bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous Identification and Quantitative Determination of Selected Aminoglycoside Antibiotics by Thin-Layer Chromatography and Densitometry
Authors: Hubicka Urszula , Krzek Jan , Woltyska Hanna , Stachacz Boóena
Published: February 2020

A TLCdensitometric method has been developed for simultaneous identification and quantitative determination of amikacin, gentamicin, kanamycin, neomycin, netilmicin, and tobramycin. This separation of antibiotics was achieved on silica gel TLC plates without a fluorescent indicator and with methanol25 ammoniachloroform (3 + 2 + 1, v/v/v) as the mobile phase. The densitometric measurements were made at 500 nm after detection with a 0.2 ninhydrin solution in ethanol. Under these conditions, good separation of the chosen aminoglycosides was obtained. The method is distinguished by high sensitivity, with the LOD from 0.25 g for amikacin to 1.00 g for gentamicin and the LOQ from 0.5 g for amikacin to 1.65 g for gentamicin, and a wide linearity range 0.756.25 g/spot for amikacin and netilmicin and 1.512.50 g/spot for other antibiotics. The precision of the determination was very good; RSD varied in the range 0.30.6.
Levels of Trans Fats in Diets Consumed in Developing Economies
Authors: Butt Masood Sadiq , Sultan Muhammad Tauseef
Published: February 2020

Cardiovascular complications are a leading cause of mortality worldwide, and dietary patterns and lifestyle are key factors responsible for their progression. Sedentary lifestyle and transient changes in nutrition have led to drastic increases in such maladies during the last few decades, and dietary changes are significant, as they are coupled with high fat intake, especially Trans fats. In developed countries, legislations and monitoring systems have resulted in reduced consumption of these metabolites. The developing world, especially South Asia, is also facing the menace of Trans fats; lack of governmental interest and ignorance among consumers are the main reasons. In these regions, the use of hydrogenated vegetable oil (ghee) and shortening in deep-fat frying of culinary items, such as samosa, paratha, bhatura, poori, and tikkies, results in increased consumption of Trans fats. Research investigations and cohort studies showed a positive correlation between consumption of Trans fats and cardiovascular disorders. In this article, Trans fats intake and its level in different products available in developing countries, particularly in South Asia, were reviewed along with information regarding processes involved in the production and possible reduction of Trans fats.
Spectrofluorometry, Thin Layer Chromatography, and Column High-Performance Liquid Chromatography Determination of Rabeprazole Sodium in the Presence of Its Acidic and Oxidized Degradation Products
Authors: Osman Afaf , Osman Mohamed
Published: February 2020

The objective of this study is to develop validated stability-indicating spectrofluorometric, TLC-densitometric, and HPLC methods for the determination of rabeprazole sodium and its degradation products. The first method was based on measuring the fluorescence intensity of the drug at 416 and 311 nm for the emission and at 320 and 274 nm for the excitation for acid and oxidized solutions, respectively. The second method was based on the separation of the drug from its acidic and oxidized degradation products followed by densitometric measurement of the intact drug spot at 284 nm. The separation was carried out on Fluka TLC sheets of silica gel 60 F254 using isopropyl alcohol30 ammonia (80 + 2, v/v) mobile phase. The third method was based on HPLC separation of rabeprazole sodium from its acidic and oxidized degradation products on a reversed-phase Waters Nova-Pak C18 column using 0.05 M potassium dihydrogen phosphatemethanolacetonitrile (5 + 3 + 2, v/v/v) pH 7 0.2 mobile phase. The proposed procedures were successfully applied for the determination of rabeprazole sodium in pure form, laboratory-prepared mixtures, tablet, and expired batch. The obtained results were statistically compared with those of a reported method and validated according to United States Pharmacopeia guidelines. Two main acidic degradation products of the drug were separated and subjected to IR spectrometry and MS to confirm their structures, and the schemes for their formation were elucidated.
Validation of the Soleris® Yeast and Mold Test for Semiquantitative Determination of Yeast and Mold in Selected Foods
Authors: Alles Susan , Shrestha Nabina , Ellsworth Amanda , Rider Alicia , Foti Debra , Knickerbocker Jake , Mozola Mark
Published: February 2020

The Soleris yeast and mold method, a growth-based test system with an optical detection end point, was evaluated for its ability to detect yeast and mold contamination in a wide variety of foods. The Soleris test was used in a semiquantitative manner, in which the test result is positive or negative at a threshold level determined by the dilution and volume of sample homogenate added to the Soleris test vial. By testing at two or more threshold levels, the contamination level can be estimated. The LOD of the Soleris method is 10 CFU/g when 1 mL of a 1:10 sample homogenate is added to the test vial. In these studies, the Soleris results were compared to plate counts obtained using the U.S Food and Drug Administration/Bacteriological Analytical Manual direct plating method, and agreement between the methods was calculated.Considering results from both internal and independent laboratory trials, overall agreement between the methods was 90. Chi-square analysis showed, with few exceptions, that results of the Soleris and direct plating methods were not statistically different. Ruggedness testing was performed, and the Soleris method was found to be robust when challenged with marginally suboptimal assay conditions. Results of inclusivity testing showed that the Soleris test vial medium supports the growth of a wide variety of yeasts and molds common to foods. Results of exclusivity testing showed that bacteria do not produce positive results, even when present in the vial in relatively high initial concentrations. The Solerismethod produces results in 72 h or less and thus offers considerable time savings in comparison to other commonly used yeast and mold methods.
Reversed-Phase Liquid Chromatographic Determination of Two Manufacturing Intermediates in D&C Red No. 34 and Its Lakes
Authors: Harp Bhakti Petigara , Barrows Julie N
Published: February 2020

