable for pasta filled with beef and cheese; frozen hash browns; cooked chicken patty; egg custard; frozen ground raw pork; and instant nonfat dried milk. The repeatability and reproducibility variances of the Petrifilm Rapid S. aureus Count Plate method were similar to those of the standard method.
Detection of Hazelnut Oil in Virgin Olive Oil by Assessment of Free Sterols and Triacylglycerols
Authors: Vichi Stefania , Pizzale Lorena , Toffano Emilio , Bortolomeazzi Renzo , Conte Lanfranco
Published: February 2020

Free sterols were evaluated as factors for discriminating between genuine virgin olive oil and hazelnut-mixed virgin olive oil. Numeric analyses of the results amplified the differences between groups. The application of this method to virgin olive oil samples and their mixtures with 10% hazelnut oil distinguished between genuine and nongenuine virgin olive oil with statistical certainty. Triacylglycerol analysis was tested for the same purpose by using parameter ΔECN42, but although it possessed a discriminating capacity, it alone could not distinguish the aforementioned groups with sufficient certainty. Free Δ7-sterols data were combined with ΔECN42 data into a single discriminating function to improve differentiation and bring more ruggedness, and for detection of low amounts (10%) of hazelnut oil in virgin olive oil. In fact, the values obtained by addition of Δ7-sterol data and ΔECN42 data showed a higher discriminating capacity than single parameters. In a single operation the method produced all the oil fractions necessary for analysis of free sterols and triacylglycerols with ECN42. Solid-phase extraction was applied in substitution of traditional chromatography on a silica column.
Fatty Acid Composition of Chlorella and Spirulina Microalgae Species
Authors: Ötleş Semih , Pire Ruhşen
Published: February 2020

Two New Age foods which contain high concentrations of whole food nutrients are the single-celled microalgae Chlorella and Spirulina. They are accepted as functional foods, which are defined as products derived from natural sources, whose consumption is likely to benefit human health and enhance performance. These foods are used as a supplement/ingredient or as a complete food to enhance the performance and state of the human body, or improve a specific bodily function. Functional foods are used mainly as products to nourish the human body after physical exertion or as a preventive measure against ailments. We determined the fatty acid compositions, particularly polyunsaturated fatty acid compositions, of Chlorella and Spirulina by capillary column-gas chromatography. The data obtained show that Spirulina contains unusually high levels of gamma-linolenic acid, an essential polyunsaturated fatty acid.
Liquid Chromatography/Electrospray Ionization/Isotopic Dilution Mass Spectrometry Analysis of n-(Phosphonomethyl) Glycine and Mass Spectrometry Analysis of Aminomethyl Phosphonic Acid in Environmental Water and Vegetation Matrixes
Authors: Grey Lorna , Nguyen Bick , Yang Paul
Published: February 2020

A liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) method was developed for the analysis of glyphosate (n-phosphonomethyl glycine) and its metabolite, aminomethyl phosphonic acid (AMPA) using isotope-labelled glyphosate as a method surrogate. Optimized parameters were achieved to derivatize glyphosate and AMPA using 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer prior to a reversedphase LC analysis. Method spike recovery data obtained using laboratory and real world sample matrixes indicated an excellent correlation between the recovery of the native and isotope-labelled glyphosate. Hence, the first performance-based, isotope dilution MS method with superior precision, accuracy, and data quality was developed for the analysis of glyphosate. There was, however, no observable correlation between the isotope-labelled glyphosate and AMPA. Thus, the use of this procedure for the accurate analysis of AMPA was not supported. Method detection limits established using standard U.S. Environmental Protection Agency protocol were 0.06 and 0.30 μg/L, respectively, for glyphosate and AMPA in water matrixes and 0.11 and 0.53 μg/g, respectively, in vegetation matrixes. Problems, solutions, and the method performance data related to the analysis of chlorine-treated drinking water samples are discussed. Applying this method to other environmental matrixes, e.g., soil, with minimum modifications is possible, assuring accurate, multimedia studies of glyphosate concentration in the environment and the delivery of useful multimedia information for regulatory applications.
Method of Determination of Appropriate Heat Treatment of Animal Meal by Immunoassay Developed for Detection of Cooked Beef: Interlaboratory Study
Authors: Björklund Erland , Pallaroni Lea , Holst Christoph von , Unglaub Wolfgang ,   Collaborators:, Bosch J , Calderon-Alvarez F , Costa J , Cowles J , Gaede W , Krause M , Marmo S , Pecoraro S , Reaney S , Sutton M , Thiele D , Wolf C
Published: February 2020

An interlaboratory trial was conducted for the validation of an enzyme-linked immunosorbent assay (ELISA) method for determination of appropriate heat treatment of animal meal. A commercially available ELISA test kit developed for the identification of beef in cooked food was used in the study. Twelve laboratories from 7 European countries examined 2 different analytical protocols to establish the most appropriate analytical method. Three different samples were used, 2 animal waste materials sterilized at 129 and 134°C (wet conditions), respectively, and a meat and bone meal material processed at dry conditions (maximum temperature, 140°C). Statistical evaluation applying t-statistics showed that the animal meal treated according to European legislation (>133°C) was clearly distinguishable from the 2 other test materials at a 99% confidence level using both analytical protocols. This method can be considered as a complementary test to the immunoassay developed for the detection of pork in cooked food that is already applied in routine analysis for the surveillance of rendering plants.