2
Experimental Conditions
GC-MS/MS Instrument
TRACE 1310 GC
iC Injector Module
Split/Splitless Injector
Injector Temperature
250 °C
Injection mode
splitless
Surge mode
300 KPa
Splitless Time
1.0 min
Analytical Column
TG-WAX MS, 30m×0.25mm×0.5μm
Carrier gas
He
（
99.999% purity
）
Flow rate
1.0 mL/min, constant flow
Oven Program
45 °C for 3 min,
25 °C/min to 130 °C,
12 °C/min to 230°C, 1min hold
Transfer line Temperature
250°C
Total analysis time
14.7 min
Total cycle time
18.4 min
TriPlus RSH Autosampler
Injection Volume
1 µL
Solvent
dichloromethane
Standard runs
3 replicate of injections each
Dilution of standard mix
1ppb, 5ppb, 10ppb, 25ppb, 100ppb,
250ppb, 500ppb
Internal standard
NDPA added to each
calibration
level at 50ppb
TSQ 8000 Triple Quadrupole GC-MS/MS system
Ionization mode
EI
Mass resolution setting
normal
Source temperature
220 °C
Scan mode
MRM, retention time-based SRM
mode
MRM Method Setup
The triple quadrupole MS method setup was performed
by using the AutoSRM software which is part of the
Thermo Scientific TSQ™ 8000 GC-MS/MS software
suite. The method generated by AutoSRM was used
without any additional manually modification. One
autosampler vial containing a standard solution of the
nitrosamine compounds to be analyzed has been used
only for the AutoSRM process.
The AutoSRM procedure automatically runs the
following three steps:
1. First a full scan analysis of the standard solution
(Figure 1). Get the most intense ions of the full scan
spectra to be used as the precursor ions.
2. Run a next analysis acquiring the product ion spectra
from the selected precursor ions (the number of
precursor ions to be used can be configured to the
analytical needs). Get the most intense product ions
from each precursor ion (optionally the desired
precursor ions can be selected manually for further
optimization).
* The transitions marked as grey color are quantitation ions
Table 1. MRM method setup using AutoSRM
Precursor
Product
Collision Energy
(eV)
Retention Time
(min)
Time Window
(min)
NDMA
74
42.1
15
7.89
1
74
43.8
5
7.89
1
NDEA
102
44.1
10
8.56
1
102
85.1
5
8.56
1
NDPA (ISTD)
130
42.9
10
9.76
1
130
113.1
5
9.76
1
NDBA
158
99.1
5
11.35
1
158
141.1
5
11.35
1
NPIP
114
41.5
15
11.80
1
114
83.9
5
11.80
1
NPYR
100
43
10
12.06
1
100
55.1
5
12.06
1
NMOR
116
56.1
10
12.47
1
116
86.1
5
12.47
1
