bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Low-Level Acrylamide in Drinking Water by Liquid Chromatography/Tandem Mass Spectrometry
Authors: Lucentini Luca , Ferretti Emanuele , Veschetti Enrico , Achene Laura , Turrio-Baldassarri Luigi , Ottaviani Massimo , Bogialli Sara 
Published: February 2020

Abstract
A simple and sensitive liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method has been developed and validated to confirm and quantify acrylamide monomer (AA) in drinking water using [13C3] acrylamide as internal standard (IS). After a preconcentration by solid-phase extraction with spherical activated carbon, analytes were chromatographed on IonPac ICE-AS1 column (9 250 mm) under isocratic conditions using acetonitrilewater0.1 M formic acid (43 + 52 + 5, v/v/v) as the mobile phase. Analysis was achieved using a triple-quadrupole mass analyzer equipped with a turbo ion spray interface. For confirmation and quantification of the analytes, MS data acquisition was performed in the multireaction monitoring mode, selecting 2 precursor ion to product ion transitions for both AA and IS. The method was validated for linearity, sensitivity, accuracy, precision, extraction efficiency, and matrix effect. Linearity in tap water was observed over the concentration range 0.12.0 g/L. Limits of detection and quantification were 0.02 and 0.1 g/L, respectively. Interday and intraday assays were performed across 3 validation levels (0.1, 0.5, and 1.5 g/L). Accuracy (as mean recovery) ranged from 89.3 to 96.2 with relative standard deviation &lt;7.98. Performance characteristics of this LC/MS/MS method make it suitable for regulatory confirmatory analysis of AA in drinking water in compliance with European Union and U.S. Environmental Protection Agency standards.
Development of a Partial Least-Squares Calibration Model for Simultaneous Determination of Elements by Inductively Coupled Plasma-Atomic Emission Spectrometry
Authors: Chaloosi Marzieh , Asadollahi Seyed Azadeh , Khanchi Ali Reza , FirozZare Mahmoud , Mahani Mohamad Khayatzadeh 
Published: February 2020

Abstract
A partial least-squares (PLS) calibration model was developed for simultaneous multicomponent elemental analysis with inductively coupled plasma-atomic emission spectrometry (ICP-AES) in the presence of spectral interference. The best calibration model was obtained using a PLS2 algorithm. Validation was performed with an artificial test set. Multivariate calibration models were constructed using 2 series of synthetic mixtures (Zn, Cu, Fe, and U, V). Accuracy of the method was evaluated with unknown synthetic and real samples.
Conclusions on Measurement Uncertainty in Microbiology
Authors: Forster Lynne I 
Published: February 2020

Abstract
Since its first issue in 1999, testing laboratories wishing to comply with all the requirements of ISO/IEC 17025 have been collecting data for estimating uncertainty of measurement for quantitative determinations. In the microbiological field of testing, some debate has arisen as to whether uncertainty needs to be estimated for each method performed in the laboratory for each type of sample matrix tested. Queries also arise concerning the estimation of uncertainty when plate/membrane filter colony counts are below recommended method counting range limits. A selection of water samples (with low to high contamination) was tested in replicate with the associated uncertainty of measurement being estimated from the analytical results obtained. The analyses performed on the water samples included total coliforms, fecal coliforms, fecal streptococci by membrane filtration, and heterotrophic plate counts by the pour plate technique. For those samples where plate/membrane filter colony counts were 20, uncertainty estimates at a 95 confidence level were very similar for the methods, being estimated as 0.13, 0.14, 0.14, and 0.12, respectively. For those samples where plate/membrane filter colony counts were &lt;20, estimated uncertainty values for each sample showed close agreement with published confidence limits established using a Poisson distribution approach.
On Using a Normal Approximation for the Noncentral t-Distribution in Determining Upper Limits for Future Sample Relative Repeatability and Reproducibility Standard Deviations
Authors: McClure Foster D , Lee Jung K 
Published: February 2020

Abstract
Formulas, based on a normal approximation for the noncentral t-distribution, were developed to compute 100p one-tailed upper limits for future sample relative repeatability and relative reproducibility standard deviations (RSDr, and RSDR,) collaboratively obtained under a completely randomized model. The accuracy of the formulas for obtaining a one-tailed upper limit for the future sample RSDr, was assessed by comparing the computed noncentral t-distribution-based upper limits with the one-tailed upper limits based on a normal approximation for the noncentral t-distribution. The accuracy of the normal approximation formula for obtaining a one-tailed upper limit for a future sample RSDR, was assessed by comparing the formula-based one-tailed upper limits with those obtained in a Monte Carlo simulation study.
Determination of Macrocyclic Lactone Drug Residues in Animal Muscle by Liquid Chromatography/Tandem Mass Spectrometry
Authors: He Limin , Zhao Donghao , Su Yijuan , Liu Yahong , Nie Jianrong , Lian Jin 
Published: February 2020

