Agriculture Reference
In-Depth Information
results obtained with a commercially available ELISA. Additionally, magnetic nano-
gold particles were also applied inmicrosphere-based lateral
flow immune-dipsticks for
the detection of AFB2 in food [96].
8.4.4.3 Surface Plasmon Resonance
SPR represents a relatively new analytical technique that has gained increasing
popularity due to its rapid, real-time, and highly selective and sensitive determi-
nation of analytes. Various applications of SPR in biochemistry, clinical diagnosis,
and food analysis have already been described and several reviews describing the
principles and bene
ts have been published [97]. SPR is an optical phenomenon
used to measure changes on the surface of thin metal
films under conditions of total
internal re
ection [81]. It allows direct detection of analytes without any labeling of
interactants. As in the case of other immunoassay-based methods, SPR sensors
have also been developed exclusively for mycotoxins of regulatory interest such as
a
atoxins, trichothecenes, ZON, fumonisins, and OTA. Some of these tests are also
commercially available [97]. There is a trend in the use of SPR technique to
develop and validate multisensors for detection and quanti
cation of numerous
mycotoxins in a single analysis. This was achieved by van der Gaag et al. [98], who
introduced a multiple SPR sensor for simultaneous determination of AFB1, DON,
ZON, and FB1. This unique device was constructed from four
flow cells containing
four types of antimycotoxin antibodies. The evaluation of a prototype of the
multiplex microimmunoassay quanti
cation sensor for DON and ZON was pub-
lished by Dorokhin et al. [99]. The limits of detection achieved in this study were
84 and 68
μ
g/kg for DON and 64 and 40
μ
g/kg for ZON in maize and wheat,
respectively.
8.4.4.4 Fluorescence Polarization Immunoassay
In
fluorescence polarization (FP) immunoassays, an analyte labeled with
uorophore
(
(fluorescein) competes with free analyte for speci
c antibody-binding sites in
solution, while
fluorescein label is measured. An
FP immunoassay has been successfully used for the determination of DON, ZON, and
OTA in wheat, corn, and some food samples [17]. In a study by Bondarenko et al.
[100], the in
fluorescence polarization of the
fluorescent-based tracers on sensitivity of the assay for
the determination of ZON and OTA was examined. The LODs (15 and 10
uence of various
g/kg for
ZON and OTA, respectively) and acceptable recoveries ranging from 84 to 97% were
obtained. The development and application of new FP immunoassay has recently
been published for simultaneous quantitative analysis of T2 and HT2 toxins in
contaminated wheat samples [101]. In this particular study, the synthesis of four
μ
fluorescein-labeled T2 or HT2 toxin tracers was carried out and their binding
responses with seven monoclonal antibodies were evaluated. Using extraction with
a methanol:water mixture (90:10, v/v), it was possible to obtain an average recovery
of 96% and a LOD as low as 8
g/kg for the sum of the toxins. The assay allowed
quantitation of target analytes within 10min.
μ
