scholarly journals Repeatability and Reproducibility of Measures of Bovine Methane Emissions Recorded using a Laser Detector

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 606
Author(s):  
Giovanni Niero ◽  
Filippo Cendron ◽  
Mauro Penasa ◽  
Massimo De Marchi ◽  
Giulio Cozzi ◽  
...  
Keyword(s):  
Linear Equation ◽  
Repeated Measurements ◽  
Coefficient Of Determination ◽  
Meat Production ◽  
Potential Candidate ◽  
Ch4 Emissions ◽  
Aggregate Function ◽  
Equation Modelling ◽  
Relative Standard ◽  
Repeatability And Reproducibility

Methane (CH4) emissions represent a worldwide problem due to their direct involvement in atmospheric warming and climate change. Ruminants are among the major players in the global scenario of CH4 emissions, and CH4 emissions are a problem for feed efficiency since enteric CH4 is eructed to the detriment of milk and meat production. The collection of CH4 phenotypes at the population level is still hampered by costly and time-demanding techniques. In the present study, a laser methane detector was used to assess repeatability and reproducibility of CH4 phenotypes, including mean and aggregate of CH4 records, slope of the linear equation modelling the aggregate function, and mean and number of CH4 peak records. Five repeated measurements were performed in a commercial farm on three Simmental heifers, and the same protocol was repeated over a period of three days. Methane emission phenotypes expressed as parts per million per linear meter (ppm × m) were not normally distributed and, thus, they were log-transformed to reach normality. Repeatability and reproducibility were calculated as the relative standard deviation of five measurements within the same day and 15 measurements across three days, respectively. All phenotypes showed higher repeatability and reproducibility for log-transformed data compared with data expressed as ppm × m. The linear equation modelling the aggregate function highlighted a very high coefficient of determination (≥0.99), which suggests that daily CH4 emissions might be derived using this approach. The number of CH4 peaks resulted as particularly diverse across animals and therefore it is a potential candidate to discriminate between high and low emitting animals. Results of this study suggest that laser methane detector is a promising tool to measure bovine CH4 emissions in field conditions.

scholarly journals UHPLC-PDA Assay for Simultaneous Determination of Vitamin D3and Menaquinone-7 in Pharmaceutical Solid Dosage Formulation

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Jehangir ◽  
Mahmood Ahmed ◽  
Muhammad Imtiaz Shafiq ◽  
Abdul Samad ◽  
Iftikhar-ul-Haq
Keyword(s):  
Vitamin D ◽  
Simultaneous Determination ◽  
Hplc Method ◽  
Coefficient Of Determination ◽  
Solid Dosage ◽  
Mobile Phases ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Ultrahigh Performance Liquid Chromatography

A newly developed method based on ultrahigh performance liquid chromatography (UHPLC) was optimized for the simultaneous determination of vitamin D3and menaquinone-7 (MK-7) in tablet formulation in the present study. UHPLC separation of vitamin D3and MK-7 was performed with ACE Excel 2 C18-PFP column (2 μm, 2.1×100 mm) at 0.6 mL min−1flow rate, whereas the mobile phase consisted of methanol/water (19:1, v/v, phase A) and isopropyl alcohol (99.9%, phase B) containing 0.5% triethylamine. Isocratic separation of both the analytes was performed at 40°C by pumping the mobile phases A and B in the ratio of50:50(v/v, pH, 6.0). Both analytes were detected at a wavelength of 265 nm and the injection volume was 1.0 μL. The overall runtime per sample was 4.5 min with retention time of 1.26 and 3.64 min for vitamin D3and MK-7, respectively. The calibration curve was linear from 5.0 to 100 μg mL−1for vitamin D3and MK-7 with a coefficient of determination (R2)≥0.9981, while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.46 and 2.21%, respectively. The proposed HPLC method was demonstrated to be simple and rapid for the determination of vitamin D3and MK-7 in tablets.

