bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Ketoconazole in Capsules by High-Performance Liquid Chromatography and Microbiological Assay
Authors: Lima Paulo Marcelo Andrade , Prado Nathália Duque , Silva Maria-Luiza Martins , Diniz Rosiane Dias Lopes , Queiroz Kelly Marques , Da Costa César Isabela , Pianetti Gérson Antônio , Santos Daniel Assis
Published: February 2020

The development and validation of an HPLC-UV method and a microbiological assay were performed for the analysis of ketoconazole in capsule formulations. The bioassay was developed using a specific agar diffusion technique with the strain of Candida albicans ATCC 18804 as the test organism. The effect of the mobile phase pH in the range of 2.57.5 on the retention and tailing factors of the ketoconazole peak was analyzed in the chromatography method and a pH value of 4.5 was considered to be adequate. A prospective validation of both methods showed adequate linearity (r2 > 0.99 for the two methods), precision, (RSD = 2.42 for intraday and 2.69 for interday precision for bioassay; RSD = 0.74 for intraday and 0.66 for interday precision for HPLC-UV), and accuracy (mean recoveries were 103 1.0 for bioassay and 99 1.0 for HPLC-UV). Student's t-test revealed no significant difference between the results obtained by the two methods (P < 0.05). The contents found for three capsule samples showed a strong correlation, as attested by Pearson's coefficient value (r = 0.9998), which also evidenced the concordance between the studied methodologies.
Simultaneous Determination of Alprazolam and Fluoxetine Hydrochloride in Tablet Formulations by High-Performance Column Liquid Chromatography and High-Performance Thin-Layer Chromatography
Authors: Patel Rashmin B , Patel Mrunali R , Shankar Madhira B , Bhatt Kashyap K
Published: February 2020

This paper describes validated HPLC and HPTLC methods for simultaneous determination of alprazolam (ALP) and fluoxetine hydrochloride (FXT) in pure powder and formulation. The HPLC separation was achieved on a Nucleosil C8 column (150 mm length, 4.6 mm id, 5 m particle size) using acetonitrilephosphate buffer pH 5.5 (45 + 55, v/v) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using acetonetolueneammonia (6.0 + 3.5 + 0.5, v/v/v) as the mobile phase. Quantification in the HPLC method was achieved with UV detection at 230 nm over the concentration range 414 g/mL for both drugs, with mean recovery of 99.95 0.38 and 99.85 0.56 for ALP and FXT, respectively. Quantification in the HPTLC method was achieved with UV detection at 230 nm over the concentration range of 4001400 ng/spot for both drugs, with mean recovery of 99.32 0.45 and 99.78 0.81 for ALP and FXT, respectively. These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of ALP and FXT in pure powder and formulations.
Determination of Aflatoxins and Ochratoxin A in High-Sugar-Content Traditional Turkish Foods by Affinity Column Cleanup and LC Fluorescence Detection
Authors: Senyuva Hamide Z , Cimen Dilek , Gilbert John
Published: February 2020

The effectiveness of an affinity column cleanup procedure followed by LC with fluorescence detection was established for the determination of aflatoxins and ochratoxin A in high-sugar-content traditional Turkish foods. Traditional foods, such as baklava (finely layered pastry filled with nuts and steeped in syrup), halvah (containing sesame paste and pistachios), cevizli sucuk (a confection made of grape juice boiled and dried on strings of nuts), Turkish delight (containing hazelnuts, pistachios, or walnuts), and pimaniye (candy made of sugar, butter, and flour), were tested, and the performance of the method was established with spiked samples. To examine the robustness of the methodology, baklava was prepared from raw materials and spiked at the initial stage of dry ingredients and through subsequent stages of preparation of dough, after cooking, and after addition of syrup and nuts. For all products, the analytical method required grinding the composite foodstuff under liquid nitrogen to form a fine powder, which was then thoroughly mixed before subsampling. After vortex extraction into methanolwater (aflatoxins) and aqueous sodium bicarbonate (ochratoxin A), the sample was filtered, diluted with phosphate-buffered saline, and then passed through either an aflatoxin or ochratoxin A affinity column before HPLC analysis with fluorescence detection (using post-column bromination for the aflatoxins). In all the traditional Turkish products, the recovery of aflatoxin B1 ranged from 77 to 98, and LODs were <0.1 g/kg. For ochratoxin A, the recoveries were from 88 to 93 and LODs were similarly <0.1 g/kg. Despite the complex nature of these traditional Turkish foods, which frequently contain products from sugar caramelization, there was no evidence of any interfering co-extractives, and the method has proved to be robust enough to be used for food control purposes.
Reprocessing and Sterilization of Single-Use Electrophysiological Catheters: Removal of Organic Carbon and Protein Surface Residues
Authors: Lester Bruce R , Boser Nicole P , Miller Keith , Schnapf Mark , Jacques Beth A , Sullivan Brian F , Marchin George L
Published: February 2020