A reversed-phase LC method was developed to determine two manufacturing intermediates in the monosulfo monoazo color additive D&C Red No. 34 and its lakes. The analytes are 2-amino-1-naphthalenesulfonic acid (Tobias acid) and 3-hydroxy-2-naphthalenecarboxylic acid (3-hydroxy-2-naphthoic acid). This method can be used for batch certification of the color additives by the U.S. Food and Drug Administration to ensure that each lot meets published specifications for coloring drugs and cosmetics. The new method uses lithium oxalate in methanolwater to dissolve the color additives for analysis. The analytes were identified by comparison of their LC retention times and UV absorption spectra with those of standards. Peak area calibrations were generally linear (R > 0.999) and recoveries were 105 for Tobias acid and 103 for 3-hydroxy-2-naphthoic acid. The limits of determination (LOD) were 0.01 for Tobias acid and 0.03 for 3-hydroxy-2-naphthoic acid. The RSDs at the specification levels were 0.9 for Tobias acid and 3.2 for 3-hydroxy-2-naphthoic acid. Survey analyses of 14 samples of certified D&C Red No. 34 straight colors and lakes from six domestic and foreign manufacturers yielded results for Tobias acid that generally agreed with results previously obtained by using a gravity elution column chromatographic method. Nine of the results for 3-hydroxy-2-naphthoic acid were 2 to 5 times higher than the results obtained using the column chromatographic method. We attribute the lower accuracy of the column chromatographic method to incomplete solubility of the samples using the method conditions and difficulty with interpreting the UV spectrophotometric results.
A Square-Wave Adsorptive Stripping Voltammetric Method for Determination of Fast Green Dye
Authors: Al-Ghamdi Ali F
Published: February 2020

Square-wave adsorptive stripping voltammetric (SW-AdSV) determinations of trace concentrations of the coloring agent fast green were described. The analytical methodology used was based on the adsorptive preconcentration of the dye on the hanging mercury drop electrode, and then a negative sweep was initiated. In pH 10 carbonate supporting electrolyte, fast green gave a well-defined and sensitive SW-AdSV peak at 1220 mV. The electroanalytical determination of this dye was found to be optimized in carbonate buffer (pH 10) with the following experimental conditions: accumulation time (120 s); accumulation potential (0.8 V); scan rate (800 mV/s); pulse amplitude (90 mV); frequency (90 Hz); surface area of the working electrode (0.6 mm2); and the convection rate (2000 rpm). Under these optimized conditions, the AdSV peak current was proportional over the concentration range 2 1086 107 M (r = 0.999), with an LOD of 1.63 1010 M (0.132 ppb). This analytical approach possessed more enhanced sensitivity than conventional chromatography or spectrophotometry, and was simple and quick. The precision of the method in terms of RSD was 0.17, whereas the accuracy was evaluated via the mean recovery of 99.6. Possible interferences by several substances usually present as food additive azo dyes (E110, E102, E123, and E129), natural and artificial sweeteners, and antioxidants were also investigated. Applicability of the developed electroanalysis method was illustrated via the determination of fast green in ice cream and soft drink samples.
Comparison of Signal-to-Noise, Blank Determination, and Linear Regression Methods for the Estimation of Detection and Quantification Limits for Volatile Organic Compounds by Gas Chromatography
Authors: Sanagi M Marsin , Ling Susie L , Nasir Zalilah , Hermawan Dadan , Wan Ibrahim Wan Aini , Naim Ahmedy Abu
Published: February 2020

LOD and LOQ are two important performance characteristics in method validation. This work compares three methods based on the International Conference on Harmonization and EURACHEM guidelines, namely, signal-to-noise, blank determination, and linear regression, to estimate the LOD and LOQ for volatile organic compounds (VOCs) by experimental methodology using GC. Five VOCs, toluene, ethylbenzene, isopropylbenzene, n-propylbenzene, and styrene, were chosen for the experimental study. The results indicated that the estimated LODs and LOQs were not equivalent and could vary by a factor of 5 to 6 for the different methods. It is, therefore, essential to have a clearly described procedure for estimating the LOD and LOQ during method validation to allow interlaboratory comparisons.
1-2 Test
Authors: Feldsine Philip , Hammack Thomas
Published: February 2020

A study was conducted to determine the efficacy of detecting low contamination levels of Salmonella in peanut butter using the 1-2 Test. This study was conducted under the AOAC Research Institute Emergency Response Validation program. A set of samples was analyzed by the 1-2 Test and the U.S. Food and Drug Administration's Bacteriological Analytical Manual reference method. Among the 90 total samples and controls, 32 samples were positive by the 1-2 Test and the reference method. Statistical analyses of these paired samples indicated that for all levels analyzed, the difference between the 1-2 Test and reference method results were not statistically different at the 5 level.
TRANSIA PLATE Salmonella Gold
Authors: Feldsine Philip , Hammack Thomas
Published: February 2020

A study was conducted to determine the efficacy of detecting low contamination levels of Salmonella in peanut butter using TRANSIA PLATE Salmonella Gold (TPSG). This study was conducted under the AOAC Emergency Response Validation program. A set of samples was each analyzed by the TPSG method and the U.S. Food and Drug Administration's Bacteriological Analytical Manual reference method. Among the 45 total samples and controls, 26 were positive by the TPSG and 24 were positive by the reference method. Statistical analyses of these unpaired samples indicated that for all levels analyzed, the difference between the TPSG and reference method results were not statistically different at the 5 level.
VIDAS Salmonella (SLM) Assay Method EasySLM with ChromID Salmonella (SM2) Agar
Authors: Johnson Ronald , Mills John , Coln-Reveles Judith , Hammack Thomas
Published: February 2020