Abstract
A robust, credible, and practical multiresidue method based on liquid chromatography/tandem/mass spectrometry (LC/MS/MS) was developed for the simultaneous determination of 9 macrocyclic lactone drugs (abamectin B1a, doramectin, erythromycin, ivermectin B1a, josamycin, kitasamycin, roxithromycin, tilmicosin, and tylosin A) in bovine, porcine, chicken, and sheep muscles. The drugs were extracted with acetonitrile, and the extracts were defatted with n-hexane and further cleaned up on a C18 solid-phase extraction cartridge. LC/MS/MS data acquisition was achieved by using the multiple-reaction monitoring (MRM) mode, i.e., 2 transitions, to provide a high degree of sensitivity and repeatability. Matrix-matched standard calibration curves were used to achieve the best accuracy of the method by compensating for the matrix effect. The calibration graphs were linear (r &gt;0.998) from 10 to 1000 ng/mL for erythromycin, josamycin, kitasamycin, roxithromycin, tilmicosin, and tylosin, and from 5 to 250 ng/mL for abamectin, doramectin, and ivermectin. The average recoveries of the 9 drugs were between 64.5 and 105, calculated by using matrix-matched calibration, with relative standard deviation values ranging from 1.6 to 14. The limits of detection were 0.1 g/kg for erythromycin, josamycin, roxithromycin, and tylosin; 0.2 g/kg for tilmicosin and kitasamycin; and 0.5 g/kg for abamectin, doramectin, and ivermectin. For confirmation, the MRM ratios for the 9 drug residues in the samples and the solvent were evaluated and found to be within the ratio criteria set by the guidelines of the European Union.
Gravimetric Determination of Acid Detergent Fiber and Lignin in Feed: Interlaboratory Study
Authors: Möller Jürgen ,   Collaborators:, Arananant J , Boonnayanont K , Danier J , Egert M , Fütö K , Horst H , Hüther L , Janjira; S , Kongchuensin R , Korol W , Kühl J , Losittisak P , Marth-Schill J , Moreira O , Petrova J , Plos S , Prinze; K , Rungrojpanich V , Schönherr J , Siourai R , Skomial J , Titya S 
Published: February 2020

Abstract
On the basis of AOAC Official Method 973.18, a collaborative study was performed to determine fractions of acid detergent fiber (ADF) and lignin (ADL) in animal feed. The study used 6 animal feed and forage samples as blind duplicates and involved 22 participants from 7 countries. The samples analyzed covered a range from 3.5 to 70 ADF and from &lt;1 to 20 ADL. Repeatability standard deviations ranged from 0.27 to 0.95 for ADF and from 0.08 to 0.59 for ADL. The reproducibility standard deviations ranged from 0.56 to 2.44 for ADF and from 0.52 to 2.09 for ADL. Analyzed samples comprised clover and grass silages, soy meal, cattle feed, wheat, and sawdust. The studied method has been published as the EN ISO 13906:2008 standard.
Application of a Stability-Indicating Thin-Layer Chromatographic Method to the Determination of Tenatoprazole in Pharmaceutical Dosage Forms
Authors: Dhaneshwar Sunil R , Bhusari Vidhya K , Mahadik Mahadeo V , Santakumari B 
Published: February 2020

Abstract
A sensitive, selective, precise, and stability-indicating thin-layer chromatographic (TLC) method was developed and validated for the determination of tenatoprazole both as a bulk drug and in formulation. The method uses TLC aluminum plates precoated with Silica Gel 60F-254 as the stationary phase and the solvent system tolueneethyl acetatemethanol (6 4 1, v/v/v). This system gave compact spots for tenatoprazole (Rf value of 0.34 0.02). Tenatoprazole was subjected to acid and alkali hydrolysis, oxidation, and photodegradation. The peaks of the degradation products were well-resolved from that of the pure drug and had significantly different Rf values. Densitometric analysis of tenatoprazole was performed in the absorbance mode at 306 nm. The linear regression analysis data for the calibration plots showed a good linear relationship over the concentration range of 1001500 ng/spot. The mean values of the correlation coefficient, slope, and intercept were 0.9989 1.42, 10.27 0.965, and 4894.2 1.24, respectively. The method was validated for precision, robustness, and recovery. The limit of detection and limit of quantitation were 50 and 100 ng/spot, respectively. Statistical analysis showed that the method is repeatable and selective for estimation of tenatoprazole. Because the method can separate the drug from its degradation products, it can be used to monitor stability.
Synthesis and Characterization of Mercapturic Acid (N-acetyl-L-cysteine)-Aflatoxin B1 Adduct and Its Quantitation in Rat Urine by an Enzyme Immunoassay
Authors: Nayak Sujatha , Tanuja Penmatsa , Sashidhar Rao Beedu 
Published: February 2020

