scholarly journals Development and Validation of a New Method for Determination of Pb and Cr in Marine Organisms by Total Reflection X-Ray Fluorescence (TXRF) Spectroscopy

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Blanca G. Beltrán ◽  
Ibiza Martínez-Serrano ◽  
Victor Ramos-Sanchez ◽  
David Chávez-Flores ◽  
Myrna C. Nevárez-Rodríguez ◽  
...  
Keyword(s):  
Internal Standard ◽  
Chelonia Mydas ◽  
Sample Volume ◽  
Marine Organisms ◽  
Total Reflection ◽  
X Ray ◽  
Relative Standard ◽  
Sample Frequency ◽  
Development And Validation

Lead and chromium contamination represents one of the most serious problems in the aquatic environments. The aim of this work was to develop and validate an accurate, sensitivity, and rapid method for the simultaneous determination of Pb and Cr at trace levels in tissues and fat of marine organisms such as turtle (Chelonia mydas), shark (Rhizoprionodon terraenovae), and dolphin (Tursiops truncatus), utilizing the total reflection X-Ray fluorescence (TXRF) spectroscopy. Working solutions were prepared in 10 mL of a solution 0.005 mol·L−1 EDTA and 1 mol·L−1 HNO3. In order to correct possible instrument drifts, 20 μg·L−1 of gallium was used as internal standard (IS). The results showed that TXRF method was linear over the concentration ranges of 5.242–100 μg·L−1 for Pb and 2.363–100 μg·L−1 for Cr. Limits of detection (LOD) achieved were 1.573 and 0.709 μg·L−1 for Pb and Cr, respectively, while limits of quantification achieved were 5.242 μg·L−1 for Pb and 2.363 μg·L−1 for Cr. The validated method was accurate and precise enough for determination of these heavy metals in samples of marine organisms as indicated by acceptable values of recovery between 90–101%. In addition, a certified reference material (BCR-279, sea lettuce) and a Centrum tablet were satisfactory analyzed, and the T-test for comparison of means revealed that there were no significant differences at the 95% confidence level between the values obtained with the proposed TXRF method and the certificated values. The repeatability of the method, expressed as relative standard deviation (RSD), was 5.1% and 4%, for Pb and Cr, respectively. In addition, other features of the developed method were a low sample volume of 10 μL, and the sample frequency achieved was 20 h−1.

X-Ray Fluorescence Spectrometric Determination of Rare Earths in Plutonium

1968 ◽  
Vol 22 (5) ◽  
pp. 434-437 ◽  
Author(s):  
E. A. Hakkila ◽  
R. G. Hurley ◽  
G. R. Waterbury
Keyword(s):  
Rare Earths ◽  
Internal Standard ◽  
Internal Standard Method ◽  
X Rays ◽  
Measured Intensity ◽  
X Ray ◽  
Low Concentrations ◽  
Relative Standard ◽  
Intensity Ratios

Two methods were evaluated for determining rare earths in plutonium: (1) For the lighter rare earths ( Z≦66), or low concentrations of the heavier rare earths, an adjacent rare earth was added as a carrier and also as an internal standard, the rare earths were separated from plutonium by fluoride precipitation, and the measured intensity ratios for the sample and for solutions having known concentrations were compared. The Lβ1 x-rays were measured for the lighter rare earths and the Lα1 x rays for the remaining lanthanides. (2) For the heavier rare earths ( Z>66), the Lα1 x-ray intensities were measured from a nitric acid solution of the sample and compared to intensities obtained for solutions having known concentrations. The minimum concentrations that could be measured with a relative standard deviation no greater than 4% by the separation internal standard method varied from approximately 0.5% for lanthanum to 0.01% for lutetium. The direct measurement of x-ray intensity was much less sensitive. Applicability of the methods was shown by successful analyses of plutonium alloys containing dysprosium, thulium, or lutetium.

Development and Validation of an RP-HPLC Method for Determination of Atorvastatin and its Hydroxyl Metabolites in Human Plasma

2020 ◽  
Vol 16 (3) ◽  
pp. 238-245
Author(s):  
Dagmara Sowińska ◽  
Alicja Pogorzelska ◽  
Marlena Rakicka ◽  
Justyna Sznura ◽  
Justyna Janowska ◽  
...  
Keyword(s):  
Human Plasma ◽  
Internal Standard ◽  
Hplc Method ◽  
Active Metabolites ◽  
Peak Separation ◽  
Rp Hplc ◽  
Increased Risk ◽  
Relative Standard ◽  
Development And Validation