A method modification study was conducted for the VIDAS Salmonella (SLM) assay (AOAC Performance Tested MethodSM 020901) using the EasySLM method to validate a matrix extension for peanut butter. The VIDAS EasySLM method is a simple enrichment procedure compared to traditional Salmonella methods, requiring only pre-enrichment and a single selective enrichment media, Salmonella Xpress 2 (SX2) broth. SX2 replaces the two selective broths in traditional methods and eliminates the M broth transfer, incubation, and subsequent pooling of M broths prior to VIDAS assay. The validation study was conducted under the AOAC Research Institute Emergency Response Validation program. VIDAS SLM was compared to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) method for detection of S. enterica ser. Typhimurium in peanut butter. All peanut butter samples were prepared, blind-coded, and shipped to the method developers' laboratory by Q Laboratories. In addition, Q Laboratories performed most probable number and reference method analyses on peanut butter samples. The VIDAS EasySLM ChromID Salmonella (SM2) Agar was previously validated in the Performance Tested Methods program for the detection of Salmonella in roast beef, raw ground pork, turkey, pork sausage, raw chicken breast, dry pet food, whole milk, ice cream, bagged spinach, shrimp (raw, peeled), raw cod, spent irrigation water, pecans, peanut butter, dry pasta, cake mix, ground black pepper, nonfat dry milk, liquid eggs, cantaloupe, and orange juice. In the matrix extension study for peanut butter, the VIDAS EasySLM method was shown to be equivalent to the appropriate reference culture procedure using both buffered peptone water pre-enrichment and the FDA-BAM lactose pre-enrichment in the two-step enrichment method with SX2 media. The current study extends the validation to include peanut butter.
Recognition of Gliadin and Glutenin Fractions in Four Commercial Gluten Assays
Authors: Allred Laura K , Ritter Bruce W
Published: February 2020

Gluten sensitivity affects nearly 1 of the population in the United States and Europe. To help these consumers avoid the health issues that result from gluten consumption, the U.S. Food and Drug Administration is attempting to establish a definition and testing protocol for gluten-free foods. Establishing this protocol depends on accurate tests that can detect and quantitate gluten. There are multiple immunoassays available for the quantitation of gluten, and most are based on one of two antibodies. These antibodies, known as the Skerritt and R5 antibodies, were examined through the use of four commercial test kits for their ability to detect the two main components of gluten, known as gliadin and glutenin, in wheat. Commercial tests based on the Skerritt and R5 antibodies demonstrated differing affinities for gliadin and glutenin, with the Skerritt-based tests recognizing glutenins more strongly, and the R5 tests recognizing gliadins more strongly. Analysis of 40 processed food samples of unknown gluten content revealed differences in gluten detection and quantitation between the Skerritt-based and R5-based assays. These discrepancies in test results may be the result of the antibody affinity differences between the Skerritt- and R5-based tests, the solubility differences between gliadins and glutenins, or a combination of these and other factors.
Simultaneous Ion Removal and Quantitation of Low-Molecular-Weight Dietary Fiber from High-Molecular-Weight Dietary Fiber Filtrates Using Liquid Chromatography
Authors: Post Brett E , Marshak Michael R , DeVries Jonathan W
Published: February 2020

Dietary fiber and its quantitation in foods have been of significant interest in the nutrition community for over 50 years. A number of AOAC Official Methods of AnalysisSM have been adopted for the analysis of dietary fiber and some of its fractions and components commensurate with the evolving discoveries of dietary fiber nutrition research. Quantitation of low-molecular-weight soluble dietary fiber (LMWSDF) has been difficult due to high solubility in a precipitating solvent mixture of four parts alcohol and one part water. AOAC Method 2001.03 effectively quantitates LWMSDF subsequent to gravimetric removal of high-molecular-weight dietary fiber using LC. However, deionization and concentration of the enzymatic digestate, necessary to assure accurate LC quantitation, requires substantial time and manual labor. A modification to the method and resulting method performance is presented that describes a means of simultaneously deionizing the digestate and quantitating the LMWSDF in a single LC injection, eliminating a number of time-consuming manual preparation steps.
Development and Validation of a Multiresidue Method for the Determination of Neonicotinoid and Macrocyclic Lactone Pesticide Residues in Milk, Fruits, and Vegetables by Ultra-Performance Liquid Chromatography/MS/MS
Authors: Kamel Alaa , Qian Yaorong , Kolbe Elizabeth , Stafford Charles
Published: February 2020

A multiresidue method was developed and validated for the determination of 13 neonicotinoid pesticides and metabolites, and nine macrocyclic lactone pesticides and veterinary drugs using SPE and ultra-performance liquid chromatography/MS/MS. The method was validated in milk, orange, spinach, apple, plum, watermelon, green bean, zucchini, broccoli, strawberry, grape, and tomato by analyzing replicates of residue-free control samples fortified with a mixture of 22 target analytes at three concentration levels. The recoveries of the analytes from the fortified matrixes were mostly within 70120, except for some of the neonicotinoid metabolites. The LOD values varied by analyte and matrix and ranged between 0.0012 ng/g. The developed method was successful in combining two widely different classes of compounds into a single analysis.
Determination of Residual Carbamate, Organophosphate, and Phenyl Urea Pesticides in Drinking and Surface Water by High-Performance Liquid Chromatography/Tandem Mass Spectrometry
Authors: Hao Chunyan , Nguyen Bick , Zhao Xiaoming , Chen Ernie , Yang Paul
Published: February 2020

