bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Thin-Layer Chromatography Methods for Quality Control of Commercial Products Containing Aesculus hippocastanum, Turnera diffusa, Matricaria recutita, Passiflora incarnata, and Tilia occidentalis
Authors: RAMÍREZ-DURÓN Rosalba , Ceniceros-Almaguer LucÍa , Salazar-Aranda Ricardo , Salazar-Cavazos Ma De La Luz , De Torres Noemi Waksman
Published: February 2020

In Mexico, plant-derived products with health claims are sold as herbal dietary supplements, and there are no rules for their legal quality control. Aesculus hippocastanum, Turnera diffusa, Matricaria recutita, Passiflora incarnata, and Tilia occidentalis are some of the major commercial products obtained from plants used in this region. In this paper, we describe the effectiveness of thin-layer chromatography methods to provide for the quality control of several commercial products containing these plants. Standardized extracts were used. Of the 49 commercial products analyzed, only 32.65% matched the chromatographic characteristic of standardized extracts. A significant number of commercial products did not match their label, indicating a problem resulting from the lack of regulation for these products. The proposed methods are simple, sensitive, and specific and can be used for routine quality control of raw herbals and formulations of the tested plants. The results obtained show the need to develop simple and reliable analytical methods that can be performed in any laboratory for the purpose of quality control of dietary supplements or commercial herbal products sold in Mexico.
Membrane Electrodes for Determination of Some -Blocker Drugs
Authors: Ramadan Nesrin K , Zaazaa Hala E
Published: February 2020

Five poly(vinyl chloride) (PVC) matrix membrane electrodes responsive to the -blockers atenolol (AT), bisoprolol fumarate (BI), timolol maleate (TI), and levobunolol HCl (LV) were developed and characterized. A precipitation-based technique with ammonium reineckate anion as an electroactive material in PVC matrix with AT, BI, TI, and LV cations was used for fabrication of Electrodes 14, respectively. Electrode 5 fabrication was based on precipitation of LV cation with tungstophosphate anion as an electroactive material. Fast and stable Nernstian responses at 1 1021 107 M for different -blockers over the pH range of 28 were found for these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was successively applied for the determination of -blockers in their pharmaceutical formulations. Validation of the method according to quality assurance standards showed the suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for the determination of the -blocker drugs by the 5 proposed selective electrodes were 100.1 0.7, 99.9 0.8, 100.0 1.1, 100.5 1.1, and 100.6 0.7% for Sensors 15, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was performed and no significant difference was found.
Liquid Chromatographic Determination of 6-, 8-, 10-Gingerol, and 6-Shogaol in Ginger (Zingiber officinale) as the Raw Herb and Dried Aqueous Extract
Authors: Lee Samiuela , Khoo Cheang , Halstead Clynton Wade , Huynh Thuy , Bensoussan Alan
Published: February 2020

The determination of 6-, 8-, 10-gingerol, and 6-shogaol in dried ginger (Zingiber officinale) and in the dried aqueous extract of ginger is reported. This is the first study to report a validated method for the determination of these 4 analytes. Several extraction solvents and methods were examined, and the optimum combination was determined. The samples were extracted at room temperature by sonication with methanol, and the extract was analyzed by liquid chromatography with photodiode array detection. A C18 column was used with a wateracetonitrile gradient mobile phase. Quantification was at 200 nm. The levels of 6-, 8-, 10-gingerol, and 6-shogaol in the raw herb were 9.3, 1.6, 2.3, and 2.3 mg/g, respectively. The levels of gingerols found in the dried aqueous extract were between 5 and 16 times lower than those in the raw herb, but the level of 6-shogaol was higher. Analyte identity was confirmed by negative-ion electrospray ionization tandem mass spectrometry, in which 2 daughter ions were obtained for each analyte. The average recovery was 97 with a relative standard deviation of <8. The limits of detection for 6-, 8-, 10-gingerol, and 6-shogaol in the raw herb were 0.22, 0.04, 0.09, and 0.07 mg/g, respectively, and in the dried aqueous extract, 0.11, 0.02, 0.02, and 0.14 mg/g, respectively.
Determination of Ubidecarenone (Coenzyme Q10, Ubiquinol-10) in Raw Materials and Dietary Supplements by High-Performance Liquid Chromatography with Ultraviolet Detection: Single-Laboratory Validation
Authors: Orozco Debra , Skamarack Jules , Reins Kelly , Titlow Barry , Lunetta Steve , Li Fang , Roman Mark
Published: February 2020

A method based on high-performance liquid chromatography with ultraviolet detection has been developed to quantify ubidecarenone [coenzyme Q10 (CoQ10)] in raw materials and dietary supplements. Single-laboratory validation has been performed on the method to determine repeatability, accuracy, selectivity, limits of detection and quantification (LOQ), ruggedness, and linearity for CoQ10. As CoQ10 can exist as the biologically active reduced form, the application of an oxidizing agent, ferric chloride, drives the equilibrium mechanics to the fully oxidized state and allows for exact quantification of total CoQ10 in the sample. This method was found to be fit and linear for the testing of materials containing CoQ10 in the range of 501000 mg/g. Repeatability precision for CoQ10 was between 2.15 and 5.00 relative standard deviation. Observed recovery of CoQ10 was found to be between 93.8 and 100.9. LOQ was found to be 9 g/mL. Further, limited studies showed that some adulterants and degraded material could be satisfactorily separated from CoQ10 and identified.
Validation of a Method Based on Triglycerides for the Detection of Low Percentages of Hazelnut Oil in Olive Oil by Column Liquid Chromatography
Authors: García-González Diego L , Viera-Macías María , Aparicio-Ruiz Ramón , Morales Maria T , Aparicio Ramón
Published: February 2020

