Ultra high performance liquid chromatography–mass
spectrometry method for metabolomics
In the discovery set, the collected sputum supernatant samples were
thawed on ice, and metabolites were extracted with acetonitrile and
methanol using previously described method22, 23.
Sputum supernatant samples were analyzed through using
an
UHPLC system (1290, Agilent Technologies) with
a
UPLC
BEH Amide (2.1 mm × 100 mm, 1.7 μm) coupled to TripleTOF 6550+6600
(Q-TOF, AB Sciex) via a previously described method with
modifications24. The detailed sputum preparation,
spectrometry method and metabolite identification were described in the
Online Data Supplement.