Agriculture Reference
In-Depth Information
Table 4.1. List of Common
N
-Nitrosamines That Can Be Present in Rubber Used for
Baby Teats with Their Corresponding Q1 and Q3 Transitions Used in LC-MS/MS
Analysis
Q1 Mass
(amu)
Q3 Mass
(amu)
PFC
Formula
Abbreviation
N
-Nitrosomethylethylamine
C
3
H
8
N
2
O
NMEA
89.0
61
N
-Nitrosodimethylamine
C
2
H
6
N
2
O
NDMA
75.0
43
N
-Nitrosodiethylamine
C
4
H
10
N
2
O
NDEA
103.1
75
N
-Nitrosomorpholine
C
4
H
8
N
2
O
2
NMOR
117.0
87
N
-Nitrosopiperidine
C
5
H
80
N
2
O
NPIP
115.1
69
N
-Nitrosopyrrolidine
C
4
H
8
N
2
O
NPYR
101.0
55
compounds that are mainly used as plasticizers for polymers such as polyvinyl-
chloride (PVC), but can also be used in adhesives, paints,
films, glues, and
cosmetics and so their potential sources are quite diverse. As such, they can
contaminate food via packaging migration. In a 2007 survey [47], most laboratories
used GC-based techniques with either electron capture detection, MS, or
ame
ionization detection, but sample preparation was lengthy or used harmful solvents
and included liquid
liquid partitioning (using dichloromethane) or gel permeation
chromatography (GPC). More recently, LC
-
MS/MS has been used to simplify
sample extraction and speed up sample analysis [48]. Ionization depends on the
phthalate class, but over 20 phthalate esters (Table 4.2) can be detected using ESI in
positive mode. When phthalate analysis is moved over to LC
-
MS/MS, a simple
methanol extraction followed by dilution is all that is needed to extract over 20
phthalates and the analysis time is then
-
<
10 min [49] compared with over 20min
using capillary GC
MS. Figure 4.5 is an example of 18 phthalates, detected in one
run, and includes some of the more prevalent contaminants (e.g., bis(2-ethylhexyl)
phthalate and benzyl butyl phthalate) (Table 4.2). In this example, the separation of
compounds was accomplished by reversed phase using a Phenomenex Kinetex C18
column (100
-
m) and a fast gradient of water containing 10mM
ammonium acetate to methanol at a
×
4.6mm; 2.6
μ
flow rate of 500
μ
l/min.
uorinated contaminants (PFCs).
This class of compounds is used for a variety of industrial applications, including
Another group of packaging migrants are per
flame retardants and stain removers. This class does not normally enter food as a result
of deliberate contamination or food processing, but rather enters the food chain via
bioaccumulation, for example, in
fish [50], so they are primarily environmental
contaminants. However, they can leach into food from coated food contact materials,
for example, nonstick cookware and food paper packaging that is oil and moisture
resistant (e.g., microwave popcorn paper bags) [51
-
54]. The two most prevalent
compounds in this class are per
uorooctanesulfonic acid (PFOA) and per
uorooctane
sulfonate (PFOS). The current method of choice for this class is LC
-
MS/MS. There
are numerous papers that have used LC
MS/MS to detect PFOS and PFOA and in all
cases this class of compounds is detected in negative ion mode normally using ESI
-