scholarly journals METHOD VALIDATION OF RIFAMPICIN ANALYSIS IN HUMAN PLASMA AND ITS APPLICATION IN BIOEQUIVALENCE STUDY

2019 ◽  
pp. 296-303
Author(s):  
ENDANG LUKITANINGSIH ◽  
FATHUL JANNAH ◽  
RATNA BUDHI PEBRIANA ◽  
RATNA DEWI PUSPITA ◽  
TAUFIQUROHMAN . ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Bioequivalence Study ◽  
Hplc Method ◽  
Coefficient Of Determination ◽  
European Medicines Agency ◽  
Pharmacokinetic Profiles ◽  
Relative Standard ◽  
Precision And Accuracy ◽  
Bioequivalence Test

Objective: This research aims to validate the method for rifampicin analysis in plasma by using High-Performance Liquid Chromatography (HPLC) that can be used to study the bioequivalence of a generic tablet of rifampicin 450 mg “X” marketed in Indonesia. Methods: Bioequivalence test was analysed using HPLC equipped with UV-Vis detector at 377 nm. The mobile phase used was acetonitrile-phosphate buffer pH 6.8 (45:55) delivered at a flow rate of 1.5 ml/min. Bioequivalence test was conducted on a limited number of subjects (n=8). The subjects were divided into two groups randomly. The pharmacokinetic profiles of the test tablet and reference tablet were statistically calculated using SPSS program to see the test tablet and reference tablet were bioequivalence or not. Results: The developed HPLC method for rifampicin analysis in plasma was sufficiently valid based on the International Conference on Harmonization (ICH) and European Medicines Agency (EMA) guideline, with precision and accuracy values were % Relative Standard Deviation (% RSD = 1.40–13.04) and % Recovery (86.24–102.13), respectively. Meanwhile, the method was linear over studied concentration (0.05 to 10.26 µg/ml) with a coefficient of determination (R2) = 0.9984. The method also had good stability and sensitivity. The result of statistical calculation showed that the generic rifampicin tablet X was bioequivalence toward the reference tablet Rimactan 450 mg. Conclusion: The test rifampicin tablet that was, the generic tablet “X” was bioequivalence toward the reference rifampicin tablet “Rimactan”.

Residue Analysis of Organophosphorus and Organochlorine Pesticides in Fatty Matrices by Gas Chromatography Coupled with Electron-Capture Detection

2006 ◽  
Vol 61 (5-6) ◽  
pp. 341-346 ◽  
Author(s):  
Jae-Woo Park ◽  
A. M. Abd El-Aty ◽  
Myoung-Heon Lee ◽  
Sung-Ok Song ◽  
Jae-Han Shim
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Simple Procedure ◽  
Linear Regression Analysis ◽  
Residue Analysis ◽  
Electron Capture Detection ◽  
Relative Standard ◽  
Wide Range ◽  
Repeatability And Reproducibility

A multiresidue method for the simultaneous determination of 22 organochlorine (OCs) and organophosphorus (Ops) pesticides (including isomers and metabolites), representing a wide range of physicochemical properties, was developed in fatty matrices extracted from meat. Pesticides were extracted from samples with acetonitrile/n-hexane (v :v, 1:1). The analytical screening was performed by gas chromatography coupled with electron-capture detection (ECD). The identification of compounds was based on their retention time and on comparison of the primary and secondary ions. The optimized method was validated by determining accuracy (recovery percentages), precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) from analyses of samples fortified at 38 to 300 ng/g levels. Correlation coefficients for the 22 extracted pesticide standard curves (linear regression analysis, n = 3) ranged from 0.998 to 1.000. Recovery studies from 2 g samples fortified at 3 levels demonstrated that the GC-ECD method provides 64.4-96.0% recovery for all pesticides except 2,4′-DDE (44.6-50.4%), 4,4′-DDE (51.1-57.5%) and 2,4′-DDT (50.0-51.2%). Both repeatability and reproducibility relative standard deviation values were < 20% for all residues. Detection limits ranged from 0.31 to 1.27 ng/g and quantification limits were between 1.04 and 4.25 ng/g. The proposed analytical method may be used as a simple procedure in routine determinations of OCs and Ops in meat. It can also be applied to the determination of pesticide multi-residues in other animal products such as butter and milk.

