bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Patulin in Apple Juice by Liquid Chromatography
Authors: Iha Maria Helena , Sabino Myrna
Published: February 2020

A method was developed and validated in-house for the determination of patulin (PAT), a toxic mold metabolite, in apple juice. The sample was extracted with ethyl acetatehexane and analyzed by liquid chromatography equipped with a C18 column and diode array detector. The mobile phase used for the quantification was waterethanol, at a flow rate of 0.5 mL/min. The method showed a mean recovery of 84.8%, the relative standard deviation obtained in the precision study was <7.7%, the quantification and detection limits were 7 and 3 μg/L, respectively, and the linear range for PAT in apple juice was 2.6650 μg/L. The ruggedness was evaluated by an intralaboratory experiment, in which 5 factors were studied, and only one was found to influence the observed results. The developed method is fast, practical, and simple; the solvents (except hexane) and reagents used were nontoxic. The results of the validation confirmed the efficiency of the method, which is sensitive enough to be used in studies required to quantify PAT in apple juice.
Evaluation of the Sanita-kun Coliforms, a Dehydrated Medium Sheet for Coliform Detection: Performance-Tested MethodSM 100402
Authors: Morita Hiroshi , Ushiyama Masashi , Aoyama Shigeyuki , Iwasaki Mihoko , Andrews Wallace H , Betts Roy , Brodsky Michael H
Published: February 2020

The Sanita-kun Coliforms 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 detection of coliforms. The medium sheet was validated with 26 food types belonging to 9 food categories (meat, poultry, fish and seafood, fruits and vegetable, dairy, chocolate or bakery, animal feeds, pasta, and miscellaneous) using violet red bile (VRB) agar method in the U.S. Food and Drug Administration's Bacteriological Analytical Manual as a reference according to the AOAC guideline. The medium sheet showed 100 inclusivity and exclusivity. Ruggedness study suggested allowances in the incubation temperature and time as 3335 and 24 4 h, respectively. The performance of 3 different lots of the medium sheets was equivalent and suggested no change of the performance at least for 3 years. In the comparative recovery study, many samples (84.6), which were inoculated with a coliform strain, showed no significant difference between the 2 methods. The linear correlation coefficient (r2) to the VRB agar was calculated as 0.94. In the repeatability study, the average relative standard deviation of total foods was 0.10 in the medium sheet. In the independent study, the medium sheet detected significantly more colonies than VRB plates in the frozen raw milk sample, while there was no significant difference between the 2 methods in raw ground beef sample. Comparative recovery study on foods, inoculated and then frozen, showed the medium sheet detected injured cells with better recovery than VRB agar. The analysts in the independent study wrote that the medium sheet was easy to use and read overall. The Sanita-kun sheet provides an alternative method to coliform count agar.
Validation of Two Commercial Lateral Flow Devices for the Detection of Peanut Proteins in Cookies: Interlaboratory Study
Authors: van Hengel Arjon J , Capelletti Claudia , Brohee Marcel , Anklam Elke , Baumgartner M-C S ,   Collaborators:, Abbott M , Baumgartner S , Bremer M , Clarke D , Cleroux C , Demeulemester C , Eckhart F , Gelencser E , Hefle S , Herrnegger H , Hörtner H , Kyriakidis S , Lowe R , Marx G , Mayer W , Paschke A , Robert M-C , Schneede K , Sherlock R , Suter D , Warner K , Werner M
Published: February 2020

Results are reported for an interlaboratory validation study of 2 commercially available lateral flow devices (dipstick tests) designed to detect peanut residues in food matrixes. The test samples used in this study were cookies containing peanuts at 7 different concentrations in the range of 030 mg peanuts/kg food matrix. The test samples with sufficient and proven homogeneity were prepared in our laboratory. The analyses of the samples (5 times per level by each laboratory) were performed by 18 laboratories worldwide, which submitted a total of 1260 analytical results. One laboratory was found to be an outlier for one of the test kits. In general, both test kits performed well. However, some false-negative results were reported for all matrixes containing <21 mg peanuts/kg cookie. It must be stressed that the test kits were challenged beyond their cut-off limits (5 mg/kg, depending on the food matrix). One test kit showed fewer false-negative results, but it led to some false-positive results for the blank materials. The sensitivity of the dipstick tests approaches that achieved with enzyme-linked immunosorbent assays.
The Use of Biosensor and Microarray Techniques in the Rapid Detection and Identification of Salmonellae
Authors: Goldschmidt Millicent C
Published: February 2020

The ever-present need for rapid and sensitive assay methods to detect foodborne pathogens, particularly the salmonellae, has led to increased incorporation of biosensor technology into microarray and other platforms. The use ofmimetics and aptamers has been added to these procedures. Nanoparticles, particularly incorporating fluorophores and quantum dots into various procedures, have decreased the size of instrumentation while increasing automation, sensitivity, and rapidity of results. This article will deal mainly with assays involving the salmonellae.
Alternative Methodology for the Analysis of Progesterone, Testosterone, and Epi-Testosterone in Bovine Liver and Veal Muscle
Authors: Fedeniuk Rick W , West Michelle , Gedir Ron , Mizuno Massey , Neiser Constance , MacNeil James D
Published: February 2020

