Double-beam thermal lens spectrometry

Simultaneous enhancement of fluorescence and thermal lensing by reversed micelles

“…The calibration plots exhibited a linear response (correlation coefficient, r = 0.994) over a concentration range of 3 X HT® to 3 X 1CT4 M. The limit of detection, LOD, defined as the amount of the sample that yielded a signal twice the standard deviation of the blank, is estimated to be 4.5 X 10'7 M which corresponds to an absorbance of about 1.3 X 10"7. This LOD value is comparable with the 5.0 X 10~7 value obtained for iodine in pure carbon tetrachloride solvent (27) and is 2 orders of magnitude lower than the LOD values obtained for neodymium and praseodymium in HC104 solution (28).…”

Modern analytical thermooptical spectroscopy

“…Numerous studies were concerned with compounds, which served as models for either estimating the instrumental sensitivity of spectrometers (or signal recording systems), 1, 3, 6, 272, 350 ± 354, 356 or examining the influence of solvents on the thermal lens effect. 1, 73 ± 75, 273, 352 ± 354, 357 For this purpose, the following simple and stable compounds, which are resistant to laser radiation, were chosen: a solution of molecular iodine in carbon tetrachloride, 73,272,351,355,357,358,378 aqueous solutions of presynthesised copper(II) complexes with EDTA 272 and acetylacetone, 77 iron(II) complexes with 1,10-phenanthroline 22,78,79,272,273,357 or its analogues 273,352 and cobalt(II) complexes with 1-(2-pyridylazo)-2naphthol 77 and ethylenediamine. 73,351 Some researchers attempted to apply known spectrophotometric procedures without modifications to thermooptical spec- troscopy, 22,26,85,108,354,356 which led to a decrease in the detection limits, but did not allow the researchers to gain the most benefit from the method.…”

Analysis of circulating lipid-phase micronutrients in humans by HPLC: Review and overview of new developments

“…In the single beam configuration, one laser serves as both the source of excitation light and the source of the probe beam. In the dual beam configuration, commonly termed the “pump and probe” arrangement, one laser serves as the “pump beam” to excite and absorb the sample, while a second laser – usually low power – is used as a “probe beam” to detect the thermal lens of the irradiated sample [136]. The application of HPLC-TLS to LPM analyses particularly in serum or plasma has been limited, to our knowledge, to one study thus far [31] in which α-carotene, β-carotene, β-cryptoxanthin, and lycopene were evaluated in plasma.…”