15N-labelled nitrite/nitrate tracer analysis by LC-MS/MS: Urinary and fecal excretion of nitrite/nitrate following oral administration to mice
In: Free Radical Biology and Medicine, Jg. 143 (2019-11-01), S. 193-202
Online
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Zugriff:
Determination of the modulation of nitrite and nitrate levels in biological samples usually poses a major challenge, owing to their high background concentrations. To effectively investigate the variation of nitrite/nitrate in vivo, in this study, we developed a15N-labelled nitrite/nitrate tracer analysis using LC-MS/MS following the derivatization with 2,3-diaminonaphthalene. This method allows for the determination of 15N-labelled nitrite/nitrate as 15N-2,3-naphthotriazole (15N-NAT) that can efficiently differentiate newly introduced nitrite/nitrate from the background nitrite/nitrate in biological matrices. We also investigated the contribution of background 14N-NAT isotopomers to 15N-NAT, which has long been overlooked in the literature. Our results indicated that the contribution of background 14N-NAT isotopomers to 15N-NAT is significant. Such contribution is constant (~2.2% under positive ion mode and 1.1% under negative ion mode), and does not depend upon the concentration of 14N-NAT or the sample matrix measured. An equation has been therefore developed, for the first time, to correct the contribution of background 14N-NAT isotopomers to 15N-NAT. With the proposed 15N-labelled nitrite/nitrate tracer analysis, the amount and percentage distribution of 15NO2- and 15NO3-, both in urine and feces, after oral administration of 15N-labelled nitrite/nitrate are clearly demonstrated. The excretions of 15NO2- and 15NO3- were significantly increased with the increasing dose implying that the dietary nitrite/nitrate intake is an important source in urine/feces. The present method allows for the simple, reliable and accurate quantification of 15NO2- and 15NO3-, and it should also be useful to trace the biotransformation of nitrite and nitrate in vivo.
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15N-labelled nitrite/nitrate tracer analysis by LC-MS/MS: Urinary and fecal excretion of nitrite/nitrate following oral administration to mice
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Autor/in / Beteiligte Person: | Rajendra Bose Muthukumaran ; Chao, Mu-Rong ; Yen, Cheng-Chieh ; Chen, Jian-Lian ; Hu, Chiung-Wen ; Chang, Yuan-Jhe |
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Zeitschrift: | Free Radical Biology and Medicine, Jg. 143 (2019-11-01), S. 193-202 |
Veröffentlichung: | Elsevier BV, 2019 |
Medientyp: | unknown |
ISSN: | 0891-5849 (print) |
DOI: | 10.1016/j.freeradbiomed.2019.08.005 |
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