bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous Separation of 14 Antiarrhythmic Drugs and Determination of Mexiletine and Flecainide by Capillary Zone Electrophoresis
Authors: Pietra Rafal , Kowalczuk Dorota , Hopkala Hanna
Published: February 2020

A method using capillary zone electrophoresis was developed for the simultaneous separation of 14 antiarrhythmic drugs belonging to various classes. The drugs are separated on a fused-silica capillary, 90 cm 75 m (72 cm effective length), with phosphate and acetate buffers as background electrolytes and UV detection at 217 nm. The effects of buffer pH, temperature, and applied voltage on the migration of the drugs were studied. The pH was found to be the most significant factor determining effective separation. The antiarrhythmic compounds are completely separated within a relatively short time (<7 min) by using 70 mM phosphate buffer at pH 7.91, an applied voltage of 28 kV, and a temperature of 32C. Mexiletine (MEX) and flecainide (FLE) were quantified under conditions of the optimum separation. The calibration graphs were constructed over the concentration range of 4.014.0 g/mL for both drugs with good correlation (r 0.9999). Detection and quantitation limits were found to be 0.5 and 1.5 g/mL for FLE and 0.7 and 2.1 g/mL for MEX, respectively. The proposed method was used for the determination of both drugs in their commercial forms with satisfactory precision (relative standard deviations of 0.361.21% for FLE and 0.781.66% for MEX) and accuracy (relative standard errors of 0.131.17% for FLE and 0.351.18% for MEX).
Analysis of Flavonol Aglycones and Terpenelactones in Ginkgo biloba Extract: A Comparison of High-Performance Thin-Layer Chromatography and Column High-Performance Liquid Chromatography
Authors: Gray Dean E , Messer Dale , Porter Andrew , Hefner Brian , Logan Dama , Harris Roger K , Clark Alice P , Algaier Joseph A , Overstreet J Diane , Smith Cynthia S
Published: February 2020

Advancements in automated high-performance thin-layer chromatography (HPTLC) have made it feasible to assess its use for the quantitative analysis of marker compounds in botanical preparations. We report here the findings of method comparisons for the terpenelactones and flavonol aglycones by column high-performance liquid chromatography (HPLC) with evaporative light scattering and UV detection, and HPTLC with a scanning densitometer. For the HPTLC assay of terpenelactones, total bilobalide, ginkgolide A, and ginkgolide B consistently achieved <70 of the total determined using HPLC, regardless of variations to postchromatographic derivatization time and temperature. Accuracy testing showed the possibility of a matrix interference. In contrast, a good relationship (95) was determined between HPTLC and HPLC for determination of total flavonol glycosides (calculated from combined quercetin, kaempferol, and isorhamnetin) from an acid-hydrolyzed Ginkgo biloba L. (GBE) sample. The HPTLC flavonol aglycone method also performed well in terms of accuracy (overall average of 96 recovery for the 3 aglycones) and consecutive plate repeatability (overall percent relative standard deviation of 4.4). It is demonstrated that HPTLC can be a time-saving complement to HPLC for routine analysis of the flavonol glycosides in GBE.
Extractive Spectrophotometric Methods for Determination of Zolmitriptan in Tablets
Authors: Aydogmus Zeynep , Inanli Ipek
Published: February 2020

Two simple and sensitive extractive spectrophotometric methods have been developed for determination of zolmitriptan (ZTP) in tablets. These methods are based on the formation of yellow ion-pair complexes between ZTP and tropaeolin OO (TPOO) and bromothymol blue (BTB) in citratephosphate buffer of pH 4.0 and 6.0, respectively. The formed complexes were extracted with dichloromethane and measured at 411.5 and 410 nm for TPOO and BTB, respectively. The best conditions of the reactions were studied and optimized. Beer's law was obeyed in the concentration ranges of 220 and 1.517 g/mL with molar absorptivities of 1.42 104 and 1.60 104 L/mol/cm for the TPOO and BTB methods, respectively. Correlation coefficients were 0.9998 and 0.9999 for TPOO and BTB methods, respectively. Limits of detection of the TPOO and BTB methods were 0.341 and 0.344 g/mL, respectively, and the limits of quantitation were 1.034 and 1.051 g/mL, respectively. Sandell's sensitivity and stability constant were also calculated. The proposed methods have been applied successfully for the analysis of the drug in its dosage forms. No interference was observed from excipients present in tablets. Statistical comparison of the results with those obtained by a high-performance liquid chromatography method showed excellent agreement and indicated no significant differences in accuracy and precision.
Monitoring Stevioside in Soju by High-Performance Liquid Chromatography and Liquid Chromatography/Mass Spectrometry
Authors: Ni Fan , Ammann Jeffrey , Mabud Abdul
Published: February 2020

A method using high-performance liquid chromatography (HPLC) with UV absorption detection was developed to monitor stevioside in soju, a distilled spirits product that is commercially available. The method uses a single-step dilution for sample preparation. It completely eliminates the time-consuming process of solid-phase extraction. A method using HPLC/mass spectrometry was optimized to confirm the identities of stevioside and other related impurities, including rebaudioside A, rebaudioside C, and dulcoside. The method was validated. The validation parameters included range (10.11007.3 ppm), precision, linearity, accuracy, robustness, system suitability, and intermediate precision. Stevioside standard solutions at 6 concentration levels were prepared for the validation work, including the tests for precision, linearity, and accuracy. The solutions were prepared in triplicate for each concentration. The relative standard deviation for the precision test was <3 for all 6 concentration levels. The correlation coefficient for the linearity within the concentration range was determined to be >0.999. The average recovery ranged from 95.7 to 101.1 for the soju samples spiked with stevioside standard. The detection limit for stevioside was estimated at 75 ppb. The method was used to screen several soju samples; no detectable stevioside was found in the samples.
Microbiological Assay for Ceftazidime Injection
Authors: Moreno Andréia De Haro , Salgado Hérida Regina Nunes
Published: February 2020

