Agriculture Reference
In-Depth Information
tip diameter is 800
m, which produces a surface area wetted with extraction solvent.
In step 3, the pipette tips and the sample extract are robotically positioned at the inlet
of the ESI chip for nano-ESI-MS analysis [43]. It has been applied to analyze
pesticides on apples.
μ
1.2.10 Headspace GC
Headspace analysis has been used for more than 30 years [44] and is still one of the
most important sample preparation techniques for gas chromatography [45]. It is
based on the principles of gas extraction, that is, on the partition of an analyte in a
heterogeneous liquid
-
vapor system. A good example is that headspace gas chroma-
tography
MS) has been successfully applied to rapidly
detect benzene, toluene, ethylbenzene,
o
-,
m
-, and
p
-xylenes, and styrene in olives and
olive oil [46].
-
mass spectrometry (HS-GC
-
1.2.11 Summary
Using these advanced extraction techniques and their automated analogs, as already
discussed, coupled with LC-MS and GC-MS techniques, more analytes per unit time
can be analyzed from an increasing range of matrices, thereby increasing throughput
in food analyses.
1.3 FUTURE PERSPECTIVES
In addition to GC
MS techniques, other techniques such as near-
infrared (NIR), nuclear magnetic resonance (NMR), and capillary electrophoresis
have also been developed for high-throughput food safety analysis. A handheld unit
based on NIR spectroscopy and chemometrics has been developed for the rapid
(
-
MS and LC
-
5min) detection and quanti
cation of economic adulterants in foods, speci
cally
<
melamine in skimmed milk powder, for potential
field use [47]. A new NMR
procedure has been developed for routine nontargeted and targeted analyses of
foods [48]. Capillary electrophoresis combined with inductively coupled plasma
mass spectrometry (CE-ICP-MS) has been developed as an analytical tool for the
characterization of nanomaterials in dietary supplements. These nanoparticles are
dif
flow fractiona-
tion and size exclusion chromatography, due to their smaller particle sizes
(typically less than 20 nm) [49].
Compared with bioanalysis, high-throughput analysis for food safety using mass
spectrometry-based techniques (LC
cult to separate with other techniques such as asymmetric
eld
MS) is not popular and gets less
attention. However, we predict that throughput for food safety analysis will be
signi
-
MS and GC
-
cantly improved with the use and development of automated sample prepara-
tion technologies, ultrahigh-performance liquid chromatography (UHPLC) and high-
resolution MS.
