Biomedical Engineering Reference
In-Depth Information
with a competitive-type assay format. Upon addition of streptomycin, the
analyte competed with glucose oxidase-labeled streptomycin (GOX-STR)
for molecular imprints on them MIP nanospheres. With the increasing
streptomycin in the sample, the conjugation amount of GOX-STR on them
MIP nanospheres decreased, leading to the change in the bioelectrocatalytic
current relative to glucose system. Under optimal conditions, the catalytic
current was proportional to STR level in the sample, and exhibited a dynamic
range of 0.05-20ng mL
-1
with a detection limit of 10pg mL
-1
STR (at 3s
B
).
Chen
et al.
reported the novel application of m-MIP in the separation
of tetracycline antibiotics from egg and tissue samples [28]. h e extraction
and clean-up procedures were carried out in a single step by blending and
stirring the sample, extraction solvent and polymers. h e analytes can be
transferred from the sample matrix to the polymers directly or through
the extraction solvent as medium. When the extraction was complete, the
polymers adsorbing the analytes were easily separated from the sample
matrix by an adscititious magnet (Figure 11.9). h e analytes eluted from
the polymers were determined by liquid chromatography-tandem mass
spectrometry. h e recoveries ranging from 72.8% to 96.5% were obtained
with relative standard deviations in the range of 2.9-12.3%. h e limit of
detection was less than 0.2 ng g
−1
. h e feasibility of this method was vali-
dated by analysis of incurred egg and tissue samples, and the results were
compared with those obtained by the classical method in which solvent
extraction, centrifugation, and subsequent clean-up and concentration by
solid-phase extraction were applied. h e proposed method reduced the
complicacy of classical method and improved the reliability of method.
5% methanol
methanol
(0.5% acetic acid)
Methanol
or water
Citrate buffer
(pH 4)
For egg
Waste
For tissue
Waste
Eluate
Stirring
Waste
5% methanol
Condition
Extraction
Seperation
Washing
Elution
Magnet
Magnetic MIPs
Sample matrices
Figure 11.9
h e extraction procedures for tetracycline by magnetic MIPs from egg and
tissue samples [Co-opted from reference 28 with permission].
