Determination of formaldehyde with the thermal lens effect

Article abstract of DOI:10.1021/ac00281a019

The laser thermal lens analysis of formaldehyde is reported. Two systems were tested, the first using a single laser in combination with a single diode detector and the second using two lasers in conjunction with a photodiode array detector. The formaldehyde solutions were prepared for colorimetry using the NIOSH method based on chromotropic acid. Improved sensitivity over standard absorption techniques is observed with enhancement factors up to 20.0 based on detection of absorptivity as low as 9 x 10^-5 cm^-5 which corresponds to a concentration of 1.5 x 10^-8 M. With collection efficiency of 95% for sampling solutions, this supports facile detection of formaldehyde in the parts-per-billion region in air. The laser thermal lens analysis of formaldehyde is reported. Two systems were tested, the first using a single laser in combination with a single diode detector and the second using two lasers in conjunction with a photodiode array detector. The formaldehyde solutions were prepared for colorimetry using the NIOSH method based on chromotropic acid. Improved sensitivity over standard absorption techniques is observed with enhancement factors up to 20. 0 based on detection of absorptivity as low as 9 multiplied by 10** minus **5 cm** minus **1 which corresponds to a concentration of 1. 5 multiplied by 10** minus **8 M. With collection efficiency of 95% for sampling solutions, this supports facile detection of formaldehyde in the parts-per-billion region in air.