A simple, sensitive, and specific biodiffusion assay for the antibacterial ceftazidime was developed using a strain of Staphylococcus epidermidis (ATCC 12228) as the test organism. Ceftazidime was measured in powder for injection at concentrations ranging from 100 to 400 g/mL. The calibration graph for ceftazidime was linear (r2 = 1), and the method validation showed that it was precise (relative standard deviation = 0.415) and accurate. The results obtained by biodiffusion assay were statistically calculated by linear parallel model and by means of regression analysis and were verified using analysis of variance. It was concluded that the microbiological assay is satisfactory for in vitro quantification of the antibacterial activity of ceftazidime in pharmaceuticals.
Evaluating Measurement Uncertainty in the Microbiological Assay of Vancomycin from Methodology Validation Data
Authors: Lourenço Felipe Rebello , Kaneko Telma Mary , Pinto Terezinha De Jesus Andreoli
Published: February 2020

Methodology validation and measurement uncertainty estimation are fundamental to obtain reliable results. The microbiological methods are widely used to determine antibiotic assay, as they permit evaluation of the analyzed antibiotic activity. A microbiological assay of vancomycin was performed with adoption of experimental design 5 1 (interpolation in 5-point standard curve assay) with final concentrations from 6.4 to 15.6 g/mL (standards) and 10.0 g/mL (sample). Bacillus subtitlis (ATCC 6633) was the microorganism used, with antibiotic medium No. 8 as base layer and inoculated layer. The plates were incubated at 37C for 18 h. The method adopted for the microbiological assay of vancomycin through agar diffusion was validated according to statistic results demonstrated for suitability of the method concerning linearity, precision, and accuracy. The estimated relative expanded uncertainty (4.3) was considered adequate for this method purpose.
Overaccumulation of Higher Polyamines in Ripening Transgenic Tomato Fruit Revives Metabolic Memory, Upregulates Anabolism-Related Genes, and Positively Impacts Nutritional Quality
Authors: Mattoo Autar K , Chung Sang Ho , Goyal Ravinder K , Fatima Tahira , Solomos Theophanes , Srivastava Alka , Handa Avtar K
Published: February 2020

Vegetables and fruits are essential components of the human diet as they are sources of vitamins, minerals, and fiber and provide antioxidants that prevent chronic diseases. Our goal is to improve durable nutritional quality of tomato fruit. We developed transgenic tomatoes expressing yeast S-adenosylmethionine decarboxylase (ySAMdc) gene driven by a fruit-specific E8 promoter to investigate the role of polyamines in fruit metabolism. Stable integration of E8-ySAMdc chimeric gene in tomato genome led to ripening-specific accumulation of polyamines, spermidine (Spd) and spermine (Spm), which in turn affected higher accumulation of glutamine, asparagine, and organic acids in the red fruit with significant decrease in the contents of valine, aspartate, sucrose, and glucose. The metabolite profiling analysis suggests that Spd/Spm are perceived as signaling organic-N metabolites by the fruit cells, resulting in the stimulation of carbon sequestration; enhanced synthesis of biomolecules; increased acid to sugar ratio, a good attribute for the fruit flavor; and in the accumulation of another vital amine, choline, which is an essential micronutrient for brain development. A limited transcriptome analysis of the transgenic fruit that accumulate higher polyamines revealed a large number of differentially expressed genes, about 55 of which represented discrete functional categories, and the remaining 45 were novel, unknown, or unclassified: amino acid biosynthesis, carotenoid biosynthesis, cell wall metabolism, chaperone family, flavonoid biosynthesis, fruit ripening, isoprenoid biosynthesis, polyamine biosynthesis, signal transduction, stress/defense-related, transcription, translation, and vacuolar function. There was a good correspondence between some gene transcripts and their protein products, but not in the case of the tonoplast intrinsic protein, which showed post-transcriptional regulation. Higher metabolic activity of the transgenic fruit is reflected in higher respiratory activity, and upregulation of chaperones and mitochondrial cytochrome oxidase transcripts compared to the control. These transgenic plants are a new resource to understand the role of Spd/Spm in fruit biology. Transcriptome analysis and metabolic profiles of Spd/Spm accumulating, transgenic fruit suggest the presence of an intricate regulation and interconnection between certain metabolic pathways that are revived when Spd and Spm likely reach a certain threshold. Thus, polyamines act as antiapoptotic regulatory molecules and are able to revive metabolic memory in the tomato fruit.
Stability-Indicating High-Performance Liquid Chromatographic Assay of Atorvastatin with Fluorescence Detection
Authors: Khedr Alaa
Published: February 2020

