bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrospray Ionization Matrix Effect as an Uncertainty Source in HPLC/ESI-MS Pesticide Residue Analysis
Authors: Kruve Anneli , Herodes Koit , Leito Ivo 
Published: February 2020

Abstract
The matrix effects in HPLC/electrospray ionization (ESI)-MS analysis are difficult to compensate for because of their large variability. It is, therefore, often more practical to include uncertainty due to the matrix effect into the uncertainty budget rather than try to compensate. This work presents an empirical approachthe matrix effect graph approachfor estimating the uncertainty due to the matrix effect in HPLC/ESI-MS analysis of pesticide residues in fruits and vegetables. At certain time intervals (1 month), a calibration graph using extracts of different fruits/vegetables as calibration solutions is prepared, and a regression line is fitted through these data. These fruits/vegetables may be either from the commodity group of the samples or from different commodity groups. The relative residuals of the calibration point peak areas are calculated and plotted against the measurement time. We term the resulting graph the matrix effect graph. The root mean square of the relative residuals is calculated and used as the estimate of relative uncertainty of the sample peak areas caused by the matrix effect. The matrix effect graph obtained over fruits/vegetables from different commodity groups can also be used to identify fruits/vegetables with extreme matrix effects. The matrix effect graph approach was used for determination of thiabendazole, aldicarb, imazalil, and methiocarb and was validated with tomato, cucumber, and sweet corn matrixes at the 0.5 mg/kg concentration level. When different commodity groups were used to compile the matrix effect graph, results of analysis of all samples agreed with the spiked concentrations within the expanded uncertainties (at k = 2 level). When the matrix effect graph was compiled using fruits from the same commodity group as the analyzed samples (fruiting vegetables in this case), agreement was found in 98 of the cases.
Development of a Gas Chromatographic/Mass Spectrometric Method for Determination of Phthalates in Oily Foods
Authors: Sannino Anna 
Published: February 2020

Abstract
A GC/MS method was developed for simultaneous determination of 12 phthalates and four other plasticizersacetyl tributyl citrate, di(2-ethylhexyl) adipate, dibutyl sebacate, di-isononyl cyclohexane 1,2-dicarboxylate (DINCH)in vegetable oil, pesto, and tomato sauce. Samples were extracted with acetonitrile and cleaned on a Florisil column. The final extract was analyzed by GC in combination with ion trap MS. The phthalates and di-isononyl cyclohexane 1,2-dicarboxylate were detected by MS/MS, while the other three plasticizers were monitored in the same GC run using full scan mode. The analytical process was validated in each matrix by the analysis of blank samples. Performance characteristics, such as linearity, LOQ, precision, and recoveries were studied. Studies at fortification levels of 0.25200 mg/kg gave mean recoveries ranging from 71 to 106 and RSD values between 7 and 12 for all compounds. LOQs were 0.0500.10 mg/kg for all the target compounds except di-isononyl phthalate, di-isodecyl phthalate, and DINCH (2.0 mg/kg).
Determination of Lycopene in Dietary Supplements and Raw Materials by High-Performance Liquid Chromatography: Collaborative Study
Authors: Waysek Edward H , Schierle Joseph , Duesterloh Andre , Deshpande Jayant , Austad John ,   Collaborators:, Austad J , Blatt Y , Chan Y F , Deshpande J , Duesterloh A , Kumar T K S , LaLuzerne P , Nemzer B , Ortiz J F L , Peadon P , Reif K , Schierle J , Stanley S , Tang C Y 
Published: February 2020

Abstract
A collaborative study was conducted to evaluate the interlaboratory performance of an LC method for lycopene in dietary supplements and the raw materials commonly used in their manufacture. Twelve laboratories from six countries agreed to participate in the study. Results from 10 laboratories were received and are reported. Five dietary supplements, including both tablets and a softgel capsule with a lycopene content ranging from 25 g to 25 mg per unit, and three raw materials, including gelatin-based beadlets, vegetarian beadlets, and a suspension in oil ranging from 5 to 20 lycopene, were analyzed as blind duplicates. In addition to the commercial products, two positive controls and a negative control were included in the study. For the raw materials studied, the repeatability relative standard deviations (RSDr) ranged from 1.49 to 5.13 for total lycopene, and the reproducibility relative standard deviations (RSDR) ranged from 3.84 to 9.21 with HorRat values from 1.23 to 3.24. For finished products, the RSDr ranged from 1.31 to 4.62, RSDR from 4.28 to 10.5, and HorRat values from 0.79 to 2.07. Corresponding values for all-trans-lycopene were significantly higher. It is recommended that the method be considered for Official First Action for all-trans- and total lycopene in finished products and raw materials.
Detection of Staphylococcal Enterotoxin B in Milk and Milk Products Using Immunodiagnostic Lateral Flow Devices
Authors: Boyle Thomas , Njoroge Joyce M , Jones Robert L , Principato Maryann 
Published: February 2020