Abstract
A simple and sensitive indirect noncompetitive enzyme immunoassay to quantitate mercapturic acid-aflatoxin B1 (AFB1) adduct in rat urine is reported. A novel procedure was developed for in vitro synthesis of an immunogen, bovine serum albumen-glutathione-aflatoxin B1 (BSA-GSH-AFB1) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride. Sulphydryl group's analysis confirmed the conjugation of SH groups to AFB1. Thin-layer chromatography and spectral analysis (absorption, fluorescence, and Fourier transform infrared) of the conjugates further confirmed the formation of the adducts. Polyclonal antibodies specific to mercapturic acid-AFB1 adduct were produced against BSA-GSH-AFB1. The assay was found to be linear in the range of 100 pg100 ng of the analyte (y ab x). A 50 displacement of BSA-GSH-AFB1 antibodies was achieved at an inhibitory concentration (IC50)of 11.9 ng GSH-AFB1 (r2 0.98) and 1.22 ng N-acetyl-L-cysteine (NAC)-AFB1 (r2 0.98). Spiking 5 g/mL of reference standard to the control rat urine showed a recovery of 98 2. The immunoassay was validated in a rodent model exposed to a single oral dose of 1 mg/kg body mass of pure AFB1. The excretion of NAC-AFB1 adduct was quantitated at the end of 24 h. The concentration of the NAC-AFB1 adduct excreted in urine as determined by the immunoassay was found to be in the range of 3.225.97 g/mg creatinine. The present method may find wide application as a biochemical tool in molecular epidemiological and intervention studies with respect to human exposure to dietary aflatoxins.
Validation of an Alternative Method for Counting Enterobacteriaceae in Foods Based on Accuracy Profile
Authors: Feinberg Max , Sohier Daniele , David Jean-Francois 
Published: February 2020

Abstract
Several years ago, microbiologists developed a harmonized standard for the validation of alternative methods against the reference method, namely International Organization for Standardization (ISO) 16140:2003. Since then a new and better statistical approach known as the accuracy profile concept has been proposed for interpretation of data collected during a validation study. This approach defines acceptability limits that are used to verify that an alternative analytical method can produce results acceptable for a defined analytical objective. This paper demonstrates how the accuracy profile approach can be efficiently applied to any data set collected according to ISO guidelines and how to interpret the final calculations to decide if a method is valid or not. The procedure was applied to data obtained in the validation of a commercial kit for the enumeration of Enterobacteriaceae in foods. A comparison of several statistical outputs derived from application of the accuracy profile demonstrated that this simple numerical method can be applied despite the non-normal distribution of bacterial colony counts.
Chromatographic Fingerprint Analysis of Pycnogenol® Dietary Supplements
Authors: Chen Pei , Song Fenhong , Lin Long-Ze 
Published: February 2020

Abstract
The bark of maritime pine (Pinus pinaster Aiton) has been widely used as a remedy for various degenerative diseases. A standard high-performance liquid chromatographic (HPLC) procedure for Pycnogenol® analysis is a method specified in the United States Pharmacopeia (USP) monograph, which requires measurement of peak areas and identification of four components of the extract: caffeic acid, catechin, ferulic acid, and taxifolin. In this study, a fingerprint analysis using an HPLC method based on the USP monograph has been developed to provide additional qualitative information for the analysis of Pycnogenol-containing dietary supplements (PDS). Twelve commercially available PDS samples were purchased and analyzed along with a standard Pycnogenol extract. Their chromatographic fingerprints were analyzed using principal component analysis. The results showed that two of the samples were not consistent with the standard reference Pycnogenol extract. One contained other active ingredients in addition to Pycnogenol, and the other may have resulted from a quality control issue in manufacturing.
A Rapid Resolution Liquid Chromatographic Method for Fingerprint Analysis of Raw and Processed Caowu (Aconitum kusnezoffii)
Authors: Qiao Yan-Ling , Zhang Ying-Hao , Zhang Wei , Zhang Jin-Lan 
Published: February 2020