Methods using SPE followed by HPLC/MS/MS analysis were developed and validated for the determination of 39 pesticides in different aquatic environmental matrixes. The target pesticides included 12 carbamates, 15 organophosphates, and 12 phenyl ureas, out of which 16 are regulated in North America. Method detection limits were in the low ng/L range using the U.S. Environmental Protection Agency's protocol and multiple reaction monitoring (MRM) data acquisition, meeting the regulatory needs in the United States, Canada, and European Union. Isotope-labeled compounds were used as injection internal standards, as well as method surrogates to improve the data quality. QC/QA data (e.g., method recovery and within-run and between-run method precision) derived from multiyear monitoring activities were used to demonstrate method ruggedness. The same QC/QA data also showed that the method exerted no obvious matrix effect on the target analytes. Parameters that affect method performance, such as preservatives, pH values, sample storage time, and sample extract storage time, were also studied in detail. Accredited by the Canadian Association for Laboratory Accreditation and licensed by the Ontario government for drinking water analysis, these methods have been applied to the analysis of drinking water, ground water, and surface water samples collected in the province of Ontario, Canada, to ensure the pristine nature of Ontario's aquatic environment. Using the scheduled MRM (sMRM) data acquisition algorithm, it was demonstrated that sMRM improved the S/N of extracted ion chromatograms by at least two- to six-fold and, therefore, enhanced the short- and long-term instrument precision, demonstrated the ability to offer high throughput multiresidue analysis, and allowed the use of two MRM transitions for each compound to achieve higher confidence for compound identification.
Development of Optimized Extraction Methodology for Cyanogenic Glycosides from Flaxseed (Linum usitatissimum)
Authors: Barthet Véronique J , Bacala Ray
Published: February 2020

A reference method (higher accuracy) and a routine method (higher throughput) were developed for the extraction of cyanogenic glycosides from flaxseed. Conditions of (essentially) complete extraction were identified by comparing grinding methods and extraction solvent composition, and optimizing solvent-to-meal ratio, extraction time, and repeat extraction. The reference extraction method consists of sample grinding using a high-speed impact plus sieving mill at 18 000 rpm with a 1.0 mm sieve coupled with triple-pooled extraction in a sonicating water bath (40C, 30 min) using 75 methanol. The routine method differs by the use of a coffee mill to grind samples and a single extraction. The 70 and 80 methanol solutions were equal and superior to other combinations from 50 to 100 aqueous ethanol or methanol. The extraction efficiencies of the routine method (relative to the reference method) was 87.9 2.0 SD (linustatin) and 87.6 1.9 SD (neolinustatin) using four composite samples that were generated from seeds of multiple cultivars over two crop years and locations across Western Canada. Ground flaxseed was stable after storage at room temperature, refrigeration, or freezing for up to 7 days, and frozen for at least 2 weeks but less than 2 months. Extracts were stable for up to 1 week at room temperature and at least 2 weeks when refrigerated or frozen.
Analysis of Beverages for Hg, As, Pb, and Cd with a Field Portable X-Ray Fluorescence Analyzer
Authors: Anderson David L
Published: February 2020

Analytical capabilities of a handheld X-ray tube analyzer for analysis of beverages were evaluated. Sets of standard solutions for the elements Hg, As, Pb, and Cd were prepared with mass fractions up to 5000 mg/kg. A thirst quencher beverage was spiked with these elements up to mass fractions of 2500 mg/kg. Portions of these solutions were placed in standard X-ray fluorescence (XRF) cells, as well as the original container, and analyzed by using a field portable Innov-X -6000s XRF tube-type analyzer. Uncorrected analyzer output usually yielded qualitative or semiquantitative results for the spiked beverages in X-ray cells. Average correction factors applied to analyzer output yielded accurate (in terms of z-scores) quantitative results for As above 20 mg/kg and qualitative or semiquantitative results for the other elements. Weighted quadratic fit calibrations provided accurate quantitative or semiquantitative results for all elements at levels above 20 mg/kg. The instrument's preset X-ray overlap correction algorithm worked well for the beverage spiked with all four elements. Spiked beverages analyzed through the wall of the original polyethylene terephthalate container produced accurate results within measurement uncertainties after application of container wall correction factors.
Microwave-Assisted Acid Extraction of Selenium from Medicinal Plants Followed by Electrothermal Atomic Absorption Spectrometric Determination
Authors: Kolachi Nida Fatima , Kazi Tasneem Gul , Baig Jameel Ahmed , Kandhro Ghulam Abbas , Khan Sumaira , Afridi Hassan Imran , Kumar Sham , Shah Abdul Qadir
Published: February 2020

A simple and rapid microwave-assisted extraction (MAE) of selenium (Se) from medicinal plants was investigated using different concentrations of nitric acid and hydrochloric acid, sample mass, heating time, microwave energy, and plant particle size. The optimization strategy was carried out using multivariate methodologies. Electrothermal atomic absorption spectrometry was used to determine Se. The accuracy of the optimized procedure was evaluated by using certified reference materials with certified values for Se and a microwave-assisted acid digestion (MD) method for comparative purpose. No significant difference was observed (P > 0.05) when comparing the values obtained by the proposed MAE and MD methods (paired t-test). Under the optimum operating conditions, the LOD obtained from the standard calibration curve was 0.012 g/L for Se. The average RSD of the MAE method varied between 4.05 and 7.53 (n 6). The proposed method was successfully applied for the determination of Se in medicinal plants used as remedies for cancerous and infection diseases.
Selective Preconcentration/Separation of Copper(II), Iron(III), and Lead(II) as Their N-Benzoyl-N,N-Diisobutylthiourea Chelates on Amberlite XAD-16 Resin
Authors: Soylak Mustafa , Kariper I Afsin
Published: February 2020

