Journal of AOAC International最新文献

Background: Water determination for plant materials generally uses loss on drying (LOD) methods. The azeotropic-toluene distillation (ATD) method is often used in pharmacopeial and food compendial monographs to determine the water content of plant materials containing volatile components because LOD will lose both water and volatile components. ATD is an environmentally hazardous method since it uses relatively large amounts of toluene with distillation.

Objective: To seek a greener approach for water determination in plant materials, USP <921> Water Determination, Method I, also known as the Karl Fischer (KF) test, is recommended due to its efficiency, specificity, and accuracy. However, it may be difficult to determine water content of plant materials using direct titration since water is tightly trapped in plant cells. An alternative approach is needed.

Methods: The United States Pharmacopeial Convention (USP) laboratory therefore developed and validated an alternative method-KF direct titration with extraction using formamide as the extraction solvent.

Results: The validation results demonstrated that the newly developed method met the required criteria for accuracy, repeatability and robustness8.

Conclusion: Using the newly established method, the water content in different species with different plant parts including fruit peel, root, rhizome, bark, cremocarp and bulb was effectively determined.

Highlights: The results generated using the KF direct titration with extraction were also compared with results of LOD applying different heating times and direct titration using different solvents (see Table 1). The differences in the results between the methods will be discussed.

Background: Polygonatum cyrtonema Hua (PCH) is widely used in traditional Chinese medicine. The components and activity are important for simultaneously quality evaluation in PCH.

Objective: This study aimed to establish an accurate, rapid and comprehensive quality evaluation method by near-infrared spectroscopy (NIR) for forecasting the total polysaccharides content (TPsC), total flavonoids content (TFC), and antioxidant activity (AA) in PCH.

Methods: PCH samples were used to establish model of TPsC, TFC, and AA in PCH by NIR combined with partial least squares regression (PLS). To enhance the accuracy of the models and remove non-essential variables, we used multiple spectral preprocessing methods and multiple chemometrics to analyze the processed full spectrum, such as competitive adaptive reweighted sampling-partial least squares regression (CARS-PLS), moving window-partial least squares regression (MW-PLS), and interval random frog-partial least squares regression (iRF-PLS). The remaining samples were used to complete external validation.

Results: Satisfactory prediction results of PLS models combined with chemometrics were obtained. The optimal chemometric of TPsC, TFC, and AA selected 157, 105, and 134 variables, respectively. For the TPsC, TFC, and AA models, which incorporated optimal spectral preprocessing and chemometric, the root mean square error of calibration (RMSEC, %) values were 0.743, 0.069, and 0.136, while the R2 values were above 0.95. The root mean square error of prediction (RMSEP, %) for these models were 1.00, 0.074, and 0.153, while R2 values were above 0.90. The remaining 20 samples were used to complete external validation, which confirmed the preeminent comparability and ability of the proposed method.

Conclusion: NIR combined with chemometrics provide an effective, fast, and nondestructive approach for evaluating quality via multiple indicators of PCH and provides a meaningful reference for evaluation of herbal medicine quality.

Highlights: NIR combined with chemometrics offers an effective, quick, nondestructive way to evaluate herbal medicine quality with multiple indicators.

Background: Aflatoxin B1 (AFB1) is widespread in various kinds of food and poses a serious threat to health when it enters the human body via the food chain.

Objective: This study aimed to establish a rapid and sensitive method for the detection of AFB1 and then combine it with HPLC for the quantitative analysis of AFB1 content.

Method: In this work, hydrothermal and sol-gel methods were employed to prepare aminoated magnetic nanoparticles featuring strong magnetism and excellent dispersion. Magnetic nanoparticles bound with antibodies can specifically capture AFB1 and then be combined with HPLC for the quantitative analysis of AFB1 content. Moreover, the key factors influencing the extraction efficiency, such as buffer type, adsorption time, elution time and volume, were optimized.

Results: The samples were spiked with AFB1 at low, medium, and high concentration levels of 5.0, 10.0, and 20.0 μg/kg, respectively. The established method exhibits good linearity within the range of 0.1-100 µg/kg, and the detection limit is as low as 0.09 µg/kg (S/N = 3). The recoveries in real samples ranged from 79.33% to 111.51%, with all relative standard deviations (RSDs) being less than 11.16% (n = 3 for each level).