Background: Atorvastatin (AT) belongs to cholesterol-lowering agents, commonly used in patients with an increased risk of cardiovascular disease. The drug, as well as its hydroxyl metabolites, exhibit pharmacological activity, and their plasma levels may be helpful in the assessment of the therapeutic effectiveness. Objective: Development and validation of a fast and reproducible RP-HPLC method with UV detection for the simultaneous determination of atorvastatin and its active metabolites, para-hydroxy-atorvastatin (p-OH-AT) and ortho-hydroxy-atorvastatin (o-OH-AT) in human plasma. Methods: Optimal conditions of chromatographic separation of the analytes, as well as rosuvastatin, chosen as an internal standard, were studied. The absorbance of the compounds was measured at λ=248 nm. Validation of the method was performed. The usefulness of the method was confirmed for determination of the analytes in plasma of patients treated with the drug. Results: Total peak separation was achieved at LiChrospher 100 RP-18 column with a mobile phase composed of methanol and water (1:1,v:v) and a flow rate of 1.2 ml/min. The method was linear in the ranges of 0.025 - 1.0 μg/ml for AT, o-OH-AT and p-OH-AT. Intra- and inter-assay precision expressed as relative standard deviation was ≤13% for AT, ≤12% for p-OH-AT and ≤11% for o-OH-AT. Intraand inter-day accuracy of the method, expressed as a relative error, was ≤15%. Conclusion: The elaborated HPLC method is specific, repeatable, reproducible, adequately accurate and precise and fulfills the validation requirements for the bioanalytical method. The method was successfully applied for analysis of atorvastatin and its o-hydroxy metabolite in plasma of patients treated with the drug.

Development and Validation of a Quantitative NMR Method for the Determination of the Commercial Tablet Formulation of Sulfasalazine

2018 ◽  
Vol 15 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Feng Su ◽  
Zi-qing Sun ◽  
Xian-rui Liang
Keyword(s):  
Maleic Acid ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Tablet Formulation ◽  
Quantitative Nmr ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Development And Validation ◽  
Good Agreement

Introduction: Quantitative NMR spectroscopy (qNMR) is a rapid, simple and efficient method for the assay of sulfasalazine (SSZ) in commercial tablet formulation. Materials and Methods: The qNMR method was demonstrated using maleic acid as an internal standard and DMSO-d6 as a solvent. The characteristic signals of SSZ at δ 8.36 ppm and maleic acid at δ 6.28 ppm were quantified. The reliability of the quantification method had been implemented successfully in validated experiments including specificity and selectivity, linearity, recovery, precision concentration rang, limit of detection (LOD), limit of quantification (LOQ), stability and robustness. Conclusion: The method was found to be liner (R2 = 0.9991) from 8.62 to 20.14 mg/0.6 mL DMSO-d6 in the drug concentration range. The maximum relative standard deviation (RSD) of recovery and precision were tested to be 0.59% and 0.65%, respectively. The LOD and LOQ were determined to be 0.02, 0.07 mg/mL, respectively. The RSD of stability was 0.05%. The robustness was demonstrated by changing four different parameters with the maximum difference less than 0.9%. In addition, the result of qNMR showed in good agreement with the HPLC and UV methods. Based on the experiments, the developed method was successfully applied to the determination of SSZ in commercial tablet.

scholarly journals Development and validation of a GC–MS method for the simultaneous determination of acetochlor, fluorochloridone, and pendimethalin in a herbicide emulsifiable concentrate formulation

2020 ◽  
Vol 32 (4) ◽  
pp. 238-241 ◽  
Author(s):  
Dandan Wang ◽  
Shengde Wu
Keyword(s):  
Internal Standard ◽  
Ternary Mixtures ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Limit Of Quantification ◽  
Emulsifiable Concentrate ◽  
Relative Standard ◽  
Replicate Measurements ◽  
Development And Validation

This paper describes a rapid method to simultaneously determine acetochlor, fluorochloridone and pendimethalin present in a herbicide emulsifiable concentrate (EC) formulation using gas chromatography–mass spectrometry (GC–MS). Selected ion monitoring mode was performed to increase the sensitivity, with dibutyl phthalate as an internal standard. The method was validated with respect to linearity, accuracy, precision, and stability. Chromatographic separation was carried out on a TG-5 MS column (30 m × 0.25 mm × 0.25 μm) with helium as the carrier gas at a flow rate of 1.0 mL/min. Calibration curves were linear over 2.0–20.0 μg/mL for each analyte, and the limit of quantification was below 20 ng/mL. Good performance in terms of recovery ranging from 94.5% to 102.5% at 3 concentration levels proved excellent accuracy. The intra- and inter-day relative standard deviations for 6 replicate measurements were always less than 5%. The developed method is simple and efficient for the routine determination of the ternary mixtures in a compound herbicide EC formulation product.

