Abstract
A direct, rapid and continuous in vivo monitoring of diffusible calcium in the blood of living rabbits has been developed using microdialysis sampling coupled on-line with flame atomic absorption spectrometry. Microdialysates perfused through implanted microdialysis probes were collected with a sample loop on an injection valve and directly introduced into the flame atomizer by a carrier solution. An ultrapure saline solution (0.9% NaCl, pH 7.2) was used as the perfusion solution at a flow rate of 20 μl min -1 via the microdialysis probe. A 0.1% La solution in 0.5% HNO 3 solution was employed as the carrier solution at a nebulizer uptake flow rate of 2.5 ml min -1 . The interval for each determination was 2.5 min (2 min of sampling time, 20 s of read time and 10 s of washing time). The performance characteristics of the on-line microdialysis-FAAS system were validated as follows: linearity range, 0-100 mg l- 1 ; detection limit (3σ, n = 7), 3.66 mg l -1 ; precision (RSD, n = 50), 6.2%. For the evaluation of analytical accuracy, the proposed on-line method was compared with the in vivo no net flux method. The use of an on-line microdialysis-FAAS system permitted the in situ, dynamic and continuous in vivo monitoring of diffusible calcium in the blood of the living rabbits after CaCl 2 administration with a temporal resolution of 2.5 min. 2005 © The Japan Society for Analytical Chemistry.