Agriculture Reference
In-Depth Information
source of 3-MCPD contamination in food. Like 3-MPCD, furan is another small,
polar, but also very volatile hazardous contaminant produced during heat treatment of
foods. Furan can be produced in several pathways, including the pyrolysis of sugars
and the breakdown of ascorbic acid [33]. Due to its polar and volatile nature, furan
lends itself to headspace GC analysis and this is the most common technique used for
its detection. In this area, solid-phase microextraction (SPME) or headspace analysis
as an extraction technique followed by GC
-
MS detection is commonly used [39
-
41].
4.3 PACKAGING MIGRANTS
As mentioned in Section 4.1, chemicals that migrate into food are covered in EU
legislation. This class of contaminants is quite extensive. This section will discuss the
ones that have been highlighted in the press and are covered in current legislation
regarding compounds that migrate from packaging into food.
Of this class of chemicals, one that has been in the news recently is bisphenol A
(BPA). BPA together with bisphenol A diglycidylether (BADGE) and its derivatives
are typical migrants from epoxy resins. Traditional sample preparation for these
migrants involved solid
liquid extraction followed by SPE cleanup, but recent
publications have shown that these migrants can be analyzed using a faster QuECh-
ERS method [42]. QuEChERS extraction of a sample normally takes about 20 min,
whereas solid
-
liquid
-
liquid extraction followed by SPE can take well over 1 h,
especially if the SPE extract needs to be blown down and reconstituted prior to
analysis. Analysis is by HPLC separation using a reversed-phase gradient on a C18
column where both the aqueous and organic phases contain formic acid followed by
ESI in positive mode. Detection levels are at the
-
liquid
-
g/kg level using a midrange LC-MS
system. In Ref [42], BPA and BADGE had typical Q1/Q3 mass transitions of 229.2/
107 and 341.2/135, respectively. BADGE can actually be present as several deriv-
atives (BADGE-2 H
2
O with Q1/Q3 mass transition of 377.3/135; BADGE-H
2
O with
Q1/Q3 mass transition of 359.2/191; BADGE-H
2
O-HCl with Q1/Q3 mass transition
of 395.2/209.1; BADGE-2HCl with Q1/Q3 mass transition of 414.3/229.2; and
BADGE-HCl with Q1/Q3 mass transition of 377.2.3/209) and these are normally all
monitored.
Another group of compounds that made headlines in 2005 for contaminating infant
formula are compounds that are used in inks on packaging labels. This class includes a
number of substances, including ITX, Irgacure, and TRP
μ
ITX is a mixture of 2-
isopropylthioxanthone and 4-isopropylthioxanthone; Irgacure contains Irgacure 819
(phenylbis-2,4,6-trimethylbenzoyl-phosphine oxide); and TRP is tri(propylene gly-
col) diacrylate (Figure 4.4). They are speci
—
cally used as photoinitiators in UV cured
inks. Again, as with BPA, LC
MS/MS methods have been developed [43] for
quantitation of these migrants and they use ESI in positive mode with ITX having Q1/
Q3 mass transitions of 255.1/213.1 and 255.1/184.1; Igracure having Q1/Q3 mass
transitions of 419.2/147.2 and 419.2/119.2; and TRP having Q1/Q3 mass transitions
of 301.2/113.3 and 301.2/55. HPLC separation of the ITX isomers is not easy (due to
their structure) (Figure 4.4) and typically they are combined into one HPLC peak
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