Research has shown that traditional solvent extraction procedures used for the analysis of endogenous steroids often give inconsistent recoveries and results. However, a single-laboratory validation of a liquid chromatography/tandemmass specrometry method using 2 product ions per transition for progesterone, testosterone, and epi-testosterone in bovine liver and veal muscle showed accuracy and precision to within 23 at concentrations ranging from 0.5 to 2.0 g/kg. Homogenized samples were pretreated with methanol to denature endogenous enzymes. Following removal of methanol, samples were treated overnight with Helix pomatia -glucuronidase to deconjugate glucuronide conjugates. Alkali digestion of the samples in KOH solutions was done under shaking at 37C for 30 min. The digestate was extracted with methyl tert-butyl ether, and the extracts were cleaned by partitioning between acetonitrilehexane, followed by solid-phase extraction cleanup on silica cartridges. In bovine liver, average recoveries exceeded 54 for all analytes, and the within-run assay coefficients of variations were <6 and 13 for high (2.0 g/kg) and low (0.3 g/kg) analyte concentrations, respectively. In veal muscle, average recoveries exceeded 60, and the analysis of blind spikes gave accuracy estimates of over 85, with coefficients of variation (CVs) <15 for all analytes. The CVs for the multiple reaction monitoring ion ratios for all compounds were <22for all validation data. The method meets the requirements for confirmatory methods as outlined in 2002/657/EC. An analyst is capable of processing up to 20 samples within 5 days.
Detection of Genetic Modification in Cured Tobacco Leaf: Proficiency Testing Using Polymerase Chain Reaction-Based Methods
Authors: Gadani Ferruccio , Ward Martin , Black Sue , Harris Neil , McDowell David , Boley Nick
Published: February 2020

The Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA; Paris, France) Task Force Genetically Modified TobaccoDetection Methods investigated the performance of qualitative and quantitative methods based on the polymerase chain reaction (PCR) for the detection and quantitation of genetically modified (GM) tobacco. In the 4 successful rounds of proficiency testing, the cauliflower mosaic virus 35S RNA promoter (CaMV 35S) and the Agrobacterium tumefaciens nopaline synthase terminator (NOS) were selected as target sequences. Blind-coded reference materials containing from 0.1 to 5.0% and from 0.15 to 4% GM tobacco were used in 2 rounds of qualitative and quantitative PCR, respectively. Eighteen laboratories from 10 countries participated in this study. Considering all methods and 2 rounds, the different laboratories were able to detect GM tobacco at the 0.1% level in 46 out of 58 tests in qualitative assays. The results of the proficiency test indicate that both end point screening and real-time quantitative methods are suitable for the detection of genetically modified organisms in tobacco leaf samples having a GM content of 0.1% or higher. The CORESTA proficiency study represents a first step towards the interlaboratory evaluation of accuracy and precision of PCR-based GM tobacco detection, which may lead to the harmonization of analytical procedures and to the enhancement of comparability of testing results produced by different laboratories.
Determination of Semicarbazide in Baby Food by Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Validation Study
Authors: Ginn Richard , Wilson Lesley , De Souza Scheilla V C , Dela Calle Maria B ,   Collaborators:, Barbosa J , Berendsen B , Bockhorn I , Brandtner M , Delahaut P , Doering T , Fuerst P , Griffin C , Gude T , Janosi A , Jaus A , Kennedy G , Mandix M , Matencio Hilla E , Plonevez S , Posyniak A , Saari L , van Bruijnsvoort M , Verdon E , Wohlfarth R
Published: February 2020

An interlaboratory validation study funded by the European Commission, Directorate General for Health and Consumer Protection (DG SANCO), was conducted to evaluate the effectiveness of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of semicarbazide (SEM) in different types of baby food at a possible future European regulatory limit (10 ng/g). The test portion of the sample was extracted with hydrochloric acid, and the analyte was derivatized with 2-nitrobenzaldehyde, with 1,2-[15N2, 13C] SEM as an internal standard. The extract was neutralized and then purified on a solid-phase extraction cartridge. The SEM was determined by reversed-phase LC with detection by MS/MS. Apple puree, rice pudding, and meat/vegetable meal baby food materials, spiked with SEM at levels of about 3, 10, and 30 ng/g, respectively, were sent to 20 laboratories in 12 different European countries, which submitted results from 17 participants. Recoveries ranged from 88.8 to 106.1%. Based on results for spiked samples (blind pairs at 3 levels), the relative standard deviations for repeatability (RSDr) ranged from 4.2 to 6.9% and the relative standard deviations for reproducibility (RSDR) ranged from 16.6 to 24.3%. The method showed acceptable within- and between-laboratory precision for all 3 matrixes, as evidenced by HorRat values, at the target levels for the determination of SEM.
Quantification of Proteins in Dairy Products Using an Optical Biosensor
Authors: Dupont Didier , Muller-Renaud StÉphanie
Published: February 2020

Two recent techniques using optical immunosensor technology were developed for the quantification of milk proteins in dairy products. The first application is the simultaneous quantification of the 3 major caseins (αS1, β, and κ). This assay consists of a 2-step sandwich strategy, with 2 monoclonal antibodies directed against the N- and C-terminal extremities of each of the caseins, respectively. This strategy permits only intact caseins to be quantified, and not their degradation products. The technique is fast (10 min), sensitive (detection limit about 0.87 μg/mL), and has been applied successfully to raw and drinking milks. In the second application, the severity of the heat treatment sustained by a milk of unknown origin is determined by quantifying separately the native and heat-denatured forms of α-lactalbumin with specific monoclonal antibodies. The technique allows discrimination of the different heat treatments studied (pasteurization, direct and indirect ultra-high temperature, sterilization), is fast (4 min), repeatable, fully automated, and requires no pretreatment of the milk sample.
Determination of Minor Proteins of Bovine Milk and Colostrum by Optical Biosensor Analysis
Authors: Indyk Harvey E , Filonzi Enrico L , Gapper Leyton W
Published: February 2020