Abstract
Staphylococcal enterotoxin B (SEB) is an extracellular pyrotoxin produced by Staphylococcus aureus, a known etiologic agent of food poisoning in humans. Lateral flow immunochromatographic devices (LFDs) designed for the environmental detection of SEB were adapted for use in this study to detect SEB in milk containing 2 fat, chocolate-flavored milk, and milk-derived products such as yogurt, infant formula, and ice cream. The advantage of using LFDs in these particular food products was its ease and speed of use with no additional extraction methods needed. No false positives were observed with any of the products used in this study. Dilution of the samples overcame the Hook effect and permitted capillary flow into the membrane. Thus, semisolid products such as ice cream and some yogurts, and products containing thickeners needed to be diluted using a phosphate-buffered saline-based buffer, pH 7.2. SEB was easily detected at concentrations of 5 g/mL and 500 ng/mL when the LFDs were used. SEB was also reliably detected at concentrations below 5 and 0.25 ng/mL, which may induce serious disease.
Establishment and In-House Validation of Simplex and Duplex PCR Methods for Event-Specific Detection of Maize SYN-E3272-5 Using a New Reference Molecule
Authors: Shen Kailin , Li Xiang , Wang Shu , Pan Yingjie , Shi Zhiyi , Sun Yongning , Yang Litao 
Published: February 2020

Abstract
Despite rapid developments in the detection techniques for genetically modified organisms (GMOs), the event-specific PCR method with high specificity is still the most used technique. In this study, event-specific simplex and duplex qualitative and quantitative detection systems were developed targeting the 3 insertion site of GM maize SYN-E3272-5 (3272) construct. A reference molecule p3272 was constructed to act as positive control and as calibrator for quantitative analysis. The LOD for simplex and duplex qualitative PCR assays was 10 copies of p3272 control DNA. LOD and the LOQ for simplex and duplex quantitative PCR assays were 10 and 25 copies of p3272 DNA, respectively. Furthermore, four practical GM maize samples were quantified using the established simplex and duplex quantitative PCR systems by in-house validation. Results from five operators showed that the bias ranged from 3.44 to 17.24 in the simplex system and from 0.42 to 16.06 in the duplex system, respectively. These results demonstrated that the established event-specific simplex and duplex qualitative and quantitative PCR systems combined with the reference molecule p3272 are suitable for the detection of GM maize 3272 and its derived products.
Effect of Radiation Sterilization on Alprenolol in the Solid State Studied by High-Performance Thin-Layer Chromatography
Authors: Marciniec Barbara , Ogrodowczyk Magdalena , Kwiecien′ Anna 
Published: February 2020

Abstract
The possibility of radiation sterilization of alprenolol (AL) has been studied. Irradiation of AL in solid form with a 25 kGy beam of electrons caused only an insignificant change in color that became more intense with increasing irradiation dose. Moreover, with increasing dose a decrease in pH, the content of water, and the degree of crystallinity were observed. AL in solid form was radiated with a high-energy electron beam (9.96 MeV) at doses from 25400 kGy and analyzed by HPTLC using the mobile phase methanolammonia 25 (99 + 1, v/v). Densitometric analysis was carried out directly from chromatograms at 270 nm. The applied method was validated and characterized by good precision (RSD = 3.95); good accuracy (80 level 100.15, 100 level 99.99, and 120 level 104.44); and low LOD (LOD = 0.52 g/zone and LOQ = 1.55 g/zone). Chromatograms recorded for samples irradiated at the doses of 25 kGy were unchanged, but at higher doses (100400 kGy) additional peaks corresponding to the radiodegradation products appeared (Rf = 0.24 and Rf = 0.40). The decrease in the concentration of AL was proportional to the applied radiation dose, and for 400 kGy the concentration of AL was 90.23. The calculated radiolytic yield of the radiodegradation process was G(AL) = 7.12 107 mol/J.
Development and Validation of Spectrophotometric and High-Performance Column Liquid Chromatographic Methods for the Simultaneous Determination of Dienogest and Estradiol Valerate in Pharmaceutical Preparations
Authors: Çağlayan Mehmet Gökhan , Palabiyik Ismail Murat , Onur Feyyaz 
Published: February 2020

