Abstract: Based on wavelet transform and first-derivative photoacoustic spectroscopy（PAS）, a new analytical method for PAS is presented. An experiment setup is specially designed to get the first-derivative spectrum,thus the sensitivity of PAS analysis is improved. In order to increase the accuracy of measurement,the wavelet transform is introduced to decompose the PAS signal into localized detail signals according to the frequency,noise and PAS signals can be discriminated by the difference of frequency,and the position of PAS peaks in time axis and the original linearity are not changed,hence the useful information can be obtained by this decomposed result. Due to the wave- let method and derivative PAS method,three weak absorption peaks which hidden in PAS of Xenon lamp output are precisely retrieved,whose wavelengths are 669.7 nm,753.4 nm and 776.5 nm, respectively. This new analytical method,which takes advantage of the virtues of physics method and software technique, can be used to improve the sensitivity and accuracy of PAS analysis effectively, and it is expected to be a useful analysis tool in biology medical and chemistry analysis.

Key words: spectral analysis, photoacoustic spectroscopy, derivative photoacoustic spectroscopy, wavelet analysis