scholarly journals Pharmacokinetics, Bioavailability and Tissue Distribution of Chitobiose and Chitotriose in Rats

2021 ◽  
Author(s):  
Mai Chen ◽  
Jiayang Jin ◽  
Xiaoguo Ji ◽  
Kunlin Chang ◽  
Juan Li ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Tissue Distribution ◽  
Relative Standard Deviation ◽  
Relative Error ◽  
Matrix Effects ◽  
Intragastric Administration ◽  
Rat Tissues ◽  
Limit Of Quantification ◽  
Rat Serum ◽  
Relative Standard

Abstract Chitooligosaccharides (COSs) have various physiological activities and broad application prospects; however, their pharmacokinetics and tissue distribution remain unclear. In this study, a sensitive and selective ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method for determining chitobiose (COS 2) and chitotriose (COS 3) in rat serum and tissues was developed. This method was successfully validated based on FDA guidelines in terms of selectivity, calibration curves (lower limit of quantification was 0.002 µg/mL for COS 2 and 0.02 µg/mL for COS 3), precision (intra-day relative standard deviation of 0.04–3.55% and inter-day relative standard deviation of 1.94–11.63%), accuracy (intra-day relative error of -1.81–11.06% and inter-day relative error of -9.41–8.63%), matrix effects, recovery (97.10–101.29%), stability, dilution integrity, and carry-over effects. Then, the method was successfully applied to the pharmacokinetics and tissue distribution study of COS 2 and COS 3 after intragastric and intravenous administration. After intragastric administration, COS 2 and COS 3 were rapidly absorbed, reached peak concentrations in the serum after approximately 0.45 h, and showed rapid elimination with clearances greater than 18.82 L/h/kg and half-lives lower than 6 h. The absolute oral bioavailability of COS 2 and COS 3 was 0.32–0.52%. COS 2 and COS 3 were widely distributed in Wistar rat tissues and could penetrated the blood-brain barrier without tissue accumulation.

General Alloy Analysis with a Gas Sheathed Tubular Electrode Arc

1971 ◽  
Vol 25 (1) ◽  
pp. 47-53 ◽  
Author(s):  
James H. Muntz
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Matrix Effects ◽  
Base Metals ◽  
Alloy Type ◽  
Relative Standard ◽  
Certified Value ◽  
Alloy Analysis ◽  
Tubular Electrode

The gas sheathed tubular electrode arc has been investigated and applied to general alloy analysis. One set of six solution standards containing 18 different elements was used. Matrix effects have been mostly controlled by using a 1 mg/ml sample or standard in a solution containing 6 mg/ml of sodium as the chloride. Fourteen different standard alloys (NBS and Alcoa) were tested, representing seven different base metals. The over-all accuracy was only about ±8% deviation from the certified value. This would permit identification of alloy type, but for greater accuracy standards more closely approximating the sample should be used. Precision for the technique is normally ±3%–4% relative standard deviation with photographic detection.

scholarly journals Voltammetric sensor based on the copper (II) amino acid complex for the determination of tryptophan enantiomers

2021 ◽  
Vol 25 (3) ◽  
pp. 193-204
Author(s):  
R. A. Zilberg ◽  
◽  
Yu. B. Teres ◽  
L. R. Zagitova ◽  
Yu. A. Yarkaeva ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Relative Error ◽  
Biological Fluids ◽  
Biologically Active ◽  
Voltammetric Sensor ◽  
Potential Sweep ◽  
Tryptophan Enantiomers ◽  
Relative Standard