Automated, rapid, sensitive, and label-free biosensor-based immunoassays for immunoglobulin G (IgG), folate binding protein, lactoferrin, and lactoperoxidase in bovine milk using surface plasmon resonance optical detection with direct binding assay format are described. Samples are prepared for analysis by direct dilution into buffer. Analysis conditions, including ligand immobilization, flow rate, contact time, and regeneration are defined and nonspecific binding considerations evaluated. The technique has been applied to the measurement of these proteins in consumer milks, colostrum, milk products, and infant formulas, and their temporal change during early bovine lactation followed.
Determination of Moisture, Starch, Protein, and Fat in Common Beans (Phaseolus vulgaris L.) by Near Infrared Spectroscopy
Authors: Hermida MarÍa , Rodriguez Natalia , Rodriguez-Otero Jose L
Published: February 2020

The presence of moisture, starch, protein, and fat was determined in common beans (Phaseolus vulgaris L.) by near infrared (NIR) spectroscopy without any previous sample pretreatment except grinding. A set of 96 samples was used to calibrate the instrument by modified partial least-squares regression. The following statistical results were achieved: standard error of calibration (SEC) = 0.31 and square correlation coefficient (R2) = 0.96 for moisture; SEC = 0.76 and R2 = 0.92 for starch; SEC = 0.39 and R2 = 0.98 for protein; and SEC = 0.14 and R2 = 0.80 for fat. To validate the calibration, a set of 25 bean samples was used. Standard errors of prediction were 0.39, 0.90, 0.56, and 0.13 for moisture, starch, protein, and fat, respectively, and R2 for the regression of measurements by the reference method versus NIR analysis were 0.94, 0.88, 0.94, and 0.74 for moisture, starch, protein, and fat, respectively. To compare the results obtained for all 4 components of the validation set by NIR spectroscopy with those obtained by the reference methods, linear regression and paired t tests were applied, and the methods did not give significantly different results, P = 0.05.
Residue Determination of Captan and Folpet in Vegetable Samples by Gas Chromatography/Negative Chemical IonizationMass Spectrometry
Authors: Barreda Mercedes , LÓpez Francisco J , Villarroya Mercedes , Beltran Joaquim , García-Baudín Jose Mara , HernÁndez Felix
Published: February 2020

A gas chromatography/negative chemical ionization-mass spectrometry (GC/NCI-MS) method has been developed for the simultaneous determination of the fungicides captan and folpet in khaki (persimmon; flesh and peel) and cauliflower. Samples were extracted with acetone in the presence of 0.1 M zinc acetate solution in order to avoid degradation of fungicides and were purified using solid-phase extraction with divinylbenzene polymeric cartridges. Purified extracts were evaporated and dissolved in hexane prior to injection into the GC/NCI-MS system. Isotope-labeled captan and folpet were used as surrogate/internal standards, and quantification was performed using matrix-matched calibration. The method showed linear response in the concentration range tested (50-2500 ng/mL). The method was fully validated with untreated blank samples of khaki (flesh and peel) and cauliflower spiked at 0.05 and 0.5 mg/kg. Satisfactory recoveries between 82 and 106% and relative standard deviations lower than 11% in all cases (n = 5) were obtained. The limit of detection for both compounds were estimated to be 0.01 mg/kg. The developed method has been applied to treated and untreated samples collected from residue trials.
Determination of Abamectin, Doramectin, Emamectin, Eprinomectin, Ivermectin, and Moxidectin in Milk by Liquid Chromatography Electrospray Tandem Mass Specrometry
Authors: Sheridan Robert , Desjardins Lucille
Published: February 2020

The avermectin and milbemycin families of compounds are derived from naturally occurring yeasts. They have proven to be potent preventatives against a variety of pests such as insects and parasites. Only eprinomectin and moxidectin are currently approved for use on lactating cattle with tolerances in milk of 12 μg/kg for eprinomectin and 40 μg/kg for moxidectin. Detection of misuse or inadvertent contamination in milk requires a sensitive and definitive analytical method. A method has been developed for the determination of 5 avermectins and 1 milbemycin in milk using a simple liquidliquid extraction and liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis. Ivermectin (IVR), doramectin (DOR), abamectin (ABA), eprinomectin (EPR), emamectin (EMA), and moxidectin (MOX) were extracted from whole milk by partitioning into acetonitrile with a subsequent solvent exchange into methanolwater. Simultaneous confirmation and quantification were achieved with LC separation, positive electrospray ionization (ESI+), and MS/MS. The limits of detection ranged from 16 pg/g (ppt) for EMA to 1.7 μg/g (ppb) for MOX.
Quantification of Tamoxifen and Metabolites and Soy Isoflavones in Human Plasma Using Liquid Chromatography with Electrospray Ionization Tandem Mass Spectrometry
Authors: Williams Lee D , Twaddle Nathan C , Churchwell Mona I , Doerge Daniel R
Published: February 2020

