Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Aflatoxin B1 in Corn Samples: Interlaboratory Study

Abstract

An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 levels in corn samples, enforced by European Union legislation. A test portion was extracted with methanolwater (80 + 20); the extract was filtered, diluted with phosphate-buffered saline solution, filtered on a microfiber glass filter, and applied to an immunoaffinity column. The column was washed with deionized water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase LC with fluorescence detection after either pre- or postcolumn derivatization. Precolumn derivatization was achieved by generating the trifluoroacetic acid derivative, used by 8 laboratories. The postcolumn derivatization was achieved either with pyridinium hydrobromide perbromide, used by 16 laboratories, or with an electrochemical cell by the addition of bromide to the mobile phase, used by 5 laboratories. The derivatization techniques used were not significantly different when compared by the Student's t-test; the method was statistically evaluated for all the laboratories. Five corn sample materials, both spiked and naturally contaminated, were sent to 29 laboratories (22 Italian and 7 European). Test portions were spiked with aflatoxin B1 at levels of 2.00 and 5.00 ng/g. The mean values for recovery were 82% for the low level and 84% for the high contamination level. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally contaminated samples (blind pairs at 3 levels), the values for relative standard deviation for repeatability (RSDr) ranged from 9.9 to 28.7%. The values for relative standard deviation for reproducibility (RSDR) ranged from 18.6 to 36.8%. The method demonstrated acceptable within- and between-laboratory precision for this matrix, as evidenced by the HorRat values.

Effect of the inclusion of adsorbents on aflatoxin B1quantification in animal feedstuffs

“…All these techniques need 54 an efficient sample extraction method. Several studies have been conducted to investigate the 55 extraction capacity of different organic/aqueous solvents, like methanol (Reif and Metzger, 1995;Stroka et al, 1999;Sharma and Marquez, 2001;Senyuva and Gilbert, 2005;Brera et al, 2007), acetone 57 (Brandurn et al, 1995;Stroka et al, 2003;Arranz et al, 2006), acetonitrile (Stroka et al, 1999) and 58 chloroform (Moller and Nyberg, 2004) solvents. Some studies investigated the organic solvent to water 59 ratio (ml solvent/ml water), the ratio of solvent to sample (ml solvent/g sample) and the matrix effects 60 (Brandburn et al, 1995;Stroka et al, 1999;Moller and Nyberg, 2004).…”

Improved Sample Selection and Preparation Methods for Sampling Plans Used to Facilitate Rapid and Reliable Estimation of Aflatoxin in Chicken Feed

“…Recovery, precision and efficiency were compliant with CEC requirements of 75–125% for recovery and HorRat < 2 for precision [ 52 , 54 , 64 ]. AOAC and other authorities also recognize HorRat < 2 as a reliable precision criterion [ 64 , 65 , 66 ]. For replication studies using native aflatoxin, precision data collected under repeatability and reproducibility conditions met the EU guidelines.…”

Fungal flora and aflatoxin contamination in Pakistani wheat kernels (Triticum aestivum L.) and their attribution in seed germination

“…The intraday and interday precision and accuracy of the HPLC method were evaluated using quality control (QC) samples [ 21 ]. Briefly, three different concentrations of each AF (0.25 ng/mL, 2.5 ng/mL, and 10 ng/mL) of QC samples were analyzed using the HPLC system and precision was calculated in terms of relative standard deviation (RSD).…”

“…For instance, Campone et al [ 17 – 19 ] reported in 2009, 2011, and 2015, the analysis of AFs in nuts, cereal products, and dried fruits using high performance liquid chromatography (HPLC) with fluorescence detection and ultrahigh-pressure liquid chromatography–tandem mass spectrometry, respectively. Waltking and Wilson [ 20 ], Brera et al [ 21 ], and Ofitserova et al [ 22 ] quantified AFB 1 and AFs in corn using HPLC with postcolumn photochemical and chemical derivatization.…”