title: Calibration by NMR for quantitative analysis: p-toluenesulfonic acid as a reference substance.
abstract: We have demonstrated the usefulness of p-toluenesulfonic acid (TsOH) as a reference substance to calibrate a water-soluble standard by NMR for quantitative analysis. In order to make TsOH convenient for this purpose, we first of all established its molar extinction coefficient under these conditions (epsilon = 351 at 262 nm). This was done by comparing it by quantitative NMR (qNMR) with a compound of known molar extinction coefficient, guanosine monophosphate. TsOH was then used as the standard in a second qNMR experiment to measure an aqueous solution of phosphoglycolate, a metabolite of interest in our laboratory. Perhaps due to its content of water, the purity of this compound was found to be 82%, lower than the value of 94% from the manufacturer.
authors.affiliation: Department of Pharmaceutical Sciences in the Bouve College of Health Sciences, Barnett Institute, Northeastern University, Boston, MA 02115, USA.
authors.forename: Gang
authors.initials: G
authors.lastname: Shao
authors.forename: Roger
authors.initials: R
authors.lastname: Kautz
authors.forename: Shiqi
authors.initials: S
authors.lastname: Peng
authors.forename: Guohui
authors.initials: G
authors.lastname: Cui
authors.forename: Roger W
authors.initials: RW
authors.lastname: Giese
mesh_terms: D001557:Benzenesulfonates / Q000032:analysis / Q000592:standards*; D002138:Calibration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D001557:Benzenesulfonates; C029501:4-toluenesulfonic acid