Tamoxifen is an important estrogen receptor antagonist used successfully for the treatment and prevention of breast cancer. The use of complementary and alternative medicines is an increasingly popular means for patients to participate in their own health care, and soy products, which contain phytoestrogens, have been widely promoted for possible beneficial effects on menopausal symptoms. The possibility that soy isoflavones could reduce tamoxifen efficacy has been demonstrated in animal models of post-menopausal breast cancer, but the occurrence of such an effect in women has not been explored. This paper describes the development and validation of a sensitive method using solid-phase extraction and isotope dilution liquid chromatography/tandem mass spectrometry with multiple reaction monitoring for the concurrent analysis of the major soy isoflavones (genistein and daidzein), an important metabolite of daidzein (equol), tamoxifen, and its important metabolites (4-hydroxytamoxifen, N-desmethyltamoxifen, and 4-hydroxy-N-desmethyltamoxifen or endoxifen) in the serum of rats and women. The limits of quantification achieved are sufficient to determine accurately and precisely the concentrations of all of these analytes in women consuming soy foods and/or therapeutic doses of tamoxifen at levels consistent with modulation of estrogen receptor-mediated functions. These procedures enable future investigations of the possible impact of diet on the outcome of breast cancer therapy.
Nuclear Receptors: Potential Biomarkers for Assessing Physiological Functions of Soy Proteins and Phytoestrogens
Authors: Xiao Chao Wu , Wood Carla , Gilani G Sarwar
Published: February 2020

Soy consumption is associated with decreased incidence of chronic diseases, including cardiovascular diseases, atherosclerosis, diabetes, osteoporosis, and certain types of cancers. However, consumption of high amounts of soy isoflavones may adversely influence endocrine functions, such as thyroid function and reproductive performance, because of their structural similarity to endogenous estrogens. Nuclear receptors are a group of transcription factors that play critical roles in the regulation of gene expression and physiological functions through direct interaction with target genes. Modulation of the abundance of these receptors, such as changing their gene expression, alters the sensitivity of the target cells or tissues to the stimulation of ligands, and eventually affects the relevant physiological functions, such as growth, development, osteogenesis, immune response, lipogenesis, reproductive process, and anticarcinogenesis. A number of studies have shown that the bioactive components in soy can modify the expression of these receptors in various tissues and cancer cells, which is believed to be a key intracellular mechanism by which soy components affect physiological functions. This review summarizes the current understanding of the modulation of nuclear receptors by soy proteins and isoflavones, and focuses especially on the receptors for estrogens, progesterone, androgen, vitamin D, retinoic acid, and thyroid hormones as well as the potential impact on physiological functions.
Liquid Chromatographic Determination of Sennosides in Cassia angustifolia Leaves
Authors: Srivastava Alpana , Pandey Richa , Verma Ram K , Gupta Madan M
Published: February 2020

A simple liquid chromatographic method was developed for the determination of sennosides B and A in leaves of Cassia angustifolia. These compounds were extracted from leaves with a mixture of methanolwater (70 + 30, v/v) after defatting with hexane. Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography and UV absorbance at 270 nm using a photodiode array detector. The method involves the use of an RP-18 Lichrocart reversed-phase column (5 μm, 125 × 4.0 mm id) and a binary gradient mobile-phase profile. The various other aspects of analysis, namely, peak purity, similarity, recovery, repeatability, and robustness, were validated. Average recoveries of 98.5 and 98.6%, with a coefficient of variation of 0.8 and 0.3%, were obtained by spiking sample solution with 3 different concentration solutions of standards (60, 100, and 200 μg/mL). Detection limits were 10 μg/mL for sennoside B and 35 μg/ML for sennoside A, present in the sample solution. The quantitation limits were 28 and 100 μg/mL. The analytical method was applied to a large number of senna leaf samples. The new method provides a reliable tool for rapid screening of C. angustifolia samples in large numbers, which is needed in breeding/genetic engineering and genetic mapping experiments.
Stability-Indicating Methods for the Determination of Disopyramide Phosphate
Authors: Salem Maissa Y , Ramadan Nesrin K , Moustafa Azza A , El-Bardicy Mohamed G
Published: February 2020

Four methods were developed for the determination of intact disopyramide phosphate in the presence of its degradation product. In the first and second methods, third-derivative spectrophotometry and first derivative of the ratio spectra were used. For the third-derivative spectrophotometric method, the peak amplitude was measured at 272 nm, while for the derivative ratio spectrophotometric method, disopyramide phosphate was determined by measuring the peak amplitude at 248 and 273 nm. Both methods were used for the determination of disopyramide phosphate in the concentration range 12.587.5 μg/mL, with corresponding mean recovery 100.8 ± 0.7% for the first method and 99.9 ± 0.7% and 99.6 ± 0.7% for the second method at 248 and 273 nm, respectively. In the third method, an ion selective electrode (ISE) was fabricated using phosphotungstic acid as an anionic exchanger, PVC as the polymer matrix, and dibutylsebacate as a plasticizer. The ISE was used for the determination of disopyramide phosphate in pure powder form in the concentration range 10-210-5 M. The slope was found to be 58.5 (mV/decade), and the average recovery was 99.9 ± 1.6%. The fourth method depended on the quantitative densitometric determination of the drug in concentration range of 0.252.5 μg/spot using silica gel 60 F245 plates and ethyl acetatechloroformammonium hydroxide (85 + 10 + 5, v/v/v) as the mobile phase, with corresponding mean accuracy of 100.3 1.1%. The 4 proposed methods were found to be specific for disopyramide phosphate in presence of up to 80% of its degradation product for the spectrophotometric methods, 90% of its degradation for the densitometric method, and 40% for the ISE method. The 4 proposed procedures were successfully applied for the determination of disopyramide phosphate in Norpace capsules. Statistical comparison between the results obtained by these methods and the official method of the drug was done, and no significant differences were found.
Spectrofluorometric Determination of Citalopram in Pharmaceutical Preparations and Spiked Human Plasma Using Organized Media
Authors: El-Sherbiny Dina T
Published: February 2020