Although evidence to date indicates that reprocessing electrophysiological (EP) catheters results in clean, sterile devices, some concerns persist with regard to the risk of residual contamination. We examined the ability of a defined reprocessing procedure coupled with a validated sterilization protocol to remove organic carbon and protein residues from worst-case soiled EP catheters resulting in clean, sterile devices. Total organic carbon (TOC) determinations indicated that detergent residues on reprocessed used catheters were nominal and significantly lower than organic carbon levels present on new catheters. Determination of the mean residual organic carbon and protein contaminants on soiled and reprocessed EP catheters further indicated that TOC and protein were reduced (99 of residue removed) below previously reported levels and current accepted standards. Moreover, reprocessed end-of-life catheters (six clinical uses, plus five reprocessings) were examined for residual microorganisms and found to be sterile. End-of-life catheters that had been inoculated with >106 CFU Bacillus atrophaeus spores and subjected to a half-cycle ethylene oxide exposure were also found to be sterile. Our data indicate that EP catheter cleaning and reprocessing using defined protocols effectively removes detergent residues and biological contamination, and provides sterile devices.
Consumption and Health Effects of Trans Fatty Acids: A Review
Authors: Teegala Shyam Mohan , Willett Walter C , Mozaffarian Dariush
Published: February 2020

Consumption of industrially produced Trans fatty acids (TFA) remains high in many populations, particularly in developing nations where partially hydrogenated vegetable oils are frequently used for home cooking and among individuals in developed countries having high intakes of bakery or processed foods. Well-controlled observational studies and randomized trials indicate that TFA consumption adversely affects multiple risk factors for chronic diseases, including numerous blood lipids and lipoproteins, systemic inflammation, endothelial dysfunction, and possibly insulin resistance, diabetes, and adiposity. Growing evidence for the latter effects is particularly concerning given the worldwide obesity pandemic and high contents of industrially produced TFA in many foods marketed toward children. Consistent evidence from prospective observational studies of habitual TFA consumption and retrospective observational studies using TFA biomarkers indicates that TFA consumption increases risk of clinical coronary heart disease (CHD). Based on the adverse effects of risk factors and consistent relationships with clinical endpoints, the evidence that TFA consumption increases CHD risk is convincing. Some evidence suggests that TFA consumption may also increase other disease outcomes, but further investigation is needed to confirm the presence and magnitude of such effects. More research is also needed to understand how specific TFA isomers of varying chain length and double bond location may affect different biologic pathways of disease. Both individual- and policy-level initiatives to decrease TFA consumption should continue, particularly in population subgroups and in developing nations with high consumption of partially hydrogenated vegetable oils.
High-Performance Thin-Layer Chromatography Densitometric Determination of β-Sitosterol in Phyllanthus Species
Authors: Sparzak Barbara , Krauze-Baranowska Mirosawa , Pobocka-Olech Loretta
Published: February 2020

An HPTLC densitometric method was established for the determination of -sitosterol in in vitro cultures of some species of the genus Phyllanthus. Two derivatization reagents commonly used in TLC for the visualization and detection of sterols, namely, anisaldehyde reagent and 5 phosphomolybdic acid, were compared with vanillin reagent. The densitometric quantification of -sitosterol was carried out on HPTLC Si60 F254 plates with the mobile phase chloroformhexanemethanol (65 + 30 + 5, v/v/v) at 525 nm. The method was validated for each derivatization reagent in terms of linearity, precision, repeatability, intra- and interday precision, LOD, and LOQ. The presence of -sitosterol was revealed in all analyzed plant material. The concentrations of -sitosterol determined ranged from 0.48 to 2.75 mg/g (dry weight). In addition, traces of -amyrin were detected in some plant samples.
A New, High-Throughput High-Performance Liquid Chromatographic/Mass Spectrometric Assay for Therapeutic Level Monitoring of Digoxin in Human Plasma
Authors: Vlase Laurian , Popa Daniela-Saveta , Muntean Dana , Mihu Dan , Leucuta Sorin
Published: February 2020

A new, high-throughput HPLC/MS assay for the quantification of digoxin in human plasma was developed and validated. The separation was performed on a Zorbax SB-C18 column under isocratic conditions using a 55 + 45 (v/v) mixture of methanol and 0.1 (v/v) formic acid in 10 M sodium acetate as the mobile phase at 45C with a flow rate of 1 mL/min. The detection of digoxin was performed in the selected ion monitoring mode (m/z 803.5). The human plasma samples (0.2 mL) were deproteinized with 7 perchloric acid in water, and aliquots of 20 L from supernatants obtained after centrifugation were directly injected into the chromatographic system. The method showed good linearity (r > 0.9926), precision (CV > 18.9), and accuracy (bias > 5.6) over the range of 0.550 ng/mL plasma. The lower LOQ was 0.5 ng/mL, and the recovery was between 92 and 106. The method is not expensive, it needs a minimum time for plasma sample preparation, and it has a run time of 2.3 min for instrument analysis (the retention time of digoxin was 1.9 min). The developed and validated high-throughput method is very simple, rapid, and efficient, with wide applications in clinical level monitoring, pharmacokinetics, and bioequivalence studies.
Use of Semipermeable Membrane Devices for Monitoring Pesticides in Indoor Air
Authors: Esteve-Turrillas Francesc A , Pastor Agustín , de la Guardia Miguel
Published: February 2020

In this work, 40 pesticides from different categories were analyzed in the air of 20 indoor places that have an intensive use of pesticides. Passive sampling was carried out by using semipermeable membrane devices (SPMDs) deployed for 7 days. SPMDs were analyzed using microwave-assisted extraction and GC/MS. PCB-195 was used as an internal standard. Recoveries ranged between 81 and 108 for many compounds, with RSD values <11. Typical LOD values for 7 days of sampling were from 0.1 to 3.1 ng/m. Propamocarb, propoxur, carbosulfan, pirimicarb, metribuzin, metalaxyl, pendimethalin, oxadiazon, phenothrin, and permethrin were detected in 11 sampling sites, with air concentrations in the range from 1 to 921 ng/m. However, the pesticide levels found cannot be considered a serious health problem according to results from other pesticide monitoring studies.
Determination of Individual Homologues and Total Content of Benzalkonium Chloride by Reversed-Phase High-Performance Liquid Chromatography Using a Short Butyl Column
Authors: Liu Fangzhu , Xiao Kang Ping , Rustum Abu M
Published: February 2020

