bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Different Extraction Parameters on a Solid-Phase Dynamic Extraction for the Gas Chromatographic Determination of d-Limonene Degradation Products by Using a Fractional Factorial Design
Authors: Kamphoff Marion , Thiele Tobias , Kunz Benno 
Published: February 2020

Abstract
Through the application of a solid-phase dynamic extraction (SPDE) method for the determination of volatile substances, different parameters may influence the extraction and desorption process and are, therefore, vital for the determination of the extracted substances via gas chromatography (GC). In this study, the influence of extraction und desorption parameters of an SPDE-GC method for the determination of the d-limonene degradation products, namely, -terpineol, (-)-carveol, and (S)-carvone, in an aqueous model system was evaluated using a factorial fractional design. The aim was to reduce the number of factors that should be considered for the optimization of an SPDE procedure for different applications. It could be shown that the extraction efficiency of -terpineol, (-)-carveol, and (S)-carvone is significantly influenced by the extraction parameters incubation temperature, number of extraction strokes, and amount of added NaCl. All 3 parameters have a positive effect on the extraction and determination of the examined d-limonene degradation products. Due to the identification of significant factors on the basis of an experimental design, the results of this study can be very useful for further development of SPDE methods for different applications.
Original Normal-Phase High-Performance Liquid Chromatographic Separation of Monoacylglycerol Classes from Extra Virgin Olive Oil Triacylglycerols for Their Stereospecific Analysis
Authors: Petrosino Teresa , Riccieri Roberto , Blasi Francesca , Brutti Monia , D’Arco Gilda , Bosi Ancilla , Maurelli Silvia , Cossignani Lina , Simonetti Maria Stella , Damiani Pietro 
Published: February 2020

Abstract
An innovative procedure to separate the 3 isomeric sn-monoacylglycerols (MAG) classes (sn-1-, sn-2-, sn-3-MAG) is described. MAGs, obtained by chemical deacylation of triacylglycerols (TAGs), have been derivatized with (S)-(+)-1-(1-naphtyl)- ethyl-isocyanate, and the resulting urethane derivatives have been separated by normal-phase high-performance liquid chromatography. This procedure allows resolution as diasteroisomers of the 2 enantiomeric classes (sn-1-MAG and sn-3-MAG), without the need of a chiral column, and to separate also the isomeric sn-2-MAG class; moreover, by introducing a chromophoric moiety, this reagent makes possible the ultraviolet detection of the analyte molecules. This procedure has been used to obtain the stereospecific analysis of the TAG fraction of extra virgin olive oil samples. The use of a nondestructive detector permitted the collection of the individual urethane classes; the fatty acid composition of each was determined by high-resolution gas chromatography, obtaining directly from the data the fatty acid distribution within each sn- position of TAGs. To validate this new method, the results have been compared with those obtained by 2 other procedures for TAG stereospecific analysis, and the obtained results were satisfactory since the proposed method gave data very similar to the other procedures.
Comparison of Hexane and Petroleum Ether to Measure Surface Oil Content
Authors: Buck Vinodini E , Barringer Sheryl A 
Published: February 2020

Abstract
Many studies have measured surface oil on potato chips and spray dried powders using either petroleum ether or hexane. This study compared the effectiveness of the 2 solvents using aluminum squares to ensure oil stays on the surface of the sample during the measurement. Aluminum squares were sprayed with soybean oil, and surface oil was measured immediately and after 1 day. Each of the 8 aluminum samples were individually dipped for 12 s in either hexane or petroleum ether. For immediately extracted samples, there was no significant difference in the amount of oil extracted using either hexane or petroleum ether. For 1-day-old samples, hexane extracted more oil than petroleum ether. Neither method extracted all of the surface oil.
Validation Study to Demonstrate the Equivalence of a Minor Modification of Assurance Enzyme Immunoassay Method, Official Method 996.14, for Detection of Listeria in Foods and Environmental Surfaces to the Reference Culture Methods
Authors: Feldsine Philip T , Kerr David E , Lienau Andrew H 
Published: February 2020

