{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T02:47:30Z","timestamp":1768704450086,"version":"3.49.0"},"reference-count":46,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2021,11,23]],"date-time":"2021-11-23T00:00:00Z","timestamp":1637625600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/50006\/2020"],"award-info":[{"award-number":["UIDB\/50006\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["program DL 551 57\/2016 - Norma transit\u00f3ria"],"award-info":[{"award-number":["program DL 551 57\/2016 - Norma transit\u00f3ria"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["SFRH\/BD\/130948\/2017)"],"award-info":[{"award-number":["SFRH\/BD\/130948\/2017)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Programa Operacional Regional Norte (NORTE2020)","award":["SFRH\/BD\/130948\/2017"],"award-info":[{"award-number":["SFRH\/BD\/130948\/2017"]}]},{"DOI":"10.13039\/501100004895","name":"European Social Fund","doi-asserted-by":"publisher","award":["SFRH\/BD\/130948\/2017"],"award-info":[{"award-number":["SFRH\/BD\/130948\/2017"]}],"id":[{"id":"10.13039\/501100004895","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>The quantitative analysis of pharmaceuticals in biomatrices by liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS\/MS) is often hampered by adduct formation. The use of the molecular ion resulting from solvent adducts for quantification is uncommon, even if formed in high abundance. In this work, we propose the use of a protonated acetonitrile adduct for the quantitative analysis of tranexamic acid (TXA) by LC-MS\/MS. The high abundance of the protonated acetonitrile adduct [M + ACN + H]+ was found to be independent of source-dependent parameters and mobile phase composition. The results obtained for TXA analysis in clinical samples were comparable for both [M + ACN + H]+ and [M + H]+, and no statistically significant differences were observed. The relative stability and structure of the [M + ACN + H]+ ions were also studied by analyzing probable structures from an energetic point of view and by quantum chemical calculations. These findings, and the studied fragmentation pathways, allowed the definition of an acetimidium structure as the best ion to describe the observed acetonitrile protonated adduct of TXA.<\/jats:p>","DOI":"10.3390\/ph14121205","type":"journal-article","created":{"date-parts":[[2021,11,30]],"date-time":"2021-11-30T23:22:56Z","timestamp":1638314576000},"page":"1205","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Acetonitrile Adducts of Tranexamic Acid as Sensitive Ions for Quantification at Residue Levels in Human Plasma by UHPLC-MS\/MS"],"prefix":"10.3390","volume":"14","author":[{"given":"Eduarda M. P.","family":"Silva","sequence":"first","affiliation":[{"name":"TOXRUN\u2014Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, 4585-116 Gandra, Portugal"},{"name":"LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3481-5809","authenticated-orcid":false,"given":"Luisa","family":"Barreiros","sequence":"additional","affiliation":[{"name":"LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"},{"name":"School of Health, Polytechnic Institute of Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida 400, 4200-072 Porto, Portugal"}]},{"given":"Sara R.","family":"Fernandes","sequence":"additional","affiliation":[{"name":"LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"},{"name":"School of Health, Polytechnic Institute of Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida 400, 4200-072 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2055-3759","authenticated-orcid":false,"given":"Paula","family":"S\u00e1","sequence":"additional","affiliation":[{"name":"Centro Hospitalar Universit\u00e1rio do Porto, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4419-6431","authenticated-orcid":false,"given":"Jo\u00e3o P. Prates","family":"Ramalho","sequence":"additional","affiliation":[{"name":"Department of Chemistry, School of Science and Technology, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"},{"name":"LAQV, REQUIMTE, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"},{"name":"Hercules Laboratory, University of \u00c9vora, Pal\u00e1cio do Vimioso, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2938-0214","authenticated-orcid":false,"given":"Marcela A.","family":"Segundo","sequence":"additional","affiliation":[{"name":"LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gross, J.H. (2017). Mass Spectrometry, Springer Nature. [3rd