Benzalkonium chloride (a mixture of alkylbenzyldimethylammonium chlorides that usually contains C-10, C-12, C-14, and C-16 homologues), commonly known as BKC, is used as a bacteriostatic agent in many household, food, and drug products. In this paper, we report a simple, rapid, robust, and stability-indicating reversed-phase HPLC method using a short butyl (C4) column for the simultaneous determination of each individual homologue content, as well as the total concentration of individual homologues in commercial bulk raw material batches of BKC samples. The chromatographic separation was performed on a 5 cm ACE C4 column with mobile phase consisting of water, acetonitrile, and potassium chloride. Even though using a short column can potentially cause some challenges to resolving certain critical pairs of peaks, we have successfully separated all of the analyte peaks (including those from stressed, degraded products) on a short column using an optimal mobile phase.
foodproof Salmonella Detection Kit
Authors: Lindhardt Charlotte , Schönenbrücher Holger , Slaghuis Jörg , Bubert Andreas , Ossmer Rolf , Junge Benjamin , Berghof-Jäger Kornelia , Hammack Thomas
Published: February 2020

The foodproof Salmonella Detection Kit was previously validated in the Performance Tested MethodsSM program for the detection of Salmonella species in a variety of foods, including milk powder, egg powder, coconut, cocoa powder, chicken breast, minced meat, sliced sausage, sausage, smoked fish, pasta, white pepper, cumin, dough, wet pet food, dry pet food, ice cream, watermelon, sliced cabbage, food dye, and milk chocolate. The method was shown to be equivalent to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) and the U.S. Department of Agriculture, Food Safety and Inspection Service's Microbiology Laboratory Guidebook reference culture procedures. In the first Emergency Response Validation (ERV) extension study, peanut butter was inoculated with S. enterica. ser Typhimurium. For the low inoculation level (1.08 CFU/25 g), a Chi-square value of 2.25 indicated that there was no significant performance difference between the foodproof Salmonella Detection Kit and the FDA-BAM reference method. For high-level inoculation (11.5 CFU/25 g) and uninoculated control, there was 100 agreement between the methods. In the second ERV extension study, peanut butter was inoculated with S. enterica. ser Typhimurium. For both inoculation levels (0.1 and 0.5 CFU/25 g by most probable number), Chi-square values of 0 indicated that there was no significant performance difference between foodproof Salmonella Detection Kit and the FDA-BAM reference method.
TaqMan Salmonella enterica Detection Kit
Authors: Tebbs Robert S , Cao Yan Y , Balachandran Priva , Petrauskene Olga , Hammack Thomas
Published: February 2020

Peanut butter spiked with Salmonella enterica ser. Typhimurium was prepared by an independent laboratory and sent to Applied Biosystems to determine the sensitivity and specificity of the TaqMan Salmonella enterica Detection Kit for detecting Salmonella in peanut butter. The samples were spiked at three levels: five no-spike (0 CFU/25 g); 20 low-spike (0.2 CFU/25 g); and 20 high-spike (2 CFU/25 g). They were coded to create a blind set of 45 samples. The samples were processed based on an unpaired test design that included enrichment in buffered peptone water for the candidate method and lactose broth for the reference method. In the candidate method, a 1 mL aliquot of enriched sample was extracted using PrepMan Ultra Sample Preparation Reagent; the sample was amplified on the Applied Biosystems 7500 real-time PCR system, and analyzed for detection of Salmonella using RapidFinder Version 1.0 software. All samples processed by the candidate method were confirmed by culture according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual procedures. Sensitivity, specificity, and Chi-square analysis were calculated by combining candidate method results with those of the reference method that were collected by the independent laboratory. The TaqMan Salmonella enterica Detection Kit showed 40 sensitivity, 100 specificity, and a Chi-square value equal to 1.52. Chi-square analysis indicated the candidate method and the reference method were comparable. Although the candidate method sensitivity was only 40 when compared with the reference method (unpaired samples), the sensitivity was >100 when the candidate method results were compared with those of the confirmation method (same sample enrichment).
DuPont Qualicon BAX System Polymerase Chain Reaction Assay
Authors: Tice George , Andaloro Bridget , Fallon Dawn , Crowley Erin , Remes Amy C , Wallace F Morgan , Hammack Thomas
Published: February 2020

A recent outbreak of Salmonella in peanut butter has highlighted the need for validation of rapid detection methods. A multilaboratory study for detecting Salmonella in peanut butter was conducted as part of the AOAC Research Institute Emergency Response Validation program for methods that detect outbreak threats to food safety. Three sites tested spiked samples from the same master mix according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) method and the BAX System method. Salmonella Typhimurium (ATCC 14028) was grown in brain heart infusion for 24 h at 37C, then diluted to appropriate levels for sample inoculation. Master samples of peanut butter were spiked at high and low target levels, mixed, and allowed to equilibrate at room temperature for 2 weeks. Spike levels were low [1.08 most probable number (MPN)/25 g]; high (11.5 MPN/25 g) and unspiked to serve as negative controls. Each master sample was divided into 25 g portions and coded to blind the samples. Twenty portions of each spiked master sample and five portions of the unspiked sample were tested at each site. At each testing site, samples were blended in 25 g portions with 225 mL prewarmed lactose broth until thoroughly homogenized, then allowed to remain at room temperature for 5565 min. Samples were adjusted to a pH of 6.80.2, if necessary, and incubated for 2226 h at 35C. Across the three reporting laboratories, the BAX System detected Salmonella in 10/60 low-spike samples and 58/60 high-spike samples. The reference FDA-BAM method yielded positive results for 11/60 low-spike and 58/60 high-spike samples. Neither method demonstrated positive results for any of the 15 unspiked samples.
Evaluation of Sanita-kun E. coli & Coliform Sheet Medium for the Enumeration of Total Coliforms and E. coli
Authors: Ushiyama Masashi , Iwasaki Mihoko
Published: February 2020

