Accreditation and Quality Assurance最新文献

An evaluation of measurement uncertainty in the determination of sulfamethoxazole (SMZ) in compound sulfamethoxazole tablets using dual-wavelength spectrophotometry is presented. The average SMZ content determined was 0.3570 g/tablet, with an average tablet mass of 0.5671 g. The method leverages the ability to minimize interference from overlapping spectral bands by measuring absorbance differences at two distinct wavelengths (257 nm and 306 nm). Sources of uncertainty, including the average mass of tablets, sample mass, and absorbance values, were systematically analyzed. Findings reveal a combined standard uncertainty for a single determination of 0.0154 g/tablet. Absorbance measurement uncertainty, particularly for the standard at 306 nm (A_C306) and the sample at 306 nm (A_s306), were identified as significant contributors to the overall uncertainties. Triplicate analysis provided a limited reduction in the impact of repeatability uncertainty, with the overall combined standard uncertainty improving minimally to 0.0154 g/tablet. These results suggest that method optimization, such as adjusting concentrations to ensure absorbance readings are in a more optimal range, or consideration of alternative techniques may be needed to enhance the precision of SMZ quantification, contributing to robust quality control in pharmaceutical analysis.

The paper points out that the current practice of evaluation of measurement uncertainty for a finite resolution of measuring instruments uses the rectangular distribution to describe such an effect. The approximate formula for a calculation of the expanded uncertainty of the normal distribution convolved with the rectangular distribution as a contributing distribution is presented and compared with the direct effect of a finite resolution simulated on the normally distributed data. The interpretation of the numeric rounding caused by a finite resolution as a variable with the rectangular distribution is discussed and the solution for estimations with a quantized distribution that is observed is suggested. This approach allows to avoid underestimation in the evaluation of measurement uncertainties, especially for routinely calibrated instruments, where the finite resolution is often the dominant contribution to the uncertainty budget.

Doxorubicin (DOX) and Docetaxel (DTX) are commonly being employed and investigated in combination therapy against cancer, however, there does not exist a validated method to simultaneously analyse these two drugs. To address this gap, a simple, rapid, and sensitive reverse-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous estimation of DOX and DTX. The optimized separation was achieved using a C18 column employing an isocratic mobile phase comprising of acetonitrile and octane sulphonic acid buffer (25:75 v/v) with a flow rate of 1 mL/min. The detection was carried out at 230 and 240 nm with DTX and DOX at retention times of 3.4 min and 7.9 min, respectively, with a total analysis duration below 10 min ideal for formulation development and research purposes. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 67.96 ng/mL and 277.86 ng/mL for DOX and 65.78 ng/mL and 268.84 ng/mL for DTX, respectively. The recoveries were within the range of 98–102% ascertaining the accuracy and precision of the method. The developed approach was used to evaluate forced degradation, matrix impact, and assay experiments in acid, base, oxidative, light and temperature-induced stress environment considering its applicability in formulation development. All the applicability studies conducted proved that the method is capable of estimating both drugs distinctively and specifically in these applications. It can be used to fulfil the unmet need for a validated analytical toolset required for industrial and research applications.

Graphical Abstract

Reproducibility in science, particularly in fields that develop and apply analytical methods, such as analytical chemistry and related disciplines, has been increasingly questioned. A survey by Monya Baker (2016) indicated that most researchers acknowledge a reproducibility crisis. Frequently cited causes include low statistical power or poor analysis, insufficient replication in the original laboratory, unavailability of methods, poor experimental design, and absence of raw data. Chemistry was the field in which researchers most frequently reported difficulty reproducing both their own and others’ experiments. This study was conducted to confirm the existence of this crisis in analytical methods, quantify its extent, and evaluate its relationship with method validation and measurement uncertainty, which are based on statistical approaches and metrological principles, using the Analytical Quality Assurance Cycle. The results suggest that the crisis is directly associated with incorrect statistical procedures, inadequate validation criteria, and deficient execution of performance characteristics, factors that directly contribute to elevated measurement uncertainty. In 28% of the evaluated methods, expanded uncertainties exceeded 100% at the first point of the linearity assessment, compromising both result reliability and metrological traceability. These observations support concerns from previous studies regarding statistical errors, insufficient replication, and limited methodological transparency. Enhancing statistical training and quality assurance in academic programs, broader adoption of open science practices, and clearer policies aligned with international guidelines, such as EURACHEM, ISO/IEC 17025, and the OECD Principles of Good Laboratory Practice, may improve the reproducibility and reliability of analytical research.

