Table 1 Optimum instrument settings for the identification and quantification of product ions

LC instrument settings

Flow rate

0.3 ml/min

Injection volume

2 µl

Run time

18 min (15 min plus 3 min post-time)

Mass spectrometer settings

Source parameter

Positive value

Gas temperature

350 °C

Gas flow

13 l/min

Nebulizer

60

Capillary voltage

4000 V

Analyte setup

Analyte

Transition (m/z)

Dwell

(ms)

Fragmentor

(V)

Collision energy

(V)

Polarity

Scan mode

RRT (min)

5-HIAA

192.1 ≥ 145.9

100

61

17

Positive

MRM

± 8.446

5-HT

177.1 ≥ 160.1

56

13

± 2.196

FLX

310.1 ≥ 148.1

51

5

± 9.201

GSH

308.1 ≥ 179.0

76

9

± 1.702

GSSG

613.2 ≥ 231.0

121

37

± 1.692

nFLX

296.1 ≥ 74.0

51

169

± 9.144

I.Std (ESC)

325.2 ≥ 108.9

76

53

± 8.963