Abstract
A sensitive and reliable rapid resolution liquid chromatographic (RRLC) method coupled with diode array detection has been developed for the fingerprint analysis of raw and processed caowu (Aconitum kusnezoffii). The RRLC fingerprints were established with a Zorbax Extend C18 analytical column (4.6 50 mm, 1.8 m) and gradient elution. Analysis run time was &lt;10 min. The method displayed good precision, stability, and repeatability in fingerprint analysis. Characteristic RRLC fingerprints of caowu were generated and used to assess the consistency and differences in the products. Raw and processed caowu from different sources were analyzed under the developed RRLC conditions, yielding contrasting RRLC fingerprints. Comparison of the RRLC fingerprints of processed and raw caowu indicated that the major constituents changed during processing. Meanwhile, a peak area ratio analysis method was applied to assess their chromatographic fingerprints. In characterizing the constituents of caowu, 11 major chromatographic peaks were identified by mass spectrometry and compared with reference standards and reference data. In summary, RRLC fingerprinting is a rapid and useful way to evaluate the quality of raw and processed caowu.
Determination of Dialkyl Phosphates as Breakdown Products of Organophosphorus Insecticides in Fruit Juices by HPTLC with Fluorescence Detection
Authors: Schwack Wolfgang , Zeisler Tatjana , Stiefel Constanze 
Published: February 2020

Abstract
Dialkyl phosphates (DAP) are common degradation products of organophosphorus pesticides that are used as urinary biomarkers for human exposure. An HPTLC method was developed for the quantitative determination of DAP in fruit juices, i.e., dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP), diethyl phosphate (DEP), and diethyl thiophosphate (DETP). Dibutyl phosphate (DBP) was used as an internal standard. The method was based on precipitation of fruit acids in the presence of barium chloride and acetonitrile and liquidliquid extraction with acetonitrilediethyl ether. Extracted DAP were derivatized with 1-(bromoacetyl)pyrene (BAP), and the BAP derivatives separated on HPTLC amino plates with dichloromethane as the mobile phase. Densitometry was performed by measurement of fluorescence at 366/&gt;400 nm. The limit of quantification (LOQ) values were between 0.8 and 1.4 ng/zone. Fluorescence enhancement was achieved by dipping the plate into a paraffin oil solution, increasing the sensitivity and resulting in an LOQ of 0.50.6 ng/zone. Repeatabilities with relative standard deviations of 3.5 (n = 5, at 1520 ng/zone) and coefficients of correlation of 0.9999 were highly satisfactory for rapid trace analysis of DAP in the fruit juices by HPTLC. The mean recoveries from apple juice spiked at 0.5 mg/L were 74, 83, 70, and 57 for DMP, DEP, DMTP, and DETP, respectively. If an application volume of 5 L of apple juice extract was applied, the LOQ in apple juice was 300 g/L. However, this can be lowered by application of higher volumes (up to 50 L) or a more concentrated derivatization batch.
Determination of Available Lysine by Planar Chromatography: A Useful Tool for Protein Quality Evaluation in Fish Feed
Authors: Vega Mario , Aranda Mario 
Published: February 2020

Abstract
Due to the essentiality of lysine for fish, its availability is commonly used as a predictor of the protein nutritional quality of fish feed. The objective of this work was to establish a high-throughput analytical method for protein quality control in fish feed through the measurement of available lysine by planar chromatography. Sample was first incubated with 1-fluoro-2,4-dinitrobenzene to obtain the dinitrophenyl-lysine derivative and then hydrolyzed with hydrochloric acid in order to release the derivative from proteins. Chromatography was performed on silica gel 60 F254 HPTLC plates using n-propanol25 ammonia (7 + 3, v/v) as mobile phase. Quantitative analysis was performed by densitometry in the absorbance mode at 360 nm. Calibration showed a polynomial relationship with an R2 of 0.9991 in the range of 25 to 125.0 ng/band. Repeatability relative standard deviation (RSD) and intermediate precision (RSD) in matrix were 0.8 and 3.6, respectively. Recoveries of spiked samples at two levels ranged from 72 to 85 with RSD from 3 to 8. This method provides the salmon feed industry with a reliable, high-throughput, and low-cost means for routine quality control of available lysine.
Improvement in Botanical Standardization of Commercial Freeze-Dried Herbal Extracts by Using the Combination of Antioxidant Capacity and Constituent Marker Concentrations
Authors: Ninfali Paolino , Gennari Lorenzo , Biagiotti Enrica , Cangi Francesca , Mattoli Luisa , Maidecchi Anna 
Published: February 2020