The purpose of this work was to develop a sensitive, selective, and validated stability-indicating high-performance liquid chromatographic (LC) assay of atorvastatin (ATV) in bulk drug and tablet form. ATV was subjected to different stress conditions, including UV light, oxidation, acid-base hydrolysis, and temperature. ATV and its degradation products were analyzed on an Agilent Zorbax XDB C18 column using isocratic elution with acetonitrile0.02 M sodium acetate, pH 4.2 (45 + 55, v/v) for 25 min. The samples were monitored with fluorescence (FL) detection at 282 nm (excitation)/400 nm (emission). The response ratio of FL to UV detection (at 247 nm) for ATV was 1.66. The method showed good resolution of ATV from its decomposition products. The photodegradation products were separated by silica gel thin-layer chromatography using double development with ethyl acetaten-hexaneglacial acetic acidmethanol (40 + 55 + 0.5 + 4.5, v/v/v/v) followed by (39 + 55 + 0.5 + 5.5, v/v/v/v), and confirmed by LC-FL analysis. The FL response was linear over the investigated range for ATV. The linear range was 101200 ng/injection, and the limit of quantitation was 2.0 ng/injection.
Determination of Zearalenone in Cereal Grains, Animal Feed, and Feed Ingredients Using Immunoaffinity Column Chromatography and Liquid Chromatography: Interlaboratory Study
Authors: Campbell Harold M , Armstrong J Fred ,   Collaborators:, Aoyama K , Biselli S , Cea J , de Rijk T , Dmytrow H , Dömsödi J , Friis-Wandall S , Gonzalez; P , Inerowicz D , Kirby P , Kozak A , Marley E , Marth-Schill J , Nordkvist E , Renaud S , Riter K , Roos A
Published: February 2020

A method using immunoaffinity column chromatography (IAC) and liquid chromatography (LC) for determination of zearalenone in cereal grains, animal feed, and feed ingredients was collaboratively studied. The test portion is extracted by shaking with acetonitrilewater (90 + 10, v/v) and sodium chloride. The extract is diluted and applied to an immunoaffinity column, the column is washed with water or phosphatebuffered saline or methanolwater (30 + 70, v/v), and zearalenone is eluted with methanol. The eluate is evaporated, the residue is dissolved in mobile phase and analyzed by reversed-phase LC with fluorescence detection. The presence of zearalenone can be confirmed using an alternate excitation wavelength or diode array detection. Twenty samples were sent to 13 collaborators (8 in Europe, 2 in the United States, one in Japan, one in Uruguay, and one in Canada). Eighteen samples of naturally contaminated corn, barley, wheat, dried distillers grains, swine feed, and dairy feed were analyzed as blind duplicates, along with blank corn and wheat samples. The analyses were done in 2 sample sets with inclusion of a spiked wheat control sample (0.1 mg/kg) in each set. Spiked samples recoveries were 89116, and for the 18 naturally contaminated samples, RSDr values (within-laboratory repeatability) ranged from 6.67 to 12.1, RSDR values (among-laboratory reproducibility) ranged from 12.5 to 19.7, and HorRat values ranged from 0.61 to 0.90.
Hierarchy of Susceptibility of Viruses to Environmental Surface Disinfectants: A Predictor of Activity Against New and Emerging Viral Pathogens
Authors: Sattar Syed A
Published: February 2020

Proper disinfection is crucial to interrupt the environmental spread of many viruses. In the case of new and emerging viruses still awaiting culture and full characterization, it is proposed that any official recommendations for disinfectant use be based on the well-established hierarchy of susceptibility to such chemicals as related to virus particle size and structure.
Multiresidue Determination of Pesticides in Acid-Clay Soils from Thailand
Authors: Amelung Wulf , Nikolakis Alexander , Laabs Volker
Published: February 2020

Tropical and temperate soils differ with respect to their chemical conditions and mineral composition. Consequently, assessment of the contamination of tropical soils with pesticides requires methods that provide exhaustive extraction from the specific soil matrix and reliable quantification. Our objective was to optimize the simultaneous extraction and determination of 32 representative pesticides (organophosphates, organochlorines, synthetic pyrethroids, triazines, acetamides, carbamates, diphenyl ethers, acylalanines, oxadiazoles, thiadiazoles, and phenoxy compounds) frequently used in Thailand. The compounds were added to a clayey Ultisol-topsoil (45 clay) from the Yom Region in Northern Thailand. Ten different solvent mixtures were tested; the use of a shake extraction with acetoneethyl acetatewater (3 + 1 + 1, v/v/v) was most effective in providing exhaustive and reproducible extraction of pesticides both from freshly fortified soil and from fortified soil after incubation for 1428 days. The pesticides were separated and quantified by using gas chromatography with mass selective detection. Except for methamidophos, which was almost completely lost during sample workup, the recoveries of all pesticides from soil ranged from 68.6 to 104 (mean standard error, 2.8) for freshly spiked samples and from 45.9 to 107 (mean standard error, 2.3) for spiked samples incubated for 14 days. The use of internal standards compensated for the losses of most pesticides during workup and increased the mean recovery of the pesticides from freshly fortified soil to 96. The method was successfully applied to the determination of environmental concentrations of pesticides in a range of Thai agricultural soils.
An Updated Liquid Chromatographic Assay for the Determination of Glyphosate in Technical Material and Formulations
Authors: Gavlick Walter K , Tomkins David F
Published: February 2020

An updated liquid chromatographic (LC) method for the determination of glyphosate in technical material and formulations was tested by 7 laboratories. Samples were dissolved in water and injected into an LC system with a C18 guard column, an anion exchange analytical column, and a phosphate buffer mobile phase with 12 to 15 methanol. Detection was by UV absorption at 195 nm or refractive index. Automated injections were made. Calculations were based on peak area comparisons with external standards. The interlaboratory study analyzed 6 matched pairs of 3 glyphosate technical materials and 3 glyphosate formulations. The matched pair results were analyzed by using the AOAC spreadsheet and Youden's matched pair calculations. Coefficients of variation for the 6 samples ranged from 0.46 to 0.85.
Determination of Low-Level Pesticide Residues in Soft Drinks and Sports Drinks by Liquid Chromatography with Tandem Mass Spectrometry: Collaborative Study
Authors: Miller Kathleen D , Milne Paul ,   Collaborators:, Baker S , Barr D , Haghani A , Loo B , Matteini P , Monson K D , Perez R , Rawn T , Rosi F , Schmitz J , Summer S , Yadlapalli S
Published: February 2020

