Measurements of Cavity Ringdown Spectroscopy of Acetone in the Ultraviolet and Near-Infrared Spectral Regions: Potential for Development of a Breath Analyzer

Abstract

We report a study on the cavity ringdown spectroscopy of acetone in both the ultraviolet (UV) and the near-infrared (NIR) spectral regions to explore the potential for development of a breath analyzer for disease diagnostics. The ringdown spectrum of acetone in the UV (282.4-285.0 nm) region is recorded and the spectrum is in good agreement with those obtained by other spectral techniques reported in the literature. The absorption cross-section of the C-H stretching overtone of acetone in the NIR (1632.7-1672.2 nm) is reported for the first time and the maximum absorption cross-section located at 1666.7 nm is 1.2 x 10(-21) cm(2). A novel, compact, atmospheric cavity with a cavity length of 10 cm has been constructed and implemented to investigate the technical feasibility of the potential instrument size, optical configuration, and detection sensitivity. The detection limit of such a mini cavity employing ringdown mirrors of reflectivity of 99.85% at 266 nm, where acetone has the strongest absorption, is approximately 1.5 ppmv based on the standard 3 criteria. No real breath gas samples are used in the present study. Discussions on the detection sensitivity and background spectral interferences for the instrument development are presented. This study demonstrates the potential of developing a portable, sensitive breath analyzer for medical applications using the cavity ringdown spectral technique.

Trace species detection in the near infrared using Fourier transform broadband cavity enhanced absorption spectroscopy: initial studies on potential breath analytes

“…This measurement is in good agreement with that of Wang et al (2004) [28] who report 1.2 × 10 -21 cm 2 at 6000 cm -1 . The peak isoprene cross section is higher reaching a maximum of 3.6 ± 0.2 × 10 -21 cm 2 at 1624.7 nm (6155 cm -1 ).…”

A fully integrated standalone portable cavity ringdown breath acetone analyzer

“…[43][44][45][46] In this method, absorbance of the atmosphere is used as the background baseline. τ atm , τ 0 , and τ breath are the ringdown times when the gas cell is filled with the laboratory atmosphere to 1 atm, the cell is vacuumed, and the cell is filled with a breath gas to 1 atm, respectively.…”

“…For example, in our previous report, a compact atmospheric ringdown cavity with a cavity length of 10 cm was constructed and implemented to explore the potential instrument portability (optical configuration and detection sensitivity). 44 That device was not integrated with electronics, a light source, a detector, pressure control, and sample introduction. The detection limit of the system was only 1.5 ppm due to the short cavity length.…”

“…One limitation of the current ringdown breath acetone analyzer is the upper-limit measurement that includes collective absorption from any other trace absorption of other compounds at 266 nm. 43 Given abundant spectral structures of acetone in a reduced pressure in the UV spectral region, 44 more accurate measurement (not the upper limit of acetone concentration) of acetone using a narrow linewidth UV laser can be achieved.…”

“…were a fully integrated standalone instrument. [43][44][45][46][47] In this work, we have built a fully integrated instrument based on the pulsed-CRDS technique for near-real time, online breath acetone measurements. This portable instrument can be readily placed in different places such as an office in a clinic to achieve quantitative analysis of breath acetone using a large number of subjects in a short period of time.…”