AOAC Final Action Methods in 2019

Table 2015.10C. LC-MS parameters

LC-MS settings a

LC-MS model

Sciex 4000

Sciex 6500

 Ionization mode  IonSpray voltage

MRM

MRM

1000 V 550 ° C

2000 V 550 ° C

 Turbo IonSpray temp.  Entrance potential (EP)  Collision gas (CAD)  Curtain gas (CUR)  Nebulizing gas (GS1)  Nebulizing gas (GS2)

10 V

10 V

Nitrogen, 5.0 Nitrogen, 20.0 Nitrogen, 60.0 Nitrogen, 60.0

Nitrogen, 5.0 Nitrogen, 20.0 Nitrogen, 60.0 Nitrogen, 60.0

 Needle position

Y = 5 mm, X = 5 mm

Y = 5 mm, X = 5 mm

LC-MS model

Agilent 6490

 Ionization mode

MRM 380 V

 Fragmentor

 Cell accelerator

5 V

 Gas temp.  Gas flow  Nebulizer

200 ° C

20 L/min

30 psi 225 ° C

 Sheath gas temp.  Sheath gas flow

11 L/min 1500 V

 Capillary +

 Nozzel voltage +  High-pressure RF +  Low-pressure RF +  Ionization mode  Capillary voltage  RF lens voltage  Source temp.  Nebulizer temp. LC-MS model

500 V 200 V 100 V

Waters TQD

MRM

2000 V 0.1 eV 150 ° C 450 ° C

 API gas

On

 Nebulizer gas  Desolvation gas

Nitrogen

900 L/h nitrogen 50 L/h nitrogen 0.25 mL/min argon

 Cone gas

 Collision gas

 API gas

On

 Nebulizer gas

Nitrogen

Transition monitored Q1/Q3 b

Analyte

Transition use/type

Dwell time, msec b

Collision energy, V b

Retention time, min

Carnitine

Quantitation

162.0/103.0 165.0/103.0 162.0/84.4 162.0/59.1 104.2/60.0 104.2/42.2 108.2/60.0

100 100 100 100 100 100 100

25 25 29 27 25 25 25

1.7 1.7 1.7 1.7 2.1 2.1

Carnitine-d3

Internal standard

Carnitine Carnitine Choline Choline

Qualifier Qualifier

Quantitation

Qualifier

Choline-d4 2.1 a  MS/MS settings may be modified except for ionization type and mode to obtain optimum chromatography and sensitivity. Exact mass ions may vary slightly from instrument to instrument because of unit resolution of quadrupole mass spectrometers. b  Settings listed are for Sciex series of LC-MS. Precursor/product masses and instrument settings may vary. Internal standard

© 2019 AOAC INTERNATIONAL