The Sanita-kun E. coli & Coliform sheet medium consists of a transparent cover film, an adhesive sheet, a layer of nonwoven fabric, and a water-soluble compound film, including a culture medium formula for the enumeration of total coliforms and differentiation of Escherichia coli. The Sanita-kun E. coli & Coliform sheet is a chromogenic medium and contains X-Gal, which is hydrolyzed by β-galactosidase from coliforms to produce a visible blue dye and Salmon-glucuronic acid, which is hydrolyzed by β-glucuronidase from E. coli to produce a red-purple dye. It is easy to distinguish the difference between E. coli and coliform (other than E. coli) colonies. Total coliforms and E. coli can be enumerated by incubating the sheet medium at 35 ± 1°C for 2124 h without further confirmation. The Sanita-kun E. coli & Coliform sheets were validated as a medium for the enumeration of E. coli and total coliform in meats and meat products using processed meat and two types of raw and frozen meats using stomacher and blender homogenization. In the stomacher homogenization, all 100 samples showed no significant difference between Sanita-kun sheet and AOAC Method 966.24. The linear correlation coefficients (r2) were calculated as 0.90 (coliform) and 0.79 (E. coli). In the blender homogenization, out of 100 samples tested, 99 showed no significant difference between Sanita-kun sheet and AOAC Method 966.24, but the count of total coliforms of Sanita-kun in one sample of uninoculated raw beef was significantly higher than that obtained by AOAC Method 966.24. The linear r2 values were calculated as 0.84 (coliform) and 0.86 (E. coli). The inclusivity and exclusivity study indicated an inclusivity rate of 100 and an exclusivity rate of 95.4. The sensitivity study showed positive results when the homogenate or dilution contained 3 CFU/mL of coliform or E. coli. The performance of four different lots of the sheets was equivalent, and suggested no change of the performance at least for 3 years at 215C. The Sanita-kun E. coli & Coliform sheet medium has been granted Performance Tested MethodSM status.
Evaluation of Immunoassays as an Alternative for the Rapid Determination of Pesticides in Wine and Grape Samples
Authors: Argarate Nerea , Arestin María , Ramón-Azcón Javier , Alfaro Begoña , Barranco Alejandro , Sánchez-Baeza Francisco , Marco M-Pilar
Published: February 2020

The main objective of this paper is to address the performance of immunochemical assays for the detection of the residues of three pesticides [atrazine, bromopropylate, and 2,4,6-trichlorophenol (TCP)] in real winery samples, such as wine, grapes, and grape juice. Different approaches have been evaluated to minimize interferences from the matrixes, and suitable working protocols have been established in order to achieve the necessary LODs, accuracy, and precision for real samples. A simple dilution of the sample proved to be sufficient for the determination of atrazine and bromopropylate in red and white wine and grape juice at the required levels of concentration. However, for TCP, an SPE procedure has been optimized using amino cartridges. The recoveries were above 85% in all cases, and the LOD values were below the parts per billion level, except for bromopropylate, which ranged between 2 and 50 µg/L, depending on the matrix. The grape matrix effect could be resolved by a simple extraction with methanol. Complete recoveries were obtained, and the final measurement procedures were able to determine selected pesticides below their maximum residue levels. The newly developed methods have been compared with standard chromatographic methods.
Development and Single-Laboratory Validation of a Method for the Determination of Total Fructans in Infant Formula
Authors: Cuany Denis , Bénet Thierry , Austin Sean
Published: February 2020

A number of methods have previously been developed for the determination of fructans in food products, resulting in the frequently used AOAC Official MethodsSM 997.08 and 999.03. Method 997.08 has a lower LOQ, but the accuracy may suffer if significant quantities of sucrose are present. Method 999.03 is less affected by sucrose, but the LOQ is not as low as that of the other method. In this work we have combined these two methods, using the sample preparation steps of AOAC Method 999.03 to remove sucrose and other free sugars, and the detection procedure of AOAC Method 997.08 to achieve a low LOQ. The resulting new method achieved an LOQ of 0.13 g/100 g with powdered products (using 1 g sample weight) and recoveries in the range of 83103 in the presence of sucrose at 12 g/100 g. Expanded measurement uncertainties were calculated and ranged from ±17.4 at oligofructose and fructooligosaccharide (FOS) concentrations of around 0.2 g/100 g to ±21.0 at FOS concentrations of 0.6 g/100 g.
Development of Methods for Multiresidue Analysis of Rice Post-Emergence Herbicides in Loam Soil and Their Possible Applications to Soils of Different Composition
Authors: Niell Silvina , Pareja Lucia , Asteggiante Lucía Geis , Roehrs Rafael , Pizzutti Ionara R , García Claudio , Heinzen Horacio , Cesio María Verónica
Published: February 2020

