379 / 471
Table 2014.04A. Volumes of each stock solution for IWS
IWS
Stock volume, µL
MIX-IS, µL
Final volume, mL
1
25
100
50
2
125
100
50
3
250
100
50
Table 2014.04B. Concentration of standards
Standard
Choline
Choline
chloride-d
9
Carnitine
Carnitine
chloride-d
3
Diluent
Final
volume, mL
µg/mL
IWS 1
1.5
1.6
0.375
0.8
Water
50
IWS 2
7.5
1.6
1.875
0.8
Water
50
IWS 3
15
1.6
3.750
0.8
Water
50
ng/mL
90%
WS 1
30
32
7.5
16
MeCN
10
WS 2
150
32
37.5
16
MeCN
10
WS 3
300
32
75
16
MeCN
10
Table 2014.04C. Microwave digestion parameters
Power
100% (1600 W)
Ramp to temperature
10 min
Hold time
40 min
Temperature
120°C
Table 2014.04D. Mass analysis parameters (Xevo TQ-S)
Standard
Retention time
typical, min
Molecular ion
(precursor)
Product
ion
Dwell, s
Cone
voltage,
V
Collision
energy, V
Choline
2.5
104.2
60.3
0.025
40
32
Choline chloride-d
9
2.5
113.4
69.3
0.025
40
30
Carnitine
4.4
162
103
0.025
30
28
Carnitine chloride-d
3
4.4
165
103
0.025
30
26
Candidates for 2016 Method of the Year
317