The native fluorescence of citalopram (CIT) was (obtained in citrate buffer of pH 6.5 with and without β-cyclodextrin (β-CD) or sodium dodecyl sulfate (SDS) as fluorescence enhancers at 305 nm using 242 nm for excitation. Micellar systems of ionic and nonionic surfactants were investigated by measuring the fluorescence intensity of the analyte-surfactant system. In slightly acidic aqueous solution of pH 6.5, CIT was better incorporated in CDs and SDS micelles. The luminescence emission from CIT was found to be greatly enhanced by SDS micelles. The fluorescence intensity enhancements in CDs medium and in SDS as ionic surfactant relative to slightly acidic aqueous solution were 125 and 250%, respectively. Organized media-enhanced spectroflourometric methods were developed for the determination of CIT, in pure form as well as in pharmaceutical preparations. The fluorescence intensity-concentration plots were rectilinear over the ranges 0.06 to 0.64, 0.04 to 0.40, and 0.02 to 0.26 μg/mL with lower detection limits of 0.02, 0.01, and 0.007 μg/mL, either in citrate buffer only or in β-CD and SDS as organized media, respectively. Furthermore, the high sensitivity attained by using SDS as organized medium allowed in vitro spectrofluorometric determination of CIT in spiked human plasma. Interference from endogenous amino acids has been overcome by using the solid-phase extraction technique; the mean recovery (n = 5) was 100.1 ± 0.8%
Determination of the Acid Value of Instant Noodles: Interlaboratory Study
Authors: Hakoda Akiko , Sakaida Kenichi , Suzuki Tadanao , Yasui Akemi ,   Collaborators: ACE Cook Co., Ltd., Development Department; Sanyo Foods Co., Ltd., Research and Development; Toyo Suisan Kaisha, Ltd., Quality Assurance Department; Nissin Food Products Co., Ltd., Food Safety Research Institute Quality Assurance Division; Myojo Foods Co., Ltd., Division of Research and Development; Center for Food Quality, Labeling and Consumer Services (Headquarters: Otaru Center, Sendai Center, Yokohama Center, Nagoya Center, Kobe Center, Okayama Center, Moji Center)
Published: February 2020

An interlaboratory study was performed to evaluate the method for determining the acid value of instant noodles, based on the Japanese Agricultural Standard (JAS), with extraction of lipid using petroleum ether at a volume of 100 mL to the test portion of 25 g. Thirteen laboratories participated and analyzed 5 test samples as blind duplicates. Statistical treatment revealed that the repeatability (RSDR) of acid value was <6.5%, and the reproducibility (RSDR) of acid value was <9.6%. The HorRat values (RSDR/predicted RSDR) were 1.21.8, where the RSDR and the predicted RSDR were obtained in terms of free fatty acids in the noodles per unit weight, using the equation [acid value = percent free fatty acids (as oleic) 1.99] and the extracted lipid contents. This method was shown to have acceptable precision by the present study.
A Reversed-Phase High-Performance Liquid Chromatographic Method for the Determination of Zafirlukast in Pharmaceutical Formulations and Human Plasma
Authors: SÜsÜl İncilay , AltinÖz Sacide
Published: February 2020

Zafirlukast (ZAF) is a leukotriene receptor antagonist used in the treatment of chronic asthma. In this study, a simple and sensitive reversed-phase, high-performance liquid chromatographic method was developed for the determination of ZAF in pharmaceutical formulations and human plasma. Piribedil was used as an internal standard. Analysis was carried out on a Nucleosil C18 100 Å(150 × mm 4.6 mm id, 5 ωm) column with acetonitrilepH 3.0 acetate buffer (70 30, v/v) as the mobile phase at a flow rate of 0.8 mL/min. The peak was detected by an ultraviolet detector set at a wavelength of 240 nm. The retention times were about 3.9 min for piribedil and 5.8 min for ZAF. The developed method was applied to the determination of ZAF in its pharmaceutical formulation and spiked human plasma. For quantification of ZAF in spiked plasma, proteins were precipitated with ethanol before chromatographic analysis. The calibration range was linear from 49.69437.50 ng/mL in spiked plasma. The absolute recovery from spiked plasma was 98.73 ± 0.42% at a concentration of 254.78 ng/mL of ZAF. No endogenous substances from plasma were found to interfere.
Rapid Determination and Confirmation of Biogenic Amines in Tuna Loin by Gas Chromatography/Mass Spectrometry Using Ethylchloroformate Derivative
Authors: Marks (Rupp) Heidi S , Anderson Collin R
Published: February 2020

