Journal of AOAC International最新文献

Background: In recent years, due to the global shortage of helium gas, the development of gas chromatography (GC) analytical methods using alternatives to helium carrier gases is necessary.

Objective: The objective of this study was to examine the applicability of hydrogen and nitrogen as alternative carrier gases using the test method for azo compounds in the Act on Control of Household Products Containing Harmful Substances of Japan.

Method: The gas chromatograph mass spectrometer (GC-MS) analytical method using hydrogen and nitrogen as alternative carrier gases was compared with a method using helium for 26 primary aromatic amines (PAAs) originated from azo dyes.

Results: When hydrogen and nitrogen were used as carrier gases under the same conditions used during analysis using helium (same column, gas flow rate, oven temperature conditions, etc.), sufficient peak separation of 26 PAAs was obtained. The sensitivities of the methods using helium and hydrogen were comparable, whereas the sensitivity was lower when nitrogen was used, with the detection limits ranging from 1/220 to 1/25. However, all carrier gases achieved quantification at concentrations below the standard value (30 μg/g) of the Act on Control of Household Products Containing Harmful Substances, and the results were in agreement with the standard value for the target product.

Conclusions: Our results indicated that hydrogen or nitrogen can be used as alternative carrier gases to helium for GC-MS analysis of azo compounds producing specific aromatic amines.

Highlights: Using hydrogen or nitrogen as an alternative carrier gas to helium, azo compounds could be quantified with excellent accuracy.

Background: Maple syrup is a sought-after commodity, and used as a condiment and a sweetener. Also, it is an active target of economically motivated adulteration (EMA), similar to other foods such as lemon juice and honey.

Objective: This study is aimed to detect low cost sugar adulteration in maple syrup via an internal standard method using malic acid through solid-phase extraction (SPE) and LC with isotope ratio mass spectrometric detection (LC-IRMS).

Methods: In this work, an optimized SPE sample preparation procedure was used for the isolation of organic acids from maple syrup. Using LC-IRMS, malic acid was separated from other organic acids and the δ13C value of malic acid was determined. Eleven maple syrup samples, domestic or imported from Canada, were evaluated for 13C/12C ratios (δ13C values) using combustion module-cavity ring down spectrometry (CM-CRDS) and compared to the δ13C values obtained from well-established elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) methods. The δ13C values of isolated malic acid analyzed by SPE-LC-IRMS were used as internal standards and compared to the δ13C values of bulk maple syrup; difference (δ13Csugars - δ13Cmalic acid) values greater than 3.6‰ are indicative of low-cost sugar adulteration.

Results: Overall, the results obtained from SPE-LC-IRMS provided a faster, novel analysis approach for determining low-cost sugar adulteration in maple syrup for regulatory purposes. This method also provided lower detectable limits of adulteration versus current literature reports using bulk analysis and comparable detection limits to Tremblay and co-workers who utilized an internal standard method.

Conclusion: SPE-LC-IRMS is a robust method that can be used for detecting adulteration in maple syrup samples for regulatory purposes.

Highlights: SPE-LC-IRMS is a faster, novel analysis approach for determining C4 adulteration in maple syrup with lower detection limits.

Background: The combination of estradiol cypionate (ECA) and medroxyprogesterone acetate (MPA) is used to prevent pregnancy in women. The analysis of the ECA and MPA combination reveals a challenge due to the strong overlap of the spectra of these compounds.

Objective: Spectrophotometry techniques along with chemometrics methods are simple, fast, precise, and low-cost for the simultaneous determination of ECA and MPA in a combined pharmaceutical dosage form.

Methods: Two developed approaches, the least-squares support vector machine (LSSVM) and fuzzy inference system (FIS), along with a spectrophotometric method were proposed to solve such a challenging overlap.

Results: Based on the cross-validation method, the regularization parameter (γ) and width of the function (σ) in the LSSVM model were optimized and the root mean square error (RMSE) values were found to be 0.3957 and 0.2839 for ECA and MDA, respectively. The mean recovery values were 99.87 and 99.63% for ECA and MDA, respectively. The FIS coupled with principal component analysis (PCA) showed mean recovery percentages equal to 99.05 and 99.50% for ECA and MDA, respectively. Also, the RMSE of both components was lower than 0.3.