Conclusions: In conclusion, a rapid and efficient analytical method for detecting AFB1 in corn, peanut and oat based on functionalized immunomagnetic beads (IMBs) coupled with HPLC-FLD have been successfully developed .The method exhibited excellent sensitivity, featuring a low method detection limit of 0.09 μg/kg, high accuracy, and remarkable precision. In comparison to traditional sample preparation techniques, this IMBs-based approach presents substantial advantages in terms of simplicity, rapidity (completing sample processing within approximately 30 minutes), and cost-effectiveness.

Highlights: The IMBs possess excellent magnetic separation capabilities, which effectively streamline the pre-processing steps.

Background: Bovine lactoferrin (bLF) has been supplemented to a variety of foods, particularly dairy products, to promote human health. Reliable analytical methods are required for accurate quantification of bLF in foods. Isolation of bLF from foods using a heparin column and quantification via HPLC have been reported (heparin method); however, its applicability remains limited.

Objective: To develop a broadly applicable method for determining bLF in dairy products by optimizing the extraction buffer conditions used in the heparin method.

Method: bLF was spiked into different dairy products and extracted using buffers with or without additives, such as urea, sodium chloride, EDTA, and Tween 20. These additives reduced interactions between bLF and dairy components and improved the interaction of bLF to the heparin column, with the buffer pH adjusted to 6.0. The extracted bLF was isolated using a heparin column and quantified via C4 reversed-phase HPLC using an external standard calibration curve.

Results: The optimized extraction buffer improved bLF recovery rates across all tested dairy product matrices.

Conclusions: An improved extraction buffer was developed that enhanced the applicability of bLF quantification using the heparin method. This optimized extraction buffer enabled reliable recovery of bLF from diverse and complex dairy product matrices.

Highlight: The optimized extraction buffer significantly improves the recovery and quantification of bLF in various dairy products, providing a versatile solution for accurate bLF analysis.

Background: Chlorogenic acid (CGA), a plant-derived phenolic compound, possesses antioxidant, anti-inflammatory, and antimicrobial activities. Accurate quantification is essential due to its therapeutic value and potential toxicity at high doses.

Objective: To develop a rapid, sensitive electrochemical method for CGA detection using spinel-based catalysts with improved conductivity.

Methods: An electrochemical sensing platform was constructed based on a nanocomposite of ZnFe2O4 and boron, sulfur and nitrogen co-doped reduced graphene oxide (BSN-rGO). This hybrid material effectively addresses the intrinsic poor conductivity of spinel oxides by leveraging the synergistic effect between the catalytic activity of ZnFe2O4 and the superior charge transport capability of BSN-rGO. The resulting sensor enabled rapid and quantitative analysis of CGA within two minutes.

Results: The sensor showed a linear detection range of 1 × 10-4 -1 × 10-1 M and a low detection limit of 1 × 10-6 M (S/N = 3). Adding standard recovery reached 97.48% to 100.75%, with RSDs of 1.02% to 2.95%, indicating excellent accuracy and reproducibility in complex matrices.

Conclusion: The proposed method enables rapid and reliable CGA detection in natural products, offering potential for pharmaceutical and food analysis.

Highlights: BSN-rGO integration enhances spinel conductivity and boosts electrochemical sensing performance.

Background: The extensive use of imported commercial Saccharomyces cerevisiae active dry powder preparations has led to a serious homogenization of wine products in China.

Objective: In recent years, there has been growing interest in developing and applying indigenous non-Saccharomyces yeasts to enhance the diversity and distinctive character of wines.

Methods: In this study, a promising indigenous strain, Hanseniaspora uvarum BF-345, previously isolated from local grape juice, was investigated due to its desirable fermentation properties, robust stress tolerance, and high β-glucosidase activity. Response surface methodology (RSM) was employed to optimize the composition of a cryoprotectant formulation for the vacuum freeze-drying of BF-345.

Results: The optimal protectant formulation was determined as follows: 5.63% skim milk powder, 12.89% maltitol, and 7.02% sucrose. Under these conditions, the viability of the freeze-dried cells reached 85.2%, representing a 27.3% increase compared to the pre-optimized formulation.

