A rapid, sensitive and accurate determination of cobalamin with double monitoring system: HPLC-UV and HPLC-ICP-OES

Recent advances in detection techniques for vitamin analysis: A comprehensive review

Vitamins are vital micronutrients that play critical roles in human growth and development. However, vitamins are highly susceptible to degradation by light, heat, oxygen, and interactions with other food components during processing and storage. Additionally, insufficient intake or malabsorption can lead to vitamin deficiencies, resulting in various diseases. Since the human body cannot synthesize most vitamins, they must be sourced through diet or supplementation. Therefore, vitamin analysis is critical for meeting human nutritional needs and ensuring quality control. In recent years, significant advancements have been made in vitamin analysis. Here, we propose a comprehensive and critical evaluation of detection methods for water- and fat-soluble vitamins that have been studied over the past five years, including microbiology-, spectroscopy-, liquid chromatography-mass spectrometry-, electrochemistry-, sensor-, and immunoassay-based analysis techniques. Notably, immunoassays are highlighted for their simplicity, affordability, and high sensitivity. Finally, the current challenges and prospects of vitamin analysis are discussed.

Optimized separation of astaxanthin stereoisomers from microbial sources using chiral HPLC

Astaxanthin (AST) is a high-value antioxidant, and its efficient isolation and utilization are challenging owing to the presence of different stereoisomers from various sources. In the present study, a semi-preparative HPLC method for the efficient separation of AST stereoisomers using a Chiralpak IC chiral column with good loading capacity and chiral recognition ability was successfully developed. The mobile phase was methanol-methyl tert-butyl ether (90 : 10, v/v), with a flow rate of 3.06 mL min-1 and a maximum injection volume of 0.32 mg. The results indicated that the purity of all-trans AST was 97.9% for Haematococcus pluvialis and 97.5% for Phaffia rhodozyma. Additionally, molecular weights and fragmentation patterns analyzed using mass spectrometry were consistent with those of all-trans AST. Linearity validation and reproducibility experiments revealed that all calibration curves had coefficients of determination (R2) greater than 0.999 and a relative standard deviation (RSD) of <3.8%. This is because all-trans AST stereoisomers could undergo specific rotations or spins due to π-π interactions, hydrogen bonding, and inclusion interactions. This process allowed the successful separation of the three all-trans AST optical isomers and provides a theoretical basis for large-scale preparation of all-trans AST stereoisomers from different sources.

Microwave-Enabled Fast Preparation of a Metal-Organic Framework Hybrid Membrane for Filtration-Enhanced Simultaneous Separation and Detection of Aflatoxin B1

Mycotoxin contamination in food and the environment seriously harms human health. Sensitive and timely detection of mycotoxins is crucial. Here, we report a dual-functional hybrid membrane with absorptivity and responsiveness for fluorescent-quantitative detection of mycotoxin aflatoxin B1 (AFB1). A biomineralization-inspired and microwave-accelerated fabrication method was established to prepare a hybrid membrane with a metal-organic framework (MOF) loaded in high density. The MOF presented high efficiency in capturing AFB1 and showed fluorescence intensity alteration simultaneously, enabling a dual adsorption-response mode. Deriving from the inherent porous structure of the hybrid membrane and the absorptive/responsive ability of the loaded MOF, a filtration-enhanced detection mode was elaborated to provide a 1.67-fold signal increase compared with the conventional soaking method. Therefore, the hybrid membrane exhibited a rapid response time of 10 min and a low detection limit of 0.757 ng mL-1, superior to most analogues in rapidity and sensitivity. The hybrid membrane also presented superior specificity, reproducibility, and anti-interference ability and even performed well in extreme environments such as strong acid or alkaline, satisfying the practical requirements for facile and in-field detection. Therefore, the membrane had strong applicability in chicken feed samples, with a detection recovery between 70.6% and 101%. The hybrid membrane should have significant prospects in the rapid and in-field inspection of mycotoxins for agriculture and food.

Chromatographic speed classification for liquid chromatography using average theoretical peak time (ATPT)

BACKGROUND

The development of analytical techniques in the field of liquid chromatography has brought new frontiers in performance and analytical speed for the technique. The proper evaluation of the analytical boundaries achieved with those developments was not addressed in the literature, since different liquid chromatography (LC) techniques have not yet received any classification regarding their chromatographic speed. Defining chromatographic analysis speed based simply on analysis time is an outdated concept since it is sample and analyte-dependent. In this context, the application of the Average Theoretical Peak Time concept (ATPT) is proposed as a unified metric for chromatographic speed classification.

RESULTS

This metric was evaluated using PCA analysis in a group of more than 50 publications, which generated the classification of LC methods in normal, high, hyper, and ultra-high-speed separations using ATPT. Normal speed (ATPT values greater than 18000 ms/peak) was found in HPLC, nano-LC, SFC, and CEC methods. Therefore, high-speed methods (ATPT values between 4000 and 18000 ms/peak) were found in UHPLC techniques, while LC × LC methods presented higher ATPT values between 1000 and 4000 ms/peak being classified as hyper-speed separations. ATPT can also be used as an optimization parameter, since older methods show higher ATPT values, while recent published papers show lower values of this metric. This behavior is justified due to the improvement of the LC methods over the years.

SIGNIFICANCE

This work fulfills the gap in chromatographic definitions and metrics, regarding analytical speed in one-dimensional and multidimensional liquid chromatographic techniques and shows that ATPT metrics is a robust parameter that can be used to classify the separation speed as well as a metric to evaluate the LC Method optimization. It also corrects the historical application of separation time as a metric for chromatographic speed.

Simultaneous determination of four cobalamins in rat plasma using online solid phase extraction coupled to high performance liquid chromatography-tandem mass spectrometry: Application to pentylenetetrazole-induced seizures in Sprague-Dawley rats

A high throughput and high sensitive online solid phase extraction coupled to high performance liquid chromatography-tandem mass spectrometry method was established and validated for simultaneous quantification of four cobalamins including OHCbl, CNCbl, AdoCbl and MeCbl in rat plasma. Analytes were first enriched on an online SPE Shim-pack MAYI-ODS column and then separated using a Poroshell 120 EC C18 analytical column. The linear range was from 0.05 to 5 ng/ml and the LLOQ was 0.05 ng/ml for all four cobalamins. In addition, this method was applied to determine the cobalamins levels in pentylenetetrazole-induced kindling rat model for the first time.

Determination of the Chemical Stability of Cyanocobalamin in Medical Food by a Validated Immunoaffinity Column-Linked HPLC Method

Cyanocobalamin, which plays an essential role in the body, is a synthetic form used in medical food. This present study aimed to develop an HPLC analysis method for determination cyanocobalamin and investigate the stability of cyanocobalamin in medical food. Validation of the developed method for cyanocobalamin was evaluated with linearity, LOD, LOQ, and accuracy. The linearity of this method was calculated with a value of the coefficient of determination (R2) ≥ 0.999. LOD and LOQ were 0.165 and 0.499 μg/kg, respectively. The recovery of medical food matrixes for accuracy was more than 97.63%. The validated method was applied for determining cyanocobalamin from medical foods. The developed method was used to examine the additives for cyanocobalamin protection. Ferric chloride and sorbitol alleviated cyanocobalamin degradation from heat and ascorbic acid. Especially, sorbitol showed a superior protective effect during the medical food production process. Therefore, this study suggests that sorbitol is a sweetener additive that prevents cyanocobalamin degradation by heat and the food matrix in medical food processing.