Development and validation of a gas chromatography/mass spectrometry method for the determination of α- and ß-2, 7, 11-cembratriene-4, 6-diols in tobacco

2016 ◽  
Vol 13 (4) ◽  
pp. 341-347
Author(s):  
Wei Gao ◽  
Naiying Wu ◽  
Wenliang Sun
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Content Type ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Development And Validation

Purpose This paper aims to present a robust method for the determination of α- and ß-2, 7, 11-cembratriene-4, 6-diols (α, ß-CBT-diol) in tobacco samples which was developed and validated by using the self-made α, ß-CBT-diol with higher purity as the standard. Design/methodology/approach After the ultrasonic extraction and clean-up procedures, samples were analyzed by gas chromatography/mass spectrometry in selected ion monitoring mode and full scan mode at the same time. A 1-heptadecanol was used as an internal standard. The important parameters, such as extraction conditions and derivation conditions, were optimized. Findings Under the optimal conditions, good results in terms of linearity (R2 > 0.999) and recoveries (93.2-107 per cent) were achieved. The limits of detection were 0.120 and 0.180 μg/ml for α- and ß-CBT-diol, respectively. α, ß-CBT-diol level of analyzed tobacco was found in the range of 34.2-1.26 × 103 μg/g with relative standard deviations below 6 per cent. Originality/value Such a strategy opens a new door towards the development of a simple, robust and sensitive method for the determination of α, ß-CBT-diol in real samples.

scholarly journals Development and Validation of Novel HPLC Bioanalytical Analysis Method for Acalabrutinib: An Anticancer Drug in Human Plasma

2020 ◽  
Vol 32 (10) ◽  
pp. 2606-2610
Author(s):  
G. Atchutarama Krishna ◽  
P. Srinivasarao ◽  
T. Benarji Patrudu ◽  
R. Chidanandaswamy
Keyword(s):  
Human Plasma ◽  
Orthophosphoric Acid ◽  
Internal Standard ◽  
Hplc Method ◽  
Linear Calibration ◽  
Liquid Liquid Extraction ◽  
Ich Guidelines ◽  
Relative Standard ◽  
Development And Validation

The aim of the work is to develop and validate the bioanalytical RP-HPLC method for determination of acalabrutinib in plasma with nifedipine drug as internal standard. Liquid-liquid extraction with diethyl ether and methanol in the ratio of 50:50 (v/v) was used for the extraction of drugs from the biological matrix. The optimized chromatography conditions consist of methanol, acetonitrile and 0.1% orthophosphoric acid in the ratio of 45:35:20 (v/v) as a mobile phase with KNAUER Eurospher II C18 Column (250 × 4.6 mm, 5μ) as stationary phase. Isocratic elution with 0.9 mL flow separates acalabrutinib at 4.6 min and nifedipine at 6.8 min. The method was validated as per ICH guidelines and linear calibration curve was obtained for the peak area ratio of acalabrutinib and nifedipine compound across a range of 50-3000 ng/mL. Greater than 90% recoveries were obtained for acalabrutinib. The relative standard deviation (%RSD) was found to be < 5% for precision studies. Hence, the method was found to be suitable for the analysis of acalabrutinib in spiked human plasma and is used for the pharmacokinetic study

Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

2003 ◽  
Vol 107 ◽  
pp. 203-206 ◽  
Author(s):  
M. Bounakhla ◽  
A. Doukkali ◽  
K. Lalaoui ◽  
H. Aguenaou ◽  
N. Mokhtar ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Total Reflection ◽  
X Ray

Development and Validation of an LC-MS/MS Method for Simultaneous Determination of Canagliflozin and Metformin HCl in Rat Plasma and its Application

2020 ◽  
Vol 16 (6) ◽  
pp. 752-762
Author(s):  
Vivek Nalawade ◽  
Vaibhav A. Dixit ◽  
Amisha Vora ◽  
Himashu Zade
Keyword(s):  
Internal Standard ◽  
Rat Plasma ◽  
Precipitation Method ◽  
Herbal Extracts ◽  
One Step ◽  
Precision And Accuracy ◽  
Development And Validation ◽  
The Impact ◽  
Metformin Hcl

Background: Food and herbal extracts rich in Quercetin (QRT) are often self-medicated by diabetics and can potentially alter the pharmacokinetics (PK) of Metformin HCl (MET) and Canagliflozin (CNG) leading to food or herb-drug interactions and reduced therapeutic efficacy. However, the impact of these flavonoids on the pharmacokinetic behaviour of MET and CNG is mostly unknown. Methods: A simple one-step protein precipitation method was developed for the determination of MET and CNG from rat plasma. The mobile phase chosen was MeOH 65% and 35% water containing 0.1% formic acid at a flow rate of 1mL/min. Results: The retention time of MET, internal standard (Valsartan) and CNG was 1.83, 6.2 and 8.2 min, respectively. The method was found to be linear in the range of 200 - 8000 ng/mL for CNG and 100 = 4000 ng/ml for MET. Precision and accuracy of the method were below 20% at LLOQ and below 15% for LQC, MQC, and HQC. Conclusion: The method was successfully applied for the determination of PK of MET and CNG by using 100 μL of rat plasma. QRT co-administration affects the PK parameters of MET and CNG. This alteration in PK parameters might be of significant use for clinicians and patients.

