Development and Application of a LC-MS/MS Method for Simultaneous Quantification of Four First-Line Antituberculosis Drugs in Human Serum

Table 1

Optimized compound-dependent MS parameters for detection of the analytes and ISs.

Compound	Precursor ion (m/z)	Product ion (m/z)	DP/V	CE/V	CXP/V
INH	138.0	121.0	50.0	18.0	10.0
RFP	823.1	791.4	100.0	13.0	14.0
EMB	205.5	116.1	50.0	40.0	10.0
PZA	124.1	81.0	50.0	25.0	6.0
INH-D4	142.0	125.1	50.0	21.0	10.0
RFP-D8	831.5	799.6	92.0	15.0	15.0
EMB-D4	209.3	120.1	50.0	21.0	10.0
PZA-D3	127.2	84.1	60.0	24.0	6.0

PZA: pyrazinamide, INH: isoniazid, RFP: rifampicin, EMB: ethambutol, DP: declustering potential, CE: collision voltage, CXP: collision cell exit potential, IS: internal standard, and MS: mass spectrum.