A collaborative study was conducted on a method for the measurement of 11 low-level pesticide residues in soft drinks and sports drinks by liquid chromatography with tandem mass spectrometry. The pesticide residues determined in this study were alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-dichlorophenoxyacetic acid (2,4-D). Blind fortification solutions containing 3 different levels of pesticide residues were provided to 9 collaborating laboratories to create test samples at concentrations of 0, 0.1, and 0.5 g/L with a 10-fold concentration for phorate in a total of 6 matrixes (2 colas, 1 diet cola, 1 clear lemon-lime soft drink, 1 orange soft drink, and 1 sports drink). Good qualitative performance of the method was demonstrated for all pesticide residues. Reproducibility relative standard deviation (RSDR) ranged from 7 to 151 for alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D at the 0.1 g/L level (1.0 g/L for phorate). At 0.5 g/L (5.0 g/L for phorate), RSDR ranged from 9 to 57 for alachlor, atrazine, butachlor isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D in all matrixes. Repeatability relative standard deviation (RSDr), applicable to the diet cola and sports drink, ranged from 0 to 124 for the 11 pesticide residues at the 0.1 g/L level (1.0 g/L for phorate). At 0.5 g/L (5.0 g/L for phorate), RSDr ranged from 4 to 26. Recoveries for the 11 pesticide residues in all matrixes ranged from 84 to 300 at the 0.1 g/L level (1.0 g/L for phorate) and from 66 to 127 at the 0.5 g/L (5.0 g/L for phorate) level. Coefficients of determination (r2) of the matrix-matched calibration curves were 0.95. It is recommended that the method be accepted by AOAC as Official First Action with a limit of quantification of 0.5 g/L for alachlor, atrazine, butachlor, isoproturon, malaoxon, methyl paraoxon, monocrotophos, phorate sulfone, phorate sulfoxide, and 2,4-D and 5.0 g/L for phorate.
Development and Validation of Column High-Performance Liquid Chromatographic and Ultraviolet Spectrophotometric Methods for Citalopram in Tablets
Authors: Menegola Jlia , Steppe Martin , Schapoval Elfrides E S
Published: February 2020

Column high-performance liquid chromatographic (LC) and UV spectrophotometric methods for the quantitative determination of citalopram, a potent and selective serotonin reuptake inhibitor, in tablets were developed. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by the reversed-phase technique on an ACE C18 column with a mobile phase composed of 0.30 triethylamine solutionacetonitrile (55 + 45, v/v) adjusted to pH 6.6 with 10 ortho-phosphoric acid at a flow rate of 1.0 mL/min and 25C. The UV spectrophotometric method was performed at 239 nm. The linearity of the LC method was in the range of 10.0070.00 g/mL, and 2.5017.50 g/mL for the UV spectrophotometric method. The interday and intraday assay precision was <1.5 (relative standard deviation) for the LC and UV spectrophotometric methods. The recoveries were in the range 100.70101.35 for the LC method and 98.4898.65 for the UV spectrophotometric method. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the 2 methods. The proposed methods are highly sensitive, precise, and accurate and can be used for the reliable quantitation of citalopram in tablets.
Comparative Validation Study to Demonstrate the Equivalence of a Minor Modification to AOAC Method 996.09 [Visual Immunoprecipitate (VIP®) for E. coli O157:H7] to the Reference Culture Methods
Authors: Feldsine Philip T , Kerr David E , Shen George S , Lienau Andrew H
Published: February 2020

The Visual Immunoprecipitate (VIP®)for the Detection of E. coli O157:H7 in Foods, AOAC Official Method 996.09, has been modified to use a simplified plastic housing for the device. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. Three foods were analyzed. In total, valid results were obtained from 240 samples and controls. Results showed that the VIP for E. coli O157:H7 is equivalent to the reference culture methods for the detection of E. coli O157:H7.
Comparative Validation Study to Demonstrate the Equivalence of a Minor Modification to AOAC Method 997.03 [Visual Immunoprecipitate (VIP®) for Listeria] to the Reference Culture Methods
Authors: Feldsine Philip T , Kerr David E , Shen George S , Lienau Andrew H
Published: February 2020

The Visual Immunoprecipitate (VIP®) for the Detection of Listeria in Foods and Environmental Surfaces, AOAC Official Method 997.03, has been modified to use a simplified housing for the device. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture methods. Two food matrixes and one environmental surface were analyzed. In total, valid results were obtained from 145 samples and controls. Results showed that the modified VIP for Listeria spp. is equivalent to the reference culture methods for the detection of Listeria.
Rapid Method for the Determination of Coumarin, Vanillin, and Ethyl Vanillin in Vanilla Extract by Reversed-Phase Liquid Chromatography with Ultraviolet Detection
Authors: Ali Laila , Perfetti Gracia , Diachenko Gregory
Published: February 2020

