Aerosol analysis by cavity-ring-down laser spectroscopy

TY - JOUR

T1 - Aerosol analysis by cavity-ring-down laser spectroscopy

AU - Bulatov, Valery

AU - Fisher, Michal

AU - Schechter, Israel

N1 - Funding Information: This research was supported by the Israel Science Foundation (Grant no. 112/1), by the James Franck Program in Laser Matter Interaction and by the Fund for promotion of research, Technion. Valery Bulatov is grateful for financial support by Ministry of Absorption for new immigrant scientists. Helpful discussions with S. Cheskis of Tel-Aviv University are much appreciated. Several discussions with A. Kachanov of Universitè Joseph Fourier, Grenoble and S. Panov of Massachusetts Institute of Technology are also acknowledged. We also thank V. Ryaboy of the Technion, Haifa, for assistance with the Fortran coding and calculations.

PY - 2002/8/21

Y1 - 2002/8/21

N2 - The cavity-ring-down technique was applied for aerosol detection. The experimental set-up was based on a pulsed dye laser pumped with the third harmonic of an Nd:YAG laser. Validation of the method was performed using calibrated aerosol flows, all under ambient conditions. The method was exemplified with non-absorbing aerosols, such as NaCl and CuCl2·2H2O, of various sizes and concentrations. The results were used for the evaluation of the corresponding aerosol extinction coefficients as a function of size, shape and index of refraction. The thus obtained aerosol extinction efficiencies were compared to theoretical models. Good agreement with theory was observed for NaCl aerosols, while the results for CuCl2·2H2O particulates required averaging over particle size and over the orientation dependent index of refraction. The actual sensitivity currently achieved was as low as an extinction coefficient of 8×10-8cm-1, which means detection capability of about six water micro-particulates per cm3. The ultimate theoretical performance of this method for aerosol detection was estimated as an extinction coefficient of 1.4×10-12cm-1, corresponding to about 100 micro-particulates per m3. These figures indicate that this method has the potential to become one of the most sensitive on-line analytical technique for aerosol detection and quantification.

AB - The cavity-ring-down technique was applied for aerosol detection. The experimental set-up was based on a pulsed dye laser pumped with the third harmonic of an Nd:YAG laser. Validation of the method was performed using calibrated aerosol flows, all under ambient conditions. The method was exemplified with non-absorbing aerosols, such as NaCl and CuCl2·2H2O, of various sizes and concentrations. The results were used for the evaluation of the corresponding aerosol extinction coefficients as a function of size, shape and index of refraction. The thus obtained aerosol extinction efficiencies were compared to theoretical models. Good agreement with theory was observed for NaCl aerosols, while the results for CuCl2·2H2O particulates required averaging over particle size and over the orientation dependent index of refraction. The actual sensitivity currently achieved was as low as an extinction coefficient of 8×10-8cm-1, which means detection capability of about six water micro-particulates per cm3. The ultimate theoretical performance of this method for aerosol detection was estimated as an extinction coefficient of 1.4×10-12cm-1, corresponding to about 100 micro-particulates per m3. These figures indicate that this method has the potential to become one of the most sensitive on-line analytical technique for aerosol detection and quantification.

KW - Aerosol

KW - Analysis

KW - CRLAS

KW - Laser

KW - Particulates

KW - Ring-down

UR - http://www.scopus.com/inward/record.url?scp=0037151701&partnerID=8YFLogxK

U2 - 10.1016/S0003-2670(02)00516-0

DO - 10.1016/S0003-2670(02)00516-0

M3 - 文章

AN - SCOPUS:0037151701

SN - 0003-2670

VL - 466

SP - 1

EP - 9

JO - Analytica Chimica Acta

JF - Analytica Chimica Acta

IS - 1

ER -