Abstract
The Assurance Enzyme Immunoassay (EIA) for the Detection of Listeria in Foods and Environmental Surfaces, AOAC Official Method 996.14, has been modified to combine the separate antibody and conjugate addition steps into one. 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, there were valid results from 145 samples and controls. Results showed that the Assurance EIA for Listeria spp. is equivalent to the reference culture methods for the detection of Listeria.
Evaluation of the VIDAS Staph Enterotoxin II (SET 2) Immunoassay Method for the Detection of Staphylococcal Enterotoxins in Selected Foods: Collaborative Study
Authors: Jechorek Robert P , Johnson Ronald L ,   Collaborators:, Agin J , Anderson G , Bennett R , Brown M , Dammann H , DuCloux W , Elems C , Hawryluk T , Hernandez C , Johnson L A , Koschmann C , Lugovaz I , Moon B , Moore S , Porter M , Purvis U , Riva J , Shaw C , Wessinger A 
Published: February 2020

Abstract
A multilaboratory study was conducted to determine the limit of detection (LOD) of Staphylococcal enterotoxins (SET) in 5 foods. Cooked chicken, ham, potato salad, pasteurized liquid whole milk, and canned mushrooms were each spiked with a different enterotoxin (A, B, C1, D, or E), and tested at 0.25 and 0.5 ng/g SET levels to determine the LOD of the assay for those foods in a collaborative study. Unspiked controls were also included. A total of 19 laboratories representing government and industry participated. In this study, 1674 test portions were analyzed, of which 1638 were used in the statistical analysis. Of the 1638 test portions used in the statistical analysis, 1104 were spiked test portions, of which 1073 were positive by the VIDAS Staph enterotoxin II (SET 2) method. The detection rates at the 0.25 ng/mL level were cooked chicken, 98.2; ham, 99.0; potato salad, 99.1; liquid whole milk, 85.2; and canned mushrooms, 100. The detection rates at the 0.5 ng/mL level were cooked chicken, 97.4; ham, 98.1; potato salad, 100; liquid whole milk, 99.0; and canned mushrooms, 100. The data indicate that the SET 2 method is capable of detecting SET at 0.25 ng/g in cooked chicken, ham, potato salad, and canned mushrooms and at 0.5 ng/g in pasteurized liquid whole milk.
Development and Validation of an Agar Diffusion Assay for Determination of Ceftazidime in Pharmaceutical Preparations
Authors: Schmidt Cleber A , Carazzo Marcelly , Laporta Luciane V , Bittencourt Celso F , Santos Marcos R , Friedrich Milene 
Published: February 2020

Abstract
Ceftazidime (CFZ) is a broad spectrum parenterallactam antibiotic of the cephalosporin family. This paper reports the development and validation of an agar diffusion microbiological assay using the cylinder-plate method for determination of CFZ in powder for injection. The validation carried out yielded good results in terms of linearity, precision, accuracy, selectivity, and robustness. The assay is based on the inhibitory effect of CFZ upon the strain of Pseudomonas aeruginosa ATCC 27853 used as the test microorganism. The results of the assays were treated statistically by analysis of variance and were found to be linear (correlation coefficient = 0.999998) in the selected range of 8.032.0 g/mL; precise [repeatability: relative standard deviation (RSD) = 1.11; intermediate precision: between-day RSD = 1.37 and between-analyst RSD = 1.41]; and accurate. The selectivity of the bioassay was evaluated by analysis of degraded samples at 50C, and the results were compared with a pharmacopeial liquid chromatographic method at the time 0, 24, and 48 h. The results demonstrated the validity of the proposed bioassay, which allows reliable quantitation of CFZ in pharmaceutical samples and can be used as a useful alternative methodology for CFZ analysis in routine quality control.
Validation of the Normocythemic Mice Bioassay for the Potency Evaluation of Recombinant Human Erythropoietin in Pharmaceutical Formulations
Authors: Barth Thiago , Oliveira Paulo R , D'Avila Felipe B , Dalmora Srgio L 
Published: February 2020