Two simple and straightforward sample preparation methods were developed for the multiresidue analysis of post-emergence herbicides in loam soil that are commonly used in rice crop cultivation. A number of strategic soil extraction and cleanup methods were evaluated. The instrumental analysis was performed by HPLC with a diode array detector. The best compromise between the recoveries (6998) and good repeatability (RSD <15) was obtained using either methanol or methanolethyl acetate (70 + 30, v/v) as extraction solvents without any further cleanup. For the first time, residues of metsulfuron methyl, bensulfuron ethyl, bentazone, cyhalofop butyl, pyrazosulfuron ethyl, propanil, and clomazone were analyzed simultaneously. Quinclorac and bispyribac sodium were also assayed, but their recoveries were below 50. Both methods had an LOD of 0.7 g/kg and could accurately determine the residues at the 2 g/kg level. These two methods could not be applied directly to other soil types as the recoveries strongly depended on the soil composition. The developed methodologies were successfully applied in monitoring 87 real-world soil samples, in which only propanil (6 to 12 g/kg) and clomazone (15 to 20 g/kg) residues could be detected.
Validation Procedures for Quantitative Food Allergen ELISA Methods: Community Guidance and Best Practices
Authors: Abbott Michael , Hayward Stephen , Ross William , Godefroy Samuel Benrejeb , Ulberth Franz , Van Hengel Arjon J , Roberts James , Akiyama Hiroshi , Popping Bert , Yeung Jupiter M , Wehling Paul , Taylor Steve L , Poms Roland Ernest , Delahaut Philippe
Published: February 2020

This document provides supplemental guidance on specifications for the development and implementation of studies to validate the performance characteristics of quantitative ELISA methods for the determination of food allergens. It is intended as a companion document to other existing publications on method validation. The guidance is divided into two sections: information to be provided by the method developer on various characteristics of the method, and implementation of a multilaboratory validation study. Certain criteria included in the guidance are allergen-specific. Two food allergens, egg and milk, are used to demonstrate the criteria guidance. These recommendations will be the basis of the harmonized validation protocol for any food allergen ELISA method, whether proprietary or nonproprietary, that will be submitted to AOAC and/or regulatory authorities or other bodies for status recognition. Regulatory authorities may have their own particular requirements for data packages in addition to the guidance in this document. Future work planned for the implementation and validation of this guidance will include guidance specific to other priority allergens.
Validation and Application of Chemometrics-Assisted Spectrophotometry and Liquid Chromatography for Simultaneous Determination of Two Ternary Mixtures Containing Drotaverine Hydrochloride
Authors: El-Gindy Alaa , Emara Samy , Shaaban Heba
Published: February 2020

Three methods were developed for the determination of two ternary mixtures containing drotaverine hydrochloride (DR) with caffeine and paracetamol (mixture 1) and DR with metronidazole and diloxanide furoate (mixture 2). The first method depends on HPLC separation on an RP C18 column at ambient temperature with the mobile phase methanolwater, pH 3.1 (50 + 50, v/v) and UV detection at 213 nm for mixture 1, and the mobile phase acetonitrile25 mM potassium dihydrogen phosphate, pH 4.6 (55 + 45, v/v) with UV detection at 235 nm for mixture 2. The other two chemometric methods applied were partial least squares (PLS-1) and principal component regression (PCR). These approaches were successfully applied to quantify the five drugs in two ternary mixtures using information included in the UV absorption spectra of appropriate solutions in the wavelength range of 210300 nm with 1 nm intervals. Calibration of PCR and PLS-1 models was evaluated by internal validation (prediction of compounds in its own designed training set of calibration), by cross-validation (obtaining statistical parameters that show the efficiency for a calibration fit model), and by external validation (using laboratory-prepared mixtures and pharmaceutical preparations). The proposed methods were successfully applied for the determination of the two ternary combinations in laboratory-prepared mixtures and commercial tablets; the results of PLS-1 and PCR methods were compared with the HPLC method, and a good agreement was found.
Determination of Immunoglobulin G in Bovine Colostrum and Milk Powders, and in Dietary Supplements of Bovine Origin by Protein G Affinity Liquid Chromatography: Collaborative Study
Authors: Abernethy Grant , Otter Don ,   Collaborators:, Arnold K , Austad J , Christiansen S , Ferreira I , Irvine F , Marsh C , Massom L R , Otter D , Pearce K , Stevens J , Szpylka J , Vyas P , Woollard D , Wu C
Published: February 2020

An AOAC collaborative study was conducted to evaluate an affinity LC procedure for measuring immunoglobulin G (IgG) in selected dairy powders. The powders were extracted with 0.15 M sodium chloride solution and the pH was adjusted to 4.6 to precipitate caseins, which would otherwise lead to an overestimation of IgG. The analyte was then bound to a commercially available Protein G affinity cartridge and selectively eluted with a glycine buffer at pH 2.5. Detection was at 280 nm and quantification was made against a calibration curve prepared from bovine serum IgG. The samples analyzed included the likely matrixes for which this assay will find commercial use, namely, high- and low-protein-content colostrum powders, tablets containing colostrum powder, and some IgG-containing dairy powders; milk protein isolate, whey protein concentrate, and skim milk powder. Eleven laboratories provided data for the study and assayed blind duplicates of six materials. The repeatability RSD values ranged from 2.1 to 4.2 and the reproducibility RSD values ranged from 6.4 to 18.5. The Protein G method with casein removal has adequate reproducibility for measuring IgG in colostrum-derived powders that are traded on the basis of IgG content as a colostral marker.
Multiresidue Determination of Pesticides in Lanolin Using Matrix Solid-Phase Dispersion
Authors: Pérez Andrés , González Gabriel , González Joaquín , Heinzen Horacio
Published: February 2020

