Agriculture Reference
In-Depth Information
Cl
Cl
H
O
Cl
O
H
O
OH
Furan
3-MCPD
1,3-DCP
Figure 4.3.
Chemical structures of furan, 3-MPCD, and 1,3-DCP.
a less retentive polar endcapped phase [32] is used, the mobile phase contains
<
1%
methanol. If additional sensitivity is needed, either because a less sensitive LC
MS/
MS detector is used or lower limits of detection are needed, then solid-phase
extraction (SPE) has been used as a means to improve detection limits and remove
matrix effects [32].
Apart from acrylamide, there are other contaminants that are produced as a result of
chemical reactions caused by heat-treated food, including chloropropanols and furan
(Figure 4.3). Chloropropanols, especially 3-monochloropropane-1,2-diol (3-MCPD)
and 1,3-dichloropropan-2-ol (1,3-DCP), are recognized by-products from heat treat-
ment of food [33]. 3-MCPD has been recognized by the European Commission
-
'
s
Scienti
ed as an
undesirable contaminant in food [34]. Chloropropanols are formed by the reaction
of glycerol or acylglycerol (present in fats) with chloride ions (e.g., sodium chloride)
in the heat processing of foods containing low levels of water. 3-MCPD can therefore
be produced by acid hydrolysis, used, for example, in soy sauce production [33]. 3-
MCPD is usually extracted from samples using SPE based on diatomaceous earth
(Extrelut) together with solvent partitioning [33]. Due to the lack of a chromophore,
HPLC
c Committee on Food as a carcinogen and has been classi
UV is not suitable and because of the small polar nature of 3-MPCD and 1,3-
DCP, direct GC analysis is dif
-
cult
—
so derivatization is needed. Of the reagents
available, hepta
uorobutyrylimidazole (HFBI) is one of the most commonly used,
and methods using HFBI derivatization followed by GC
-
MS analysis [33] have been
recognized as
cial Method 2000.01) as well
as by the European standardization body (EN 14573) [35]. LC
fit for purpose by the AOAC (AOAC Of
MS/MS has not been
used to detect 3-MCPD directly as 3-MCPD ionization is not very ef
-
cient, resulting
in low sensitivity. Recently, LC
MS/MS has been used to detect intermediates of 3-
MPCD (3-MCPD esters) and presentations at the 2012 annual AOACmeeting [36,37]
showed that LC
-
MS/MS can directly detect the individual glycidyl ester species. In
one of these papers, a normal phase separation on an ODS column using a gradient
from methanol (containing 10mM ammonium formate and 0.1% formic acid) to
isopropanol was used to separate the esters, followed by atmospheric pressure
chemical ionization (APCI) to ionize them [36]. Samples were prepared by solvent
extraction followed by SPE on a silica-based media [36]. In contrast, GC
-
MS uses
acid hydrolysis to cleave these esters before detecting the total amount of 3-MCPD in
the sample, preventing detection of the native esters. Such 3-MCPD esters have been
found in margarine and baby food. There is ongoing research into this topic [38] as the
toxic properties of these contaminants are still unknown and they can act as a further
-