Abstract
Simultaneous determination of dienogest (DIE) and estradiol valerate (EST) in sugar-coated tablets was performed by using HPLC and spectrophotometry. In HPLC, the separation was achieved on an ACE C8 column using the mobile phase acetonitrileNH4NO3 (0.03 M, pH 5.4; 70 + 30, v/v) at a flow rate of 2 mL/min. The detection wavelength was 280 nm, and cyproterone acetate was selected as an internal standard. The linearity range was 3.045.0 g/mL for DIE and 18.0100.0 g/mL for EST. As spectrophotometric methods, two chemometric methods, principal component regression and partial least-squares, were developed. In the chemometric techniques, the concentration data matrix was prepared by using mixtures containing these drugs in methanolwater (3 + 1, v/v). The absorbance data matrix corresponding to the concentration data matrix in these methods was obtained by the measurement of absorbances in their zero-order spectra; then, the calibration was obtained by using the data matrix for the prediction of unknown concentrations of DIE and EST in their binary mixture. Working ranges were found as 2.024.0 g/mL for DIE and 20.0270.0 g/mL EST in the methods. These three developed methods were validated and successfully applied to a pharmaceutical preparation, a sugar-coated tablet, and the results were compared with each other.
Rapid HPLC Determination of Pioglitazone in Human Plasma by Protein Precipitation and Its Application to Pharmacokinetic Studies
Authors: Islambulchilar Ziba , Valizadeh Hadi , Zakeri-Milani Parvin 
Published: February 2020

Abstract
A simple and rapid HPLC method with UV detection was developed for the determination of pioglitazone in human plasma. The method was based on protein precipitation using perchloric acid on an ODS column. The mobile phase consisted of a mixture of phosphate buffer, methanol, acetonitrile, and 12 M perchloric acid (54 + 33 + 12 + 1, v/v/v/v). The UV detector was set at 269 nm. Under these conditions, the retention time of pioglitazone was 5.2 min. The standard curve was linear over the range of 502000 ng/mL pioglitazone in human plasma. The within-day and between-day precision studies showed high reproducibility, with CV less than 5. The LOQ was 44.2 ng/mL. The method has been applied to a bioequivalence study after administration of pioglitazone as 30 mg tablets to 12 healthy volunteers.
Development of a Size-Exclusion HPLC Method with Evaporative Light-Scattering Detection for the Quantitation of Polysorbate 80 in Houttuynia cordata Injection
Authors: Wu Yi , Li Xiao D , Lin Rui C , Jin Shao H 
Published: February 2020

Abstract
A rapid and accurate size-exclusion HPLC method for the quantitation of polysorbate 80 (PS80) in Houttuynia cordata injection, a Chinese traditional medicine, was developed and validated. The assay was conducted on an Agilent 1100 HPLC system with a TosoHaas TSKgel G2000 SWXL column (30 cm 7.8 mm, 5 m particle size) and an Alltech evaporative light-scattering detector (ELSD) 2000. The mobile phase was 20 mmoL/L ammonium acetateacetonitrile (90 + 10, v/v) delivered at a flow rate of 0.6 mL/min under isocratic conditions. The ELSD was operated in the impactor off mode, the drift tube temperature was set at 110C, and nitrogen flow was maintained at 2.3 L/min. The LOD was 0.25 mg/mL. Linearity was obtained between the log of concentration (C) and the log of peak area (Y) of PS80 in the range of 0.520 mg/mL according to the equation: Log Y = 1.4529 Log C 0.8232 (r2 = 0.9976). An RSD of 1.6 (n = 6) for the determination demonstrated the good precision of the optimized method. PS80 content in several commercial H. cordata injection products from different manufacturers was determined. The data for PS80 content is useful in evaluation of the safety of the products from different manufacturers.
Evaluation of DuPont Qualicon BAX System PCR Assay for Yeast and Mold
Authors: Wallace F Morgan , Burns Frank , Fleck Lois , Andaloro Bridget , Farnum Andrew , Tice George , Ruebl Joanne 
Published: February 2020