The difference between theoretical and empirical triglyceride content is a powerful tool to detect the presence of any vegetable oil in olive oil. The current drawback of the method is the separation between equivalent carbon number ECN42 compounds, which affects the reliability of the method and, hence, its cutoff limit. The determination of the triglyceride profile by liquid chromatography using propionitrile as the mobile phase has recently been proposed to improve their quantification, together with a mathematical algorithm whose binary response determines the presence or absence of hazelnut oil. Twenty-one laboratories from 9 countries participated in an interlaboratory study to evaluate the performance characteristics of the whole analytical method. Participants analyzed 12 samples in duplicate, split into 3 intercomparison studies. Statistically significant differences due to the experimental conditions were found in some laboratories, which were detected as outliers by use of Cochran's and Grubbs' tests. The relative standard deviations (RSD) for repeatability and reproducibility were determined following the AOAC Guidelines for Collaborative Studies. The analytical properties of the method were determined by means of the sensitivity (0.86), selectivity (0.94), and reliability (72) for a cutoff limit of 8 (probability 94).
Simplified Pesticide Multiresidue Analysis of Soybean Oil by Low-Temperature Cleanup and Dispersive Solid-Phase Extraction Coupled with Gas Chromatography/Mass Spectrometry
Authors: Li Li , Xu Yanjun , Pan Canping , Zhou Zhiqiang , Jiang Shuren , Liu Fengmao
Published: February 2020

A simple, fast, and economical method has been developed for the simultaneous determination of 28 various types of pesticides in soybean oil. Pesticides of low molecular mass were separated from the fat of the oil, which has a high molecular mass, by using low-temperature fat precipitation, followed by a cleanup process based on dispersive solid-phase extraction with primary secondary amine and C18 as sorbents and magnesium sulfate for the removal of residual water. The results for all pesticides determined by gas chromatography with mass spectrometry in the selected-ion monitoring mode were linear, and the matrix effect of the method was evaluated. Recoveries of most pesticides were acceptable at fortification levels of 0.02, 0.05, 0.2, and 1 mg/kg. The relative standard deviation was <20 even for determinations without internal standards. Limits of quantitation ranged from 20 to 250 g/kg.
Determination of Benzoylurea Insecticide Residues in Tomatoes by High-Performance Liquid Chromatography with Ultraviolet-Diode Array and Atmospheric Pressure Chemical Ionization-Mass Spectrometry Detection
Authors: Markoglou Anastasios N , Bempelou Eleftheria D , Liapis Konstantinos S , Ziogas Basil N
Published: February 2020

A simple and sensitive method using high-performance liquid chromatography/mass spectrometry (LC/MS) was developed and validated for simultaneous determination of 5 benzoylurea insecticidesdiflubenzuron, triflumuron, teflubenzuron, lufenuron, and flufenoxuronin tomatoes. Residues were successfully separated on a C18 column by methanolwater isocratic elution. Detection was carried out by an ultraviolet diode array detector (UV-DAD) coupled with a quadrupole mass spectrometer, using atmospheric pressure chemical ionization (APCI) in negative-ion mode. The main ions were the deprotonated molecules [MH] for triflumuron, and the anions formed by elimination of hydrofluoric acid [MHHF] for diflubenzuron and flufenoxuron, and [M2HHF] for lufenuron and teflubenzuron. The calibration plots were linear for both detectors over the range 0.05 to 10 g/mL, and the method presented good quality parameters. The limits of detection for standard solutions were 0.0080.01 mg/L (equivalent to 0.080.1 ng injected) for both detectors, and the limits of quantification (LOQs) were approximately 10 times lower than national maximum residue levels (MRLs). Depending on the compound and the detector, the LOQ values ranged from 0.2 to 0.4 ng injected. The optimum LC-UV-DAD/APCI-MS conditions were applied to the analysis of benzoylureas in tomatoes. The obtained recoveries from fortified tomato samples (50 g), extracted with ethyl acetate and purified by solid-phase extraction on silica sorbent, were 88100 and 92.9105 for the UV-DAD and MS detectors, respectively, with precision values (relative standard deviations) of 2.911 and 3.714, respectively. The method was applied to 12 tomato samples from local markets, and diflubenzuron and lufenuron were detected in only one sample at concentrations lower than the MRLs. The results indicate that the developed LC/MS method is accurate, precise, and sensitive for quantitative and qualitative analysis at low levels of benzoylureas required by legislation.
Determination of Alkylphenol Ethoxylates in Textiles by Normal-Phase Liquid Chromatography and Reversed-Phase Liquid Chromatography/Electrospray Mass Spectrometry
Authors: Wang Chao , Ma Qiang , Wang Xing
Published: February 2020

Comprehensive analytical methods based on pressurized liquid extraction followed by normal-phase liquid chromatography (NPLC) with ultraviolet detection and reversed-phase liquid chromatography (RPLC)/electrospray mass spectrometry (MS) have been developed for determination of alkylphenol ethoxylates (APEOs) in textile samples. NPLC with an aminosilica column allowed for the chromatographic separation of APEOs according to the increasing number of ethylene units and revealed the exact distribution of individual oligomers. RPLC coupled with electrospray MS was highly sensitive and enabled the complete qualitative and quantitative determination of individual APEOs in textile samples. The 2 analytical methods based on different chromatographic separation mechanisms, i.e., NPLC and RPLC, may provide complementary information of APEOs in textile materials. The 2 detection methods were successfully applied to the investigation of various textile samples, and the data of our research suggested actual pollution in real textile products.
Transgenic Approaches for Cyanogen Reduction in Cassava
Authors: Siritunga Dimuth , Sayre Richard
Published: February 2020

