Absorption, quenching, and enhancement by tracer in acetone/toluene laser-induced fluorescence*

Abstract

To measure the equivalent ratio distribution of the two-stage lean premixed (DLP) flame, we propose using acetone/toluene planar laser-induced fluorescence (PLIF) technology to simultaneously measure the concentrations of the two components. Appropriate excitation laser wavelength and filters are used to assess the influence of acetone and toluene on each other’s fluorescence signal at room temperature. Experimental results show that acetone has a strong absorption effect on toluene’s fluorescence signal, the effective absorption cross-section is 5.77 × 10−20 cm−2. Acetone has an obvious quenching effect on the toluene fluorescence signal, and the Stern–Volmer coefficient is 0.50 kPa−1. The collisions between the molecules of toluene and acetone will lead to the enhancement of the fluorescence signal of acetone, and the enhancement coefficient is exponential with the acetone’s concentration. The quantitative relationship between the fluorescence intensity and the concentrations of the two tracers is obtained by establishing the photophysical model of toluene and acetone’s fluorescence signals.

Quantitative acetone/toluene planar laser‐induced fluorescence measurements of equivalent ratio

“…In our previous studies, we investigated the absorption, quenching, and enhancement effects of the tracer on the fluorescence signal between acetone and toluene. 47 In this paper, we develop a new acetone/toluene PLIF, enabling the simultaneous quantitative measurement of the concentration distribution of two gas components with smaller measurement uncertainty, and verify the reliability of its measurement results using OH-PLIF.…”

“…Acetone would quench toluene fluorescence and toluene would enhance acetone fluorescence due to sensitized fluorescence, 47 and the fluorescence signal emitted by toluene is partially absorbed by acetone. In the ambient conditions of room temperature and atmospheric pressure with nitrogen, the quantitative relationship between two tracers' concentration and the respective fluorescence intensity is expressed by…”

“…Acetone would quench toluene fluorescence and toluene would enhance acetone fluorescence due to sensitized fluorescence, 47 and the fluorescence signal emitted by toluene is partially absorbed by acetone. In the ambient conditions of room temperature and atmospheric pressure with nitrogen, the quantitative relationship between two tracers' concentration and the respective fluorescence intensity is expressed by $$$\begin{array}{c}{S}_{{\rm{t}}}(x)={k}_{{\rm{t}}}{E}_{0}\text{exp}\left({\int }_{0}^{x}-({\sigma }_{{\rm{a}}}{n}_{{\rm{a}}}(x)+{\sigma }_{{\rm{t}}}{n}_{{\rm{t}}}(x))dx\right){n}_{{\rm{t}}}(x)\\ \frac{1}{0.5{n}_{{\rm{a}}}(x)+1}\exp \left({\int }_{0}^{{L}_{{\rm{a}}}}-0.014{n}_{{\rm{a}}}(x)dx\right),\end{array}$$$ $$$\begin{array}{c}{S}_{{\rm{a}}}(x)={k}_{{\rm{a}}}{E}_{0}\exp \left({\int }_{0}^{x}-({\sigma }_{{\rm{a}}}{n}_{{\rm{a}}}(x)+{\sigma }_{{\rm{t}}}{n}_{{\rm{t}}}(x))dx\right){n}_{{\rm{a}}}(x)\\ (\text{exp}(0.009{n}_{{\rm{a}}}{(x)}^{2}-0.205{n}_{{\rm{a}}}(x)+1.011){n}_{{\rm{t}}}(x)+1),\end{array}$$$where S t , n t , σ t , and k t represent the fluorescence intensity, concentration, absorption cross‐sectio...…”

Determination of Oil Pollutants by Microchannel Laser Induced Fluorescence Technology

“…Compared with other spectral techniques, LIF has the following advantages : LIF is a zero background spectral technique with high sensitivity ( up to 10 -12 -10 -9 M, 5-6 orders of magnitude lower than UV-IR absorption method ) [10], [11]. Fluorescence emission is omnidirectional and can be collected from various angles [12]. Due to the large size of the sample cell and low degree of automation of the conventional LIF detection system, microfluidic, as a miniaturized, integrated, high-throughput and low-cost analysis technology [13]- [15], can well solve these problems, and has been widely used in chemistry, biology, medicine, agricultural engineering and other related fields.…”