Development of an Ultrasonication-Assisted Extraction Based HPLC With a Fluorescence Method for Sensitive Determination of Aflatoxins in Highly Acidic Hibiscus sabdariffa

Abstract

The high acidity and complex components of Hibiscus sabdariffa have provided major challenges for sensitive determination of trace aflatoxins. In this study, sample pretreatment of H. sabdariffa was systematically developed for sensitive high performance liquid chromatography-fluorescence detection (HPLC-FLD) after ultrasonication-assisted extraction, immunoaffinity column (IAC) clean-up and on-line post-column photochemical derivatization (PCD). Aflatoxins B1, B2, G1, G2 were extracted from samples by using methanol/water (70:30, v/v) with the addition of NaCl. The solutions were diluted 1:8 with 0.1 M phosphate buffer (pH 8.0) to negate the issues of high acidity and matrix interferences. The established method was validated with satisfactory linearity (R > 0.999), sensitivity (limits of detection (LODs) and limits of quantitation (LOQs) of 0.15–0.65 and 0.53–2.18 μg/kg, respectively), precision (RSD <11%), stability (RSD of 0.2–3.6%), and accuracy (recovery rates of 86.0–102.3%), which all met the stipulated analytical requirements. Analysis of 28 H. sabdariffa samples indicated that one sample incubated with Aspergillus flavus was positive with aflatoxin B1 (AFB1) at 3.11 μg/kg. The strategy developed in this study also has the potential to reliably extract and sensitively detect more mycotoxins in other complex acidic matrices, such as traditional Chinese medicines, foodstuffs, etc.

Advances in immunoassay‐based strategies for mycotoxin detection in food: From single‐mode immunosensors to dual‐mode immunosensors

“…In the past few decades, chemical analysis, instrumental analysis (Kunz et al., 2020; Liu et al., 2018; Rodriguez‐Carrasco et al., 2014; Wei, Liu, et al., 2019), enzyme‐linked immunoassay (Oplatowska‐Stachowiak et al., 2016), and other emerging methods (Liu, Ying, et al., 2019; Yang et al., 2020; Zhao et al., 2020) have provided accurate and sensitive detection of mycotoxins. Among the chemical analysis, thin‐layer chromatography (TLC) was first reported (Lin et al., 1998), which is inexpensive, simple, easy to operate, stable, and suitable for preliminary screening of large‐scale samples.…”

Analysis of 16 mycotoxins in genuine traditional Chinese medicine for five medicinal parts: Classification of analytical method based on PANI@CS extraction-UPLC-MS/MS

“…The quality standards and safety risks of TCMs must comply with international norms whenever go abroad. The commonly used pretreatment methods in the laboratory are organic solvent microwave ultrasonic extraction [ [17] , [18] , [19] ], solid-phase extraction [ 20 , 21 ], and dispersed solid-phase extraction [ [22] , [23] , [24] ]. The commercial solid phase extraction column is expensive, and the detection target is specific and relatively single.…”