For cassava to become a safe and acceptable crop, it is necessary to reduce the cyanogen levels in cassava foods. While this objective can be achieved by processing procedures, recent findings have shown that it is also possible to achieve it by suppression of cyanogen synthesis or by accelerating cyanogen turnover and volatilization. In 2003, cyanogen-free cultivars were generated by selective inhibition CYP79D1/D2 gene expression. The CYP79D1/D2 enzymes catalyze the first-dedicated step in cyanogen synthesis. Tissue-specific inhibition of CYP79D1/D2 expression in leaves lead to a 99 reduction in root cyanogen levels, indicating that the cyanogenic glycoside, linamarin, is synthesized in leaves and transported to roots. An alternative strategy to the reduce cyanogen content is to enhance cyanogen detoxification and cyanide volatilization during processing. This strategy has the advantage that cyanogen levels in unprocessed roots are not altered, potentially providing protection against herbivory and/or theft. To produce cultivars that promote rapid cyanide volatilization, hydroxynitrile lyase (HNL), which catalyzes the last step in cyanogenesis, was overexpressed in roots. Elevated HNL activity resulted in a 3-fold increase in the rate of cyanogen turnover. Importantly, the cyanogen content of the transformed and wild-type plants was identical, a potential benefit for farmers.
Application of Current Allergy Assessment Guidelines to Next-Generation Biotechnology-Derived Crops
Authors: Bannon Gary A , Martino-Catt Susan
Published: February 2020

In any single day, our immune systems are exposed to thousands of different proteins from the environment and the food we eat. In a portion of the human population, some of those proteins will stimulate the immune systems to synthesize immunoglobulin E in an allergenic response. The discrepancy between the vast numbers of proteins we encounter and the limited number of proteins that actually become allergens have led scientists on a quest to discover what unique features exist that make proteins destined to be allergens. The information gained from these studies has led to an allergy assessment strategy that characterizes the potential allergenicity of biotechnology products prior to their commercialization. This testing strategy appears to be effective as shown by the fact that there have been no clinically documented food allergic reactions to any of the biotechnology proteins introduced into food crops, to date. The next generation of biotechnology products will most likely contain more complex traits, including nutritionally enhanced food crops, and the question arises as to whether the current allergy assessment strategy will be sufficient to protect the health of the consuming public. In this paper, we discuss general allergen characteristics in order to better understand how proteins become allergens, summarize the current allergy assessment process, evaluate the different aspects of this process for their adequacy in determining the allergenic potential of engineered functional foods, and, finally, we assess the possibility of new technologies having a positive impact on the allergy assessment of nutritionally enhanced crops.
Development of Agricultural Biotechnology and Biosafety Regulations Used to Assess the Safety of Genetically Modified Crops in Iran
Authors: Mousavi Amir , Malboobi Mohammad A , Esmailzadeh Nasrin S
Published: February 2020

Rapid progress in the application of biotechnological methodologies and development of genetically modified crops in Iran necessitated intensive efforts to establish proper organizations and prepare required rules and regulations at the national level to ensure safe application of biotechnology in all pertinent aspects. Practically, preparation of a national biotechnology strategic plan in the country coincided with development of a national biosafety framework that was the basis for the drafted biosafety law. Although biosafety measures were observed by researchers voluntarily, the establishment of national biosafety organizations since the year 2000 built a great capacity to deal with biosafety issues in the present and future time, particularly with respect to food and agricultural biotechnology.
Determination of Pesticide Residues in Lettuce by Gas Chromatography with Electron-Capture Detection
Authors: Fenoll Jose , Hellin Pilar , Lopez Josefa , Gonzalez Alberto , Flores Pilar
Published: February 2020

A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesticides in different varieties of lettuce (Lactuca sativum) was developed. Lettuce samples were extracted by homogenization with acetone and partitioned into ethyl acetatecyclohexane. Subsequent sample cleanup was not needed. Final determination was made by capillary gas chromatography (GC) with electron-capture detection (ECD). Confirmation analysis of pesticides was performed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recovery by the GCECD method obtained for these compounds varied from 66.4 to 119.2 with relative standard deviations <7.7. The GCECD method has good linearity, and the detection limit for the pesticides studied varied from 0.1 to 3.8 g/kg. The proposed method was used to determine pesticide levels in different types of lettuce grown in soils from experimental fields.
Headspace Solid-Phase Microextraction for the Gas Chromatographic Analysis of Organophosphorus Insecticides in Vegetables
Authors: Fytianos Konstantinos , Drimaropoulou Garyfallia , Raikos Nikolaos , Theodoridis Georgios , Tsoukali Helen
Published: February 2020