Conclusion: The prepared active dry yeast complied with the Chinese national standard GB/T 20886.2-2021, and maintained a viability above 70% after 6 months of sealed storage at 4 °C.

Highlights: In micro-vinification trials with Cabernet Sauvignon, the fermentation system inoculated with the freeze-dried powder exhibited higher yeast cell counts and more favorable fermentation kinetics than that inoculated with a liquid seed culture.

Background: The market demand of honey in Bangladesh is raising day by day, but there are concerns about the quality of both farm-fresh and branded honey which are available in the market.

Objectives: This study evaluates the physicochemical and antioxidant properties of farm-fresh and branded honey from the Bangladeshi market.

Methods: The moisture content (MC) and total soluble solid (°Bx) were determined by refractometer; the electrical conductivity (EC) determined by digital conductivity meter; total phenol (TP), total flavonoid (TF) and HMF were measured by Folin-Ciocalteu, aluminum chloride and ultra high performance liquid chromatography-diode array detector (UHPLC-DAD) respectively; and antioxidant capacity was assessed by 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method.

Results: The results revealed that, farm-fresh honey samples exhibited greater content of moisture (>20%), (329.63 ± 1.63 to 986.05 ± 4.81 mg GAE/kg), total flavonoid (95.09 ± 4.99 to 454.73 ± 2.45 mg QE/kg) and antioxidant capacity (IC50 value of DPPH, 47.91 ± 0.19 to 73.66 ± 0.30 mg/mL) compared to branded honey samples (p < 0.05). The HMF amount was varied from 0.82 ± 0.00 to 241.24 ± 2.41 (mg/kg), with forty-two percent (42%) of branded honey samples exceeding both the Bangladesh Standards and Testing Institution (BSTI) and Codex Alimentarius standard limit (80 mg/kg), whereas all farm-fresh honey samples were within the acceptable limit. In multivariate analysis, the principal component (PC1 & PC2) analysis explains 81.30% of the total variance.

Conclusions: Based on compliance with BSTI and Codex HMF limit, farm fresh honey samples meet the acceptable HMF threshold, whereas 42% of branded honey exceeded the standard limit.

Highlights: Analyzed 45 honey samples (farm-fresh, national, international) for physicochemical parameters; Farm-fresh honey exhibited higher moisture, phenolics, flavonoids and antioxidant activity; 42% of branded honeys exceeded HMF standard limits (BSTI and Codex); all farm-fresh samples were within permissible limit.

Background: Pantoprazole is a selective proton pump inhibitor used in its sodium form in pharmaceuticals. Determining its impurities is crucial for drug purity and safety.

Objective: This study aims to develop a faster impurity analysis method than the European Pharmacopoeia (EP) method.

Methods: An Agilent Zorbax SB Phenyl (250 × 4.6 mm, 5.0 µm) column was used for HPLC, and a Restek Ultra Biphenyl (100 × 2.1 mm, 3.0 µm) column for UPLC. A 65:35 (v/v) potassium dihydrogen/dipotassium hydrogen phosphate buffer (pH 7.40)-acetonitrile mixture was the mobile phase. Analyses were performed at 290 nm with flow rates of 1.0 mL/min (HPLC) and 0.25 mL/min (UPLC). Injection volumes were 20 µL (HPLC) and 3.5 µL (UPLC).

Results: The analysis times of the impurity determination methods developed are 15 min shorter for the HPLC method and 30 minutes shorter for the UPLC method compared to the EP method. The developed methods were validated according to ICH guidelines, demonstrating high linearity (R2 > 0.99 over the concentration range of 0.03-2.27 µg/mL), accuracy with mean recoveries ranging from 95.0% to 105.0%, and precision with intra- and inter-day RSD values below 2%. Forced degradation studies under acidic, alkaline, oxidative, thermal, and photolytic conditions confirmed that the methods are stability-indicating, with the ability to separate all major degradation products of pantoprazole sodium.

Conclusion: The method was validated according to International Conference on Harmonisation (ICH) guidelines, and forced degradation studies were also performed. This study presents optimized HPLC and UPLC methods that allow faster impurity analysis and detection of an additional non-compendial impurity, Pantoprazole-N-oxide.

Highlights: As a result of shorter analysis times, a significant cost reduction has also been proven with numerical data. In addition, a performance-cost comparison of two different analytical technologies was made.