A preconcentration/separation procedure for copper(II), iron(III), and lead(II) ions has been established for use prior to their flame atomic absorption spectrometric determination. The presented procedure is based on adsorption of analyte ions on Amberlite XAD-16 resin as their N-benzoyl-N,N-diisobutylthiourea chelates. The influence of analytical parameters including pH of the solutions and type of eluent on the recoveries of Cu(II), Fe(III), and Pb(II) ions was investigated. The recoveries of the analytes were generally >95. No interference effects were observed from alkaline, earth alkaline, or transition metals on the recoveries of the studied metals. The LODs based on 3 were 1.9 g/L for Cu, 5.9 g/L for Fe, and 3.1 g/L for Pb. Validation of the procedure was carried out by analyzing standard reference material 1568a (rice flour). The procedure was applied to the determination of analytes in natural water samples.
Tendency for Interlaboratory Precision in the GMO Analysis Method Based on Real-Time PCR
Authors: Kodama Takashi , Kurosawa Yasunori , Kitta Kazumi , Naito Shigehiro
Published: February 2020

The Horwitz curve estimates interlaboratory precision as a function only of concentration, and is frequently used as a method performance criterion in food analysis with chemical methods. The quantitative biochemical methods based on real-time PCR require an analogous criterion to progressively promote method validation. We analyzed the tendency of precision using a simplex real-time PCR technique in 53 collaborative studies of seven genetically modified (GM) crops. Reproducibility standard deviation (SR) and repeatability standard deviation (Sr) of the genetically modified organism (GMO) amount () was more or less independent of GM crops (i.e., maize, soybean, cotton, oilseed rape, potato, sugar beet, and rice) and evaluation procedure steps. Some studies evaluated whole steps consisting of DNA extraction and PCR quantitation, whereas others focused only on the PCR quantitation step by using DNA extraction solutions. Therefore, SR and Sr for GMO amount () are functions only of concentration similar to the Horwitz curve. We proposed SR 0.1971C0.8685 and Sr 0.1478C0.8424, where C is the GMO amount (). We also proposed a method performance index in GMO quantitative methods that is analogous to the Horwitz Ratio.
Stability-Indicating High-Performance Thin-Layer Chromatographic Method for Quantitative Determination of Omeprazole in Capsule Dosage Form
Authors: Jha Preeta , Parveen Rabea , Khan Suroor A , Alam Ozair , Ahmad Sayeed
Published: February 2020

A novel HPTLC method has been developed and validated for quantitative determination of omeprazole (OPZ) in capsule dosage form. The method was validated according to the International Conference on Harmonization guidelines for accuracy, precision, linearity, specificity, and robustness. HPTLC aluminum sheets precoated with silica gel 60F254 were used as the stationary phase and chloroformmethanol (9 + 1) as the mobile phase. The mobile phase was found to give compact bands for OPZ (Rf value of 0.39 0.12) in densitometric analysis in the absorbance mode at 302 nm. The linear regression analysis data for the calibration plots showed good linearity (r2 = 0.997) with respect to peak area in the concentration range 503000 ng/band. The mean values of the slope and intercept were 9.896 0.0753 and 1870.761 16.866, respectively. The method was also applied for stability testing of OPZ in different stress conditions and found to be accurate, linear, precise, robust, specific, and stability indicating. The method proposed can be used for QC and stability testing of different dosage forms such as tablets and capsules, as well as for bulk drug analysis of OPZ.
Using a First-Derivative Spectrophotometric Method for Simultaneous Determination of Fe(II) and Ni(II) in Mineral Vitamins by Interaction with 2,4-Diamino-5-(2-hydroxy-5-nitrophenylazo)benzenesulfonic Acid Sodium Salt in the Presence of Tween 20
Authors: Hashem Elham Y , Seleim Mohamed M , El-Zohry Ahmed M
Published: February 2020

A highly selective and sensitive derivative spectrophotometric method has been developed for the determination of Fe(II) and Ni(II) in different mineral vitamins. The method is based on the formation of binary complexes of Fe(II) and Ni(II) with 2,4-diamino-5-(2-hydroxy-5-nitrophenylazo) benzenesulfonic acid sodium salt (Mordant Brown 33) at pH 5.6 with Tween 20. At max 512 and 493 nm, the molar absorbtivity was 2.09 104 and 0.58 104 L/mol cm for Fe(II) and Ni(II), respectively. Fe(II) can be determined in the range 0.552.79 g/mL in the presence of 2.92 g/mL Ni, and Ni(II) can be determined in the range 1.173.5 g/mL in the presence of 2.79 g/mL Fe(II) in the presence of Tween 20 (4). The detection limits were 9.0 and 15.0 ng/mL for Fe(II) and Ni(II), respectively. The effect of foreign ions was elucidated. The RSD values were, in all instances, less than 1.3. The proposed method was successfully applied for the simultaneous determination of Fe(II) and Ni(II) in different mineral vitamins.
Determination of Carbamazepine and Its Impurities Iminostilbene and Iminodibenzyl in Solid Dosage Form by Column High-Performance Liquid Chromatography
Authors: Džodić Predrag Lj , ivanovi Ljiljana J , Proti Ana D , Zeevi Mira L , Joci Biljana M
Published: February 2020