Residues of organophosphorus insecticides (diazinon, methyl parathion, fenitrothion, malathion, and parathion) were determined in 13 different vegetable matrixes by headspace solid- phase microextraction performed with a polydimethyl-siloxane fiber (100 m). Determination was carried out by gas chromatography with a nitrogen-phosphorus detector. Limits of detection and quantification were <0.005 and 0.017 mg/kg, respectively; thus, the limits of maximum residue levels (MRLs) required by European regulations can be verified without difficulty. Pesticide residues were found in 38% of the 125 fresh commercial samples (imported and domestic) that were analyzed. Residues of methyl parathion and parathion, which were withdrawn in Greece in 2003, were detected in 36.8 and 4% of all samples, respectively. The MRLs were exceeded overall by 1%.
Exact One-Tailed 100p Upper Limits for Future Sample Repeatability Relative Standard Deviations Obtained in Single and Multilaboratory Repeatability Studies
Authors: McClure Foster D , Lee Jung K
Published: February 2020

Formulas are derived to obtain exact one-tailed 100p upper limits (p and p) for future sample repeatability relative standard deviations, based on a noncentral t-distribution, for multi- and single-laboratory repeatability studies, respectively, used in the validation of analytical methods.
Validation of High-Performance Thin-Layer Chromatographic Methods for the Identification of Botanicals in a cGMP Environment
Authors: Reich Eike , Schibli Anne , DeBatt Alison
Published: February 2020

Current Good Manufacturing Practices (cGMP) for botanicals stipulates the use of appropriate methods for identification of raw materials. Due to natural variability, chemical analysis of plant material is a great challenge and requires special approaches. This paper presents a comprehensive proposal to the process of validating qualitative high-performance thin-layer chromatographic (HPTLC) methods, proving that such methods are suitable for the purpose. The steps of the validation process are discussed and illustrated with examples taken from a project aiming at validation of methods for identification of green tea leaf, ginseng root, eleuthero root, echinacea root, black cohosh rhizome, licorice root, kava root, milk thistle aerial parts, feverfew aerial parts, and ginger root. The appendix of the paper, which includes complete documentation and method write-up for those plants, is available on the J. AOAC Int. Website (http://www.atypon-link.com/AOAC/loi/jaoi).
Single-Laboratory Validation of a Liquid Chromatographic/Tandem Mass Spectrometric Method for the Determination of Free and Total Carnitine in Infant Formula and Raw Ingredients
Authors: Starkey Dustin E , Denison James E , Seipelt C Thomas , Jacobs Wesley A
Published: February 2020

A reversed-phase liquid chromatographic/tandem mass spectrometric method was developed and validated for the determination of free carnitine (FC) and total carnitine (TC) in infant formula and raw ingredients. Preparation of samples for FC determination required only nonvolumetric dilution in water, followed by filtration. Determination of TC in whey-based samples required a common saponification procedure, which hydrolyzed the acylcarnitines to FC. L-Carnitine standards were prepared in water at 3 concentrations (7.5, 30, and 60 ng/mL). L-Carnitine-d3 was incorporated in the sample and standard preparations as a stable isotope internal standard (ISTD), which helped to normalize signal suppression due to fouling of the ionization source, or matrix effects. A short C8 column (50 2.1 mm id) was used for liquid chromatography, with mobile phases consisting of 0.1 heptafluorobutyric acid in water and methanol. L-Carnitine and the ISTD eluted at about 2 min, and the injection-to-injection cycle time was about 11 min. Multiple-reaction monitoring was used for quantitation by monitoring the ion transitions m/z 162 > 103 and 162 > 85 for L-carnitine, and m/z 165 > 103 and 165 > 85 for the ISTD. The values for overall method precision for a whey-based infant formula, a protein hydrolyzate infant formula, and a water-soluble vitamin/amino acid premix were relative standard deviations of 1.32, 1.86, and 3.33, respectively. The overall mean recoveries were between 97.3 and 102.8. Additionally, the method results showed good correlation with those obtained for a radioenzymatic assay done in-house.
Detection of Ricin in Food Using Electrochemiluminescence-Based Technology
Authors: Garber Eric A E , O’Brien Thomas W
Published: February 2020

Ricin is a toxic ribosome inactivating protein (RIP-II) present in beans of the castor plant, Ricinus communis. Its potential as a biodefense threat has made the rapid, sensitive detection of ricin in food important to the U.S. Food and Drug Administration. Samples of juice, dairy products, soda, vegetables, bakery products, chocolate, and condiments were spiked with varying concentrations of ricin and analyzed using a 96-well format, electrochemiluminescence (ECL) immunoassay. Assay configurations included the use of a monoclonal capture antibody coupled with either a polyclonal or monoclonal detector antibody. The samples and detector antibodies were either added sequentially or in combination during the capture step. Using the polyclonal antibody, 0.04 ng/mL ricin was detected in analytical samples prepared from several beverages. By simultaneously incubating the sample with detector antibody, it was possible to decrease the assay time to a single 20 min incubation step with a limit of detection <10 ng/mL. Assays run according to this single incubation step exhibited a hook effect (decrease in signal at high concentrations of ricin), but because of the large signal-to-noise ratio associated with the ECL assay, the response remained above background and detectable. Thus, the ECL assay was uniquely suited for the screening of samples for ricin.
Instrumental Neutron Activation Analysis of Different Products from the Sugarcane Industry in PakistanPart 1: Essential Elements for Nutritional Adequacy
Authors: Waheed Shahida , Ahmad Shujaat
Published: February 2020

