DEVELOPMENT AND VALIDATION OF A FAST AND SIMPLE HPLC-UV METHOD TO DETERMINE CAFFEINE IN GUARANA (Paullinia cupana) FOOD SUPPLEMENTS

Caffeine and guarana are safe foods according to the American (FDA) and Brazilian (ANVISA) health agencies. However, data regarding the composition, quality, and safety of guarana-based food supplements sold in Brazil are limited. Most of the methods used for quantification of caffeine and other guarana chemical markers are based on complex extraction techniques as well as on gradient elution and do not evaluate the matrix effect nor the uncertainty estimation measurement. A simple and selective method for caffeine detection has been developed and validated using HPLC-UV. It shows linearity between 1 and 10 µg mL-1, has a significant matrix effect (p < 0.05) and its expanded uncertainty varies from 6.9 to 16.7%. Other parameters (selectivity, recovery, precision, robustness, limits of detection, and quantification) were satisfactory. The present study has analyzed 30 commercial samples of guarana-based food supplements (powders and capsules). Powder samples have shown an average caffeine level of 25.27 ± 5.20 mg g-1 while capsules 28.53 ± 13.81 mg g-1. No significant difference between the two types of samples has been observed (p > 0.005).

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Development and Validation of HPLC/UV-Spectrophotometric Procedures for Metronidazole Quantitative Determination

International Journal of Pharmaceutical Quality Assurance ◽

10.25258/ijpqa.v9i3.13663 ◽

2018 ◽

Vol 9 (3) ◽

Author(s):

Klimenko Lina Yu ◽

Shkarlat Galyna L ◽

Shovkova Zoia V ◽

Yaremenko Vitaliy D ◽

Shpychak Oleg S

Keyword(s):

Quantitative Determination ◽

Sodium Hydroxide Solution ◽

Gradient Elution ◽

Calibration Model ◽

Column Temperature ◽

Medical Laboratories ◽

Accuracy And Precision ◽

Development And Validation ◽

Gradient Elution Mode ◽

Potential Object

Metronidazole is the most popular representative of antiprotozoal medicines from the group of 5-nitroimidazoles. Metronidazole blocks the enzymes of alcohol dehydrogenase and acetaldehyde dehydrogenase, therefore when its joint taking with alcohol it is observed the strong intoxication syndrome and fatal poisonings too. Therefore metronidazole can be a potential object of chemical toxicological investigations. The purpose of our paper is to develop HPLC/UV-procedure of metronidazole quantification with application of the system of HPLC-analyzer MiLiChrome® A-0230 implemented in practice of forensic medical laboratories in Russia and Ukraine and carry out step-by-step validation of the developed procedure. Chromatographic conditions: Eluent A (0.2 M LiClO4 – 0.005 M HClO4) and Eluent B (acetonitrile) wereused as the mobile phase components; HPLC microcolumn Ø2×75 mm and ProntoSIL 120-5-C18 AQ, 5 μm were used as an analytical column; temperature was 40°С; flow rate was 100 μl/min; gradient elution mode was from 5% to 100% Eluent B for 40 min, then 100% Eluent B for 3 min; detection was performed at 277 nm. Retention time for metronidazole is 5.95 min. Since metronidazole is easy soluble and stable enough in the solutions of diluted alkalis 0.001 M sodium hydroxide solution has been proposed for preparation of the solutions in developing HPLC/UV-procedure of metronidazole quantification. Validation of the procedure has been carried out in the variants of the method of calibration curve and method of standard by such parameters as in process stability, linearity/calibration model, accuracy and precision within 3 different analytical runs using different batches of reagents and different glassware; experiments have been performed by three different analysts. New procedure of metronidazole quantitative determination by the method of HPLC/UV has been developed. Its validation has been carried out and acceptability for application has been shown.

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A Modified QuEChERS Extraction and LC-MS/MS Method for the Determination of Pesticide Residues in Curry Leaves (Murraya koenigii)

Current Chromatography ◽

10.2174/2213240606666181226143757 ◽

2019 ◽

Vol 6 (1) ◽

pp. 30-41

Author(s):

Ranjith Arimboor ◽

Karunkara Ramakrishna Menon ◽

Natarajan Ramesh Babu ◽

Haneesh Chandran

Keyword(s):