A gas chromatography-mass spectrometry (GC/MS) method is described for the easy rapid determination and simultaneous confirmation of the biogenic amines putrescine (PUT), cadaverine (CAD), histamine (HTA), and spermidine (SPD) in fresh frozen tuna loin. The method can also be used to monitor tyramine (TYR). The method involves homogenization of fish tissue, extraction of biogenic amines into trichloroacetic acid solution, centrifugation, alkalization, and derivatization of supernatant with ethylchloroformate. All seafood species were fortified to contain 2.5, 5.0, 10.0, 12.5, and 25.0 μg/g (ppm) PUT, CAD, and SPD; and 10.0, 20.0, 40.0, 50.0, and 100.0 μg/g (ppm) HTA. Determination was based on standard curves for each analyte using peak areas with matrix standards equivalent to a concentration range bracketing the spike level. A set of 5 matrix controls (unfortified tuna tissue) was also analyzed; only endogenous SPD was found in all samples. The interassay average recoveries ranged from 57 to 79% across analytes and spike levels.
Development and Validation of Three Stability-Indicating Methods for Determination of Bisacodyl in Pure Form and Pharmaceutical Preparations
Authors: Metwally Fadia H , Abdelkawy Mohammed , Naguib Ibrahim A
Published: February 2020

Three new, simple, sensitive, and accurate stability-indicating methods were developed for quantitative determination of bisacodyl in the presence of its degradation products, monoacetyl bisacodyl (I) and desacetyl bisacodyl (II), in enteric coated tablets, suppositories, and raw material. The first is a spectrodensitometric method in which the drug is separated from I and II on silica gel plates using chloroformacetone (9 + 1, v/v) as the mobile phase with ultraviolet detection of the separated bands at 223 nm over a concentration range of 0.2-1.4 g/band for bisacodyl with mean recovery 100.35 ± 1.923%. The second method is fourth derivative D4 spectrophotometry, which allows determination of bisacodyl in the presence of its degradation products in raw material at 223 nm using acetonitrile as the solvent with adherence to Beer's law over the concentration range 2-18 μg/mL with mean recovery 99.77 ± 1.056%. In the third method, the spectrophotometric data of bisacodyl, I, and II using absolute ethanol as solvent were processed by 3 chemometric techniques: classical least-squares, principal component regression, and partial least-squares. A training set consisting of 15 mixtures containing different ratios of bisacodyl, I, and II was used for construction of the 3 models. A validation set consisting of 6 mixtures was used to validate the prediction ability of the suggested models. The 3 chemometric methods were applicable over a concentration range between 2-14 μg/mL for bisacodyl with mean recovery of 99.97 ± 0.865, 100.01 ± 0.749, and 99.97 ± 0.616% for the 3 models, respectively. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied to the analysis of raw material and pharmaceutical formulations containing bisacodyl, except for the second method that applies only for raw material. The validity of the suggested procedures was further assessed by applying the standard addition technique; the recoveries obtained were in accordance with those given by the reference method.
Determination of Two Antibacterial Binary Mixtures by Chemometrics-Assisted Spectrophotometry
Authors: Mohamed Abd El-Maaboud I , Abdelmageed Osama H , Refaat Ibrahim H
Published: February 2020

Simple chemometrics-assisted spectrophotometric methods are described for determination of 2 antibacterial binary mixtures. The mixtures are composed of norfloxacin in combination with tinidazole and erythromycin (as ethylsuccinate ester or stearate salt) in combination with trimethoprim. The normal UV absorption spectra of each pair of drugs in the studied mixtures, in the range of 200-400 nm, showed a considerable degree of spectral overlapping: 77.5% for the norfloxacintinidazole mixture and 84.3% for the erythromycintrimethoprim mixture. Resolution of the norfloxacintinidazole mixture and trimethoprim in the presence of erythromycin was accomplished successfully by using zero-crossing first derivative (1D), classical least-squares (CLS) regression analysis, and principal component regression (PCR) analysis methods. In addition, an alternative simple and accurate colorimetric method was developed for the determination of erythromycin in the presence of trimethoprim using 2,4-dinitrophenylhydrazine. All variables affecting the development of the colored chromogen were studied and optimized, and the product was measured at 526-529 and 538-542 nm for erythromycin stearate and erythromycin ethylsuccinate, respectively. For zero-crossing, first derivative technique Beer’s law was obeyed in the general concentration range of 250 μg/mL for norfloxacin, tinidazole, and trimethoprim with good correlation coefficients (0.9994-0.9996). Overall limits of detection (LOD) and quantification (LOQ) ranged from 0.59 to 2.81 and 1.96 to 9.33 μg/mL, respectively. The obtained results from CLS and PCR were compared with those obtained from a 1D spectrophotometric method. With the exception of erythromycin, overall recoveries in the average range of 97.33-103.0% were obtained with a considerable degree of accuracy when the suggested methods were applied to analysis of synthetic binary mixtures, some commercial dosage forms such as tablets and oral suspension without interference from the commonly encountered excipients and additives. For the colorimetric method, Beer's law was obeyed in the general concentration range of 7.21-28.84 μg/mL erythromycin with good correlation coefficients (0.9980-0.9996). Overall LOD and LOQ ranged from 0.73 to 1.65 and 2.43-5.49 μg/mL, respectively. Erythromycin derivatives were determined in the commercial dosage form, without interference from trimethoprim-encountered excipients and additives. The obtained results, with both chemometric and colorimetric methods, have been compared with those obtained from reported methods, and proper F- and t-values were observed, indicating no significant difference between the results of the suggested methods and reported method(s). The good percentage recoveries and proper statistical data obtained proved the efficiency of the proposed procedures for the determination of the studied drugs in their binary mixtures as well as in the commercial dosage forms with quite satisfactory precision.
Spectrofluorometric Determination of Fluvoxamine in Dosage Forms, Spiked Plasma, and Real Human Plasma by Derivatization with Fluorescamine
Authors: El-Enany Nahed
Published: February 2020