Jaggery, brown sugar, white sugar, and molasses collected from the local sugarcane industry of Pakistan have been analyzed for essential elements in order to estimate their nutritional adequacy. Instrumental neutron activation analysis was used to determine Ca, Cl, Co, Cr, Fe, K, Mg, Mn, Na, and Zn through sequential, short, medium, and long irradiation times. Maximum concentrations for most of these elements were determined in molasses, with lower concentrations determined in jaggery and brown sugar; white sugar contained trace amounts of all essential elements. Contributions to the weekly Recommended Dietary Allowance (RDA) values for the elements were estimated only for jaggery, brown sugar, and white sugar because molasses in Pakistan is not consumed as a dietary item. Jaggery contributes the highest percentages of Cr, Mg, Mn, and Zn, whereas the highest percentages of Cl, Fe, K, and Na can be acquired from brown sugar. The contribution of white sugar to the weekly RDAs for these elements is negligible, indicating that white sugar is a poor source of the essential elements. However, the introduction of molasses to the diet can contribute to an adequate intake of these elements.
Second Derivative Synchronous Fluorescence Spectroscopy for the Simultaneous Determination of Metoclopramide and Pyridoxine in Syrup and Human Plasma
Authors: El-Enany Nahed
Published: February 2020

A rapid, simple, and highly sensitive second derivative synchronous fluorometric method has been developed for the simultaneous determination of metoclopramide (MT) and pyridoxine (PY) in a binary mixture. The method is based on measurement of the native fluorescence of these drugs at = 80 nm in methanol. The different experimental parameters affecting the native fluorescence of the drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the ranges of 0.020.4 and 0.12 g/mL for MT and PY, respectively. The limits of detection were 0.003 and 0.007 g/mL and the limits of quantification were 0.008 and 0.02 g/mL for MT and PY, respectively. The proposed method was successfully applied to the determination of MT and PY in synthetic mixtures and in commercial syrup. The results were in good agreement with those obtained with a reported method. The high sensitivity attained by the proposed method allowed the determination of MT in spiked and real human plasma samples. The mean percent recoveries of MT from spiked and real human plasma (n = 3) were 93.72 3.15 and 89.72 2.19, respectively.
Determination of Bisphenol Ain Water by Isotope Dilution Headspace Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry Without Derivatization
Authors: Cao Xu-Liang , Corriveau Jeannette
Published: February 2020

The original solid-phase microextraction (SPME) fibers use an epoxy resin adhesive that releases bisphenol A (BPA) during thermal desorption of the fiber. This adversely affects the method detection limit and accuracy when these products are used for the determination of BPA. In this work, 5 new metal alloy SPME fibers that do not use epoxy resins were compared for the extraction of BPA in water. The performance of the optimum SPME fiber with 60 m carbowax-polyethylene glycol coating for the headspace SPME of BPA in water was investigated systematically under different extraction conditions. Salt was found to increase the partitioning of BPA from water into the headspace until saturation was reached. Partitioning of BPA from water into the headspace also increased at higher extraction temperatures, as did longer extraction times. However, extraction of BPA from water onto the SPME fiber was not improved for solutions adjusted to pH 2 compared to the unadjusted neutral solutions. The new BPA method showed good linearity over the concentration range of 2.5 to 40 g/L [correlation coefficient (r2) = 0.995] .The method detection limit for BPA was 0.5 g/L, while the instrument detection limit was as low as 0.05 g/L. Good repeatability was observed for BPA at levels of 5 and 20 g/L with relative standard deviation values <10. The automated headspace SPME method developed in this work was used to investigate migration of BPA from polycarbonate bottles into water, and levels of BPA in water ranged from 1.7 to 4.1 g/L.
Pesticide Residue Analysis of a Dietary Ingredient by Gas Chromatography/Selected-Ion Monitoring Mass Spectrometry Using Neutral Alumina Solid-Phase Extraction Cleanup
Authors: Jeong Mijeong Lee , Zahn Michael , Trinh Thao , Brooke Fay A , Ma Wenwen
Published: February 2020

A sample cleanup procedure has been developed to remove coextractives that interfere with pesticide residue analysis of a dietary ingredient (Product B), an extract consisting of Scutellaria baicalensis and Acacia catechu. Samples were extracted using 1 acetic acid in acetonitrile, followed by solid-phase extraction and analysis by capillary gas chromatography with mass spectrometry in the selective-ion monitoring mode. Neutral alumina (alumina N) was found to be the most effective sorbent to remove coextractives from Product B; other materials that were tested but failed to remove interference were graphitized carbon black/primary-secondary amine (PSA), octadecylsilane (C18), Florisil, Oasis MCX, and strong anion exchange-PSA. The method was specifically developed for Product B, which was spiked with 41 organochlorine and organophosphorus pesticides, and resulted in the recovery of 80 to 120 at U.S. Pharmacopeia limits (0.06 to 4 g/g) for the majority of the pesticides.
Uncertainties of Method Performance Statistics Based on a Balanced Completely Randomized Model Interlaboratory Study
Authors: McClure Foster D , Lee Jung K
Published: February 2020

Using exact and asymptotic distributions, formulas were developed to derive population variances and uncertainties, and their corresponding unbiased estimates, for the method performance statistics, i.e., the sample mean (y_bar..), the repeatability variance and standard deviation and (sr2 and sr), and the reproducibility variance and standard deviation (sR2 and sR) and obtained from collaborative study of an analytical method.
Determination of Coenzyme Q10 Content in Raw Materials and Dietary Supplements by High-Performance Liquid Chromatography-UV: Collaborative Study
Authors: Lunetta Steven , Roman Mark ,   Collaborators:, Chandrah A , Edamura T , Honda T , LeVanseler K , Nagarajan M , Patel N , Reif K , Schaneberg B , Sullivan D , Trussardo L
Published: February 2020

