Temperature Measurement Using Fluorescence

M. K. Chyu and D. J. Bizzak, Surface Temperature Measurement Using a Laser-Induced Fluorescence Thermal Imaging System, ASMEJ. of Heat Transfer, 116, pp. 263-266,1994. 

Temperature measurement using a single fluorescent dye is the simplest adaptation of fluorescent thermometry at the microscale. If the intensity of the illuminating light flux, /q, is assumed constant in both space and time, then the ratio of the emitted fluorescence intensity measured at a temperature T to that measured at a reference temperature for a fixed dye concentration is given by the ratio of the quantum efficiencies of the fluorescent dye at these temperatures ... 

More recently, Natrajan and Christensen [10] considered the development of a two-dye fluorescence method for temperature measurement using a pulsed, Nd YAG laser as the illumination... 

Lavieille, P., Lemoine, F., Lavergne, G., Levouche, M. (2001). Evaporating and combusting droplet temperature measurements using two-color laser-induced fluorescence. Experiments in Fluids, 31,45-55. 

Ross D, Gaitan M, Locascio LE (2001) Temperature measurement in microfluidic systems using a temperature-dependent fluorescent dye. Anal Chem 73 4117-4123 Sammarco TS, Bums MA (1999) ThermocapiUary pumping of discrete drops in microfabricated analysis devices. AlChE J 45 350-366... 

Solid-surface luminescence analysis involves the measurement of fluorescence and phosphorescence of organic compounds adsorbed on solid materials. Several solid matrices such as filter paper, silica with a polyacrylate binder, sodium acetate, and cyclodextrins have been used in trace organic analysis. Recent monographs have considered the details of solid-surface luminescence analysis (1,2). Solid-surface room-temperature fluorescence (RTF) has been used for several years in organic trace analysis. However, solid-surface room-temperature phosphorescence (RTF) is a relatively new technique, and the experimental conditions for RTF are more critical than for RTF. 

The data were collected using fluorescence measurements, which allow both identification and quantitation of the fluorophore in solvent extraction. Important experimental considerations such as solvent choice, temperature, and concentrations of the modifier and the analytes are discussed. The utility of this method as a means of simplifying complex PAH mixtures is also evaluated. In addition, the coupling of cyclodextrin-modified solvent extraction with luminescence measurements for qualitative evaluation of components in mixtures will be discussed briefly. 

Exciplex methodhas also been proposed for droplet temperature measurement. In an oxygen environment, however, the fluorescence from the exciplex is quenched by the oxygen. In addition, fuel droplets may contain aromatic hydrocarbons that can produce fluorescence emissions, masking the fluorescence spectrum of the dopants used for the temperature determination. 

Each solvent used was observed to contain no impurities which fluoresce in the spectral region of interest. All solution concentrations used were in the range 10-5 to 10 4 M. Polymer films were cast onto quartz plates from either chloroform or dichloromethane solutions containing 4% (wt/wt) of polymer. The films were air dried at room temperature and had an average thickness of 65 10 )lm. The absorption spectra of the polymer films were measured using an appropriate PMMA or PS film as the reference. 

DMABN suffers from the fact that dual fluorescence is only observable for polar media. Therefore, the pretwisted ester DMPYRBEE has been developed which shows dual fluorescence also in alkane solvents. 9 This probe allowed measurement of nonpolar polymeric siloxane oils and a comparison with the corresponding measurements using an EXCIMER probe. As expected from the decreased reaction volume necessary for the TICT photoreaction, the latter is usable down to much lower temperatures (higher viscosities) and probes a larger fraction of free volume. 26 ... 

The subsequent development of laser diode sources at low cost, and improved electronic detection, coupled with new probe fabrication techniques have now opened up this field to higher-temperature measurement. This has resulted in an alexandrite fluorescence lifetime based fiber optic thermometer system,(38) with a visible laser diode as the excitation source which has achieved a measurement repeatability of l°C over the region from room temperature to 700°C, using the lifetime measurement technique. 

It is now clear that in the absence of molecular oxygen most proteins phosphoresce in aqueous solutions at ambient temperature.(10) In this chapter we discuss the use of phosphorescence of tryptophan to study proteins, with emphasis on measurements at room temperature. Comparisons between phosphorescence and the more commonly used fluorescence spectroscopy are made. Comprehensive reviews of protein luminescence have been written by Longworth.(n 12 1 A discussion on the use of phosphorescence at room temperature for the study of biological materials was given by Horie and Vanderkooi.(13)... 

By using the techniques mentioned before, room-temperature x s for about 50 alkanes were determined. In Fig. 2, we show the fluorescence quantum yields as a function of lifetimes. The 4>[ values were generally taken from the work of Rothman et al. [25] most of the fluorescence quantum yields were measured using 165-nm photons for excitation. This wavelength is close to the absorption onset of most alkanes and (with the exception of the smaller molecules) the measured quantum yield is close to the fluorescence quantum yield of the relaxed Si molecules [26]. The plot in Fig. 2 is similar to the plot we published in Ref. 59 using only our measurements. Here we use practically all the data that are available in the literature. For most of the alkanes, several lifetime measurements were published. When... 

Phosphorimetric methods have been used to determine such substances as nucleic acids, amino acids, and enzymes. However, this is not a widely used method since it cannot be run at room temperature. Measurements are usually performed with liquid nitrogen to prevent degradation due to collision deactivation. Fluorometric methods are used to determine both inorganic and organic species. Instruments used for measuring fluorescence and phosphorescence are fluorometers and spectrofluorometers, respectively. These instruments are similar to ultraviolet and visible spectrometers,... 

Zarowin (121) measured the fluorescent lifetime of neodymium in calcium tungstate at room temperature using a multiple-sampling technique. He found different values for the 4F3/2->479/2 and the 4F3/2 4/n/2 transitions, the results being 160 16 and 230 15 /xsec, respectively. As he points out, these results are indeed very surprising. It was not clear to Zarowin whether the experimental data are suspect or whether the lifetime is indeed different. 

Femtosecond Ti-Sapphire oscillator (CDP, TiF50, 100 fs, 80 MHz, 0.3 W, 800 run) pumped with diode pumped solid state laser (Coherent, Verdi) was used to excite the system. The time- and spectral-resolved fluorescence spectra of C522 were measured by using up-conversion set-up (CDP, FOG100). The p-cyclodextrin, C42H70O35, and coumarin C522, C14H12F3NO2, used in these experiments were produced by Cyclolab and Radiant Dyes Chemie, respectively. All experiments were performed at room temperature and used water was twice deionised. 

The radiative lifetimes of many excited states of Li,16 Na,17-21K,22 Rb,23-25 and Cs,26-28 have been measured using a variety of techniques, the most common being time resolved laser induced fluorescence, which is typically carried out using a cell, as shown in Fig. 4.4. In all cases, the observed lifetimes are in reasonable agreement with values calculated in the coulomb approximation, corrected for the decrease due to black body radiation.29 In the following chapter we show that if the 0 K lifetime of a state is r that its lifetime at a finite temperature T is given by24 30... 

Non-contact temperature measurement inside microfluidic channels was achieved by using fluorescence quenching of a rhodamine dye. The intensity of the dye fluorescence is temperature-sensitive in a range temperature of 5-95°C [795], Another on-chip temperature measurement method was achieved by measuring... 

---