scholarly journals Assessment of the Adequacy of Gauge Repeatability and Reproducibility Study Using a Monte Carlo Simulation

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Chunghun Ha ◽  
David S. Kim ◽  
SeJoon Park
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
System Analysis ◽  
Performance Metrics ◽  
Repeated Measurements ◽  
Percentage Error ◽  
Nested Design ◽  
Reproducibility Study ◽  
Measurement System Analysis ◽  
Repeatability And Reproducibility

ANOVA gauge repeatability and reproducibility study is the most popular tool for measurement system analysis. Two experimental designs can be applied depending on the durability of the objects. If repeated measurements are possible or sufficient homogeneous nonrepeatable samples are available, crossed design is appropriate; otherwise, nested design should be used. In this paper, we investigated the adequacy of ANOVA gauge repeatability and reproducibility study from the perspective of practitioners. We proposed a Monte Carlo simulation that is close to the realistic procedure to evaluate the adequacy of both structures. During the evaluation, we considered the average performance metrics, percentage of correct decision, histogram shape, and symmetric mean absolute percentage error for the four popular performance metrics, namely, % Study Variation, % Contribution, % Tolerance, and the number of distinct categories. The experimental results show that the nested design fails to judge the precision of the gauge while the crossed design succeeds.

scholarly journals HPLC-UV method for quantification of favipiravir in pharmaceutical formulations

2020 ◽  
Author(s):  
İbrahim Bulduk
Keyword(s):  
High Performance ◽  
Potassium Dihydrogen Phosphate ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Dihydrogen Phosphate ◽  
Potential Candidate ◽  
Column Temperature ◽  
Candidate Drug ◽  
System Suitability ◽  
Relative Standard

AbstractFavipiravir (FVP), a pyrazine analog, has shown antiviral activity against a wide variety of viruses. It is considered to be worth further investigation as a potential candidate drug for COVID-19. It is not officially available in any pharmacopoeia. A rapid, simple, precise, accurate, and isocratic high performance liquid chromatography (HPLC) method has been developed for routine quality control of favipiravir in pharmaceutical formulations. Separation was carried out by C18 column. The mobile phase was a mixture of 50 mM potassium dihydrogen phosphate (pH 2.3) and acetonitrile (90:10, v/v) at a flow rate of 1 mL min−1. The ultraviolet (UV) detection and column temperature were 323 nm, and 30 °C, respectively. The run time was 15 min under these chromatographic conditions. Excellent linear relationship between peak area and favipiravir concentration in the range of 10–100 μg mL−1 has been observed (r2, 0.9999). Developed method has been found to be sensitive (limits of detection and quantification were 1.20 μg mL−1 and 3.60 μg mL−1, respectively), precise (the interday and intraday relative standard deviation (RSD) values for peak area and retention time were less than 0.4 and 0.2%, respectively), accurate (recovery, 99.19–100.17%), specific and robust (% RSD were less than 1.00, for system suitability parameters). Proposed method has been successfully applied for quantification of favipiravir in pharmaceutical formulations.

scholarly journals Determination of Low-Level Agricultural Residues in Soft Drinks and Sports Drinks by Liquid Chromatography/Tandem Mass Spectrometry: Single-Laboratory Validation

2007 ◽  
Vol 90 (2) ◽  
pp. 521-533 ◽  
Author(s):  
Nathan Paske ◽  
Bryan Berry ◽  
John Schmitz ◽  
Darryl Sullivan
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Pesticide Residues ◽  
Agricultural Residues ◽  
Soft Drinks ◽  
Coefficient Of Determination ◽  
Tandem Mass ◽  
Sports Drinks ◽  
Relative Standard

