Received: 21 March 2020 Revised: 5 May 2020 Accepted: 5 May 2020
DOI: 10.1002/sscp.202000022
RESEARCH ARTICLE
Determination of aflatoxins in rice samples after magnetic solid
phase extraction using MIL-101(Cr)/magnetite nanocomposite
Mohammad Bagher Sabeghi
1
Hamid Reza Ghasempour
2
Mohammad Kazem Koohi
3
Nasser Karimi
2
1
Department of Food Science and
Technology, Faculty of Agriculture,
Kermanshah Branch, Islamic Azad
University, Kermanshah, Iran
2
Department of Biology, Faculty of Science,
Razi University, Kermanshah, Iran
3
Department of Basic Sciences, Faculty of
Veterinary Medicine, University of Tehran,
Tehran, Iran
Correspondence
Hamid Reza Ghasempour, Department of
Biology, Faculty of Science, Razi University,
Kermanshah, Iran.
Email: ghasempourh11@gmail.com
An easy and fast method named magnetic solid phase extraction was developed using a
magnetite/metal–organic framework nanocomposite for extraction and quantification
of four toxic aflatoxins (B1, B2, G1, G2) in rice samples. The synthesis of nanoadsor-
bent was confirmed with various characterization methods. The high-performance liq-
uid chromatography with fluorescence instrument was used for the subsequent analy-
sis. Optimization of effective variables was conducted via experimental design strat-
egy. After optimization, detection limits are obtained in the range of 0.03–0.1 ng/g
and calibration plots were linear in the domain of 0.1–4.0 ng/g. Method precision
was 7.3–12% (within-day precision, n = 3 sample, 0.5 ng/g; between-day precision,
n = 3 day, 0.5 ng/g). The accuracy of the current method was confirmed by the official
method based on the immunoaffinity column procedure. The statistical t-test analy-
sis exhibited that there is no significant difference between the two methods at 95%
confidence level and hence the new method is accurate. Finally, the new method was
utilized for determining and extracting of the aflatoxins in rice samples.
KEYWORDS
aflatoxins, magnetic solid phase extraction, magnetite, rice samples
1 INTRODUCTION
Aflatoxins (AFs), highly oxygenated heterocyclic mycotox-
ins, are produced as secondary metabolites by the food
spoilage fungi, especially Aspergillus flavus, Aspergillus
parasiticus, and Aspergillus nomius [1]. AFs are at the cen-
ter of attention owing to their drastic toxic effects on ani-
mal and human health as well as their high abundance
[1–3]. AFs are produced in diverse agricultural products like
dried fruits, rice, nuts, and cereals [4]. Among the vari-
ous AFs, AFB1, AFB2, AFG1, and AFG2 have been found
in food and feed [5]. These compounds exhibit potency of
Article Related Abbreviations: AF, aflatoxin; CCD, central composite
design; FLD, fluorescence detection; IAC, immunoaffinity column; MNP,
magnetite nanoparticle; MSPE, magnetic solid phase extraction; VSM,
vibrating sample magnetometry.
mutagenicity, carcinogenicity, and toxicity in the order of
AFB1 > AFG1 > AFB2 > AFG2. The International Agency
of Research on Cancer (IARC) has classified these AFs as
Group 1 carcinogens [6]. The European Commission has reg-
ulated the maximum residue levels of AFB1 as 2 ng/g and
total AFs as 4 ng/g in consumed rice of human, while these
values in Iranian regulations are 5 and 30 ng/g, respectively
[7,8]. Thereby, various analytical methods have been utilized
for monitoring and determination of these toxic compounds
in various matrices including foods and feeds [8,9]. Owing to
the complexity of real matrices and very low levels of AFs,
appropriate sample preparation procedures are vital to elim-
inate the matrix effect and to concentrate the target analytes
prior to the analysis step [9].
Extraction of AFs from food samples can be performed
by a water–organic solvent mixture [10–12]. Diverse meth-
ods have been utilized to exclude the matrix interferences
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