An accurate and precise RP-HPLC method was developed and validated for the determination of carbamazepine and its impurities iminostilbene and iminodibenzyl in a tablet formulation with fluphenazine as an internal standard. Buffermethanol (50 + 50, v/v) was used as the mobile phase. During validation, specificity, linearity, precision, accuracy, LOD, LOQ, and robustness of the method were tested. The method was proven to be specific against placebo interference. Linearity was evaluated over the concentration range of 100500, 0.050.25, and 0.10.5 g/mL, and the r values were 0.9994, 0.9997, and 0.9979 for carbamazepine, iminostilbene, and iminodibenzyl, respectively. Intraday precision of the method was good, and RSD was below 2 for all analytes. The accuracy of the method ranged from 100.69 to 102.10, 99.76 to 102.66, and 99.26 to 100.08 for carbamazepine, iminostilbene, and iminodibenzyl, respectively. LOD was 0.0125, 0.025, and 0.05 g/mL and LOQ was 0.05, 0.05, and 0.1 g/mL for carbamazepine, iminostilbene, and iminodibenzyl, respectively. Robustness of the method was proven by using a chemometric approach. The method was successfully applied to the analysis of commercially available carbamazepine tablets and showed good repeatability, with RSD below 2.
Stability-Indicating Validated HPLC Method for Simultaneous Determination of Oral Antidiabetic Drugs from Thiazolidinedione and Sulfonylurea Groups in Combined Dosage Forms
Authors: Gumieniczek Anna , Berecka Anna , Komsta ukasz
Published: February 2020

For type 2 diabetes treatment, combinations of drugs from the thiazolidinedione and sulfonylurea groups are now available in the same tablet or capsule. Therefore, a stability-indicating and validated HPLC method was developed for simultaneous determination of pioglitazone, rosiglitazone, and glipizide in combined dosage forms. The examined drugs were subjected to different conditions such as acid and base, temperature, and UV light, and degradation of pioglitazone and glipizide was observed under thermal and acidic stress. However, selectivity of the presented method for pioglitazone, rosiglitazone, and glipizide assay against their degradation products was confirmed. It was also demonstrated to be robust, resisting small deliberate changes in pH of the buffer, flow rate, and percentage of acetonitrile in the mobile phase. The presented method utilizes a LiChrospher RP18 column (125 4.0 mm), acetonitrile in phosphate buffer at pH 4.3 (40 + 60, v/v) as the mobile phase, and UV detection at 225 nm for pioglitazone/glipizide or 245 nm for rosiglitazone/glipizide. The method was validated with respect to linearity, precision, and accuracy. Finally, the elaborated procedure was applied for the QC of pioglitazone/glipizide and rosiglitazone/glipizide mixtures.
Determination of Multiresidue Pesticides in Green Tea by Using a Modified QuEChERS Extraction and Ion-Trap Gas Chromatography/Mass Spectrometry
Authors: Steiniger David , Lu Guiping , Butler Jessie , Phillips Eric , Fintschenko Yolanda
Published: February 2020

The pesticide residues in exported and imported tea products must not exceed the maximum residue limits (MRLs) regulated by the import countries. Tea is a complex matrix that obfuscates the determination of pesticide residues. Many available methods for multiresidue pesticide analysis of tea are time-consuming and require many cleanup steps. The objective of this study was to develop a simple multiresidue method by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and ion-trap GC/MS/MS, which can identify, confirm, and quantify pesticides in complex matrixes. A tea product was homogenized with water, and the pesticides were extracted with acetonitrile containing 1 acetic acid. The extract was subjected to centrifugation, initial cleanup with dispersive SPE (dSPE), solvent exchange, and final cleanup with dSPE. Diethyl-d10-parathion and triphenyl phosphate were used as the internal standard and surrogate, respectively. The final extract was injected into an ITQ 700 gas chromatograph/mass spectrometer. Quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient of >0.9930 for the 22 pesticides selected for the study. The recoveries of the 22 pesticides ranged from 78 to 115, except those for diazinon (130) and malathion (122), with an average RSD of 8.7. The LOD values of all of the pesticides, except for terbufos, were below the MRLs set by the European Union and Japan.
HPLC, TLC, and First-Derivative Spectrophotometry Stability-Indicating Methods for the Determination of Tropisetron in the Presence of Its Acid Degradates
Authors: Abdel-Fattah Laila S , El-Sherif Zeinab A , Kilani Khadiga M , El-Haddad Dalia A
Published: February 2020

Three stability-indicating assay methods were developed for the determination of tropisetron in a pharmaceutical dosage form in the presence of its degradation products. The proposed techniques are HPLC, TLC, and first-derivative spectrophotometry (1D). Acid degradation was carried out, and the degradation products were separated by TLC and identified by IR, NMR, and MS techniques. The HPLC method was based on determination of tropisetron in the presence of its acid-induced degradation product on an RP Nucleosil C18 column using methanolwateracetonitriletrimethylamine (65 + 20 + 15 + 0.2, v/v/v/v) mobile phase and UV detection at 285 nm. The TLC method was based on the separation of tropisetron and its acid-induced degradation products, followed by densitometric measurement of the intact spot at 285 nm. The separation was carried out on silica gel 60 F254 aluminum sheets using methanolglacial acetic acid (22 + 3, v/v) mobile phase. The 1D method was based on the measurement of first-derivative amplitudes of tropisetron in H2O at the zero-crossing point of its acid-induced degradation product at 271.9 nm. Linearity, accuracy, and precision were found to be acceptable over concentration ranges of 40240 g/mL, 110 g/spot, and 636 g/mL for the HPLC, TLC, and 1D methods, respectively. The suggested methods were successfully applied for the determination of the drug in bulk powder, laboratory-prepared mixtures, and a commercial sample.
Development and Validation of an HPLC/MS/MS Method for Determining the Thiazolidinone PG15 in Rat Plasma
Authors: UchôA FláVia D T , Palma Eduardo C , Souza Natalia F , Lima Maria C A , Galdino Suely L , Pitta Ivan R , Costa Teresa Dalla
Published: February 2020

