title: Rapid spectrophotometric pH measurements based on the dual-wavelength technique.
abstract: A spectrophotometric method for the measurement of pH in solutions of lidocaine hydrochloride (Xylocaine) for injection is presented. 4-Nitrophenol is used as an indicator for determinations of pH in the range 6.5-7.0. The method was found to be faster than the conventional potentiometric method, mainly due to the utilization of a computer-controlled photodiode array spectrophotometer for the measurements. A further advantage with the spectrophotometric method is that errors arising from varying liquid junction potentials are avoided.
authors.affiliation: Astra Pharmaceutical Production AB, Analytical Control, S-151 85 Södertälje, Sweden.
authors.forename: P A
authors.initials: PA
authors.lastname: Johansson
authors.forename: G
authors.initials: G
authors.lastname: Ostling
authors.forename: J
authors.initials: J
authors.lastname: Drakenberg