Abstract
The normocythemic mice bioassay was validated for the potency evaluation of the recombinant human erythropoietin (rhEPO) against the European Pharmacopoeia Biological Reference Preparation for erythropoietin. The bioassays were performed in 8-week-old female BALB/c mice, which received multiple daily injections of standard or sample solutions (3 + 3), for 4 days. The blood sampling was performed 24 h after the last injection and the reticulocytes were counted by automated flow cytometry. Method validation investigated parameters such as linearity, precision, accuracy, specificity, and robustness, giving results within the acceptable range. The dose-response curve was linear in the concentration range of 164 international units (IU)/mL, and the value of the determination coefficient (r2) was 0.9708. The bioassay was applied for the potency evaluation of rhEPO pharmaceutical products containing alfa or beta forms, expressed in different cell lines, giving biological potencies within 82.79 and 119.70 of the stated potency. The precision index calculated by the weight for the independent assays was &gt;247. The results demonstrated the validity of the bioassay for the potency assessment of pharmaceutical formulations contributing to ensure the therapeutic efficacy of the biological medicine.
Column High-Performance Liquid Chromatographic Determination of Norfloxacin and Its Main Impurities in Pharmaceuticals
Authors: Mielji Branislava , Popovi Gordana , Agbaba Danica , Markovi Slavko , Simonovska Breda , Vovk Irena 
Published: February 2020

Abstract
A gradient reversed-phase column high-performance liquid chromatographic method was developed for the detection and quantification of norfloxacin and its major impurities in norfloxacin-containing pharmaceuticals. Chromatographic separations were performed under the following experimental conditions: column, Zorbax SB RP-18 (5 m, 250 4.6 mm); injection volume, 20 L; mobile phase, 0.05 M NaH2PO4 (pH 2.5)acetonitrile (87 + 13) for 16 min and (58 + 42) for 9 min (stepwise gradient); and flow rate, 1.3 mL/min. All analyses were performed at 25C, and the eluate was monitored at 275 nm using a diode array detector. Linearity (correlation coefficient = 0.999), recovery (99.3101.8), relative standard deviation (0.20.7), and quantitation limit (0.120.47 g/mL) were evaluated and found to be satisfactory. The method is simple, rapid, and convenient for purity control of norfloxacin in both raw materials and dosage forms.
Improved Extraction Method for the Determination of Iron, Copper, and Nickel in New Varieties of Sunflower Oil by Atomic Absorption Spectroscopy
Authors: Ansari Rehana , Kazi Tasneem G , Jamali Mohammad K , Arain Mohammad B , Sherazi Syed T , Jalbani Nusrat , Afridi Hassan I 
Published: February 2020

Abstract
A simple and fast procedure is proposed for the extraction of iron (Fe), copper (Cu), and nickel (Ni) in 16 varieties of sunflower seed oil samples using an ultrasonic bath. The experimental parameters of the ultrasonic-assisted extraction (UAE) method were optimized to improve the sensitivity and detect the metals at trace levels in minimum time. Conventional wet acid digestion method was used for comparative purposes. The optimum recovery of all 3 metals was obtained by UAE for 7 min, while the separation of aqueous and organic phases after extraction using centrifugation (UAE-2) required 3 min, as compared to the conventional equilibration method (UAE-1) that required 90 min. The respective recoveries of Cu, Fe, and Ni obtained with UAE-2 were in the range of 95.897.5, 93.598.3, and 95.698.2, respectively, for different varieties of sunflower oil samples. Accuracy was determined by the standard addition method. Under the optimum operating conditions, the limits of detection obtained from the standard addition curves were 21.7, 20.4, and 35.6 ng/mL for Fe, Cu, and Ni, respectively. The fact that all varieties of sunflower oil contain significant amounts of Fe, Cu, and Ni indicates the deterioration of sunflower oil quality immediately after extraction from seeds, which poses a threat to oil quality and human health.
Single-Laboratory Validation of a Method for the Determination of Furan in Foods by Using Headspace Gas Chromatography/Mass Spectrometry, Part 2Low-Moisture Snack Foods
Authors: Nyman Patricia J , Morehouse Kim M , Perfetti Gracia A , Diachenko Gregory W , Holcomb Jim R 
Published: February 2020

Abstract
In 2004, a quantitative headspace (HS) gas chromatographic/mass spectrometric method was developed and used to determine furan in approximately 300 foods. This method was modified and validated for the determination of furan in low-moisture snack foods. The modifications include a smaller test portion size and lower HS oven temperature. The limits of detection ranged from 0.4 ng/g in graham crackers to 4.4 ng/g in pretzels. Recoveries from samples fortified at 0.5, 1, 2, and 3 times the levels of incurred furan found in the samples ranged from 96 to 102, and HorRat values showed that the recovery data met the criteria for repeatability. The modified method was shown to be reliable for the determination of furan in foods when test portions were equilibrated for 30 min in a 60C HS oven. The modified method was used to conduct a survey of furan in 22 low-moisture snack foods. All of the samples were found to contain furan ranging from 3.7 ng/g in graham crackers to 60 ng/g in corn chips. Results from the survey were consistent with results obtained for similar snack foods analyzed by a U.S. Food and Drug Administration field laboratory.
Development and Validation of a Stability-Indicating Column High-Performance Liquid Chromatographic Assay Method for Determination of Nebivolol in Tablet Formulation
Authors: Kachhadia Pankaj K , Doshi Ashish S , Joshi Hitendra S 
Published: February 2020