ICH/FDA Guidelines-Compliant Validated Stability-Indicating HPLC-UV Method for the Determination of Axitinib in Bulk and Dosage Forms

2020 ◽  
Vol 16 (8) ◽  
pp. 1106-1112
Author(s):  
Ibrahim A. Darwish ◽  
Nasr Y. Khalil ◽  
Mohammad AlZeer
Keyword(s):  
High Performance ◽  
Kinase Inhibitor ◽  
Degradation Products ◽  
Internal Standard ◽  
Dosage Forms ◽  
Uv Detector ◽  
Stability Indicating ◽  
Therapeutic Benefits ◽  
Relative Standard

Background: Axitinib (AXT) is a member of the new generation of the kinase inhibitor indicated for the treatment of advanced renal cell carcinoma. Its therapeutic benefits depend on assuring the good-quality of its dosage forms in terms of content and stability of the pharmaceutically active ingredient. Objective: This study was devoted to the development of a simple, sensitive and accurate stabilityindicating high-performance liquid chromatographic method with ultraviolet detection (HPLC-UV) for the determination of AXT in its bulk and dosage forms. Methods: Waters HPLC system was used. The chromatographic separation of AXT, internal standard (olaparib), and degradation products were performed on the Nucleosil CN column (250 × 4.6 mm, 5 μm). The mobile phase consisted of water:acetonitrile:methanol (40:40:20, v/v/v) with a flow rate of 1 ml/min, and the UV detector was set at 225 nm. AXT was subjected to different accelerated stress conditions and the degradation products, when any, were completely resolved from the intact AXT. Results: The method was linear (r = 0.9998) in the concentration range of 5-50 μg/ml. The limits of detection and quantitation were 0.85 and 2.57 μg/ml, respectively. The accuracy of the method, measured as recovery, was in the range of 98.0-103.6% with relative standard deviations in the range of 0.06-3.43%. The results of stability testing revealed that AXT was mostly stable in neutral and oxidative conditions; however, it was unstable in alkaline and acidic conditions. The kinetics of degradation were studied, and the kinetic rate constants were determined. The proposed method was successfully applied for the determination of AXT in bulk drug and dosage forms. Conclusions: A stability-indicating HPLC-UV method was developed and validated for assessing AXT stability in its bulk and dosage forms. The method met the regulatory requirements of the International Conference on Harmonization (ICH) and the Food and Drug Administration (FDA). The results demonstrated that the method would have great value when applied in quality control and stability studies for AXT.

Bioanalytical Method Development and Validation for the Determination of Vasopressin Receptor Antagonist Conivaptan in Mouse Plasma at NanoLevel and its Pharmacokinetic Application

2019 ◽  
Vol 15 (5) ◽  
pp. 591-598 ◽  
Author(s):  
Haitham Alrabiah ◽  
Ahmed Bakheit ◽  
Sabray Attia ◽  
Gamal A.E. Mostafa
Keyword(s):  
Method Development ◽  
Internal Standard ◽  
Vasopressin Receptor ◽  
Mouse Plasma ◽  
Precipitation Procedure ◽  
Validation Parameters ◽  
The Us ◽  
Method Development And Validation ◽  
Development And Validation

Background: Conivaptan inhibits two of vasopressin receptor (vasopressin receptor V1a and V2). Conivaptan is used for the treatment of hyponatremia, and in some instances, for the treatment of the heart failure. Methods: The present study aimed to develop a simple, sensitive, and accurate HPLC with ultraviolet detection for the assay of conivaptan (CON) in mouse plasma using bisoprolol as internal standard (IS). A precipitation procedure was used to extract CON and the IS from the mouse plasma. CON was chromatographically separated using a C18 analytical column at 25°C. The separation was carried out using a mixture of phosphate buffer (50 mM): acetonitrile (60: 40, v/v, pH 4.5) with a flow rate of 1.0 mL/min and detection was performed at 240 nm. Results: The assay was validated according to the US Food and Drug (FDA) guidelines. The method demonstrated linearity over a concentration range of 150 - 2000 ng/mL (correlation coefficient: r 2 = 0.9985). The mean recovery of CON from the mouse plasma was 101.13%. All validation parameters for CON were within the acceptable range. Conclusion: The investigated method has been shown to be suitable for estimating the CON in plasma samples, and this method is sensitive and highly selective, allowing the estimation of its concentrations up to the nano-scale. The suggested method was successfully used in a pharmacokinetic study of CON in mouse plasma.

Sign in / Sign up

Export Citation Format

Share Document