Conclusion: The analysis results of a real sample (injection suspension) using the proposed methods were compared with HPLC by a one-way analysis of variance (ANOVA) test, and no significant differences were found in the results.

Highlights: Intelligent methods were proposed for the simultaneous determination of ECA and MPA. The least-squares support vector machine and fuzzy inference system along with spectrophotometry were used. HPLC as a reference method was performed and compared with chemometrics methods. The benefits of the proposed approaches are that they are rapid, simple, low-cost, and accurate.

Background: Its broad applicability and capacity to separate numerous components in a single chromatographic run led to the initial recognition of reversed-phase (RP)-HPLC as an analytical technique.

Objective: The objective of this study was to create a straightforward and reliable method for accurately and precisely measuring the amount of tapinarof in both the topical formulation and the active pharmaceutical ingredient. Additionally, a robust HPLC assay was developed specifically for analyzing the topical formulation.

Methods: In this study, chromatographic analysis was conducted using a Kromosil C18 column with dimensions of 250 × 4.6 mm and a particle size of 5 microns. The mobile phase consisted of a phosphate buffer and methanol in a ratio of 100:900 (v/v). The flow rate was set at 1.0 mL/min, with an injection volume of 10 µL and a run time of 6 min using isocratic elution. UV detection was performed at a wavelength of 313 nm, and the temperature was maintained at 30°C. The analysis showed well-separated peaks with a high number of theoretical plates, a low tailing factor, and consistent retention time. Validation of the method was conducted, and all validation parameters were found to be within the acceptable limits.

Results: A method that is simple, accurate, and precise has been developed to estimate the amount of tapinarof in a topical formulation and active pharmaceutical ingredient. The optimized method involved the use of a column temperature set at 30°C, 90% methanol as the mobile phase, and a flow rate of 1.0 mL/min. The retention time for tapinarof was determined to be 2.88 min. The method exhibited linearity in the concentration range of 5 to 30 µg/mL (with an R2 value greater than 0.999) for tapinarof.

Conclusion: The topical formulated cream and active pharmaceutical ingredient showed more than 90% dissolution within 5 min. The method developed in this study utilized photo diode array (PDA) for peak integrity and purity confirmation, making it suitable for the quantification of tapinarof in both topical formulations and active pharmaceutical ingredients.

Highlights: The method was validated and can be recommended for routine analysis in QC laboratories.

Background: Sulfite is the oldest and most widely used additive in our food supply with antioxidant and preservative properties. Due to its allergenic-like reactions and other adverse health effects, its use is regulated by international regulatory bodies. Therefore, food industries as well as regulatory laboratories must ensure that the maximum concentration of sulfite permitted is not exceeded. The AOAC INTERNATIONAL-approved official method for the quantification of sulfites is the Optimized Monier-Williams Method (AOAC Official Method 990.28), which consists of a time-consuming titration.

Objective: The present study aims to demonstrate the reliability of the BIOFISH 300 SUL, a simple, fast, and accurate method, as an alternative, for the quantification of total sulfites in shrimp, with a lower LOQ than that of the OMA 990.28, set at 10 mg/Kg.

Methods: The BIOFISH 300 SUL method is a highly specific biosensor based on its proprietary enzyme-based electrode, for the rapid quantification of total sulfite. The test kit consists of an electrochemical reader (biosensor BIOFISH 300) and disposable electrodes (Biotest) that are capable of providing an electrical signal proportional to the amount of sulfite in the sample analyzed. The method mainly consists of the extraction of sulfite from the solid matrix in an aqueous solution, and its subsequent quantification by the device in less than 3 min.

Results: Comparative studies between BIOFISH 300 SUL and OMA 990.28 were conducted for naturally contaminated and spiked samples of raw and boiled shrimp with sulfite levels covering the 7-150 mg/kg range in order to determine linearity, recovery, repeatability, intermediate reproducibility, and accuracy.