Abstract
A simple, precise, and accurate isocratic reversed-phase (RP) stability-indicating column high-performance liquid chromatographic (HPLC) assay method was developed and validated for determination of nebivolol in solid pharmaceutical dosage forms. Isocratic RP-HPLC separation was achieved on a Phenomenex Luna C8 (2) column (250 mm 4.6 mm id, 5 m particle size) using mobile phase composed of acetonitrilepH 3.5 phosphate buffer (35 + 65, v/v) at a flow rate of 1.0 mL/min, and detection was performed at 280 nm using a photodiode array detector. The drug was subjected to oxidation, hydrolysis, photolysis, and heat to apply stress conditions. The method was validated for specificity, linearity, precision, accuracy, robustness, and solution stability. The method was linear in the drug concentration range of 40160 g/mL with a correlation coefficient of 0.9999. The repeatability relative standard deviation (RSD) for 6 samples was 0.69, and the intermediate precision (RSD) for 6 samples was 1.39. The accuracy (recovery) was between 98.57 and 99.55. Degradation products produced as a result of stress studies did not interfere with detection of nebivolol, and the assay can thus be considered stability-indicating.
Development and Validation of a Liquid Chromatographic/Tandem Mass Spectrometric Method for Determination of Tetracycline in Human Plasma: Application to Bioequivalence Study
Authors: Brum Liberato , Pugens Ana Maria , Pritsch Mariely Camila , Mantovani Patricia Bertuol , dos Santos Maurício Bedim , Manfio Josélia Larger 
Published: February 2020

Abstract
A fast, sensitive, and specific liquid chromatographic/tandem mass spectrometric method was developed and validated for determination of tetracycline in human plasma. Tetracycline and oxytetracycline [internal standard (IS)] were extracted from the plasma by protein precipitation. The mobile phase consisted of acetonitrileformic acid 0.1 (48 + 52, v/v), run at a flow rate of 1 mL/min (split 1:5). Detection was performed by positive electrospray ionization in multiple reaction monitoring mode, monitoring the transitions 444.8 &gt; 410.0 and 461.0 &gt; 426.0 for tetracycline and IS, respectively. The analysis was performed in 3.5 min and the method was linear in the plasma concentration range of 506000 ng/mL. The mean extraction recoveries for tetracycline and IS from plasma were 92.14 and 94.04, respectively. Method validation investigated parameters such as the linearity, precision, accuracy, specificity, and stability, giving results within the acceptable range. The proposed method was successfully applied for determination of tetracycline in human plasma samples to support bioequivalence studies.
Development of a New High-Performance Liquid Chromatographic Method for the Determination of Ceftazidime
Authors: de Haro Moreno Andréia , Salgado Hérida Regina Nunes 
Published: February 2020

Abstract
A rapid, accurate, and sensitive high-performance liquid chromatographic (HPLC) method was developed and validated for the determination of ceftazidime in pharmaceuticals. The method validation parameters yielded good results and included range, linearity, precision, accuracy, specificity, and recovery. The excipients in the commercial powder for injection did not interfere with the assay. Reversed-phase chromatography was used for the HPLC separation on a Waters C18 (WAT 054275; Milford, MA) column with methanolwater (70 + 30, v/v) as the mobile phase pumped isocratically at a flow rate of 1.0 mL/min. The effluent was monitored at 245 nm. The calibration graph for ceftazidime was linear from 50.0 to 300.0 g/mL. The values for interday and intraday precision (relative standard deviation) were &lt;1. The results obtained by the HPLC method were calculated statistically by analysis of variance. We concluded that the HPLC method is satisfactory for the determination of ceftazidime in the raw material and pharmaceuticals.
Fatty Acid Profile of Canadian Dairy Products with Special Attention to the trans-Octadecenoic Acid and Conjugated Linoleic Acid Isomers
Authors: Mendis Sanjaya , Cruz-Hernandez Cristina , Ratnayake Walisundera M N 
Published: February 2020