A rapid, sensitive, and simple HPLC/MS/MS method was developed and validated for the determination of (5Z,E)-3-[2-(4-chlorophenyl)-2-oxoethyl]-5-(1H-indol-3-ylmethylene)-thiazolidine-2, 4-dione (PG15) in rat plasma using chlortalidone as an internal standard (IS). Analyses were performed using a C18 column and isocratic elution with acetonitrilewater (90 + 10, v/v) containing 10 mM ammonium hydroxide (pH 8.0) as the mobile phase pumped at 0.3 mL/min. Detection was performed by MS with negative ion mode electrospray ionization. Rat plasma samples were prepared by deproteinizing with acetonitrile. Detected fragments were 395.1 > 171.9 for PG15 and 337.3 > 189.9 for the IS. Calibration curves were linear from 10 to 1000 ng/mL, with the determination coefficient >0.99. The intraday and interday precisions were less than 12.2 and 11.3, respectively. The applicability of the HPLC/MS/MS method for pharmacokinetic studies was tested using plasma samples obtained after oral administration of PG15 to rats, and it provided the necessary sensitivity, linearity, precision, accuracy, and specificity.
Determination of Chlorantraniliprole Residues in Crops by Liquid Chromatography Coupled with Atmospheric Pressure Chemical Ionization Mass Spectrometry/Mass Spectrometry
Authors: Grant Joann , Rodgers Carol A , Chickering Clark D , Hill Sidney J , Stry James J
Published: February 2020

An analytical method is presented for the determination of chlorantraniliprole residues in crops. Chlorantraniliprole residues were extracted from crop matrixes with acetonitrile after a water soak. The extracts were passed through a strong anion-exchange (SAX) SPE cartridge stacked on top of a reversed-phase (RP) polymer cartridge. After both cartridges were rinsed and vacuum-dried, the SAX cartridge was removed, and chlorantraniliprole was eluted from the RP polymer cartridge with acetonitrile. The acetonitrile eluate was evaporated to dryness, reconstituted, and analyzed using an LC/MS/MS instrument equipped with an atmospheric pressure chemical ionization source. The method was successfully validated at 0.010, 0.10, and 10 mg/kg for the following crop matrixes: potatoes, sugar beets (tops), lettuce, broccoli, soybeans, soybean forage, tomatoes, cucumbers, oranges, apples, pears, peaches, almonds (nutmeat), rice grain, wheat grain, wheat hay, corn stover, alfalfa forage, cottonseed, grapes, and corn grain. The average recoveries from all crop samples fortified at the method LOQ ranged from 91 to 108, with an overall average recovery of 97. The average recoveries from all crop samples fortified at 10 times the method LOQ ranged from 89 to 115, with an overall average recovery of 101. For all of the fortified control samples analyzed in this study, the overall average recovery was 99.
Solid-Phase Extraction of Antimony Using Chemically Modified SiO2-PAN Nanoparticles
Authors: Kaur Anupreet , Gupta Usha
Published: February 2020

A new analytical method using 1-(2-pyridylazo)-2-naphthol (PAN)-modified SiO2 nanoparticles as solid-phase extractant has been developed for the preconcentration of trace amounts of Sb(III) in different water samples. Conditions of the analysis such as preconcentration factor, effect of pH, sample volume, shaking time, elution conditions, and effects of interfering ions for the recovery of the analyte were investigated. The adsorption capacity of nanometer SiO2-PAN was found to be 186.25 mol/g at optimum pH and the LOD (3) was 0.60 g/L. The extractant showed rapid kinetic sorption. The adsorption equilibrium of Sb(III) on nanometer SiO2-PAN was achieved in 10 min. Adsorbed Sb(III) was easily eluted with 4 mL 2 M hydrochloric acid. The maximum preconcentration factor was 62.20. The method was applied for the determination of trace amounts of Sb(III) in various water samples (tap, mineral water, and industrial effluents).
Fast Analysis of Polybrominated Diphenyl Ethers in Eggs Using Selective Pressurized Liquid Extraction Coupled with Online GPC-GC/MS
Authors: Liu Yin-Ping , Li Jing-Guang , Zhao Yun-Feng , Zhang Lei , Zhou Rui , Wu Yong-Ning , Zhu Ling-Yan
Published: February 2020

