Agriculture Reference
In-Depth Information
Table 4.4. Examples of Sudan Dyes Found in Food with Their Corresponding Q1 and Q3
Transitions Used in LC-MS/MS Analysis
Q1 Mass
(amu)
Q3 Mass
(amu)
Sudan Dye
Formula
CAS No.
Dimethyl yellow
C
14
H
15
N
3
60-11-7
226.1
120.1/105.1
Fast Garner GBC
C
14
H
15
N
3
97-56-3
226.1
91.1/107.1
Orange II (positive)
C
16
H
12
N
2
O
4
S
633-96-5
329.1
156/128
Orange II (positive)
C
16
H
12
N
2
O
4
S
633-96-5
327.0
171/80
Para Red
C
16
H
11
N
3
O
3
6410-10-2
294.1
156.1/128.1
C
28
H
31
N
2
O
3
+
Rhodamine B
81-88-9
443.2
399.1/355.1
Sudan I
C
16
H
12
N
2
O
842-07-9
249.1
93/156.1
Sudan II
C
18
H
16
N
2
O
3118-97-6
277.1
121.1/106.1
Sudan III
C
22
H
16
N
4
O
85-86-9
353.1
197.1/128.1
Sudan IV
C
24
H
20
N
4
O
85-83-6
381.1
224.1/225.1
Sudan Orange G
C
12
H
10
N
2
O
2
2051-85-6
215.1
93.1/122.1
Sudan Red 7B
C
24
H
21
N
5
6368-72-5
380.2
183.1/115.1
Sudan Red B
C
24
H
20
N
4
O
3176-79-2
381.2
224.1/156.1
Sudan Red G
C
17
H
14
N
2
O
2
1229-55-6
279.1
123.1/108.1
D5-Sudan I (internal
standard)
254.1
156
D6-Sudan IV
(internal standard)
387.1
106
range [60]. In comparison with GC
tof
reduced sample preparation and run time and still provide lower limits of detection.
For example, when analyzing pet food and infant formula by LC
-
MS, LC
-
MS/MS methods have the bene
MS/MS, the
samples can be easily extracted under acidic conditions before the sample is
centrifuged,
-
63].
Melamine and cyanuric acid are small polar compounds and have been separated
using a normal phase gradient on a hydrophilic interaction liquid chromatography
(HILIC) column [61,63] or by adding hepta
filtered, and diluted before analysis [61
-
uorobutyric acid (HFBA) or trideca-
fluoroheptanoic acid (TFHA) and analyzing samples on a C18 column (both ion pair
reagents are added to both the sample vial and the mobile phase). Ion pair reagents
suppress the response in negative mode, so typically just melamine is detected in this
type of method and this approach has been used successfully to test for melamine in
milk-based products [62]. When a HILIC separation is used, a period method can be
set up, where half the analysis run is dedicated to the detection of cyanuric acid in
negative mode and the polarity of the system is changed to positive mode to allow
detection of melamine. An example of a chromatogram obtained using HILIC is
shown in Figure 4.8. In this
gure, both compounds have been detected by ESI,
cyanuric acid in negative mode (Q1/Q3 mass transitions of 128/42 and 128/85)
and melamine in positive mode (Q1/Q3 mass transitions of 127/60, 127/68, and
127/85) [63].
The case of melamine contamination for commercial gain has started a worrying
trend and recently another nitrogen-rich compound, dicyandiamide, has been found in
