Difference-frequency-based tunable absorption spectrometer for detection of atmospheric formaldehyde.
High-sensitivity detection of formaldehyde (CH2O) at 3.5315 micrometers (2831.64 cm-1) is reported with a diode-laser-pumped, fiber-coupled, periodically poled LiNbO3 spectroscopic source. This source replaced the Pb-salt diode laser Dewar assembly of an existing tunable diode-laser absorption spectrometer designed for ultrasensitive detection of CH2O. Spectra are recorded with 2f-modulation spectroscopy and zero-air rapid background subtraction. Initial measurements reported here, determined from multiple measurements of a flowing 7.7 parts per billion by volume (ppbv, parts in 10(9)) CH2O in air mixture, indicate replicate precisions as low as 0.24 ppbv.
Lancaster
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DG
Electrical and Computer Engineering Department, Rice University, Houston, Texas 77005, USA.
Fried
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A
Wert
B
B
Henry
B
B
Tittel
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FK
D001272:Atmosphere / Q000737:chemistry*; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005557:Formaldehyde / Q000032:analysis*; D007834:Lasers; D007854:Lead; D013055:Spectrophotometry, Infrared / Q000295:instrumentation*
D005557:Formaldehyde; D007854:Lead