Residual Analysis of Aflatoxins in Spice by HPLC Coupled with Solid-Phase Dispersive Extraction and Solid-Phase Fluorescence Derivatization Method

Abstract

Background Aflatoxins (AFs) are carcinogenic mycotoxins. A simple, quick, and accurate method for the micro-analysis of AFs in foodstuffs, especially spices, is needed. Objective A sophisticated pretreatment method that combines solid-phase dispersive extraction (SPDE) and solid-phase fluorescence derivatization using immunoaffinity (IA) gel as the solid phase was developed to analyze AFs in spices simply, quickly, and sensitively by liquid chromatography with fluorescence detection. Methods White and black pepper samples were extracted with a mixed solution of methanol/water (4:1) and then diluted with 7% aqueous solution of Triton-X. The solution was subjected to clean-up by SPDE using IA gel. Trifluoroacetic acid was added to the IA gel for on-site solid-phase fluorescence derivatization. Results Chromatograms containing well-separated peaks and few interference peaks from contaminants were obtained. The method detection limit of AFs in white and black pepper was 0.15–0.29 ng/g. Repeatability and intermediate precision were less than 10% and 15%, respectively, and accuracy was 61.7–87.8%. In addition, inter-laboratory precision was less than 29% and mean recovery was 61.5–76.7%. A favorable Z-score of |Z| ≦ 1 was obtained in seven laboratories, although one laboratory gave 2 < |Z| < 3. Conclusions The validity, reliability, practicality, and robustness of the developed method were verified. Highlights By using SPDE and solid-phase fluorescence derivatization in combination for AF analysis, fluorescence derivatization during clean-up was realized, leading to simplification of the pretreatment operation.

Developments in mycotoxin analysis: an update for 2020-2021

“…One of the recent advances in mycotoxin analysis was the development of an advanced pre-treatment technique for the analysis of aflatoxins in spices (Saito et al, 2020). This FLD method uses dispersive solid phase extraction (dSPE) together with solid-phase fluorescence derivatization and immunoaffinity gel to provide a simple, quick, and yet sensitive liquid chromatography technique for detecting aflatoxins.…”

“…In developing the method, pepper samples (black and white) were extracted using a 4:1 v/v methanol-water mixture and then diluted using a 7% Triton X solution. The resulting solution was then treated with dSPE, immunoaffinity gel, and trifluoroacetic acid to yield a 0.15-0.29 μg/kg solid phase fluorescence derivatization detection limit in white and black pepper with 61.7-87.8% recovery and intermediate precision <15% (Saito et al, 2020). The method demonstrated good performance, however the trifluoroacetic acid derivatization is not stable and this can cause complications while analysing multiple samples on one analytical sequence.…”

Elucidation of Factors for Chiral Conversion of α-Lipoic Acid in Dietary Supplement

“…SPDE was performed according to our previous method [18][19][20][21][22]. Briefly, a Captube was set on top of @Roka, and a conventional 2.0 mL micro test tube was attached to the bottom of @Roka.…”

Analysis of Methamphetamine in Urine by HPLC with Solid-Phase Dispersive Extraction and Solid-Phase Fluorescence Derivatization

“…In addition, the pretreatment column used in this system needs to be replaced every 40 to 50 sample injections, making the method impractical, and furthermore, the repeated use of the same pretreatment column is a potential cause of carryover-a problem that remains to be solvedinforensicappraisal.Despitetheseissues,fluorescence detectionHPLC(HPLC-FL)isconsideredanexcellenttoolfor MA analysis because the instruments used are highly versatile and have relatively high sensitivity. We have recently developed a novel extraction method called "solid-phase dispersive extraction(SPDE)" 10,[19][20][21][22][23][24] to overcome some of the drawbacks of the conventional cartridge-type solid-phase extraction (SPE)method.SPDEisperformedinaclosedsystemandcan beusedforinfectiousand/orchemicallyhazardoussamples.…”

“…The solid-phase derivatization method, which is a develop-mentalapplicationofSPDE,isamethodofreactingthetarget substance with a derivatization reagent while it is retained in the solid-phase, and has demonstrated usefulness in the analysis of mycotoxins in food. 25) In the present study, we adopted SPDE for the analysis of MA in urine, and investigated a solid-phase fluorescence derivatization method using FMOC forthefluorescencederivatizationofMAinthesolidphaseto achievehighsensitivityandselectivity.Herewereportthedevelopment of this simple and rapid HPLC-FL method for the determination of MA in urine.…”