Abstract In this study, sponsored by PepsiCo Inc., a method was validated for measurement of 11 pesticide residues in soft drinks and sports drinks. The pesticide residues determined in this validation were alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, paraoxon-methyl, phorate, phorate sulfone, phorate sulfoxide, and 2,4-dichlorophenoxyacetic acid (2,4-D) when spiked at 0.100 g/L (1.00 g/L for phorate). Samples were filtered (if particulate matter was present), degassed (if carbonated), and analyzed using liquid chromatography with tandem mass spectrometry. Quantitation was performed with matrix-matched external standard calibration solutions. The standard curve range for this assay was 0.0750 to 10.0 g/L. The calibration curves for all agricultural residues had coefficient of determination (r2) values greater than or equal to 0.9900 with the exception of 2 values that were 0.9285 and 0.8514. Fortification spikes at 0.100 g/L (1.00 g/L for phorate) over the course of 2 days (n = 8 each day) for 3 matrixes (7UP, Gatorade, and Diet Pepsi) yielded average percent recoveries (and percent relative standard deviations) as follows (n = 48): 94.4 (15.2) for alachlor, 98.2 (13.5) for atrazine, 83.1 (41.6) for butachlor, 89.6 (24.5) for isoproturon, 87.9 (24.4) for malaoxon, 96.1 (9.26) for monocrotophos, 101 (25.7) for paraoxon-methyl, 86.6 (20.4) for phorate, 101 (16.5) for phorate sulfone, 93.6 (25.5) for phorate sulfoxide, and 98.2 (6.02) for 2,4-D.

scholarly journals Development and Validation of a UHPLC-ESI-MS/MS Method for Quantification of Oleandrin and Other Cardiac Glycosides and Evaluation of Their Levels in Herbs and Spices from the Belgian Market

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 243 ◽  
Author(s):  
Svetlana V. Malysheva ◽  
Patrick P. J. Mulder ◽  
Julien Masquelier
Keyword(s):  
Cardiac Glycosides ◽  
Solid Phase ◽  
Plant Secondary Metabolites ◽  
Naturally Occurring ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass ◽  
Repeatability And Reproducibility ◽  
Culinary Herbs ◽  
The Mean ◽  
Development And Validation

Cardiac glycosides (CGs) are naturally occurring plant secondary metabolites that can be toxic to humans and animals. The aim of this work was to develop a targeted analytical method utilizing liquid chromatography—tandem mass spectrometry (LC-MS/MS) for quantification of these plant toxins in a herbal-based food and human urine. The method included oleandrin, digoxin, digitoxin, convallatoxin, and ouabain. Samples of culinary herbs were extracted with acetonitrile and cleaned using Oasis® MAX solid-phase extraction (SPE), while samples of urine were diluted with acidified water and purified on Oasis® HLB SPE cartridges. Limits of quantification were in the range of 1.5–15 ng/g for herbs and 0.025–1 ng/mL for urine. The mean recovery of the method complied with the acceptable range of 70–120% for most CGs, and relative standard deviations were at maximum 14% and 19% for repeatability and reproducibility, respectively. Method linearity was good with calculated R² values above 0.997. The expanded measurement uncertainty was estimated to be in the range of 7–37%. The LC-MS/MS method was used to examine 65 samples of culinary herbs and herb and spice mixtures collected in Belgium, from supermarkets and local stores. The samples were found to be free from the analyzed CGs.