The quality of cachaça and vodka is influenced by the organic congeners formed during their production, which can be toxic in high concentrations, requiring monitoring. To ensure reliability and traceable results, the application of the ISO/IEC 17025 standard in distilled beverage laboratories is essential. This standard covers metrological tools, such as method validation, use of certified reference material (CRM) and proficiency test (PT). This article presents the development and application of these tools to support reliability in analytical results, including method validation to verify the fitness of use, production of a CRM for internal quality control, and implementation of a PT as a practical application of the CRM. These tools were developed according to ISO 17034, ISO 33405:2024, and ISO 17043:2023. Statistical approaches were used throughout the study to ensure reliability in uncertainty estimation and performance evaluation. National laboratories collaborated in the quality control of distilled beverages and received CRM and PT samples, along with a protocol for future CRM production and PT implementation in this sector.

The aim of this paper is to describe a metrological approach for measurement uncertainty evaluation, applied to the quantification of melamine in a food matrix, being melamine a well-known food adulterant with harmful effects on health. The work provides insights on the calibration process of a Raman spectroscope, carried out in the melamine amount fraction range (0.16–5.0) mg L⁻¹ and based on the application of Weighted Total Least-Squares regression. The focus is on the evaluation of the measurement uncertainty associated to the recovery efficiency of the method. As a case study, an experimental method previously developed and validated at INRiM and based on the Surface Enhanced Raman Spectroscopy was considered as a starting point. The Law of Propagation of Uncertainty was applied to evaluate the measurement uncertainty of the results. The proposed approach for the uncertainty evaluation could be applied to the detection of the levels of melamine in real samples, as milk or milk-derived ingredients.

Background

Valaciclovir is an antiviral drug that requires accurate and sensitive analytical methods for quantification in pharmaceutical formulations and biological matrices. This study presents the development and validation of two analytical techniques in accordance with ICH Q2(R2) and M10 guidelines: a reversed-phase high-performance liquid chromatography (RP-HPLC) method and a novel chromogenic UV–visible spectrophotometric method extended to biosamples.

Results

The RP-HPLC method provided rapid and precise quantification of valaciclovir, with a retention time of 3.177 min. Linearity was observed in the range of 10–60 µg/mL, with a limit of detection of 0.0702 µg/mL and a limit of quantification of 0.2128 µg/mL. The method demonstrated high accuracy, specificity, and reproducibility, making it suitable for routine pharmaceutical analysis. The second method involved a chromogenic reaction between valaciclovir and MBTH reagent in the presence of ferric ammonium sulfate, forming a green chromogen with maximum absorbance at 618 nm. This method showed linearity from 10 to 550 µg/mL and further the method was validated as per ICH M10 guidelines. For biological analysis, human serum samples were processed using a protein precipitation method and analyzed successfully. Validation confirmed its suitability for bioanalytical use.

Conclusions

Both methods are sensitive, accurate, and validated for the quantification of valaciclovir. RP-HPLC is ideal for pharmaceutical analysis, while the UV–visible method offers a simple, cost-effective alternative for biological samples.

A modified quick, easy, cheap, effective, rugged and safe analytical method was utilized for extraction, and GC–MS/MS was used for detection of the residues of novaluron and lambda-cyhalothrin in/on cabbage when applied at the recommended dose, i.e. 75 and 15 g a.i. ha⁻¹, and 1.25 times the recommended, i.e. 93.75 and 18.75 g a.i. ha⁻¹, respectively. The analytical method was validated as per European Union guidelines. These insecticides dissipated following first-order kinetics, with half-lives of 1.99 and 1.46 days at the recommended dose and 2.83 and 1.89 days at 1.25 times the recommended dose for novaluron and lambda-cyhalothrin, respectively. No residues were present in the soil at the time of harvest. These insecticides were safe for human consumption, as the TMDI < MPI, aHQ & cHQ were less than one for both the doses. Removal of outer leaves was the most effective method for maximum per cent reduction in residues.

The National Institute for Environmental Studies (NIES) developed the NIES CRM No. 13-a, a new certified reference material for human hair, using scalp hair from Asian females. This CRM represents a significant advancement in support of global mercury exposure assessments and offers unparalleled reliability and scope compared with existing materials. We aimed to provide a comprehensive overview of the preparation, certification, and application of NIES CRM No. 13-a. In total, 806 bottles (3 g each) were produced, with thorough homogenization ensured through sieving and blending. Certified values for total mercury (1.06 ± 0.07 mg/kg), methylmercury (0.858 ± 0.075 mg/kg), and key trace elements (arsenic, cadmium, lead, selenium, and zinc) were determined through extensive collaborative analyses involving 20 laboratories. Additional reference values were provided for calcium, magnesium, sodium, sulfur, antimony, barium, copper, iron, and manganese. Rigorous stability and homogeneity assessments demonstrated the stability of the CRM for over 10 years and consistency across sample units, even for challenging elements such as selenium. The CRM also includes information values of stable mercury isotope ratios, reflecting their growing importance as exposure tracers. This enhancement in accuracy and traceability facilitates accurate mercury and trace element assessments in human hair, enabling improved biomonitoring of mercury exposure, dietary studies, toxicological evaluations, human health risk evaluations, and regulatory compliance.