Abstract
Evaluations were conducted to test the performance of the BAX System PCR assay which was certified as Performance Tested MethodSM 010902 for screening yeast and mold in yogurt, corn starch, and milk-based powdered infant formula. Method comparison studies performed on samples with low-level inoculates showed that the BAX System demonstrates a sensitivity equivalent to the U.S. Food and Drug Administration's Bacteriological Analytical Manual culture method, but with a significantly shorter time to obtain results. Tests to evaluate inclusivity and exclusivity returned no false-negative and no false-positive results on a diverse panel of isolates, and tests for lot-to-lot variability and tablet stability demonstrated consistent performance. Ruggedness studies determined that none of the factors examined affected the performance of the assay.
Multiresidue Method for the Determination of Organophosphorus Pesticides in Cereal Matrixes
Authors: Mariani Maurizio Boccacci , D'aiuto Virginia , Giannetti Vanessa 
Published: February 2020

Abstract
Our research was focused on a preliminary comparison of three cleanup procedures for the determination of 26 organophosphorus (OP) pesticide residues in cereal matrixes. The aim of the study was to reduce the analytical problems associated with the presence of high-molecular-weight compounds in these matrixes in order to improve the efficiency of the chromatographic separation. The method was based on the extraction of OP pesticides from the samples with the use of petroleum ether, acetone, and dichloromethane, and on three different cleanup procedures, followed by GC identification. The first procedure was carried out with a multicartridge system; the second procedure consisted of a low-temperature lipid precipitation; for the third procedure, acid and neutral alumina were used for cleanup of the extract. The use of deactivated acidic alumina as the adsorbent medium and the use of n-hexanedichloromethaneethyl acetate (6 + 3 + 1, v/v/v) as the eluting system were preferred. After purification, the residue was injected into a gas chromatograph for separation followed by nitrogen-phosphorus detection; the identities of the OP pesticides in positive samples were confirmed by GC/MS. The proposed method could be extended to the determination of other OP pesticides in various food matrixes in routine analysis.
Simple and Rapid RP-HPLC Method for Simultaneous Determination of Acyclovir and Zidovudine in Human Plasma
Authors: Sharma Megha , Nautiyal Pragya , Jain Surendra , Jain Deepti 
Published: February 2020

Abstract
Combination therapy with acyclovir and zidovudine is used for the treatment of herpes-infected immunocompromised patients. In the view of the optimal drug concentrations (minimum effective concentrations) for viral suppression and avoidance of drug toxicity, monitoring of drug levels has been considered essential to determine drug concentrations in plasma after administration of a dose of acyclovir and zidovudine. A simple, precise, and rapid RP-HPLC method has been developed for this purpose. Chromatographic separation was performed using methanolwater (50 + 50, v/v), pH 2.5 adjusted with orthophosphoric acid, as an isocratic mobile phase at a flow rate of 0.8 mL/min with an Inertsil ODS (C18) column (5 µm particle size, 250 ⨯ 4.60 mm id). Detection was carried out using a UV photo diode array detector at 258 nm. The plasma samples were prepared by a protein precipitation method. The retention time for acyclovir and zidovudine was 3.5 ± 0.2 and 6.2 ± 0.3 min, respectively. The method was linear in the range of 2001800 and 4003600 ng/mL with LOQ of 200 ng (SD = ±1.4) and 400 ng (SD = ±0.9) for zidovudine and acyclovir, respectively, in plasma. The mean accuracy was 98.0 and 96.4, with average extraction recovery of 64.8 ± 2.1 and 77.5 ± 1.7 for lower nominal concentrations of acyclovir and zidovudine, respectively.
Single-Laboratory Validation of a Refined AOAC HPLC Method 2005.06 for Oysters, Cockles, and Clams in UK Shellfish
Authors: Turner Andrew D , Hatfield Robert G , Rapkova-Dhanji Monika , Norton Deirdre M , Algoet Myriam , Lees David N 
Published: February 2020