Liquid Chromatographic Method for Determination of Iodine in Milk: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 711-719 ◽  
Author(s):  
David Sertl ◽  
William Malone ◽  
◽  
P Beljaars ◽  
C Blake ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Powdered Milk ◽  
Insoluble Material ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract Nine laboratories participated in an AOAC International/ International Dairy Federation collaborative study on a liquid chromatographic (LC) method for determination of iodine in milk. Liquid milk is passed through a 25 000 MW membrane filter to remove protein and insoluble material. Iodine (in the form of iodide) in the clear filtrate is separated by reversed-phase ion-pair LC and is detected electrochemically. Participants analyzed 2 commercial pasteurized whole milks and 5 nonfat dry milk powders in blind duplicate. Each sample was tested in duplicate on 2 days. Repeatability and reproducibility standard deviations (sr and SR, respectively) and repeatability and reproducibility relative standard deviations (RSDr and RSDR, respectively) for determinations of iodine in whole milk (mean recovery, 86.7%) were as follows: sr, 22 μg/L; SR, 22 μg/L; RSDr, 8.2%; and RSDR, 8.3%. For powdered milk (mean recovery, 91 %), the values were as follows: sr, 0.14 μg/g; SR, 0.22 μg/g; RSDr, 9.0%; and RSDR, 12.7%. The method was adopted first action by AOAC International.

scholarly journals Carbon and Tin-Based Polyacrylonitrile Hybrid Architecture Solid Phase Microextraction Fiber for the Detection and Quantification of Antibiotic Compounds in Aqueous Environmental Systems

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1670 ◽  
Author(s):  
Sandip Mondal ◽  
Jialing Jiang ◽  
Yin Li ◽  
Gangfeng Ouyang
Keyword(s):  
Solid Phase Microextraction ◽  
Tin Dioxide ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Tap Water ◽  
Coefficient Of Determination ◽  
Lower Amount ◽  
Custom Made ◽  
Relative Standard ◽  
Detection And Quantification

In this study, the detection and quantification of multiple classes of antibiotics in water matrices are proposed using a lab-made solid phase microextraction (SPME) fiber coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lab-made fiber was prepared using a graphene oxide (G), carbon nanotubes (C), and tin dioxide (T) composite, namely GCT, with polyacrylonitrile (PAN) as supporting material. The detected antibiotics were enrofloxacin, sulfathiazole, erythromycin, and trimethoprim. The custom-made fiber was found to be superior compared with a commercial C18 fiber. The excellent reproducibility and lower intra-fiber relative standard deviations (RSDs 1.8% to 6.8%) and inter-fiber RSDs (4.5% to 8.8%) made it an ideal candidate for the detection of traces of antibiotics in real environmental samples. The proposed validated method provides a satisfactory limit of detection and good linear ranges with higher (>0.99) coefficient of determination in the aqueous system. Application of the method was made in different real water systems such as river, pond and tap water using the standard spiking method. Excellent sensitivity, reproducibility, lower amount of sample detection and higher recovery was found in a real water sample. Therefore, the extraction method was successfully applied to the detection and quantification of multiple classes of antibiotics in different aqueous systems with satisfactory results.

Gas Chromatographic Determination of Nicotine in Environmental Tobacco Smoke: Collaborative Study

1989 ◽  
Vol 72 (6) ◽  
pp. 1002-1006
Author(s):  
Michael W Ogden
Keyword(s):  
Environmental Tobacco Smoke ◽  
Tobacco Smoke ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Selective Detection ◽  
Mainstream Smoke ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method for determination of vapor phase nicotine in environmental tobacco smoke (ETS) was collaboratively studied by 6 laboratories. Nicotine is desorbed from XAD-4 sample tubes with ethyl acetate containing triethylamine and determined by gas chromatography with nitrogen-selective detection. Each collaborator received blind duplicate samples at each of 6 nicotine concentrations. Three concentrations were generated by spiking XAD-4 tubes with known amounts of nicotine; the remaining 3 concentrations were ETS samples obtained in a carefully controlled environmental chamber containing sidestream and exhaled mainstream smoke from 1R4F Kentucky reference cigarettes. Repeatability and reproducibility relative standard deviations ranged from 4.4 to 11.1% and from 7.0 to 11.1%, respectively, for nicotine concentrations evaluated (up to 6 ng/cu m). The method has been adopted official first action.

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