A method is described for determining coumarin, vanillin, and ethyl vanillin in vanilla extract products. A product is diluted one-thousand-fold and then analyzed by reversed-phase liquid chromatography using a C18 column and a mobile phase consisting of 55 acetonitrile45 aqueous acetic acid (1) solution at a flow rate of 1.0 mL/min. Peaks are detected with a UV detector set at 275 nm. Vanilla extracts were spiked with 250, 500, and 1000 g/g each of coumarin, vanillin, and ethyl vanillin. Recoveries averaged 97.4, 97.8, and 99.8 for coumarin, vanillin, and ethyl vanillin, respectively, with coefficient of variation values of 1.8, 1.3, and 1.3, respectively. No significant difference was observed among the 3 spiking levels. A survey of 23 domestic and imported vanilla extract products was conducted using the method. None of the samples contained coumarin. The surveyed samples contained between 0.4 to 13.1 and 0.4 to 2.2 mg/g vanillin and ethyl vanillin, respectively.
Simultaneous Determination of Tetracylines and Quinolones Antibiotics in Egg by Ultra-Performance Liquid Chromatography-Electrospray Tandem Mass Spectrometry
Authors: Jia Xiaofei , Shao Bing , Wu Yongning , Yang Yi , Zhang Jing
Published: February 2020

We report here an ultra-performance liquid chromatography coupled with tandem mass spectrometric (MS/MS) method for the simultaneous quantitation of multiclass veterinary drugs in egg. The analysis of the target compounds, including 7 tetracyclines and 4 types of quinolones, may be accomplished in 15 min of total run time. The egg was extracted with ethylenediaminetetraacetic acidMcIlvaine buffer solution and further purified using a polymer-based Oasis HLB solid-phase extraction cartridge. A C18 column was used to separate the analytes followed by MS/MS using an electrospray ion source. The overall average recoveries of the analytes based on matrix-fortified calibration ranged from 71 to 112 with acceptable relative standard deviations of <20 for 6 trials. For all of the target compounds, the limits of quantitation ranged between 0.02 and 4.29 g/kg. The proposed method is sufficiently sensitive and highly selective.
Determination of Albendazole and Its Metabolites in the Muscle Tissue of Hybrid Striped and Largemouth Bass Using Liquid Chromatography with Fluorescence Detection
Authors: Rummel Nathan , Shaikh Badar
Published: February 2020

A liquid chromatographic method was developed for the determination of albendazole and its metabolites albendazole sulfoxide, albendazole sulfone, and albendazole-2-aminosulfone from largemouth and hybrid striped bass muscle tissue with adhering skin. The muscle tissue samples were made alkaline with potassium carbonate and extracted with ethyl acetate. The extracts were further subjected to cleanup by using a series of liquidliquid extractions. After solvent evaporation, the residue was reconstituted in mobile phase and chromatographed. The chromatography was carried out on a reversed-phase Luna C18 column, using acetonitrilemethanol buffer as the mobile phase. The analytes were detected by fluorescence with excitation and emission wavelengths of 290 and 330 nm, respectively. The average recoveries from the fortified muscle tissue of the 2 fish species for albendazole (25100 ppb), albendazole sulfoxide (8.7552.5 ppb), albendazole sulfone (110 ppb), and albendazole-2-aminosulfone (10100 ppb) were 89, 82, 99, and 74, respectively. The coefficient of variation for each compound was 20 in all cases. The procedure was applied to the determination of albendazole and its 3 metabolites in the muscle tissue of the 2 fish species after orally dosing them with albendazole.
Single-Laboratory Validation of a Method for the Determination of c-Phycocyanin and Allophycocyanin in Spirulina (Arthrospira) Supplements and Raw Materials by Spectrophotometry
Authors: Yoshikawa Noritaka , Belay Amha
Published: February 2020

A single-laboratory validation study was conducted for a 2-wavelength spectrophotometric method for the determination of c-phycocyanin (cPC) and allophycocyanin (aPC) in Spirulina supplements and raw materials. The absorption maxima of cPC and aPC are at 620 and 650 nm, respectively. The concentrations of the analytes were calculated from measurement of absorbance at 2 wavelengths. This method provided linear responses for cPC and aPC in the range of 25250 g/mL. Duplicate determinations of cPC and aPC in 4 different test materials on 5 different days resulted in relative standard deviations of 0.31.0 and 1.01.5 for cPC and aPC, respectively. Recoveries were 99.2102.4 and 100.0104.0 for cPC and aPC, respectively. The results were satisfactory for the determination of cPC and aPC in Spirulina supplements.
Determination of Fumonisins B1 and B2 in Corn by Liquid Chromatography/Mass Spectrometry with Immunoaffinity Column Cleanup: Single-Laboratory Method Validation
Authors: Senyuva Hamide Z , Ozcan Sureyya , Cimen Dilek , Gilbert John
Published: February 2020

A single-laboratory method validation was conducted to establish the effectiveness of an immunoaffinity column cleanup procedure followed by liquid chromatography/mass spectrometry (LC/MS) for the determination of fumonisins B1 and B2 (FB1+ FB2) in corn. The test portion is extracted with acetonitrilemethanolwater (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an immunoaffinity column. FB1 + FB2 are removed with methanol and directly determined by reversed-phase LC with MS detection using selected-ion monitoring of 2 characteristic ions in each case. Test portions of blank corn samples were spiked with a mixture of FB1 + FB2 to give total levels of 200 and 500 ng/g, respectively. Recoveries of both FB1 and FB2 from spiked samples averaged 90.4101. Based on results for spiked raw corn (triplicates at 2 levels), the relative standard deviation for repeatability ranged from 2.8 to 7.1. The accuracy of the method was demonstrated by analysis of Food Analysis Performance Assessment Scheme (FAPAS) test material. The method was also applied to a small survey of processed corn products such as corn chips, cornflakes, and popcorn.
Simultaneous Determination of Nickel and Copper by H-Point Standard Addition MethodFirst-Order Derivative Spectrophotometry in Plant Samples After Separation and Preconcentration on Modified Natural Clinoptilolite as a New Sorbent
Authors: Roohparvar Rasool , Taher Mohammad Ali , Mohadesi Alireza
Published: February 2020