Conclusion: The BIOFISH 300 SUL method demonstrated high accuracy and precision for the whole range of quantification (7-150 mg/kg). Its ease of use and fast response make it the ideal technology to be implemented by the industry.

Highlights: BIOFISH 300 SUL was adopted as a First Action Official MethodSM by the AOAC Expert Review Panel for Sulfites in Seafood Methods in February 2021 after rigorous review.

Background: Staphylococcus is a genus of Gram-positive bacteria, known to cause food poisoning and gastrointestinal illness in humans. Additionally, the emergence of methicillin-resistant S. aureus (MRSA) strains has caused a major health care burden worldwide. Cronobacter is a group of Gram-negative bacteria that can survive in extreme dry conditions. Cronobacter sakazakii is known to contaminate powdered infant formula and cause life-threatening infections in neonates. Vibrio is a genus of human-pathogenic Gram-negative bacteria that can cause foodborne illness by consuming undercooked or raw seafood. Vibrio parahaemolyticus can cause serious gastrointestinal disease in humans. Thus, rapid identification of Staphylococcus spp., Cronobacter spp., and Vibrio spp. is crucial for the source tracking of contaminated food, as well as to measure the transmission dynamics of these bacterial pathogens causing foodborne diseases and outbreaks.

Objective: This single-laboratory performance evaluation study used the VITEK MS system to evaluate the potential of MALDI-TOF MS technology for rapid identification of S. aureus-like, C. sakazakii-like, and V. parahaemolyticus-like isolates of public health importance.

Method: A total of 226 isolates recovered from various food, environmental surveillance samples, and other sources were identified by bioMérieux VITEK 2 and VITEK MS systems as Staphylococcus spp., Cronobacter spp., and Vibrio spp. Five American Type Culture Collection (ATCC) reference Gram-positive and Gram-negative bacterial isolates were also tested to complete the study. In addition, for some Staphylococcus spp. isolates, whole genome sequencing (WGS) and DNA sequencing of 16S rRNA partial region were also performed for species identification.

Results: The VITEK MS system was able to provide species identification to all 96 isolates of Staphylococcus spp. and to all 29 isolates of Vibrio spp. examined with a high confidence value (99.9%). Similarly, species identification was observed for the majority of spots (245 of 303) for the 101 Cronobacter spp. isolates (∼82.0%) with a high confidence value (99.9%), and genus level identification was noticed for the rest of the Cronobacter spp. isolates (18.0%; 58 of the 303 spots) analyzed. Species identification data generated by VITEK 2 system were comparable to data obtained by the VITEK MS system.

Conclusions: The VITEK MS system is a reliable high-throughput platform that can rapidly identify Staphylococcus, Vibrio, and Cronobacter to the genus level, as well as S. aureus, C. sakazakii, V. parahaemolyticus, and other closely related foodborne isolates and bacterial isolates from additional sources, in most cases.

Highlights: The VITEK MS system can be used in the rapid genus and species identification of human-pathogenic Staphylococcus spp., Cronobacter spp., and Vib

Soil samples are complex matrixes; therefore, soil sample preparation is a critical step, and one that is usually expensive, time-consuming, and labor intensive. The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method, originally developed for the determination of pesticides in fruits and vegetables, has been recently modified and adopted for the analysis of pesticides in soil. This paper reviews all aspects of sample preparation, including extraction and clean-up, and describes the applications of conventional and modified QuEChERS techniques. It also presents a comparison of the QuEChERS method with other methods used for sample preparation for determination of pesticides in soil.

The most important advances in planar chromatography published between November 1, 2013 and November 1, 2015 are reviewed in this paper. Included are an introduction to the current status of the field; student experiments, books, and reviews; apparatus and techniques for sample preparation and TLC separations; detection and identification of separated zones; quantitative analysis; preparative layer chromatography; and thin layer radiochromatography. Selected applications are given in the various sections of the review.