A voltammetric sensor based on a composite of polyarylene phthalide and graphitized carbon black Carboblack C modified with chelate complexes of L-argenato-L-alaninate of copper (II) has been developed for the recognition and selective determination of tryptophan enantiomers. The conditions for modifying the sensor are optimized, the effective surface area (A = 4.38 ± 0.06 mm2) and the effective resistance (Ret = 1.29 ± 0.08 kΩ) are calculated. The optimal conditions for recording voltammograms of tryptophan enantiomers are selected: the range of operating potentials is 0.5-1.2 V, the potential sweep rate is 20 mV/s, the holding time of the electrode in the test solution is 5 s. The electrochemical and analytical characteristics of the sensor were studied when registering differential pulse voltammograms of tryptophan enantiomers. It is shown that the dependence of the analytical signal on the concentration is linear in the range from 1.25·10-6 to 1·10-3 M with detection limits of 0.90·10-6 M for L-Trp and 0.66·10-6 M for D-Trp. The developed sensor shows the greatest sensitivity to D-Trp. The sensor has been successfully tested to determine the content of L- and D-Trp in enantiomer solutions in the presence of excipients that are part of medicines and biologically active additives. The proposed sensor allows the determination of tryptophan enantiomers in human urine and blood plasma. To evaluate the analytical capabilities of the sensor, the "entered-found" method was used. When determining tryptophan enantiomers in model solutions, the relative standard deviation does not exceed 2.3 %, and the relative error is 1.7 %. When determining D- and L-Trp in biological fluids, the relative standard deviation ranges from 0.3-1.7 %, and the relative error ranges from 0.3-5.6 %. The research results show that there is no significant systematic error.

Voltammetric Determination of Metals in Copper Alloys at Trace and Ultratrace Concentrations

2003 ◽  
Vol 68 (8) ◽  
pp. 1437-1448 ◽  
Author(s):  
Clinio Locatelli ◽  
Giancarlo Torsi
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Relative Error ◽  
Analytical Procedure ◽  
Copper Alloys ◽  
Voltammetric Determination ◽  
Standard Reference Materials ◽  
Relative Standard ◽  
Precision And Accuracy

The present work describes the analytical procedures for the voltammetric determination of Cu, Pb, Cd, Zn, Fe, Mn, Co, Ni, Sn, Sb and Bi in copper alloys. The possibility of determining simultaneously metal concentrations in the case of interference of the voltammetric signals due to the peak overlapping is also highlighted and discussed. The analytical procedure was verified by the analysis of the standard reference materials: commercial bronze A NIST-SRM 1115, gunmetal BCS-CRM 207/2, high tensile brass BCS-CRM 390. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were in all cases lower than 6%. The limits of detection for each element were also reported.

Chromatographic Quantification of Ivermectin and Pranziquantel in the Tablets Using Stability Indicating RP-HPLC Method

2019 ◽  
Vol 25 (3) ◽  
pp. 254-261
Author(s):  
Naga Venkata Suresh Kumar Devaka ◽  
Vallabhaneni Madhusudhan Rao
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Hplc Method ◽  
Assay Method ◽  
Array Detector ◽  
Limit Of Quantification ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Relative Standard

Background: A new stability indicating RP-HPLC based assay method was developed to quantify ivermectin and praziquantel simultaneously and applied effectively to tablets. Methods: The simultaneous assay of ivermectin and praziquantel by RP-HPLC was done using an YMC C18 (250 mm × 4.6 mm, 5 µm) column with a mobile phase mixture of 0.1M disodium hydrogen phosphate (pH 4.5) and acetonitrile (55:45, v/v) using a isocratic flow rate of 1.0 ml/min and measured at 242 nm using photodiode array detector. All parameters were validated following the ICH guiding principles. The method was applied to quantify ivermectin and praziquantel simultaneously in tablets. Results: The retention values of ivermectin and praziquantel were 3.465 min and 4.468 min, respectively. The method’s linearity was found to be 1-3 µg/ml (ivermectin) and 25-75 µg/ml (praziquantel). The limit of detection was 0.010 µg/ml (ivermectin) and 0.046 µg/ml (praziquantel); limit of quantification was 0.033 µg/ml (ivermectin) and 0.155 µg/ml (praziquantel). The percent relative standard deviation of ivermectin and praziquantel was ˂1.0%. The percent assay was 99.51% and 99.20% for ivermectin and praziquantel, respectively. In tablets, the percent recovery of ivermectin and praziquantel was 99.60% and 99.38% with a percent relative standard deviation value of 0.353% and 0.106%, respectively. Stability indicating capability of the method was demonstrated through the stress degradation studies. Conclusion: The developed method was proved to be selective, precise and accurate for the quality control of ivermectin and praziquantel in tablets.