An efficient, fast, and accurate matrix solid-phase dispersion sample cleanup procedure was developed specifically for the determination of pesticide residues in lanolin. The scope of the method for organophosphorus, organochlorine, and pyrethroid insecticides is the same as that of official methods from various pharmacopeias. After lanolin dispersion on C18 bonded silica, pesticides are eluted with acetonitrile saturated with n-hexane. Recoveries ranged from 83 to 118 with RSD values of <20 for most pesticides listed, in compliance with the requirements of European and U.S. pharmacopeias.
Construction of Measurement Uncertainty Profiles for Quantitative Analysis of Genetically Modified Organisms Based on Interlaboratory Validation Data
Authors: Macarthur Roy , Feinberg Max , Bertheau Yves
Published: February 2020

A method is presented for estimating the size of uncertainty associated with the measurement of products derived from genetically modified organisms (GMOs). The method is based on the uncertainty profile, which is an extension, for the estimation of uncertainty, of a recent graphical statistical tool called an accuracy profile that was developed for the validation of quantitative analytical methods. The application of uncertainty profiles as an aid to decision making and assessment of fitness for purpose is also presented. Results of the measurement of the quantity of GMOs in flour by PCR-based methods collected through a number of interlaboratory studies followed the log-normal distribution. Uncertainty profiles built using the results generally give an expected range for measurement results of 50200 of reference concentrations for materials that contain at least 1 GMO. This range is consistent with European Network of GM Laboratories and the European Union (EU) Community Reference Laboratory validation criteria and can be used as a fitness for purpose criterion for measurement methods. The effect on the enforcement of EU labeling regulations is that, in general, an individual analytical result needs to be <0.45 to demonstrate compliance, and >1.8 to demonstrate noncompliance with a labeling threshold of 0.9.
High-Performance Thin-Layer Chromatography and Three-Dimensional Image Analysis for the Determination of Rutin in Pharmaceutical Preparations
Authors: Soponar Florin , MoŢ Augustin C , Sârbu Costel
Published: February 2020

A novel HPTLC method was developed for fast and simple quantitative determination of rutin in pharmaceutical preparations. The proposed method combines the advantages of HPTLC with the comfort and the convenience of digital processing of images. For the separation of rutin, silica gel with attached amino groups was used as the stationary phase and ethyl acetateformic acidmethanolwater (10 + 0.9 + 1.1 + 1.7, v/v/v/v) as the mobile phase. The chromatographic plate was sprayed with 2-aminoethyldiphenyl borate solution for visual detection of the spots. For the construction of a three-dimensional chromatogram, Melanie 7.0 software was used together with an HP flatbed scanner that allowed capture of the images on chromatographic plates. The calibration curve was linear within the range of 0.954.78 g/spot with an r value of 0.9984. The RSD for six replicates at three concentration levels was less than 3, while the recovery was between 97.28 and 103.27. The proposed method was found to be simple, precise, sensitive, and accurate and has been applied for the determination of rutin in two commercial drugs. The results were compared with the results of other techniques that generate bidimensional chromatograms and validated by UV-Vis spectrophotometry.
Validated HPTLC Methods for Quantification of Mexiletine Hydrochloride in a Pharmaceutical Formulation
Authors: Pietraś Rafał , Skibiński Robert , Komsta Łukasz , Kowalczuk Dorota , Panecka Ewa
Published: February 2020

Two simple, accurate, and precise HPTLC methods have been established for the determination of mexiletine hydrochloride, an antiarrhythmic agent, in Mexicord capsules. Analyses were performed in horizontal chambers on RP C18F254s and normal-phase amino (NH2) HPTLC precoated plates with the mobile phases tetrahydrofurancitrate buffer, pH 4.45 (3 + 7, v/v) and chloroformtetrahydrofuranhexaneethylamine (3 + 2 + 5 + 0.1, v/v/v/v), respectively. The plates were developed for a distance of 40 mm in both cases. Densitometric measurements were achieved in the UV mode at 217 nm based on peak areas with semilinear calibration curves (R2 0.97) in the concentration range 0.58.0 g/spot for the NH2 and C18 HPTLC methods. The elaborated chromatographic methods were validated in accordance with International Conference on Harmonization guidelines in terms of linearity, accuracy (99.64 for NH2 and 99.53 for C18), precision (intraday RSD 1.16 and 2.71, respectively), sensitivity (LOD 0.1 g/spot for both systems), and specificity.
Microwave-Assisted Extraction Coupled with Single Drop Microextraction and High-Performance Column Liquid Chromatography for the Determination of Trace Estrogen Adulterants in Soybean Isoflavone Dietary Supplements
Authors: Xiao Xiaohua , Yin Yi , Hu Yuling , Li Gongke
Published: February 2020

