Quantitation of S-Adenosylmethionine and S-Adenosylhomocysteine in Plasma Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry

Fig. 1

HPLC -ESI-MS/MS ion chromatogram of SAM (m/z 399.1 > 250.1), SAH (m/z 385.1 > 136.1), SAM-D₃ (m/z 402.1 > 250.1) and SAH-D₄ (m/z 389.1 > 138.1). Concentration of SAM and SAH is 95 nM and 41 nM, respectively

3.2 Data Analysis

Instrumental operating parameters are given in Tables 1 and 2.

Table 1

HPLC -ESI-MS/MS operating conditions

(a) HPLC (SAM and SAH)^a
Column temp.	40 °C
Flow rate	0.20 mL/min
Gradient	Time (min)	Mobile phase A (%)
	0	75
	7	0
	7.1	75
	10	Stop
(b) MS/MS tune settings^b
Entrance Potential (V)	10
Curtain gas (psi)	20
CAD gas	Medium
Ion spray (V)	5000
Temp (°C)	700
GS 1 (psi)	40
GS 2 (psi)	50
Resolution Q1 and Q3	Unit

^aOptimized for Shimadzu Nexera liquid chromatography system equipped with Phenomenex EZ:faast, 3 μm, 250 × 2 mm analytical column; Mobile phase A: 4 mM ammonium acetate, 0.1 % formic acid and 0.1 % heptafluorobutyric acid in water; Mobile phase B: 0.1 % formic acid in methanol

^bOptimized for AB Sciex 5500QTRAP^®. Tune settings may vary slightly between instruments

Table 2

HPLC -ESI-MS/MS operating conditions