Sample Preparation ◽

Matrix Effect ◽

Retention Time ◽

Pesticide Residues ◽

Mobile Phase ◽

Preparation Technique ◽

Modified Quechers ◽

Curry Leaves ◽

Ms Analysis ◽

The Matrix

Background:Increased consumer demand for curry leaves free from pesticides demands fast and reliable analytical methods for the analysis of pesticide residues.Objective:The optimization of a QuEChERS based sample preparation technique with improved analytical accuracy by removing interfering matrix components for LC-MS/MS analysis of pesticide residues from curry leaves.Methods:A modified QuEChERS solid phase extraction method was developed and validated for the analysis of 26 pesticides in fresh and dried curry leaves. The effects of the sample preparation steps and column retention time on the matrix suppression of analyte ions were also evaluated.Results:Validation parameters were found within an acceptable range. The matrix effect evaluation studies showed that the QuEChERS sample preparation was able to minimize the ion suppression of analytes due to co-eluting matrix of components and that a d-SPE clean up step had major role in reducing matrix effect. The gradient mobile phase with longer retention time for analytes resulted in comparatively lesser matrix effects than the isocratic mobile phase of non-polar nature. Even after the clean up, a considerable number of compounds had more than 20% reduction in their MS response in the gradient mobile phase.Conclusion:This study emphasized the need of proper sample clean up before a LC-MS/MS analysis and the usage of matrix matched standards and mobile phase that ultimately results in an appropriate analyte separation in reasonable retention times.

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On the matrix-effect in the excitation of the atomic emission spectra of magnesites

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19651303 ◽

1965 ◽

Vol 30 (4) ◽

pp. 1303-1310 ◽

Cited By ~ 1

Author(s):

M. Matherny ◽

N. Pliešovská ◽

Ž. Rybárová

Keyword(s):

Matrix Effect ◽

Emission Spectra ◽

Atomic Emission ◽

The Matrix

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Selective Determination of Entecavir in the Presence of Its Oxidative Degradate by Spectrophotometric and Chromatographic Methods

Journal of AOAC International ◽

10.1093/jaoacint/qsab015 ◽

2021 ◽

Author(s):

Heba M El-Sayed ◽

Laila E Abdel Fattah ◽

Hisham E Abdellatef ◽

Maha A Hegazy ◽

Mai M Abd El-Aziz

Keyword(s):

High Selectivity ◽

Oxidative Degradation ◽

Hplc Method ◽

Peak Amplitude ◽

Quality Analysis ◽

Official Method ◽

Selective Determination ◽

Significant Difference ◽

Development And Validation

Abstract Background Entecavir (ENT) is an antiretroviral agent prescribed for treatment of HBV and HIV. Objective Development and validation of three simple, sensitive, selective, and precise methods for determination of ENT in presence of its oxidative degradation product (ENT deg.). Methods The first method was based on second derivative (D2) spectrophotometry through measuring the peak amplitude of D2 spectra at 293.6 nm. The second one is mean centering of the ratio spectra (MCR), which allowed measuring the peak amplitude at 280.0 nm. While the third method was HPLC; where ENT was separated from ENT deg. using Zobrax C18column and methanol: water (30:70, v/v), pH 3 as a mobile phase. The three developed methods were validated according to ICH guidelines. Results Linearity range of ENT was 5.00–50.00 μg/mL for both D2and MCR. However, higher sensitivity was achieved using HPLC (1.00–50.00 μg/mL). Accuracy of ENT were 100.60%±0.547, 101.55%±1.2071 and 100.61%±1.207 for D2, MCR and HPLC methods, respectively, and precision was within 1.280. Conclusions The developed methods were successfully applied for the determination of ENT in Tecavir® tablets without interference from ENT deg. They showed no significant difference compared with the official method as well as they could be applied in the quality analysis of ENT with high selectivity, accuracy, and precision. Highlights ENT was quantified using two spectrophotometric (D2 and MCR) methods and an HPLC method in presence of ENT deg. The proposed methods were applied to analysis of ENT tablets with high selectivity, sensitivity, and accuracy.

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The Development of a Paediatric Phoneme Discrimination Test for Arabic Phonemic Contrasts

Audiology Research ◽

10.3390/audiolres11020014 ◽

2021 ◽

Vol 11 (2) ◽

pp. 150-166

Author(s):

Hanin Rayes ◽

Ghada Al-Malky ◽

Deborah Vickers

Keyword(s):

Closed Set ◽

Retest Reliability ◽

Response Options ◽

Phoneme Discrimination ◽

Significant Difference ◽

Age Appropriate ◽

Hearing Children ◽

Test Retest Reliability ◽

Development And Validation ◽

Arabic Speaking

Objective: The aim of this project was to develop the Arabic CAPT (A-CAPT), a Standard Arabic version of the CHEAR auditory perception test (CAPT) that assesses consonant perception ability in children. Method: This closed-set test was evaluated with normal-hearing children aged 5 to 11 years. Development and validation of the speech materials were accomplished in two experimental phases. Twenty-six children participated in phase I, where the test materials were piloted to ensure that the selected words were age appropriate and that the form of Arabic used was familiar to the children. Sixteen children participated in phase II where test–retest reliability, age effects, and critical differences were measured. A computerized implementation was used to present stimuli and collect responses. Children selected one of four response options displayed on a screen for each trial. Results: Two lists of 32 words were developed with two levels of difficulty, easy and hard. Assessment of test–retest reliability for the final version of the lists showed a strong agreement. A within-subject ANOVA showed no significant difference between test and retest sessions. Performance improved with increasing age. Critical difference values were similar to the British English version of the CAPT. Conclusions: The A-CAPT is an appropriate speech perception test for assessing Arabic-speaking children as young as 5 years old. This test can reliably assess consonant perception ability and monitor changes over time or after an intervention.