ed.].","DOI":"10.1007\/978-3-319-54398-7"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"6625","DOI":"10.1007\/s00216-020-02825-z","article-title":"Determination of neuropeptide Y Y1 receptor antagonist BIBP 3226 and evaluation of receptor expression based on liquid chromatography coupled with tandem mass spectrometry","volume":"412","author":"Barreiros","year":"2020","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1016\/j.jpba.2018.01.013","article-title":"Gas-phase structural characterization of neuropeptides Y Y1 receptor antagonists using mass spectrometry: Orbitrap vs triple quadrupole","volume":"151","author":"Silva","year":"2018","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1016\/j.jpba.2016.12.028","article-title":"Development and validation of a liquid chromatography-MS\/MS method for simultaneous quantification of tenofovir and efavirenz in biological tissues and fluids","volume":"136","author":"Barreiros","year":"2017","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2228","DOI":"10.1002\/rcm.7697","article-title":"Characterization of 2,3-diarylxanthones by electrospray mass spectrometry: Gas-phase chemistry versus known antioxidant activity properties","volume":"30","author":"Silva","year":"2016","journal-title":"Rapid Commun. Mass Spectrom."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"898","DOI":"10.1002\/mas.20247","article-title":"Electrospray: From ions in solution to ions in the gas phase, what we know now","volume":"28","author":"Kebarle","year":"2009","journal-title":"Mass Spectrom. Rev."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Erngren, I., Nestor, M., Pettersson, C., and Hedeland, M. (2021). Improved sensitivity in hydrophilic interaction liquid chromatography-electrospray-mass spectrometry after removal of sodium and potassium ions from biological samples. Metabolites, 11.","DOI":"10.3390\/metabo11030170"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.chroma.2019.03.015","article-title":"Rapid and selective screening for toxic phorbol esters in Jatropha curcas seed oil using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry","volume":"1597","author":"Verardo","year":"2019","journal-title":"J. Chromatogr. A"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/j.jchromb.2018.09.028","article-title":"Quantitative analysis of 4 beta- and 4 alpha-hydroxycholesterol in human plasma and serum by UHPLC\/ESI-HR-MS","volume":"1100","author":"Hautajarvi","year":"2018","journal-title":"J. Chromatogr. B"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"695","DOI":"10.1002\/jms.3218","article-title":"Sodium adduct formation efficiency in ESI source","volume":"48","author":"Kruve","year":"2013","journal-title":"J. Mass Spectrom."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"585","DOI":"10.1016\/j.jasms.2003.12.013","article-title":"Adduct formation in quantitative bioanalysis: Effect of ionization conditions on paclitaxel","volume":"15","author":"Mortier","year":"2004","journal-title":"J. Am. Soc. Mass Spectrom."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.jchromb.2015.05.004","article-title":"Determination of pseudoprotodioscin in rat plasma by UPLC-MS\/MS: Assay development and application to pharmacokinetic study","volume":"1026","author":"Liao","year":"2016","journal-title":"J. Chromatogr. B"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1002\/jms.3174","article-title":"Lithium adduct as precursor ion for sensitive and rapid quantification of 20 (S)-protopanaxadiol in rat plasma by liquid chromatography\/quadrupole linear ion trap mass spectrometry and application to rat pharmacokinetic study","volume":"48","author":"Bao","year":"2013","journal-title":"J. Mass Spectrom."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1007\/s13361-017-1626-y","article-title":"Adduct formation in ESI\/MS by mobile phase additives","volume":"28","author":"Kruve","year":"2017","journal-title":"J. Am. Soc. Mass Spectrom."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1987","DOI":"10.1007\/s13361-014-0975-z","article-title":"Acetonitrile adduct formation as a sensitive means for simple alcohol detection by LC-MS","volume":"25","author":"Bogseth","year":"2014","journal-title":"J. Am. Soc. Mass Spectrom."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"5867","DOI":"10.1021\/ac400619g","article-title":"Analysis of (functionalized) fullerenes in water samples by liquid chromatography coupled to high-resolution mass spectrometry","volume":"85","author":"Kolkman","year":"2013","journal-title":"Anal. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1931","DOI":"10.1007\/s00216-012-6005-8","article-title":"Liquid chromatography-mass spectrometry for C-60 fullerene analysis: Optimisation and comparison of three ionisation techniques","volume":"403","author":"Li","year":"2012","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1826","DOI":"10.1007\/s13361-011-0191-z","article-title":"Optimization and comparison of ESI and APCI LC-MS\/MS methods: A case study of irgarol 1051, diuron, and their degradation products in environmental samples","volume":"22","author":"Maragou","year":"2011","journal-title":"J. Am. Soc. Mass Spectrom."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1002\/rcm.3333","article-title":"Study on the formation of an amoxicillin adduct with methanol using electrospray ion trap tandem mass spectrometry","volume":"22","author":"Grujic","year":"2008","journal-title":"Rapid Commun. Mass Spectrom."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"823","DOI":"10.1002\/jms.495","article-title":"Sensitive liquid chromatographic\/tandem mass spectrometric method for the determination of beclomethasone dipropionate and its metabolites in equine plasma and urine","volume":"38","author":"Guan","year":"2003","journal-title":"J. Mass Spectrom."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1016\/j.microc.2017.06.020","article-title":"Analytical methods for quantification of tranexamic acid in biological fluids: A review","volume":"134","author":"Silva","year":"2017","journal-title":"Microchem J."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.jpba.2017.04.024","article-title":"LC-MS\/MS determination of tranexamic acid in human plasma after phospholipid clean-up","volume":"141","author":"Fabresse","year":"2017","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1016\/j.jpba.2014.01.026","article-title":"Development of SPME method for concomitant sample preparation of rocuronium bromide and tranexamic acid in plasma","volume":"92","author":"Gorynski","year":"2014","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1016\/j.jpba.2013.12.005","article-title":"Quantification of total and unbound tranexamic acid in human plasma by ultrafiltration liquid chromatography\/tandem mass spectrometry: Application to pharmacokinetic analysis","volume":"91","author":"Delavenne","year":"2014","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1097\/FTD.0b013e3182400540","article-title":"Therapeutic monitoring of tranexamic acid concentration: High-throughput analysis with solid-phase microextraction","volume":"34","author":"Bojko","year":"2012","journal-title":"Ther. Drug Monit."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3781","DOI":"10.1016\/j.jchromb.2011.08.003","article-title":"Determination of tranexamic acid concentration by solid phase microextraction and liquid chromatography-tandem mass spectrometry: First step to in vivo analysis","volume":"879","author":"Bojko","year":"2011","journal-title":"J. Chromatogr. B"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"553","DOI":"10.1016\/j.jchromb.2011.01.005","article-title":"Plasma and cerebral spinal fluid tranexamic acid quantitation in cardiopulmonary bypass patients","volume":"879","author":"Sniecinski","year":"2011","journal-title":"J. Chromatogr. B"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1016\/j.cca.2010.01.005","article-title":"A validated assay for the quantitative analysis of tranexamic acid in human serum by liquid chromatography coupled with electrospray ionization mass spectrometry","volume":"411","author":"Abe","year":"2010","journal-title":"Clin. Chim. Acta"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1016\/j.jchromb.2004.03.013","article-title":"Liquid chromatography-tandem mass spectrometry method for the determination of tranexamic acid in human plasma","volume":"805","author":"Chang","year":"2004","journal-title":"J. Chromatogr. B"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.microc.2018.08.061","article-title":"Determination of tranexamic acid in human plasma by UHPLC coupled with tandem mass spectrometry targeting sub-microgram per milliliter levels","volume":"144","author":"Barreiros","year":"2019","journal-title":"Microchem. J."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2824","DOI":"10.1055\/s-0036-1589535","article-title":"Acetonitrile as a building block and reactant","volume":"50","author":"Hoff","year":"2018","journal-title":"Synthesis"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1175","DOI":"10.1039\/a607626b","article-title":"Formation of hemiaminals by N-protonation of ketenimines (etheneimines) sterically hindered at carbon","volume":"2","author":"Hegarty","year":"1997","journal-title":"J. Chem. Soc. Perkin Trans."