An international collaborative study was conducted of a high-performance liquid chromatographic (HPLC)-UV method for the determination of coenzyme Q10 (CoQ10, ubidecarenone) in raw materials and dietary supplements. Ten collaborating laboratories determined the total CoQ10 content in 8 blind duplicate samples. Sample materials included CoQ10 raw material and 4 finished product dietary supplements representing softgels, hardshell gelatin capsules, and chewable wafers. In addition, collaborating laboratories received a negative control and negative control spiked with CoQ10 at low and high levels to determine recovery. Materials were extracted with an acetonitriletetrahydrofuranwater mixture. Ferric chloride was added to the test solutions to ensure all CoQ10 was in the oxidized form. The HPLC analyses were performed on a C18 column using UV detection at 275 nm. Repeatability relative standard deviations (RSDr) ranged from 0.94 to 5.05. Reproducibility relative standard deviations (RSDR) ranged from 3.08 to 17.1, with HorRat values ranging from 1.26 to 5.17. Recoveries ranged from 74.0 to 115. Based on these results, the method is recommended for Official First Action for determination of CoQ10 in raw materials and dietary supplement finished products containing CoQ10 at a concentration of >100 mg CoQ10/g test material.
Ultraviolet-Photodiode Array and High-Performance Liquid Chromatographic/Mass Spectrometric Studies on Forced Degradation Behavior of Glibenclamide and Development of a Validated Stability-Indicating Method
Authors: Bansal Gulshan , Singh Manjeet , Jindal Kaur Chand , Singh Saranjit
Published: February 2020

A forced degradation study on glibenclamide was performed under conditions of hydrolysis, oxidation, dry heat, and photolysis and a high-performance column liquid chromatographic-ultraviolet (HPLC-UV) method was developed to study degradation behavior of the drug under the forced conditions. The degradation products formed under different forced conditions were characterized through isolation and subsequent infrared/nuclear magnetic resonance/mass spectral analyses, or through HPLC/mass spectrometric (HPLC/MS) studies. The drug degraded in 0.1 M HCl and water at 85C toamajor degradation product, 5-chloro-2-methoxy-N-2-(4-sulfamoylphenyl)ethyl]benzamide (III), and to a minor product, 1-cyclohexyl-3-[[4-(2-aminoethyl)-phenyl]sulfonyl]urea (IV). Upon prolonged heating in the acid, the minor product IV disappeared, resulting in formation of 5-chloro-2-methoxy-benzoic acid (II) and an unidentified product (I). Heating of the drug in 0.1 M NaOH at 85C yielded II and IV as the major products and I and III as the minor products. The drug and the degradation products formed under different conditions were optimally resolved on a C18 column using ammonium acetate buffer (0.025 M, pH 3.5)acetonitrile (45 + 55) mobile phase at a flow rate of 0.6 mL/min, with detection at 230 nm. The method was validated for linearity, precision, accuracy, and specificity. Limit of detection (LOD) and limit of quantitation (LOQ) values were also determined. The method could be successfully applied for simultaneous quantification of glibenclamide and the major product, III. The response of the method was linear in a narrow [0.410 g/mL, correlation coefficient (r2 = 0.9982] and a wide (0.4500 g/mL, r2 = 0.9993) concentration range for glibenclamide, and in the concentration range of 0.02550 g/mL (r2 = 0.9998) for III. The method proved to be precise and accurate for both glibenclamide and III. It was specific for the drug and also selective for each degradation product, and LOQ values for the drug were 0.1 and 0.4 g/mL, whereas those for III were 0.010 and 0.025 g/mL, respectively.
Determination of Vitamin B12 in Food Products by Liquid Chromatography/UV Detection with Immunoaffinity Extraction: Single-Laboratory Validation
Authors: Campos-Gimnez Esther , Fontannaz Patric , Trisconi Marie-Jose , Kilinc Tamara , Gimenez Catherine , Andrieux Pierre
Published: February 2020

A fast and simple method to determine vitamin B12 in foods is presented. The method allows, in addition to the determination of added cyanocobalamin, the determination of natural vitamin B12 forms, making it also applicable to nonfortified products, especially those that are milk-based. Vitamin B12 is extracted in sodium acetate buffer in the presence of sodium cyanide (100C, 30 min). After purification and concentration with an immunoaffinity column, vitamin B12 is determined by liquid chromatography with UV detection (361 nm). The method has been validated in analyses of a large range of products: milk- and soy-based infant formulas, cereals, cocoa beverages, health care products, and polyvitamin premixes. The method showed appropriate performance characteristics: linear response over a large range of concentrations, recovery rates of 100.8 7.5 (average standard deviation), relative standard deviation of repeatability, RSDr, of 2.1, and intermediate reproducibility, RSDiR, of 4.3. Limits of detection and quantitation were 0.10 and 0.30 g/100 g, respectively, and correlation with the reference microbiological assay was good (R2= 0.9442). The proposed method is suitable for the routine determination of vitamin B12 in fortified foods, as well as in nonfortified dairy products. It can be used as a faster, more selective, and more precise alternative to the classical microbiological determination.
Trace Element Profile of a Wild Edible Mushroom (Suillus granulatus)
Authors: Arce Silvia , Cerutti Soledad , Olsina Roberto , Gomez Mara R , Martnez Luis D
Published: February 2020

