{"doi":"10.1016/j.mex.2021.101412","title":"Quantitative determination of nitric oxide from tissue samples using liquid chromatography—Mass spectrometry","abstract":"Ever since it was found to mediate the endothelium-dependent dilation of blood vessels, nitric oxide (NO) has generated enormous research interest throughout the biological sciences. Over thirty years of research has identified NO as a ubiquitous and versatile regulatory factor utilized by both vertebrates and invertebrates. The short lifetime and low concentration of NO make quantitation difficult. Here we report a method for measuring NO using the selective reaction with 2-​(4-​carboxyphenyl)-​4,​5-​dihydro-​4,​4,​5,​5-​tetramethyl-1H-​imidazolyl-​1-​oxy-​3-​oxide (carboxy-PTIO) to form carboxy-PTI. We used tandem mass spectrometry to verify the validity of this reaction, and liquid chromatography - mass spectrometry to quantitate the amount of carboxy-PTI formed. Using diethylamine nonoate as a NO donor we demonstrate this method can quantitate NO concentrations with a detection limit of 5 nM. We successfully determined the amount of NO generated endogenously by frog heart/aorta when stimulated by carbachol, a non-selective acetylcholine receptor agonist. Based on these results, we suggest that this technique can be useful for the quantitative determination of NO in biological samples.•We report a method to measure NO by reacting it with carboxy-PTIO to form carboxy-PTI.•The carboxy-PTI is quantified by liquid chromatography mass spectrometry (LCMS).•This method can quantitate NO concentrations ranging from 5 nM to 1 µM.","journal":"MethodsX","year":2021,"id":208348,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9522,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":393629,"name":"Elaine M. Marzluff","orcid":null,"position":1,"is_corresponding":false},{"id":391981,"name":"Clark A. Lindgren","orcid":"0000-0001-5918-8464","position":2,"is_corresponding":false},{"id":630126,"name":"Stephen X. Zhang","orcid":"0000-0001-7743-9247","position":0,"is_corresponding":true}],"reference_count":45,"raw_metadata":null,"created_at":"2026-07-18T23:51:57.582057Z","pmid":"34430307","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}