A sensitive, simple, and selective spectrofluorometric method was developed for the determination of fluvoxamine (FXM) in pharmaceutical formulations and biological fluids. The method is based upon the reaction between the drug and fluorescamine in borate buffer of pH 8.0 to yield a highly fluorescent derivative that is measured at 481 nm after excitation at 383 nm. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. The method was applied for the determination of the drug over the concentration range of 0.11.1 μg/mL with a detection limit of 0.01 μg/mL (2 10-8 M). The proposed method was successfully applied to the analysis of commercial tablets. The results obtained were in good agreement with those obtained using a reported spectrophotometric method. The method was applied for the determination of FXM in spiked human plasma with recovery (n = 4) of 97.32 1.23%, while that in real human plasma (n = 3) was 90.79 2.73%. A proposal for the reaction pathway is presented.
Microbiological Assay for Cefoxitin Sodium in Dosage Form
Authors: Nunes Salgado Hrida Regina , Gomes Tozo Greici Cristiani
Published: February 2020

A microbiological assay applying the cylinder-plate method is described for determination of the activity of cefoxitin sodium in injectables. Using a strain of Staphylococcus epidermidis ATCC 12226 as the test organism, cefoxitin sodium was measured in concentrations ranging from 50.0 to 200.0 g/mL. The validation showed that the method was linear (r = 0.9998), precise (RSD = 0.81%), and accurate. It was concluded that the microbiological assay is satisfactory for quantitation of cefoxitin sodium in injectables.
Gas Chromatographic Determination of Pesticide Residues in Malt, Spent Grains, Wort, and Beer with Electron Capture Detection and Mass Spectrometry
Authors: Vela Nuria , Prez Gabriel , Navarro Gins , Navarro Simn
Published: February 2020

A method for the simultaneous determination of 9 pesticides (dinitroanilines, organophosphorus, triazoles, and pyrimidines) in several products (malt, spent grains, wort, and beer) of the beer industry is reported. Solid samples (malt and spent grains) are extracted by homogenization with a waterhexane mixture, and the pesticides are partitioned with dichloromethane. Liquid samples (wort and beer) are extracted by sonication with a hexanedichloromethane mixture. Determination of pesticide residues was made by capillary gas chromatography with an electron capture detector (ECD). Confirmation of the compounds was performed by gas chromatography/ion trap mass spectrometry in the selected ion monitoring mode. Detection limits for GCECD varied from 0.2 to 5.5 pg for trifluralin and malathion, respectively. Recoveries of the pesticides from spiked samples ranged from 81.2 to 113.7% with a relative standard deviation between 3.47.5%. The method presents good linearity over the studied range (0.0052 g/mL). The proposed method is rapid and reliable and can be useful for routine monitoring during brewing.
Determination of Synthetic Hormones in Animal Urine by High-Performance Liquid Chromatography/Mass Spectrometry
Authors: Rbies Antoni , Cabrera Albert , Centrich Francesc
Published: February 2020

A method was developed for the extraction of stanozolol, taleranol, zeranol, hexestrol, dienestrol, ethynylestradiol, diethylstilbestrol, and trenbolone from animal urine. The analytes were extracted from the matrix by enzymatic hydrolysis, solid-phase extraction, and liquidliquid extraction. Detection and quantitation were performed on a high-performance liquid chromatography system coupled to a triple quadrupole mass spectrometer. The identification criteria met the European Union regulations. Validation of this method established a decision limit between 0.2 and 0.9 μg/L and a detection capability between 0.3 and 1.0 μg/L, depending on the analyte.
Kinetic Spectrophotometric Determination of Ethamsylate in Dosage Forms
Authors: El-Enany Nahed , Belal Fathalla , Rizk Mohamed
Published: February 2020

A simple and sensitive kinetic method has been developed for the determination of ethamsylate (ESL) in its pharmaceutical preparations. The method is based upon oxidation of ESL with 3-methyl-2-benzothiazolinone hydrazone hydrochloride in presence of cerium(IV) ammonium sulfate at room temperature for 20 min. The absorbance of the reaction product is measured at 514 nm. The absorbance-concentration plot was rectilinear over the range of 430 g/mL (r = 0.9999). The lower detection limit was 0.267 g/mL (9.110 106 M) and the lower quantitation limit was 0.808 g/mL. The different experimental parameters affecting the development and stability of the reaction product were studied and optimized. The proposed method was applied to the determination of ESL in formulations, and the results obtained were in good agreement with those obtained using a reference method. The proposed method was also used for the in vitro detection of ESL in spiked human plasma at its therapeutic concentration level.
Evaluation of Quantitative Recovery Methods for Listeria monocytogenes Applied to Stainless Steel
Authors: Kang David , Eifert Joseph D , Williams Robert C , Pao Steven
Published: February 2020