For the simultaneous determination of nickel(II) and copper(II) in plant samples, a rapid and accurate method was developed. In this method, solid-phase extraction (SPE) and first-order derivative spectrophotometry (FDS) are combined, and the result is coupled with the H-point standard addition method (HPSAM). Compared with normal spectrophotometry, derivative spectrophotometry offers the advantages of increased selectivity and sensitivity. As there is no need for carrying out any pretreatment of the sample, the spectrophotometry method is easy, but because of a high detection limit, it is not so practical. In order to decrease the detection limit, it is suggested to combine spectrophotometry with a preconcentration method such as SPE. In the present work, after separation and preconcentration of Ni(II) and Cu(II) on modified clinoptilolite zeolite that is loaded with 2-[1-(2-hydroxy-5-sulforphenyl)-3-phenyl-5-formazano]-benzoic acid monosodium salt (zincon) as a selective chromogenic reagent, FDS-HPSAM, which is a simple and selective spectrophotometric method, has been applied for simultaneous determination of these ions.With optimum conditions, the detection limit in original solutions is 0.7 and 0.5 ng/mL, respectively, for nickel and copper. The linear concentration ranges in the proposed method for nickel and copper ions in original solutions are 1.1 to 3.0 103 and 0.9 to 2.0 103 ng/mL, respectively. The recommended procedure is applied to successful determination of Cu(II) and Ni(II) in standard and real samples.
Determination of Trace Amounts of Nickel, Manganese, Cobalt, and Zinc in Environmental Samples After Separation and Preconcentration by Use of Polyacrylic Acid/Alumina Sorbent
Authors: Sabermahani Fatemeh , Taher Mohammad Ali
Published: February 2020

Manganese, nickel, cobalt, and zinc are elements that appear together in many real samples. In this work, a simple, rapid, and sensitive method has been used for the simultaneous separation and preconcentration of trace amounts of these elements using water-soluble polyacrylic acid on alumina as a sorbent in a glass column system. A solution containing Mn, Ni, Co, and Zn was passed through the column at pH 7, and desorption was carried with 5.0 mL of 0.03 M nitric acid. Linearity was maintained between 0.255.0 103, 0.046.0 103, 0.108.0 103, and 0.0281.0 103 ng/mL for Ni, Mn, Co, and Zn, respectively, in the original solution. Eight replicate determinations of a mixture containing 1.0 g/mL of each of the elements in the final solution gave relative standard deviations of 1.4, 1.5, 2.4, and 1.2 for Ni, Mn, Co, and Zn, respectively. The sorption capacities for Mn (mg/g sorbent) obtained were 16.0 for Mn, 9.0 for Ni, 12.0 for Co, and 10.0 for Zn. By using 5.0 mL elution solution, preconcentration factors of 400, 500, 700, and 460 could be obtained for Ni, Mn, Zn, and Co, respectively.
Determination of Decoquinate in Animal Feeds by Liquid Chromatography: Collaborative Study
Authors: Sanchez Anivis A , Campbell Harold M ,   Collaborators:, Ahmed M S , Albert K , Applegate C , Bekele E , Cruz C , Dalgleish J , Dudiková L , Elson C. Focht K , Genouel C , Joubert M , Kirby P , Le Bouquin R , Lerch R , McManus K , Menefee L , Moura S , Murley V , Petrova J , Rues M-C , Siegel V S , Stephens B , Warrick D , Williams S M
Published: February 2020

The performance characteristics of a liquid chromatographic (LC) method for the analysis of decoquinate (DEC) in supplements, premixes, and complete animal feeds at medicating and trace levels were collaboratively studied. DEC is extracted from ground feed samples with 1 calcium chloridemethanol solution using mechanical agitation for 90 min. After centrifugation for 5 min and dilution (if necessary), an aliquot of the extract is diluted with water. The diluted extracts are filtered and analyzed by reversed-phase LC with fluorescence detection. Suspect positive trace-level samples are confirmed by using an alternate excitation wavelength. Fourteen test samples of medicated feeds, supplement, and medicated premix, along with 8 test samples for trace-level analysis, were sent to 13 collaborators (one in Canada, 4 in Europe, and 8 in the United States). Test samples were analyzed as blind duplicates. Acceptable results were received from 12 laboratories for the medicated test samples and from 13 laboratories for the trace-level samples. Repeatability relative standard deviation estimates ranged from 1.3 to 5.6. Reproducibility relative standard deviations estimates ranged from 2.8 to 6.1, and HorRat values ranged from 0.22 to 0.74.
Determination of Hydrastine and Berberine in Goldenseal Raw Materials, Extracts, and Dietary Supplements by High-Performance Liquid Chromatography with UV: Collaborative Study
Authors: Brown Paula N , Roman Mark C ,   Collaborators:, Chang C , Jin C , Kuriyedath R , Lidstone S , Ly L , Ma Y-C , Sigmund P , Smith R , Wijewickreme N
Published: February 2020