scholarly journals Development of an Analytical Method for Quantitation of Deoxynivalenol by UPLC–MS-MS: A Preliminary Assessment of Gestational and Lactational Transfer in Rats

2020 ◽  
Author(s):  
Melanie A Rehder Silinski ◽  
Jennifer A Gilliam ◽  
Reshan A Fernando ◽  
Veronica G Robinson ◽  
Dori Germolec ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Relative Error ◽  
Limit Of Detection ◽  
Food Sources ◽  
Trichothecene Mycotoxin ◽  
Preliminary Assessment ◽  
Mean Relative Error ◽  
Relative Standard ◽  
Lactational Transfer

Abstract Deoxynivalenol (DON) is the most widely distributed trichothecene mycotoxin in grain-based foods and animal feed. Exposure to DON is widespread as it has been detected in food sources from around the world. The objective of this work was to develop a method to quantitate DON in biological matrices and apply it in a preliminary assessment of gestational and lactational transfer of DON following exposure of pregnant rats. The method used protein precipitation followed by ultra-performance liquid chromatography–tandem mass spectrometry. The method was evaluated in male Sprague Dawley rat plasma over the concentration range ∼2–1,000 ng/mL. The method was linear (r ≥ 0.99), accurate (mean relative error ≤ ±4.9%) and precise (relative standard deviation ≤ 5.5%). The mean absolute recovery was 85.9%. The limit of detection was 0.35 ng/mL. The method was also evaluated in gestational day (GD) 18 Hsd:Sprague Dawley®SD® dam plasma and fetal homogenate (mean % relative error ≤ ±16.9; % relative standard deviation ≤ 9.5). Concentrations of DON in dam plasma stored at −80°C for at least 29 days and in fetal homogenate for at least 43 days were within 97.9 to 120% of Day 0 concentrations, demonstrating that DON is stable in these matrices. The method was used to quantitate DON in rat maternal plasma, amniotic fluid, GD 18 fetuses and postnatal day (PND) 4 pups following exposure of dams to 0 (control) and 1 mg/kg DON beginning on GD 6 and continuing through gestation and lactation for a preliminary assessment of maternal transfer. In animals exposed to 1 mg/kg/day, similar concentration of DON was found in GD 18 dam plasma and fetuses, demonstrating significant gestational transfer. The concentration of DON in PND 4 dam plasma was similar to that in GD 18 dam plasma. However, DON was not detected in PND 4 pup plasma above the limit of detection of the assay, demonstrating absence of transfer of DON to pups via lactation.

scholarly journals Spectrophotometic Determination of Caffeine and Vitamin B6 in Selected Beverages, Energy/Soft Drinks and Herbal Products

2021 ◽  
Vol 28 (1) ◽  
pp. 22-29
Author(s):  
A.L. Ogunneye ◽  
O.O. Banjoko ◽  
M.R. Gbadamosi ◽  
O.H. Falegbe ◽  
K.H. Moberuagba ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Vitamin B6 ◽  
Limit Of Detection ◽  
Soft Drinks ◽  
Sensitivity Limit ◽  
Limit Of Quantification ◽  
Herbal Products ◽  
Relative Standard

In this study, a simple, sensitive and reproducible spectrophotometric technique has been developed and validated for the determination of caffeine and vitamin B6 in beverages, energy/soft drinks and herbal products. The determination of caffeine and vitamin B6 in the respective samples were carried out at maximum (λmax) absorbance of 272 and 290 nm respectively. The method was validated in terms of linearity, sensitivity (limit of Detection (LOD) and limit of Quantification (LOQ), accuracy (% Recovery), precision (relative standard deviation). The method was linear from (4-20 µg/ml and 50 - 250 µg/ml with r 2 of 0.9991 and 0.9996 for vitamin B6 and caffeine respectively. The accuracy of the method ranged from 99.48 - 101.42% for caffeine and 99.94% - 102.35% for vitamin B6. The detection limit and quantification limit were 0.192 µg/ml and 0.640 µg/ml for vitamin B6 while 0.0155 µg/ml and 0.0518 µg/ml was obtained for caffeine. The method for the two analytes was found to be precise as the percentage relative standard deviation was below 5%. Therefore, the method proposed in this study is rapid, suitable and can be used as a quality control index for caffeine and vitamin B6 in beverages, energy/soft drinks and herbal products in industries. Keywords: Caffeine, Vitamin B6, Beverages, Energy/Soft drinks, Herbal products, Spectrophotometry