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1802","DOI":"10.1016\/j.jasms.2010.06.017","article-title":"Gas-phase Meerwein reaction of epoxides with protonated acetonitrile generated by atmospheric pressure ionizations","volume":"21","author":"Wu","year":"2010","journal-title":"J. Am. Soc. Mass Spectrom."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1025","DOI":"10.1002\/rcm.4458","article-title":"Using density functional theory to rationalise the mass spectral fragmentation of maraviroc and its metabolites","volume":"24","author":"Wright","year":"2010","journal-title":"Rapid Commun. Mass Spectrom."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"721","DOI":"10.1248\/cpb.c21-00079","article-title":"Application of quantitative NMR spectroscopy to the quality evaluation of diclofenac gargles as hospital preparations","volume":"69","author":"Akira","year":"2021","journal-title":"Chem. Pharm. Bull."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"444","DOI":"10.1021\/op500395b","article-title":"An improved and practical synthesis of tranexamic acid","volume":"19","author":"Li","year":"2015","journal-title":"Org. Process Res. Dev."},{"key":"ref_37","unstructured":"European Medicines Agency (2021, July 05). Guideline Bioanalytical Method Validation EMEA\/CHMP\/EWP\/192217\/2009. Available online: https:\/\/www.ema.europa.eu\/en\/documents\/scientific-guideline\/guideline-bioanalytical-method-validation_en.pdf."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"5559","DOI":"10.1073\/pnas.1914237117","article-title":"Science is not a signal detection problem","volume":"117","author":"Wilson","year":"2020","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_39","first-page":"12","article-title":"Low replicability can support robust and efficient science","volume":"11","author":"Lewandowsky","year":"2020","journal-title":"Nat. Commun."},{"key":"ref_40","unstructured":"(2021, July 05). ICH Guideline Q2(R1), Validation of Analytical Procedures: Text and Methodology, 541. Available online: https:\/\/www.ema.europa.eu\/en\/ich-q2-r1-validation-analytical-procedures-text-methodology."},{"key":"ref_41","unstructured":"Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Barone, V., Petersson, G.A., and Nakatsuji, H. (2016). Gaussian 16 Rev. C.01, Gaussian, Inc."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1007\/s00214-007-0310-x","article-title":"The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: Two new functionals and systematic testing of four M06-class functionals and 12 other functionals","volume":"120","author":"Zhao","year":"2008","journal-title":"Theor. Chem. Acc."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"362","DOI":"10.1002\/mas.10008","article-title":"Practical implications of some recent studies in electrospray ionization fundamentals","volume":"20","author":"Cech","year":"2001","journal-title":"Mass Spectrom. Rev."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"6378","DOI":"10.1021\/jp810292n","article-title":"Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielectric constant and atomic surface tensions","volume":"113","author":"Marenich","year":"2009","journal-title":"J. Phys. Chem. B"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"9955","DOI":"10.1002\/chem.201200497","article-title":"Supramolecular binding thermodynamics by dispersion-corrected density functional theory","volume":"18","author":"Grimme","year":"2012","journal-title":"Chem.-Eur. J."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"291","DOI":"10.12688\/f1000research.22758.1","article-title":"Goodvibes: Automated thermochemistry for heterogeneous computational chemistry data","volume":"9","author":"Luchini","year":"2020","journal-title":"F1000Research"}],"container-title":["Pharmaceuticals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8247\/14\/12\/1205\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:34:31Z","timestamp":1760168071000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8247\/14\/12\/1205"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,11,23]]},"references-count":46,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2021,12]]}},"alternative-id":["ph14121205"],"URL":"https:\/\/doi.org\/10.3390\/ph14121205","relation":{},"ISSN":["1424-8247"],"issn-type":[{"value":"1424-8247","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,11,23]]}}}