Methanol hplc grade

Dasatinib (98.44%), nilotinib (99.77%), and ponatinib (98.96%) were obtained from ChemScene; bosutinib (≥98%) was obtained from Cayman Chemical; HPLC‐grade acetonitrile was obtained from Merck KGaA; and potassium dihydrogen phosphate, phosphoric acid, HPLC‐grade methanol, and isopropanol were obtained from Nacalai Tesque. Pooled human serum was obtained from Cosmo Bio.

HPLC grade methanol and ethanol, formic acid, and sodium trifluoroacetate (NaTFA) were purchased from Nacalai Tesque Inc., Kyoto, Japan. MALDI grade 2,5-dihydroxybenzoic acid (DHBA) was purchased from Sigma-Adlrich Inc. (St. Louis, MO, USA). Albiflorin was purchased from ChromaDex Inc. (Irvine, CA, USA). Paeoniflorin was purchased from LKT laboratories, Inc. (St. Paul, MN, USA). Rutin, a flavonoid glycoside, was purchased from Extrasynthese S.A. (Genay, France).

DAAQ (melting point, 319°C) and 3-methylxanthine (m.p. >300°C) were purchased from Tokyo Chemical Industry CO., LTD., Tokyo, Japan. Epinastine (m.p. 205–208°C) was purchased from BLD Pharmatech Ltd., Shanghai, P.R. China. Camptothecin (m.p. 275–277°C) was purchased from Alomone Labs, Israel. Methanol (HPLC grade) was purchased from NACALAI TESQUE, INC., Kyoto, Japan. Water was produced by an ultrapure water production system from Milli-Q IQ 7003 (Merck KGaA, Darmstadt, Germany) with ion-exchange filtration by activated carbon.
5 mM DAAQ was prepared in 60% methanol. 2 mM Epinastine, camptothecine, and 3-methylxanthine were prepared in 60% methanol.
The analytes were premixed with a 5 mM DAAQ solution or a 60% methanol solution (50 : 50, v/v), and a 1 μL aliquot of the premixed analyte solution was deposited on the MALDI-MS plate.