An Automated Procedure for the Determination of Ammonia in Tobacco

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
P.F. Collins ◽  
W.W. Lawrence ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Distillation Method ◽  
Relative Standard ◽  
Tobacco Sample ◽  
Automated Determination

AbstractA procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

How Certain Are the Reported Ionic Conductivities of Thiophosphate-Based Solid Electrolytes? an Interlaboratory Study

2020 ◽  
Author(s):  
Saneyuki Ohno ◽  
Tim Bernges ◽  
Johannes Buchheim ◽  
Marc Duchardt ◽  
Anna-Katharina Hatz ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ionic Conductivity ◽  
Relative Standard Deviation ◽  
Solid Electrolytes ◽  
Ionic Conductivities ◽  
Ionic Conductors ◽  
Energy Storage Devices ◽  
Activation Barriers ◽  
Storage Devices ◽  
Relative Standard

<p>Owing to highly conductive solid ionic conductors, all-solid-state batteries attract significant attention as promising next-generation energy storage devices. A lot of research is invested in the search and optimization of solid electrolytes with higher ionic conductivity. However, a systematic study of an <i>interlaboratory reproducibility</i> of measured ionic conductivities and activation energies is missing, making the comparison of absolute values in literature challenging. In this study, we perform an uncertainty evaluation via a Round Robin approach using different Li-argyrodites exhibiting orders of magnitude different ionic conductivities as reference materials. Identical samples are distributed to different research laboratories and the conductivities and activation barriers are measured by impedance spectroscopy. The results show large ranges of up to 4.5 mScm<sup>-1</sup> in the measured total ionic conductivity (1.3 – 5.8 mScm<sup>-1</sup> for the highest conducting sample, relative standard deviation 35 – 50% across all samples) and up to 128 meV for the activation barriers (198 – 326 meV, relative standard deviation 5 – 15%, across all samples), presenting the necessity of a more rigorous methodology including further collaborations within the community and multiplicate measurements.</p>

scholarly journals Indirect and Direct Determination of the Casein Content of Milk by Kjeldahl Nitrogen Analysis: Collaborative Study

1998 ◽  
Vol 81 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Raw Milk ◽  
Method Performance ◽  
Relative Standard ◽  
Milk Casein

Abstract The classic method for determination of milk casein is based on precipitation of casein at pH 4.6. Precipitated milk casein is removed by filtration and the nitrogen content of either the precipitate (direct casein method) or filtrate (noncasein nitrogen; NCN) is determined by Kjeldahl analysis. For the indirect casein method, milk total nitrogen (TN; Method 991.20) is also determined and casein is calculated as TN minus NCN. Ten laboratories tested 9 pairs of blind duplicate raw milk materials with a casein range of 2.42- 3.05℅ by both the direct and indirect casein methods. Statistical performance expressed in protein equivalents (nitrogen ⨯ 6.38) with invalid and outlier data removed was as follows: NCN method (wt%), mean = 0.762, sr = 0.010, SR = 0.016, repeatability relative standard deviation (RSDr) = 1.287℅, reproducibility relative standard deviation (RSDR) = 2.146%; indirect casein method (wt℅), mean = 2.585, repeatability = 0.015, reproducibility = 0.022, RSDr = 0.560℅, RSDR = 0.841; direct casein method (wt℅), mean = 2.575, sr = 0.015, sR = 0.025, RSDr = 0.597℅, RSDR = 0.988℅. Method performance was acceptable and comparable to similar Kjeldahl methods for determining nitrogen content of milk (Methods 991.20, 991.21,991.22, 991.23). The direct casein, indirect casein, and noncasein nitrogen methods have been adopted by AOAC INTERNATIONAL.

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