title: Determination of l-tryptophan and l-kynurenine derivatized with (R)-4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole by LC-MS/MS on a triazole-bonded column and their quantification in human serum.
abstract: The concentrations of l-tryptophan (Trp) and the metabolite l-kynurenine (KYN) can be used to evaluate the in-vivo activity of indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO). As such, a novel method involving derivatization of l-Trp and l-KYN with (R)-4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole (DBD-PyNCS) and separation by high-performance liquid chromatography (HPLC) with tandem mass spectrometric (MS/MS) detection on a triazole-bonded column (Cosmosil HILIC®) was developed to determine their concentrations. The optimized mobile phase, CH3 CN/10 mm ammonium formate in H2 O (pH 5.0) (90:10, v/v) eluted isocratically, resulted in satisfactory separation and MS/MS detection of the analytes. The detection limits of l-Trp and l-KYN were approximately 50 and 4.0 pm, respectively. The column temperature affected the retention behaviour of the Trp and KYN derivatives, with increased column temperatures leading to increased capacity factors; positive enthalpy changes were revealed by van't Hoff plot analyses. Using the proposed LC-MS/MS method, l-Trp and l-KYN were successfully determined in 10 μL human serum using 1-methyl-l-Trp as an internal standard. The precision and recovery of l-Trp were in the ranges 2.85-9.29 and 95.8-113%, respectively, while those of l-KYN were 2.51-16.0 and 80.8-98.2%, respectively. The proposed LC-MS/MS method will be useful for evaluating the in vivo activity of IDO or TDO. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Shuuhei
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Iizuka
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Ryousuke
authors.initials: R
authors.lastname: Kuwabara
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sakamoto
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Miyagi
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Onozato
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ichiba
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba, 274-8510, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukushima
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D017879:Isothiocyanates / Q000737:chemistry*; D007737:Kynurenine / Q000097:blood*; D057230:Limit of Detection; D008297:Male; D010069:Oxadiazoles / Q000737:chemistry*; D012015:Reference Standards; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014230:Triazoles / Q000737:chemistry*; D014364:Tryptophan / Q000097:blood*
chemical_list: C107817:4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole; D017879:Isothiocyanates; D010069:Oxadiazoles; D014230:Triazoles; D007737:Kynurenine; D014364:Tryptophan