Abstract
Botanical extracts are standardized to 1 marker compounds (MCs). This standardization provides a certain level of quality control, but not complete quality assurance. Thus, industries are looking for other satisfactory systems to improve standardization. This study focuses on the standardization of herbal medicines by combining 2 parameters: the concentration of the MC and antioxidant capacity. Antioxidant capacity was determined with the oxygen radical absorbance capacity (ORAC) method and the concentrations of the MCs, by high-performance liquid chromatography. Total phenols were also determined by the Folin-Ciocolteau method. The ORAC values, expressed as mol Trolox equivalents/100 g (ORAC ), of 12 commercial herbal extracts were related to the ORAC values of the respective pure MCs at the concentrations at which the MCs occur in products (ORAC-MC ). The ORAC values of 11 extracts were higher than those of the respective MCs and the ratios ORAC-MC /ORAC ranged from 0.007 to 0.7, whereas in the case of Olea europaea leaves, the same ratio was 1.36. The ORAC parameters and their ratios, as well as the linear relationship between ORAC-MC and ORAC , are described and discussed as tools for improving the standardization of herbal products and detecting modifications due to herb processing and storage.
Rapid and Selective UV Spectrophotometric Method for the Analysis of Ceftazidime
Authors: de Haro Moreno Andréia , Salgado Hérida Regina Nunes 
Published: February 2020

Abstract
A new UV spectrophotometric method was developed for quantitative evaluation of ceftazidime preparations. The UV detector was set at 255 nm. Beer's law is obeyed in the concentration range of 7.014.0 g/mL. The method was found to be selective, linear, accurate, and precise in the specified ranges. Intra- and interday variability for the method were &lt;2 relative standard deviation. Common excipients used as additives in pharmaceutical preparations do not interfere with the proposed method. This method was successfully used for quantification of ceftazidime in pure form and in pharmaceutical preparations.
Validation of an HPLC Method for Determination of Pentoxifylline in Human Plasma and Its Application to Pharmacokinetic Study
Authors: Sripalakit Pattana , Saraphanchotiwitthaya Aurasorn 
Published: February 2020

Abstract
An HPLC method suitable for routine determination of pentoxifylline in human plasma has been adapted and validated. Sample preparation was done by solid-phase extraction. Chloramphenicol was used as the internal standard. The linear range was from 15400 ng/mL (r2 = 0.9994), with a limit of quantitation of 15 ng/mL. The limit of detection was found to be 5 ng/mL. The intra- and interday accuracy ranged from 98.0 to 110.2 and the coefficient of variation was not more than 8.8 for both intra- and interday precision. The absolute recoveries of pentoxifylline and chloramphenicol from human plasma were &gt;97. The method was validated with excellent specificity, accuracy, precision, recovery, and stability. The pharmacokinetic study of a generic pentoxifylline 400 mg tablet in healthy Thai male volunteers after a single dose administration was determined by this developed assay.
Development and Validation of a Liquid Chromatographic Method for the Simultaneous Determination of Estradiol, Estriol, Estrone, and Progesterone in Pharmaceutical Preparations
Authors: Wilson Phyllis 
Published: February 2020

Abstract
Progesterone and estrogens are hormones produced in the human body that are essential for regulating many vital functions. The three major estrogens produced by women are estriol, estradiol, and estrone. Progesterone is a naturally occurring hormone in both men and women. Pharmaceuticals containing estrogens alone or estrogens in combination with progesterone are commonly used in therapy. Patients requiring unique combinations of the drugs rely on pharmacies to compound the ingredients. In order to assess the potency of drugs containing combinations of estrogens and progesterone, a method was developed to determine all four ingredients simultaneously. The liquid chromatographic method utilized a Bondapak C18 column with an isocratic mobile phase of acetonitrilewater (50 + 50, v/v) at a flow rate of 1.0 mL/min and temperature of 30C. Under these conditions, the order of elution was estriol, estradiol, and estrone, followed by progesterone. UV detection was at 205 nm to monitor elution of the estrogens, then switched to 270 nm to monitor progesterone. The method was applied to the analysis of pharmacy-compounded drugs containing combinations of the hormones. Validation studies demonstrated that the method is accurate and precise.