The ability of Listeria monocytogenes to attach to various food contact surfaces, such as stainless steel, polypropylene, and rubber compounds, is well documented. The retention of these or other pathogenic bacteria on food contact surfaces increases the risk of transmission to food products. The objective of this study was to compare several methods for quantitative recovery of Listeria monocytogenes from stainless steel surfaces. A cocktail of 4 serotypes of Listeria monocytogenes mixed in equivalent concentrations was inoculated onto type 304 stainless steel coupons in a 2 2 cm area. After 1 h exposure, coupons were sampled by one of the following methods: (1) swabbing with a premoistened Dacron swab; (2) rinsingwith phosphate-buffered saline; (3) direct contact onto tryptic soy agar containing 0.6% yeast extract (TSA + YE) plates for 10 s; (4) sonication in an ultrasonic water bath (40 kHz); (5) contact with the bristles of a sonicating brush head for 1 min; and (6) indirect contact (24 mm distance) with a sonicating brush head for 1 min. The 3 sonication methods yielded higher recovery than the other 3 methods (P < 0.05). Brushing the coupons with the sonicating brush head (contact or noncontact) yielded a recovery level of about 60%. The lowest cell recovery (about 20%) was observed with the swab and direct agar contact methods. After a 12 h exposure, recoveries ranged from 17.4 (brush contact method) to 2% (swab method).
Sampling Hazelnuts for Aflatoxin: Effect of Sample Size and Accept/Reject Limit on Reducing the Risk of Misclassifying Lots
Authors: Ozay Guner , Seyhan Ferda , Yilmaz Aysun , Whitaker Thomas B , Slate Andrew B , Giesbrecht Francis G
Published: February 2020

About 100 countries have established regulatory limits for aflatoxin in food and feeds. Because these limits vary widely among regulating countries, the Codex Committee on Food Additives and Contaminants began work in 2004 to harmonize aflatoxin limits and sampling plans for aflatoxin in almonds, pistachios, hazelnuts, and Brazil nuts. Studies were developed to measure the uncertainty and distribution among replicated sample aflatoxin test results taken from aflatoxin-contaminated treenut lots. The uncertainty and distribution information is used to develop a model that can evaluate the performance (risk of misclassifying lots) of aflatoxin sampling plan designs for treenuts. Once the performance of aflatoxin sampling plans can be predicted, they can be designed to reduce the risks of misclassifying lots traded in either the domestic or export markets. A method was developed to evaluate the performance of sampling plans designed to detect aflatoxin in hazelnuts lots. Twenty hazelnut lots with varying levels of contamination were sampled according to an experimental protocol where 16 test samples were taken from each lot. The observed aflatoxin distribution among the 16 aflatoxin sample test results was compared to lognormal, compound gamma, and negative binomial distributions. The negative binomial distribution was selected to model aflatoxin distribution among sample test results because it gave acceptable fits to observed distributions among sample test results taken from a wide range of lot concentrations. Using the negative binomial distribution, computer models were developed to calculate operating characteristic curves for specific aflatoxin sampling plan designs. The effect of sample size and accept/reject limits on the chances of rejecting good lots (sellers' risk) and accepting bad lots (buyers' risk) was demonstrated for various sampling plan designs.
Determination of Added Sulfites in Dried Garlic with a Modified Version of the Optimized Monier-Williams Method
Authors: Lafeuille Jean-Louis , Lefevre Stephane , Achouri Djamila
Published: February 2020

The optimized Monier-Williams method is slightly modified so that it could be applied for determining sulfite content in dried garlic. Dried garlic sample is directly acidified in a reactor at a pH below 3. At this pH level, the alliinase enzyme activity is irreversibly blocked, and the sulfur-containing amino acids such as alliin (the most abundant) present in dried garlic cannot be transformed into corresponding thiosulfinates such as allicin, which is absent in dried garlic. This prevents allicin from reacting with added sulfites and being probably converted to S-allyl thiosulfate, which is not volatile and has no taste. It is found that at a pH below 2.4 and at boiling water temperature, alliin produces sulfur dioxide in adequate quantity to explain the false-positive results when utilizing the optimized Monier-Williams method with allicin suppression for unsulfited dried garlic samples. Finally, when garlic samples are stabilized in a phosphoric acid buffer at a final pH around 2.4, no sulfite is produced during the Monier-Williams distillation, which is further proof there are no naturally occurring sulfites in unsulfited dried garlic under these mild conditions.
Validation of Erythromycin Microbiological Assay Using an Alternative Experimental Design
Authors: Loureno Felipe Rebello , Kaneko Telma Mary , Pinto Terezinha De Jesus Andreoli
Published: February 2020

The agar diffusion method, widely used in antibiotic dosage, relates the diameter of the inhibition zone to the dose of the substance assayed. An experimental plan is proposed that may provide better results and an indication of the assay validity. The symmetric or balanced assays (2 2) as well as those with interpolation in standard curve (5 1) are the main designs used in the dosage of antibiotics. This study proposes an alternative experimental design for erythromycin microbiological assay with the evaluation of the validation parameters of the method referring to linearity, precision, and accuracy. The design proposed (3 1) uses 3 doses of standard and 1 dose of sample applied in a unique plate, aggregating the characteristics of the 2 2 and 5 1 assays. The method was validated for erythromycin microbiological assay through agar diffusion, revealing its adequacy to linearity, precision, and accuracy standards. Likewise, the statistical methods used demonstrated their accordance with the method concerning the parameters evaluated. The 3 1 design proved to be adequate for the dosage of erythromycin and thus a good alternative for erythromycin assay.