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Evaluation of the matrix effect in the quantitative bio-oil analysis by gas chromatography

Fuel ◽

10.1016/j.fuel.2020.119866 ◽

2021 ◽

Vol 290 ◽

pp. 119866

Author(s):

Eliane Lazzari ◽

Érica A. Souza Silva ◽

Thiago R. Bjerk ◽

Jaderson K. Schneider ◽

Elina Bastos Caramão

Keyword(s):

Gas Chromatography ◽

Matrix Effect ◽

Oil Analysis ◽

Bio Oil ◽

The Matrix

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Development and Validation of a Sensitive, Specific and Reproducible UPLC-MS/MS Method for the Quantification of OJT007, A Novel Anti-Leishmanial Agent: Application to a Pharmacokinetic Study

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094624 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4624

Author(s):

Maria Rincon Nigro ◽

Jing Ma ◽

Ololade Tosin Awosemo ◽

Huan Xie ◽

Omonike Arike Olaleye ◽

...

Keyword(s):

Formic Acid ◽

High Performance ◽

Leishmania Major ◽

Internal Standard ◽

Gradient Elution ◽

Rat Plasma ◽

The Matrix ◽

Liquid Chromatography Tandem Mass ◽

Positive Mode ◽

Acquity Uplc

OJT007 is a methionine aminopeptidase 1 (MetAP1) inhibitor with potent anti-proliferative effects against Leishmania Major. In order to study its pharmacokinetics as a part of the drug development process, a sensitive, specific, and reproducible ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. Voriconazole was used as the internal standard to generate standard curves ranging from 5 to 1000 ng/mL. The separation was achieved using a UPLC system equipped with an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm) with 0.1% formic acid in acetonitrile and 0.1% formic acid in water as the mobile phase under gradient elution at a flow rate of 0.4 mL/min. The mass analysis was performed with a 4000 QTRAP® mass spectrometer using multiple-ion reaction monitoring (MRM) in the positive mode, with the transition of m/z 325 → m/z 205 for OJT007 and m/z 350 → m/z 101 for voriconazole. The intra- and inter-day precision and accuracy were within ±15%. The mean extraction recovery and the matrix effect were 95.1% and 7.96%, respectively, suggesting no significant matrix interfering with the quantification of the drug in rat plasma. This study was successfully used for the pharmacokinetic evaluation of OJT007 using the rat as an animal model.

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Dilution of QuEChERS Extracts Without Cleanup Improves Results in the UHPLC-MS/MS Multiresidue Analysis of Pesticides in Tomato

Food Analytical Methods ◽

10.1007/s12161-020-01921-1 ◽

2021 ◽

Author(s):

Fabiane M. Stringhini ◽

Lucila C. Ribeiro ◽

Graziela I. Rocha ◽

Juliana D. de B. Kuntz ◽

Renato Zanella ◽

...

Keyword(s):

Matrix Effect ◽

Practical Method ◽

Analysis Method ◽

Multiresidue Analysis ◽

Limit Of Quantification ◽

Chromatography Tandem Mass Spectrometry ◽

The Matrix ◽

Liquid Chromatography Tandem Mass ◽

Ultrahigh Performance Liquid Chromatography ◽

Positive Results

AbstractTomato is well-known to be one of the most cultivated and consumed vegetables worldwide and frequently contain pesticide residues. Therefore, a simple multiresidue method was established and validated to determine 129 pesticides and metabolites in tomato samples using a modified acetate QuEChERS without cleanup for sample preparation and determination by ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Dilution of the raw extract in different proportions of mobile phase was evaluated and a dilution of 10 times presented adequate results improving analysis performance while minimizing the matrix effect. Validation performed according to SANTE guideline presented satisfactory results. Practical method limit of quantification was 0.01 mg kg−1 for most compounds. Recoveries between 70 and 120% with precision ≤ 20% were found for most compounds and spike levels evaluated. Matrix effect results were not significant for most part of compounds. Method proved to be simple, robust, and effective to be applied in routine analysis. Method applicability was performed by analysis of samples commercialized in Brazil and positive results were found demonstrating the importance of the proposed method.

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