A multilaboratory collaborative study was conducted on a high-performance liquid chromatographic (HPLC) method utilizing UV detection, previously validated using AOAC single-laboratory validation guidelines for determination of hydrastine and berberine in goldenseal (Hydrastis canadensis L.) raw materials, extracts, and dietary supplements at levels ranging from 0.4 to 6 (w/w). Nine collaborating laboratories determined the hydrastine and berberine content in 8 blind samples. Sample materials included powdered botanical raw materials, whole root material, and 4 finished product dietary supplements containing either goldenseal powdered root material or extract. The materials were extracted with an acidified water and acetonitrile solution. HPLC analyses of the extracts were performed on a C18 column using UV detection at 230 nm. Results for powdered root material and capsule products ranged from about 0.2 (w/w) for each alkaloid to about 4 (w/w) for each alkaloid. Liquid tincture results were approximately 40005000 g/mL for each alkaloid. Reproducibility relative standard deviations (RSDR) for hydrastine ranged from 2.68 to 6.65, with HorRat values ranging from 0.77 to 1.89. RSDR for berberine ranged from 5.66 to 7.68, with HorRat values ranging from 1.32 to 2.12. All finished products containing goldenseal extract yielded HorRat values <2.0. Based on these results, the method is recommended for Official First Action for determination of hydrastine and berberine in goldenseal raw materials and dietary supplement finished products containing powdered goldenseal and goldenseal extract.
Determination of Moisture and Fat in Meats by Microwave and Nuclear Magnetic Resonance Analysis: Collaborative Study
Authors: Leffler Timothy P , Moser Cindy R , McManus Bobbie J , Urh John J , Keeton Jimmy T , Claflin Amy ,   Collaborators:, Adkins K , Claflin A , Davis C , Elliot J , Goin P , Horn C , Humphries J , Ketteler K , Perez P , Steiner G
Published: February 2020

Ten laboratories participated in a collaborative study to determine the total moisture and fat in raw and processed meat products by microwave drying and nuclear magnetic resonance (NMR) spectroscopy. Meat products were prepared following the AOAC Method and analyzed using CEM Corp.'s SMART Trac Moisture and Fat Analysis system. SMART Trac provides moisture results by measuring the weight loss on drying by microwave energy. The dried sample is then analyzed by NMR spectrometry for fat content. Moisture and fat results are displayed and reported by the SMART Trac as a percentage (g/100 g). Microwave drying is an AOAC-approved reference method (Method 985.14), Moisture in Meat and Poultry Products. NMR spectrometry is a secondary technique used to determine the concentration of various constituents in biological, organic, or chemical samples. The study design was based on Youden's matched pair principle for collaborative tests. For the purposes of this study, 10 laboratories each tested 10 Youden matched pairs, for a total of 20 samples. The study samples represented a range of products processed daily in plant operations. Included were raw meat samples (beef, pork, chicken, and turkey) as well as processed meats (beef hot dog, pork sausage, and ham). The total moisture content of the undiluted samples, as received for the purposes of this study, was determined by AOAC Method 950.46 and ranged from 54.03 to 74.99. The total fat content of the undiluted samples was determined by AOAC Method 960.39 and ranged from 1.00 to 29.79. Statistical analysis of study results for total moisture yielded a relative standard deviation for repeatability (RSDr) range of 0.14 to 0.95 and a relative standard deviation for reproducibility (RSDR) range of 0.26 to 0.95. Statistical analysis for total fat yielded similar RSDr and RSDR range of 0.74 to 4.08. Results for turkey had higher RSDr and RSDR values, both at 12.6, due to low fat content and possibly to the separation of the samples observed by some of the collaborators. Results demonstrate that microwave drying with NMR is a rapid, practical method providing results equivalent to AOAC Methods 950.46 (Forced Air Oven Drying) and 960.39 (Soxhlet Ether Extraction) in raw and processed meat products.
Modification of AOAC Method 973.31 for Determination of Nitrite in Cured Meats
Authors: Mohamed Ashraf A , Mubarak Ahmed T , Fawy Khaled F , El-Shahat Mohamed F
Published: February 2020

A modification of AOAC Method 973.31 is proposed to improve the extraction efficiency of nitrite from cured meat samples and its subsequent quantification based on the diazotization-coupling reaction of sulfanilamide with N-1-naphthyl)ethylenediamine dihydrochloride (NED). The various experimental parameters were thoroughly investigated. A 5 g meat sample was mixed with 400 mL water; the pH of the mixture was adjusted to 5.5 0.3 and allowed to stand for 2 h on a water bath at 80C, with occasional shaking for the complete extraction of nitrite. After quantitative filtration, an aliquot was mixed with chloroaceticchloroacetate buffer, pH 1.80 0.05, sulfanilamide, and NED, and the absorbance of the resulting azodye was recorded at 540 nm against water as a reference. Following the recommended procedure, a linear calibration graph was obtained for up to 0.8 g/mL NO2, with a correlation coefficient of 0.9996 and a detection limit (based on the 3 Sb-criterion) of 5.6 ng/mL NO2. The proposed method was conveniently applied to various cured meat samples and was validated by comparison with the original AOAC method and by recovery experiments that gave quantitative results (9498) with convenient reproducibility. Statistical analysis of the analytical data could not detect any systematic error and revealed the high accuracy and precision of the proposed method.
Determination of Copper in Water and Plant Samples by Flame Atomic Absorption Spectrometry After Preconcentration on Octadecyl Silica Membrane Disks Modified with a Recently Synthesized Schiff's Base
Authors: Shamspur Tayebeh , Mostafavi Ali , Sheikhshoaie Iran
Published: February 2020