Seventeen elements, Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, V, and Zn (macroelements and trace elements) were investigated by Atomic Spectrometries on a particular wild edible mushroom collected in the central region of Argentina during 2 different years in the same season. The metal content profile in Suillus granulatus samples is given. The found quantities of Na, K, Ca, Mg, Fe, P, V, and Al were 0.40, 10.84, 0.48, 0.30, 0.57, 4.24, 0.18, and 1.23 g/kg dry weight, respectively. The levels of Li, Cu, Zn, Cd, Co, Ni, Cr, and Mn were 0.98, 23.02, 22.30, 0.26, 0.16, 1.17, 0.90, and 28.75 mg/kg dry weight, respectively. Pb was not detected at the investigated levels. The results indicate that the levels of metals in the analyzed samples are not considered to be a health risk. In order to demonstrate the validity of our method, a recovery study was performed with acceptable results.
A Rapid and Easy Multiresidue Method for the Determination of Pesticide Residues in Vegetables, Fruits, and Cereals Using Liquid Chromatography/Tandem Mass Spectrometry
Authors: Takatori Satoshi , Okihashi Masahiro , Okamoto You , Kitagawa Yoko , Kakimoto Sachiko , Murata Hiroshi , Sumimoto Tatsuo , Tanaka Yukio
Published: February 2020

The applicability of a rapid and easy multiresidue method for determination of pesticide residues in agricultural products by using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was examined. Pesticide residues were extracted with acetonitrile in a disposable tube using a homogenizer, followed by salting out with anhydrous magnesium sulfate and sodium chloride. The extract was purified with a double-layered cartridge column (graphite carbon black/primary-secondary amine silica gel). After removal of the solvent, the extract was resolved in methanolwater and analyzed with LC/MS/MS. Recovery tests of 99 pesticide residues from 7 agricultural products were performed at 20 and 100 ng/g. Throughout all of the agricultural products tested, 47 pesticides exhibited satisfactory recoveries (70120) and relative standard deviations (<20) at both concentrations. The time for processing of 12 samples to test solutions was approximately 23 h. This method could be useful for determination of pesticide residues in agricultural products.
An Isocratic Reversed-Phase High-Performance Liquid Chromatographic Method for the Simultaneous Determination of Benzoyl Peroxide and the Related Compounds Benzoic Acid, Benzaldehyde, Ethyl Benzoate, Methylparaben, and Propylparaben in Dermal Preparations
Authors: Ali Mohammed Shahid , Rafiuddin Syed , Munir Muhammad Imran , Ghori Mohsin , Khatri Aamer Roshanali
Published: February 2020

A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of benzoyl peroxide and the related compounds benzoic acid (BA), methylparaben, benzaldehyde, propylparaben, and ethyl benzoate. The compounds are separated on a column containing octadecyl silane chemically bonded to porous silica particles. The mobile phase is acetonitrilebuffer (45 + 55, v/v). Solutions are injected into the chromatographic system under isocratic conditions at a constant flow rate of 1.5 mL/min with UV detection at 235 nm. Analysis of stability samples showed rapid accumulation of BA by thermal degradation. A rationale has been established for the acceptable limit of BA in the formulation, which already contains BA (0.2) as a preservative. The proposed method is efficient and determines the active compound and 5 related compounds in a run time of 20 min. The method was validated according to the guidelines of the International Conference on Harmonization and demonstrated good agreement with the validation requirements.
Nonextractive Procedure and Precolumn Derivatization with 7-Chloro-4-nitrobenzo-2-oxa-1,3-diazole for Trace Determination of Trimetazidine in Plasma by High-Performance Liquid Chromatography with Fluorescence Detection
Authors: Darwish Ibrahim A , Mahmoud Ashraf M , Khalil Nasr Y
Published: February 2020

A highly sensitive high-performance liquid chromatographic method with fluorescence detection has been developed and validated in a single laboratory for the trace determination of trimetazidine (TMZ) in human plasma. Fluoxetine (FLX) was used as the internal standard. TMZ and FLX were isolated from plasma by protein precipitation with acetonitrile and derivatized by heating with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole in pH 8 borate buffer at 70C for 30 min. Separations were performed in the isocratic mode on a Nucleosil CN column with the mobile phase acetonitrile10 mM sodium acetate buffer (pH 3.5)methanol (47 + 47 + 6, v/v/v) at a flow rate of 1.0 mL/min. The derivatized samples were excited at 470 nm and monitored at an emission wavelength of 530 nm. Under the optimum chromatographic conditions, a linear relationship with a good correlation coefficient (r 0.9997, n 5) was obtained for the peak area ratio of TMZ to FLX and for TMZ concentrations of 1120 ng/mL. The proposed method has the lowest limits of detection and quantitation reported to date for the determination of TMZ in plasma with values of 0.3 and 0.95 ng/mL, respectively. The values for intra- and interassay precision were satisfactory; the relative standard deviations were 4.04. The accuracy of the method was demonstrated; the recoveries of TMZ from spiked human plasma were 98.13102.83 0.24.04. The method has high throughput because of its simple sample preparation procedure and short run time (<10 min). The results demonstrated that the proposed method would have great value when applied in pharmacokinetic studies for TMZ.
Development and Validation of Reversed-Phase Column High-Performance Liquid Chromatographic and First-Derivative UV Spectrophotometric Methods for Estimation of Voriconazole in Oral Suspension Powder
Authors: Prajapati Arun M , Patel Satish A , Patel Natvarlal J , Patel Dipti B , Patel Sejal K
Published: February 2020