Abstract
Current scientific evidence indicates that consumption of industrial trans fatty acids (TFA) produced via partial hydrogenation of vegetable oils increases the risk of coronary heart disease. However, some studies have suggested that ruminant TFA, especially vaccenic acid (VA or 11t-18:1) and rumenic acid (RA or 9c,11t-18:2), which is a conjugated linoleic acid (CLA) isomer, may have potential beneficial health effects for humans. To date, no concerted effort has been made to provide detailed isomer composition of ruminant TFA and CLA of Canadian dairy products, information that is required to properly assess their nutritional impacts. To this end, we analyzed the fatty acid profile of popular brands of commercial cheese (n = 17), butter (n = 12), milk (n =8), and cream (n = 4) sold in retail stores in Ottawa, Canada, in 20062007 by silver nitrate thin-layer chromatography and gas liquid chromatography. The average total TFA content of cheese, butter, milk, and cream samples were 5.6, 5.8, 5.8, and 5.5 of total fatty acids, respectively. VA was the major trans-octadecenoic acid (18:1) isomer in all the Canadian dairy samples with average levels of (as total trans-18:1) 33.9 in cheese, 35.6 in butter, 31.0 milk, and 30.1 in cream. The different dairy products contained very similar levels of CLA, which ranged from 0.5 to 0.9 of total fat. RA was the major CLA isomer of all the dairy products, accounting for 82.483.2 of total CLA. There were no significant differences (P &gt; 0.05) in the fatty acid profile between the 4 different dairy groups, which suggests lack of processing effects on the fatty acid profile of dairy fat.
Proficiency Testing Program for the Determination of Total Arsenic, Cadmium, and Lead in Seawater Shrimp
Authors: Kong Mei-Fung , Chan Serena , Wong Yiu-Chung 
Published: February 2020

Abstract
The proficiency testing (PT) program for 97 worldwide laboratories for determining total arsenic, cadmium, and lead in seawater shrimp under the auspices of the Asia-Pacific Laboratory Accreditation Cooperation (APLAC) is discussed. The program is one of the APLAC PT series whose primary purposes are to establish mutual agreement on the equivalence of the operation of APLAC member laboratories and to take corrective actions if testing deficiencies are identified. Pooled data for Cd and Pb were normally distributed with interlaboratory variations of 21.9 and 34.8, respectively. The corresponding consensus mean values estimated by robust statistics were in good agreement with those obtained in the homogeneity tests. However, a bimodal distribution was observed from the determination of total As, in which 14 out of 74 participants reported much smaller values (0.4826.4 mg/kg) as compared with the mean values of 60.9 mg/kg in the homogeneity test. The use of consensus mean is known to have significant deviation from the true value in bi- or multimodal distribution. Therefore, the mode value, a better estimate of central tendency, was chosen to assess participants' performance for total As. Estimates of the overall uncertainty from participants varied in this program, and some were recommended to acquire more comprehensive exposure toward important criteria as stipulated in ISO/IEC 17025.
Identification of Food-Derived Bioactive Peptides in Blood and Other Biological Samples
Authors: Sato Kenji , Iwai Koji , Aito-Inoue Misako 
Published: February 2020

Abstract
Recent studies have demonstrated the presence of food-derived peptides in human blood after ingestion of enzymatic hydrolysates of food proteins, while most peptides in food are degraded into amino acids during digestion and absorption. To capture and clarify the food-derived peptides in blood, solid-phase extraction (SPE) using a mini-spin column packed with a strong cation exchanger was developed. This technique allows the use of a nonvolatile acid such as trichloroacetic acid, a strong protein denaturant, for the deproteinizing procedure. To improve resolution of hydrophilic peptide and increase specificity and sensitivity in the detection of peptide by reversed-phase high-performance liquid chromatography (RP-HPLC) after subfractionation by size-exclusion chromatography (SEC), peptides are derivatized with phenyl isothiocyanate. The resultant phenyl thiocarbamyl (PTC)-peptides can be resolved with high resolution and sensitivity by RP-HPLC. By comparing chromatograms of PTC derivatives from blood before and after ingestion of a peptide sample, food-derived peptide can be detected. The isolated PTC-peptide can be applied to a peptide sequencer based on the Edman degradation reaction.