A simple, selective, reliable, and sensitive method for the determination of trace amounts of Cu2+ ions in aqueous samples is proposed. The Cu2+ ions are adsorbed quantitatively during the passage of aqueous samples through an octadecyl (C18) silica membrane disk modified by a symmetrical tetradentate Schiff base ligand, N,N'-bis(4-phenylazo salicylaldimine) 3-chloro-1,2-phenylenediamine (H2L). The retained Cu2+ ions were then stripped from the disk by elution with the minimal amount of nitric acid solution and determined by flame atomic absorption spectrometry. Various parameters, such as the effect of pH, flow rate, type and amount of eluent, and the effects of various cationic interferences on the recovery of ions were studied. The proposed method permitted large enrichment factors (about 550 and higher). The limit of detection of the method was 1.5 102 g/L. The use of the same disk modified with 6 mg H2L for at least 30 times showed no change in the recovery of Cu2+ ions. The accuracy of the method was confirmed by determination of Cu2+ ions in standard samples [National Institute of Environmental Studies (NIES) No. 2 and Nippon Keikinzoku Kogyo (NKK) No. 920]. The results demonstrated good agreement with certified values.
Evaluation of a Method for Determining Concentrations of Isoeugenol, an AQUI-S Residue, in Fillet Tissue from Freshwater Fish Species
Authors: Meinertz Jeffery R , Schreier Theresa M , Bernardy Jeffry A
Published: February 2020

AQUI-S is a fish anesthetic/sedative that is approved for use in a number of countries throughout the world and has the potential for use in the United States. The active ingredient in AQUI-S is isoeugenol. A method for determining isoeugenol concentrations in edible fillet tissue is needed for regulatory purposes, including surveillance and potential use in studies fulfilling human food safety data requirements if U.S. Food and Drug Administration approval is pursued. A method was developed and evaluated for determining isoeugenol concentrations in fillet tissue using relatively common procedures and equipment. The method produced accurate and precise results with fillet tissue from 10 freshwater fish species. The percentage of isoeugenol recovered from samples fortified with isoeugenol at nominal concentrations of 1, 50, and 100 g/g for all species was always >80 and <97. Within-day precision for samples fortified at those same concentrations was 10, and day-to-day precision was 4.0. Method precision with fillet tissue containing biologically incurred isoeugenol was 8.1. There were no or minimal chromatographic interferences in control fillet tissue extracts from 9 of the 10 species. The method detection limits for all but one species ranged from 0.004 to 0.014 g/g, and the quantitation limits ranged from 0.012 to 0.048 g/g.
Available Lysine in Foods: A Brief Historical Overview
Authors: Moughan Paul J , Rutherfurd Shane M
Published: February 2020

A brief historical overview is presented on the development of the science addressing lysine bioavailability in foods. Early observations that dietary protein utilization did not always correlate with gross amino acid composition led to an understanding that the amino acid lysine, in particular, can be easily damaged during food processing. Conventional amino acid analysis, involving a strong acid hydrolysis step, can lead to a significant degree of overestimation of lysine in processed foods. More recently, it has been found that not only food lysine content values but also estimates of lysine digestibility and digestible lysine contents may be erroneous. Estimates of absorbed (true ileal digestible) reactive lysine are accurate measures of available lysine. Technically, bioassays such as the slope-ratio assay determine utilized rather than available lysine.
Lunasin: A Novel Cancer Preventive Seed Peptide that Modifies Chromatin
Authors: de Lumen Ben O
Published: February 2020

Lunasin is a novel cancer preventive peptide whose efficacy against chemical carcinogens and oncogenes has been demonstrated in mammalian cells and a skin cancer mouse model. In contrast, constitutive expression of the lunasin gene in mammalian cells leads to arrest of cell division and cell death. Isolated and characterized in soy, lunasin peptide is also documented in barley and wheat and is predicted to be present in many more seeds because of its possible role in seed development. Initial studies show that lunasin is bioavailable in mice when orally ingested. Lunasin internalizes into mammalian cells within minutes of exogenous application, and localizes in the nucleus after 18 h. It inhibits acetylation of core histones in mammalian cells but does not affect the growth rate of normal and established cancer cell lines. An epigenetic mechanism of action is proposed whereby lunasin selectively kills cells being transformed or newly transformed cells by binding to deacetylated core histones exposed by the transformation event, disrupting the dynamics of histone acetylationdeacetylation.
Biopharming to Increase Bioactive Peptides in Rice Seed
Authors: Yang Lijun , Wakasa Yuhya , Takaiwa Fumio
Published: February 2020

The production of high-value pharmaceutical proteins and peptides in transgenic plants is an attractive and economically feasible alternative to conventional mammalian cell, yeast, and bacterial systems. In contrast to vegetative tissues, rice seeds allow higher accumulation of recombinant proteins and long-term stable storage. Rice is not only consumed as a staple food by a majority of the world's population, but is also used as a model monocot for biotechnological manipulation. Daily oral consumption of transgenic rice seeds that accumulate high concentrations of food-derived or synthetic bioactive peptides can be expected to provide a safe, reliable, and consistent oral delivery system that would contribute to the promotion of human health care.
Determination of Cyclamate in Foods by Ultraperformance Liquid Chromatography/Tandem Mass Spectrometry
Authors: Sheridan Robert , King Thomas
Published: February 2020

A highly sensitive and selective method that requires minimal sample preparation was developed for the confirmation and quantitation of cyclamate in a variety of foods by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). Sample preparation consisted of homogenization followed by extraction and dilution of cyclamate with water. HPLC separation was achieved using a bridged ethyl hybrid C18 high-pressure column with a mobile phase consisting of 0.15 acetic acid and methanol. Under electrospray ionization negative conditions, quantitation was achieved by monitoring the fragment m/z 79.7 while also collecting parent ion m/z 177.9. Two food matrixes, diet soda and jelly, were subjected to a validation procedure in order to evaluate the applicability of the method. The cyclamate limit of detection for both matrixes was determined to be 0.050 g/g with a limit of quantitation of 0.150 g/g. The correlation coefficient of the calibration curves was >0.9998 from 0.0005 to 0.100 g/mL. The method has been used for the determination of cyclamate in several foods and the results are presented.