Flow-injection determination of total ammonia and total carbon dioxide in blood based on gas-diffusion separation and with a bulk acoustic wave impedance sensor.
A novel flow-injection (FIA) system, for the rapid and direct determination of both total ammonia (T[NH3]) and total carbon dioxide (T[CO2]) in clinical blood samples, has been developed. Samples were injected into a carrier stream of H2O, then emerged with a reagent stream, where the analyte was converted into a gaseous species and diffused across a PTFE gas-permeable membrane into an acceptor stream. The trapped NH3/CO2 in the acceptor was determined on line by a bulk acoustic wave (BAW) impedance sensor. At a through-put of 20 and 65 h(-1), the proposed system exhibited a linear frequency response up to 200 micromol l(-1) ammonium and 20 mmol l(-1) bicarbonate with a detection limit of 1.0 and 10 micromol l(-1), respectively. Results obtained for T(NH3) in serum and T(CO2) in plasma were in agreement with those obtained by the conventional glutamate dehydrogenase (GDH) method and gas-sensing electrode method, respectively. The effects of composition of acceptor stream, cell constant of conductivity electrode, sample volume, flow rate and potential interferents on the FIA signals were also discussed.
Su
X L
XL
New Material Research Institute, Chemistry and Chemical Engineering College of Hunan University, Changsha, People's Republic of China.
Yu
B S
BS
Tan
H W
HW
Yang
X R
XR
Nie
L H
LH
Yao
S Z
SZ
D000162:Acoustics; D000641:Ammonia / Q000097:blood*; D002245:Carbon Dioxide / Q000097:blood*; D004058:Diffusion; D004566:Electrodes; D017022:Flow Injection Analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012680:Sensitivity and Specificity
D002245:Carbon Dioxide; D000641:Ammonia