Abstract
In 2009, a refined HPLC method based on AOAC Official MethodSM 2005.06 was developed and validated for the determination of paralytic shellfish poisoning (PSP) in mussels. A single-laboratory validation study of this method was undertaken here for the analysis of PSP toxins in oysters, cockles, clams, and razor clams. The method was characterized for selectivity, sensitivity, linearity, precision, repeatability, recovery, ruggedness, and uncertainty of measurement. Validation data were utilized to determine method performance characteristics for non-mussel bivalves for all commercially available certified reference toxins, extending the method to dcNEO and dcGTX2,3, where available. A period of parallel testing of oysters, cockles, and clams enabled a comparison of sample toxicities obtained using mouse bioassay (MBA) and HPLC methodologies, although only a very low number of PSP-positive samples were obtained through the United Kingdom official control monitoring program. Results from the MBA and HPLC methods were well-correlated for PSP-negative samples, but the low number of naturally contaminated PSP-positive samples has prevented any comparative statistical assessment of method performance for non-mussels between the two official methods. However, some evidence for potentially significant differences in total saxitoxin equivalents obtained by the two methods in some species has highlighted the need for further comparative testing in non-mussel samples to be conducted prior to implementation of the HPLC method in routine official control monitoring programs.
Simultaneous Determination of Eight Synthetic Permitted and Five Commonly Encountered Nonpermitted Food Colors in Various Food Matrixes by High-Performance Liquid Chromatography
Authors: Dixit Sumita , Khanna Subhash K , Das Mukul 
Published: February 2020

Abstract
A simple and sensitive HPLC method has been developed for the simultaneous determination of eight permitted food colors and five commonly encountered nonpermitted colors in various food commodities, including sugar-, fat-, and starch-based food matrixes. The method uses a specific food category-based cleanup/treatment procedure before color extraction to avoid the interference of food matrixes, and to obtain the optimal color extraction. Analysis was performed on a reversed-phase C18 -Bondapak column with ammonium acetate and acetonitrile gradient elution as the mobile phase; a programmable max-specific visible detection was used to monitor colors to obtain the higher sensitivity and expanded scope needed for multicolor blends having diverse absorption maxima. All colors showed good linearity, with regression coefficients of 0.99740.9999. The LOD and LOQ values ranged from 0.01 to 0.12 mg/L, and from 0.04 to 0.83 mg/L or mg/kg, respectively. The intraday and interday precision tests produced good RSD values, and the recoveries from different food matrixes ranged from 82 to 104%. The method offers high sensitivity for analysis of a wide variety of food matrixes containing a broad scope of multicolor blends. Two nonpermitted colors, orange II and metanil yellow, were found. Also, a number of samples contained permitted colors at levels two-to seven-fold higher than those prescribed.
New Anion-Exchange Solid-Phase Extraction Support Used for Preconcentration and Determination of Lead in Water Samples by Flame Atomic Absorption Spectrometry
Authors: Panahi Homayon Ahmad , Feizbakhsh Ali Reza , Tafazoli Zahra , Moniri Elham , Nezhati Mahshid Nikpour , Moghaddam Hamid Hashemi , Kelahrodi Somayeh Rangbar 
Published: February 2020

Abstract
A new chelating resin was prepared by coupling Amberlite XAD-2 with Brilliant Green through an azo spacer. The resulting resin has been characterized by FTIR spectrometry, elemental analysis, and thermogravimetric analysis and studied for the preconcentration and determination of trace Pb(II) ions from solution samples. The anionic complex of Pb(II) and iodide was retained on the resin by the formation of an ion associate with Brilliant Green on Amberlite XAD-2 in weak acidic medium. The optimum pH value for sorption of the metal ion was 5.5. The sorption capacity of the functionalized resin is 53.8 mg/g. The chelating resin can be reused for 20 cycles of sorptiondesorption without any significant change in sorption capacity. A recovery of 103% was obtained for the metal ion with 0.1 M EDTA as the eluting agent. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The resin was subjected to evaluation through batch binding and column chromatography of Pb(II). The equilibrium adsorption data of Pb(II) on modified resin were analyzed by Langmuir, Freundlich, and Temkin models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined to be 0.192, 13.189, and 3.418 at pH 5.5 and 25C. The method was applied for lead ion determination in tap water samples.
Separation of Four Mixtures of Pesticides by Pressurized Planar Electrochromatography (PPEC)
Authors: Tuzimski Tomasz 
Published: February 2020

Abstract
Examples of separations of four mixtures of pesticides by pressurized planar electrochromatography (PPEC) under different operating conditions are presented. The samples were separated on a prewetted RP-18W chromatographic plate in a system with acetonitrilebuffer as the mobile phase. A potential of 2.3 kV was applied to a 10 cm long plate to create the electric field. Reproducible retention of pesticides was obtained during PPEC in the closed system when the sorbent layer of the plate was prewetted and equilibrated with the mobile phase. The reported separations of pesticides by PPEC are over 10 times faster than the corresponding separations by TLC.