A sensitive and accurate method consisting of microwave-assisted extraction (MAE) coupled with single drop microextraction (SDME) and HPLC was developed for the determination of four trace estrogen adulterants, including estriol (E3), estradiol (E2), ethinyl estradiol (EE), and estrone (E1), in different soybean dietary supplements. The samples were extracted by MAE; the extracts were cleaned up and enriched by SDME, and then analyzed by HPLC. The conditions of MAE were optimized, and the effects of solvent and extraction time in SDME on the enrichment capacity were studied. The enrichment factors of E3, E2, EE, and E1 under the optimized conditions were 247-, 335-, 316-, and 319-fold, respectively. The linear range of the MAE-SDME-HPLC method ranged from 5.0 to 180.0 g/L, and the detection limit from 1.1 to 1.2 g/L. The RSD ranged from 7.9 to 9.6. Three soybean dietary supplements, including oral liquid, capsule, and tablet forms, were analyzed. The spike recovery was more than 70, with RSD lower than 13.2. It was shown that the proposed method was accurate, sensitive, and suitable for the determination of trace analytes in complex samples.
Simultaneous Determination of Imipramine Hydrochloride and Chlordiazepoxide in Pharmaceutical Preparations by Spectrophotometric, RP-HPLC, and HPTLC Methods
Authors: Patel Sejal K , Patel Natvarlal J
Published: February 2020

A binary mixture of imipramine HCl and chlordiazepoxide was determined by three different methods. The first involved determination of imipramine HCl and chlordiazepoxide using the first derivative spectrophotometric technique at 219 and 231.5 nm over the concentration ranges of 120 and 224 g/mL with mean accuracies of 99.47 0.78 and 101.43 1.20, respectively. The second method utilized RP-HPLC with methanolacetonitrile0.065 M ammonium acetate buffer (45 + 25 + 30, v/v/v, pH adjusted to 5.6 0.02 with phosphoric acid) as the mobile phase pumped at a flow rate of 1.0 mL/min. Quantification was achieved using UV detection at 240 nm over concentration ranges of 0.254.0 and 0.11.6 g/mL, with mean accuracies of 101.17 0.56 and 100.67 0.40 for imipramine HCl and chlordiazepoxide, respectively. The third method was HPTLC with carbon tetrachlorideacetonetriethylamine (pH 8.3; 6 + 3 + 0.3, v/v/v) as the mobile phase. Quantification was achieved with UV detection at 240 nm over concentration ranges of 50600 and 20240 ng/spot with mean accuracies of 99.51 0.59 and 100.59 0.84 for imipramine HCl and chlordiazepoxide, respectively. The suggested procedures were checked using prepared mixtures, and were successfully applied for the analysis of pharmaceutical preparations. The accuracy and precision of the methods were confirmed when the standard addition technique was applied. The results obtained by applying the proposed methods were statistically analyzed.
Optimization and Establishment of a Validated Stability-Indicating HPLC Method for Study of the Stress Degradation Behavior of Metoprolol Succinate
Authors: Phale Mitesh D , Hamrapurkar Purnima D
Published: February 2020

A stability-indicating HPLC method has been established for analysis of metoprolol succinate in the presence of products generated in a stress degradation study. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis, and thermal decomposition. Extensive degradation was found to occur in an alkaline medium and under thermal stress. Minimum degradation was observed in an acidic medium and under photolytic and oxidative stress. Successful separation of the drug from its degradation products formed under stress conditions was achieved on a C18 column using sodium dihydrogen phosphate bufferacetonitrile (70 + 30) mobile phase. The flow rate was 1 mL/min, and the detection wavelength was 274 nm. The method was validated for linearity, range, precision, accuracy, LOQ, and LOD. Because the method effectively separates the drugs from their degradation products, it can be used as a stability-indicating method.
Ionic Liquid-Based, Single-Drop Microextraction for Preconcentration of Cobalt Before Its Determination by Electrothermal Atomic Absorption Spectrometry
Authors: Amjadi Mohammad , Manzoori Jamshid L , Abulhassani Jafar
Published: February 2020

An effective and environmentally friendly single-drop microextraction method was developed for the preconcentration of ultratraces of cobalt before its determination by electrothermal atomic absorption spectrometry (ETAAS). A microdrop of 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM][PF6], was used to extract Co(II) ions as an ammonium pyrroldinedithiocarbamate (APDC) complex. The sensitivity was improved by increasing the volume of the suspended drop. Several variables affecting microextraction efficiency and the ETAAS signalsuch as pyrolysis and atomization temperature, pH, APDC concentration, extraction time, drop volume, and stirring ratewere investigated and optimized. Under the optimum experimental conditions, the detection limit (3 SD) was 0.04 g/L, and the enrichment factor was 120. The RSD for five replicate determinations of Co(II) at 0.5 g/L was 4.5. The developed method was validated by analysis of a Standard Reference Material and applied to the determination of cobalt in water samples.
A Porous Graphitized Carbon Column HPLC Method for the Quantification of Paracetamol, Pseudoephedrine, and Chlorpheniramine in a Pharmaceutical Formulation
Authors: Kalogria Eleni , Koupparis Michael , Panderi Irene
Published: February 2020

A simple, rapid, and stability-indicating HPLC method has been developed, fully validated, and applied to the quantification of paracetamol, pseudoephedrine hydrochloride, and chlorpheniramine maleate in a pharmaceutical formulation, using hydrochlorothiazide as an internal standard. Chromatographic separation was achieved isocratically on an RP porous graphitized carbon analytical column (125 2.1 mm id, particle size 5 m) using 5.0 mM ammonium acetateacetonitrile (35 + 65, v/v) mobile phase at a flow rate of 0.50 mL/min. UV spectrophotometric detection at 220 nm was used. The method had linear calibration curves over the range of 3070 g/mL for paracetamol, 1.84.2 g/mL for pseudoephedrine hydrochloride, and 120280 ng/mL for chlorpheniramine maleate. The intraday and interday RSD values were less than 3.2 for all compounds, while the relative error was less than 2.9. Accelerated stability studies performed under various stress conditions proved the selectivity of the method. The developed method was applied successfully to QC and content uniformity tests of commercial tablets.
Validation of a Novel, Fully Automated High Throughput High-Performance Liquid Chromatographic/Tandem Mass Spectrometric Method for Quantification of Pantoprazole in Human Plasma
Authors: Dotsikas Yannis , Apostolou Constantinos , Soumelas Stefanos , Kolocouri Filomila , Ziaka Afroditi , Kousoulos Constantinos , Loukas Yannis L
Published: February 2020