This research paper describes validated reversed-phase high-performance column liquid chromatographic (RP-HPLC) and first-derivative UV spectrophotometric methods for the estimation of voriconazole (VOR) in oral suspension powder. The RP-HPLC separation was achieved on Phenomenex C18 column (250 4.6 mm id, 5 m particle size) using wateracetonitrile (40 + 60, v/v; pH adjusted to 4.5 0.02 with acetic acid) as the mobile phase at a flow rate of 1.4 mL/min and ambient temperature. Quantification was achieved with photodiode array detection at 255 nm over the concentration range of 0.11 g/mL with mean recovery of 99.49 0.83 for VOR by the RP-HPLC method. Quantification was achieved with UV detection at 266 nm over the concentration range of 820 g/mL with mean recovery of 99.74 0.664 for VOR by the first-derivative UV spectrophotometric method. These methods are simple, precise, and sensitive, and they are applicable for the determination of VOR in oral suspension powder.
Determination of Pesticides in Water Samples from the Wieprz-Krzna Canal in the czysko-Wodawskie Lake District of Southeastern Poland by Thin-Layer Chromatography with Diode Array Scanning and High-Performance Column Liquid Chromatography with Diode Array Detection
Authors: Tuzimski Tomasz
Published: February 2020

High-performance thin-layer chromatography with diode array scanning (TLC-DAD) and high-performance column liquid chromatography with a diode array detector (HPLC-DAD) were used to screen water samples for pesticides. Atrazine, clofentezine, chlorfenvinphos, hexaflumuron, terbuthylazine, lenacyl, neburon, bitertanol, and metamitron were enriched from canal water samples by solid-phase extraction (SPE) on octadecyl silane (C18)/styrene-divinylbenzene-1, C18, C18 Polar Plus, and cyanopropyl (CN) cartridges. Recovery rates were high for all extraction materials except CN, for which values for all pesticides were lower. SPE was used for both preconcentration and fractionation of the analytes. Analytes were eluted by means of methanol and dichloromethane. Methanol eluates were analyzed by HPLC-DAD and dichloromethane eluates by TLC-DAD. The method was validated for precision, repeatability, and accuracy. Calibration graphs were linear between 0.1 and 50.0 g/mL for all pesticides, and correlation coefficient (r) values were between 0.9994 and 1.000 as determined by HPLC-DAD. Calibration graphs were linear between 0.1 and 1.5 g/spot for all pesticides, and r values were between 0.9899 and 0.9987 as determined by TLC-DAD. The limit of detection was between 0.04 and 0.23 g/spot for TLC-DAD and 0.02 and 0.45 g/mL for HPLC-DAD.
Analysis of Brain Lipids by Directly Coupled Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry and High-Performance Thin-Layer Chromatography
Authors: Fuchs Beate , Nimptsch Ariane , Süß, Rosmarie , Schiller Jürgen
Published: February 2020

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is a soft ionization MS technique providing only minor fragmentation of the analyte. Therefore, the method is basically suitable for mixture analysis, although the ion yields strongly depend on the basicity/acidity of the analyte in relation to the applied matrix. Accordingly, less sensitively detectable compounds may be suppressed by more sensitively detectable compounds. Thus, separation of the mixture into the individual compounds is normally indispensable. This paper demonstrates the capabilities and limitations of a direct, simple, and inexpensive MALDI-high-performance thin-layer chromatography (HPTLC) coupling for the analysis of a crude lipid extract from porcine brain. Brain lipids were chosen because they represent a rather complex mixture and are of currently significant research interest. It was found that normal-phase HPTLC-separated lipids can be easily characterized by direct MALDI-TOF-MS analysis with sufficient resolution to allow the assignment of virtually all lipid classes, even rather minor species such as phosphorylated phosphoinositides or complex glycolipids as gangliosides. Advantages and disadvantages of this approach are discussed.
Determination of Plant Hormones in Fertilizers by High-Performance Liquid Chromatography with Photodiode Array Detection: Method Development and Single-Laboratory Validation
Authors: Gambino Grazia Laura , Pagano Pietro , Scordino Monica , Sabatino Leonardo , Scollo Emanuele , Traulo Pasqualino , Gagliano Giacomo
Published: February 2020

A simple and reliable high-performance liquid chromatographic method that uses photodiode array detection was developed for the simultaneous determination of 12 native and synthetic plant hormones, i.e., plant growth regulators (PGRs), in fertilizers, such as 1-naphthol, 2,4-dichlorophenoxyacetic acid, 4-(2,4-dichlorophenoxy)butyric acid, 4-chlorophenoxyacetic acid, indole-3-acetic acid, 4-(3-indolyl)butyric acid, dichlorprop, (4-chloro-2-methylphenoxy)acetic acid, -naphthaleneacetic acid, 1-naphthaleneacetamide, -naphthoxyacetic acid, and thidiazuron. The method was experimentally validated for routine regulatory application, and the following analytical parameters were assessed for all PGRs studied: linearity; specificity; precision (relative standard deviation) and accuracy, both measured at 3 concentration levels (0.1, 0.05, and 0.01, w/w); ruggedness; limit of detection; and limit of quantification. Results were satisfactory for all method validation parameters tested and for all PGRs studied, demonstrating the suitability of the method for the determination of PGRs in fertilizers. The uncertainty of measurement was also estimated at 3 concentration levels for all PGRs by using the approach of the International Organization for Standardization, described in its Guide to the Expression of Uncertainty in Measurement. The method was applied to 20 samples of liquid fertilizer with declared biostimulant properties.