Follow the directions from Golden 4 Life to step 4.
At step 5, reconstitute in an appropriate LC-MS/MS diluent, e.g. aq. 2 mM Amm. acetate/MeOH (~60:40, based on the initial gradient condition below).
Details are lifted from a Thermo Scientific application note.
LC/ESI/MS
LC System: Thermo Scientific Rheos 2000 pump
Column: Hypersil GOLD 3 μm, 50 × 2.1 mm
Part Number: 25003-052130
Mobile Phase: A: 2mM NH4Ac in water/methanol (95:5)
B: 2mM NH4Ac in methanol
Gradient: Time (min) .. %B
0.0 .... 55
3.0 .... 85
3.1 .... 95
4.0 .... 55
5.0 .... 55
Flow Rate: 0.3 mL/min
Injection Volume: 10 μL
MS System: Thermo Scientific MSQ Plus™
Detection: Negative ESI (400° C, 90 eV)
Scan Range: 0–2.45 min SIM m/z 368.9; 2.46–4.0 min SIM m/z 498.8
Selected Ions: m/z 368.9 (fragment of PFOA m/z 412.8 → 368.9) m/z 498.8 (PFOS)
Dwell Time: 0.6 s
Mo