An automated high-throughput HPLC/MS/MS method was developed for the quantitative determination of pantoprazole in human plasma. Only 100 L plasma was placed in 2.2 mL 96 deep-well plates, and both pantoprazole and omeprazole (IS) were extracted from human plasma by liquidliquid extraction, using diethyl etherdichloromethane (70:30, v/v) as the organic solvent. Robotic liquid-handling workstations were used for all liquid transfer and solution preparation steps and resulted in a short sample preparation time. After vortexing, centrifugation, and freezing, the supernatant organic solvent was evaporated and reconstituted in a small volume of reconstitution solution. Sample analysis was performed by utilizing the combination of RP-HPLC/MS/MS, with positive-ion electrospray ionization and multiple reaction monitoring detection. The chromatographic run time was set at 1.8 min with a flow rate of 0.6 mL/min on a Nucleosil octylsilyl (C8) analytical column. The method was proven to be sensitive, specific, accurate, and precise for the determination of pantoprazole in human plasma. The method was applied to a bioequivalence study after per os administration of a 40 mg pantoprazole gastric retentive tablet.
Listeria monocytogenes: Knowledge Gained Through DNA Sequence-Based Subtyping, Implications, and Future Considerations
Authors: Nightingale Kendra
Published: February 2020

The purpose of subtyping is to differentiate bacterial isolates beyond the classification of species or subspecies. Subtyping methods can be grouped into two broad categories based on the cellular components targeted: (1) phenotypic subtyping methods that differentiate isolates by the enzymes, proteins, or other metabolites expressed by the cell, and (2) molecular subtyping methods that discriminate isolates based on interrogation of nucleic acid sequences. The two major types of molecular subtyping methods include band-based methods based on fragment pattern data or DNA fingerprints, and methods that generate DNA sequence data. Molecular subtyping methods have shown that Listeria monocytogenes isolates can be classified into four genetic lineages or divisions. Although band-based molecular subtyping methods continue to serve as the gold standard for routine molecular subtyping of most clinically important foodborne pathogens, including L. monocytogenes, the explosion of recently completed and ongoing DNA sequencing projects, and thus available DNA sequence data, have stimulated efforts to develop highly discriminatory and high-throughput DNA sequence-based subtyping methods for L. monocytogenes. L. monocytogenes represents one of the most highly sequenced human pathogens; more than 20 genome sequences are currently available for this organism. This review provides an overview of the concepts behind subtyping and discusses the application of molecular subtyping methods, with an emphasis on DNA sequence-based subtyping methods to characterize L. monocytogenes.
High-Performance Thin Layer Chromatography for Quality Control of Multicomponent Herbal Drugs: Example of Cangzhu Xianglian San
Authors: Li Zhi , Merfort Irmgard , Reich Eike
Published: February 2020

Due to their complexity, multicomponent herbal drugs pose enormous analytical challenges for quality control (QC). Although they may have traditionally been used for hundreds of years, the information about their chemical composition is often still limited. Selecting suitable markers to monitor the identity and potency of the mixture is, therefore, difficult. There is also the possibility of natural variability for each plant. This paper illustrates a pragmatic and practical approach to QC of a multicomponent herbal drug by HPTLC. Cangzhu Xianglian San (CXS), composed of the herbal drugs Coptis rhizome, Aucklandia root, and Atractylodes rhizome (30 + 20 + 60, w/w/w), is used as an example. A characteristic fingerprint can be generated for CXS with tolueneethyl acetatemethanolisopropanolwater (60 + 30 + 20 + 15 + 3, v/v/v/v/v) mobile phase on HPTLC silica gel 60 conditioned with ammonia. While the corresponding monograph of the Chinese Veterinary Pharmacopoeia focuses only on the detection of berberine, one of the principal components of Coptis rhizome, the proposed method of identification determines the presence of all three components in the drug after derivatization with anisaldehyde reagent. The same method can also be used to quantitatively determine the content of berberine by scanning densitometry. This paper provides details about the validation of the qualitative and quantitative determinations.
Sensitive Determination of Indomethacin in Pharmaceuticals and Urine by Sequential Injection Analysis and Optosensing
Authors: Molina-García Lucía , Córdova M Luisa Fernández-de , Ruiz-Medina Antonio
Published: February 2020

A selective and sensitive method based on coupling of sequential injection analysis (SIA) and optosensing was developed and applied to the determination of indomethacin in pharmaceutical and urinary samples. After alkaline hydrolysis, the fluorescent product generated from indomethacin is inserted in the flow system, transitorily retained on an active solid support (Sephadex QAE A-25) filling the flowcell, and monitored at 283/371 nm (λex/λem). The system was calibrated for two sample volumes, 100 and 1000 µL. It showed a linear dynamic range of 0.56.5 ng/mL, with an LOD of 0.15 ng/mL and an RSD of 3.9% (n = 10) when the highest sample volume was used. The proposed fluorometric SIA optosensor was applied to the determination of indomethacin in both pharmaceuticals and urine samples, and satisfactory results were obtained.