This article reports the applicability of online gel permeation chromatography (GPC)-GC/MS for the determination of seven predominant polybrominated diphenyl ethers (PBDEs) in eggs to effectively eliminate matrix interference. Selective pressurized liquid extraction using acidic alumina as a fat retainer was used for cleanup of the PBDEs in eggs. It was selected because of its advantages: simpler operation, minimum time spent on sample handing to get fat-free extracts, and low volume of solvent consumption. After concentration, the extract was directly injected for online GC/MS operated in the negative ion chemical ionization mode with a 15 m capillary column. Recoveries of spiked samples were between 75.1 and 102.0, with RSDs (n = 3) ranging from 3.6911.47 when spiked at levels of 2 and 20 ng/g, dry mass. The LOD varied from 0.2534 ng/g, dry mass. The proposed method was proven to be rapid, efficient, and reliable for the trace determination of PBDEs in eggs.
Modification and Validation of a High-Performance Liquid Chromatography Method for Quantification of Huperzine A in Huperzia Crispata
Authors: Yu Lijun , Shi Yunfeng , Huang Jianan , Gong Yushun , Liu Zhonghua , Hu Weixin
Published: February 2020

The present study describes a rapid and sensitive HPLC method for the quantification of huperzine A (HupA) in Huperzia Crispata (Huperziaceae). The sample extraction and preparation involved a simple, time-saving, single-solvent extraction, with each sample being analyzed within 12 min. The mobile phase was ammonium acetate (0.1 M, pH 6.0)methanol (64 + 36, v/v) at a flow rate of 1.0 mL/min. Detection was at 308 nm. The calibration curve was linear from 0.049 to 7.84 µg (R2 = 0.9997), with intraday and interday precision RSD of less than 2%. The extraction recovery rate was over 98.49%. Quantification of HupA was performed using this modified method, and the content of HupA was 1.86 times higher in the whole plant of H. crispata (218.17 ± 1.55 µg/g) than in that of H. serrata (117.03 ± 2.97 µg/g). In the whole plant of H. crispata, HupA mainly accumulated in the actively growing shoot tips, the apical bud, and the 10 youngest leaves, reaching 455.23 ± 2.97 µg/g. The content of HupA in the samples from sunshine-sheltered sites was 3.45 times higher than in that from sunshine-abundant sites. The satisfactory results indicate that this modified method can be applied in the quality control of large-scale Huperziaceae plant extracts and that changes should be made in the cultivation of H. crispata so as to maximize the production of HupA.
Comparison of Limulus Amebocyte Lysates with the United States Pharmacopeial Pyrogen Test and the Portable Test System for Radiopharmaceuticals
Authors: Santos-Oliveira Ralph
Published: February 2020

Radiopharmaceuticals play an important role in modern nuclear medicine, and 18F-FDG (2-[18F] fluoro-2-deoxy-D-glucose) is the most frequently used in imaging examinations today. The pyrogen test represents an important parameter for the quality of radiopharmaceuticals since most of them, 18F-FDG included, are injectable solutions. However, the standard test proposed by the U.S. Pharmacopeia using limulus amebocyte lysates takes too long (about 1 h). An alternative test is the Portable Test System, which takes no more than 15 min. In order to compare both tests, 10 batches of 18F-FDG produced in the Nuclear Engineering Institute, Rio de Janeiro, Brazil, were analyzed. The results showed that in 40% of the samples analyzed, different results were found. From the total analyzed, 20% showed totally diverging results, and 80% demonstrated partial similarity. These differences have a great impact in the choice of the test used for radiopharmaceutical injectable solutions and the importance of validation tests before the implementation in the daily routine.
Quantitative Structure-Retention Relationship Studies as an Analytical Tool in the Determination and Modeling of Pesticide Residues in Plant Organisms
Authors: Buszewski Bogusaw , Michel Monika
Published: February 2020

Crop models use mathematical equations to simulate the physical and chemical processes that generally control the uptake, translocation, and sorption of pesticides in all parts of plants. Our interest is focused on method optimization to determine the new compounds using stationary and mobile phases with different physicochemical properties. The work deals with five fungicides composed of nitrogen-containing heterocycles, 1,2,4-triazoles. The sample preparation liquid extraction and solid-phase-based methods are used to determine and model the pesticide residues in plants organisms. Analysis of these compounds is generally carried out by GC or HPLC coupled to different detectors, especially to mass spectrometers, in hyphenated techniques that have been extremely developed in recent years. The relationships between the chromatographic retention factor (k) and those physicochemical properties that are relevant in quantitative structure-retention relationship (QSRR) studies were investigated. The accuracy of the simple linear regressions between the chromatographic retention and the descriptors for all of the compounds was satisfactory (correlation coefficient 0.83 ≥ R2 ≥ 0.99). The QSRR models of these nitrogen-containing heterocyclic compounds could be predicted with a multiple linear regression equation having the statistical index R2 = 1.00. Evaluation of chromatographic properties of the new stationary phases and description of the molecular separation mechanism using the QSRR method, including molecular modeling, were performed. A universal model is presented that links the physicochemical parameters describing the fungicide compounds with the anatomical, physiological, and biochemical properties of the plant.
Application of HPLC and TLC with Diode Array Detection After SPE to the Determination of Pesticides in Water Samples from the Zemborzycki Reservoir (Lublin, Southeastern Poland)
Authors: Tuzimski Tomasz
Published: February 2020

The application of TLC with a diode array detector (TLC-DAD) and HPLC-DAD after SPE for identification and quantitative analysis of pesticides in water samples is demonstrated. The procedures described for the determination of compounds are inexpensive and can be applied to routine analysis of analytes in water samples after preliminary cleanup and concentration by SPE. Average recoveries for four different cartridges and three solvents by the proposed HPLC-DAD method after SPE also are presented. The efficiency of the SPE procedure was evaluated using real water samples from the Zemborzycki Reservoir, near Lublin, southeastern Poland. The method was validated for precision, repeatability, and accuracy.