214
inherent in aflatoxin analysis currently include sampling, subsampling, and sample
extraction methods and also the analytical variation associated with the chosen analytical method (Holcomb et al. 1992).
Other methods of detection were elaborated such as immunoaffinity column
immune-enzymatic and immunochemical methods. Another very recent technique
by electrochemical immunosensor sensitive to AFB1 based on carbon nanotubes
with simple walled, this immunosensor was based on an indirect competitive binding. The detection limit is 3.5 pg/mL. In addition, the immunosensor was successfully applied for determination of AFB1 in corn powder, which showed a good
correlation with the results obtained by high-performance liquid chromatography
(Luan et al. 2015; Zhang et al. 2016).
An accurate and rapid LC-ESI-MS/MS analytical method was developed and
validated for the simultaneous determination of aflatoxins B1, B2, G1, and G2 in
lotus seeds. The samples were firstly extracted with methanol-water solution (80:20,
v/v) and then cleaned up by immunoaffinity columns. The mass spectrometer was
operated in the positive ionization electrospray (ESIþ) mode using multiple reaction
monitoring (MRM) for analysis of four aflatoxins. The limits of detection (LODs)
of aflatoxins B1, B2, G1, and G2 were 0.007, 0.005, 0.003, and 0.005 mg kg
1
based
on a signal-to-noise ratio of 3:1, respectively. The limits of quantification (LOQs) of
aflatoxins B1, B2, G1, and G2 were 0.02, 0.015, 0.01, and 0.015 mg kg
1
based on a
signal-to-noise ratio of 10:1, respectively. Recoveries for samples of spiked lotus
seeds were all above 66% with relative standard deviation all below 15% for all
compounds. Nineteen out of twenty batches of lotus seeds collected from different
drugstores or markets in China were found to be contaminated with aflatoxins at
different levels ranging from 0.02 to 688.4 mg kg
1
(Liu et al. 2013).
TLC was the first method used for aflatoxin determination, but was replaced in
the early 1980s in developed countries owing to the technical progress in HPLC and
later in ELISA and fluorimetric techniques. These modern methods offer several
advantages over TLC, but the instrumental requirements also increased. Currently
available TLC, HPLC, or ELISA methods have been reviewed, and it was concluded that the determination of less than 1 ng/g aflatoxin B1 (thus supporting
European legislation (e.g., EC/1525/98) and most of the other legislation worldwide) is no longer an analytical challenge. A method for aflatoxins in various food
matrices, using HPLC at a level of 2 ng/g aflatoxin B1, or 4 ng/g total aflatoxins, has
recently been collaboratively trial-tested and is in the process of being adopted as an
official method. The main progress is based on easily available powerful analytical
approaches, such as the production of specific antibodies for aflatoxins, which are
used for ELISA and immunoaffinity cleanup as well as improved and wellestablished detection systems, for example, for increasing the fluorescence of aflatoxins. Using HPLC, the latter can be achieved by post-column derivatization by
bromination by various means or irradiation by UV light. The excellent performance of mycotoxins detection techniques was referred to immunoaffinity column
as mentioned by (Chiodini et al. 2006).
N. M. Abdelmotilib et al.
inherent in aflatoxin analysis currently include sampling, subsampling, and sample
extraction methods and also the analytical variation associated with the chosen analytical method (Holcomb et al. 1992).
Other methods of detection were elaborated such as immunoaffinity column
immune-enzymatic and immunochemical methods. Another very recent technique
by electrochemical immunosensor sensitive to AFB1 based on carbon nanotubes
with simple walled, this immunosensor was based on an indirect competitive binding. The detection limit is 3.5 pg/mL. In addition, the immunosensor was successfully applied for determination of AFB1 in corn powder, which showed a good
correlation with the results obtained by high-performance liquid chromatography
(Luan et al. 2015; Zhang et al. 2016).
An accurate and rapid LC-ESI-MS/MS analytical method was developed and
validated for the simultaneous determination of aflatoxins B1, B2, G1, and G2 in
lotus seeds. The samples were firstly extracted with methanol-water solution (80:20,
v/v) and then cleaned up by immunoaffinity columns. The mass spectrometer was
operated in the positive ionization electrospray (ESIþ) mode using multiple reaction
monitoring (MRM) for analysis of four aflatoxins. The limits of detection (LODs)
of aflatoxins B1, B2, G1, and G2 were 0.007, 0.005, 0.003, and 0.005 mg kg
1
based
on a signal-to-noise ratio of 3:1, respectively. The limits of quantification (LOQs) of
aflatoxins B1, B2, G1, and G2 were 0.02, 0.015, 0.01, and 0.015 mg kg
1
based on a
signal-to-noise ratio of 10:1, respectively. Recoveries for samples of spiked lotus
seeds were all above 66% with relative standard deviation all below 15% for all
compounds. Nineteen out of twenty batches of lotus seeds collected from different
drugstores or markets in China were found to be contaminated with aflatoxins at
different levels ranging from 0.02 to 688.4 mg kg
1
(Liu et al. 2013).
TLC was the first method used for aflatoxin determination, but was replaced in
the early 1980s in developed countries owing to the technical progress in HPLC and
later in ELISA and fluorimetric techniques. These modern methods offer several
advantages over TLC, but the instrumental requirements also increased. Currently
available TLC, HPLC, or ELISA methods have been reviewed, and it was concluded that the determination of less than 1 ng/g aflatoxin B1 (thus supporting
European legislation (e.g., EC/1525/98) and most of the other legislation worldwide) is no longer an analytical challenge. A method for aflatoxins in various food
matrices, using HPLC at a level of 2 ng/g aflatoxin B1, or 4 ng/g total aflatoxins, has
recently been collaboratively trial-tested and is in the process of being adopted as an
official method. The main progress is based on easily available powerful analytical
approaches, such as the production of specific antibodies for aflatoxins, which are
used for ELISA and immunoaffinity cleanup as well as improved and wellestablished detection systems, for example, for increasing the fluorescence of aflatoxins. Using HPLC, the latter can be achieved by post-column derivatization by
bromination by various means or irradiation by UV light. The excellent performance of mycotoxins detection techniques was referred to immunoaffinity column
as mentioned by (Chiodini et al. 2006).
N. M. Abdelmotilib et al.