Near-Field Thermal Lens Detection at 257 nm as an Alternative to Absorption Spectrometric Detection in Combination with Electromigrative Separation Techniques
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- 作者：Natalia Ragozina ; Stefan Heissler ; Werner Faubel ; and Ute Pyell
- 刊名：Analytical Chemistry
- 出版年：2002
- 出版时间：September 1, 2002
- 年：2002
- 卷：74
- 期：17
- 页码：4480 - 4487
- 全文大小：131K
- 年卷期：v.74,no.17(September 1, 2002)
- ISSN：1520-6882
文摘
A device is presented that permits detection of analytesabsorbing electromagnetic radiation at 
= 257 nm (infused-silica capillaries with 75-
m i.d.) via the near-fieldthermal lens effect. The detector was realized by using afrequency-doubled argon ion laser as pump laser and alaser diode (emission wavelength, 633 nm) coupled intoa monomode optical fiber as probe laser. Comparing theperformance of this detector to the performance of acommercial absorption spectrometric detector working at = 257 nm equipped with a unit for on-column detectionin fused-silica capillaries showed a substantial improvement in detection limits (up to 30-fold improvement) forthe near-field thermal lens detector (NF-TLD). The feasibility of the NF-TLD for sensitive detection of nonfluorescent analytes in real samples after separation by micellarelectrokinetic chromatography was shown taking thedetermination of nitroaromatic compounds in contaminated water from a former ammunition plant as anexample. Dependence of the thermal lens signal on pumplaser power, velocity of the mobile phase, and chopperfrequency was investigated. A linear calibration range over2 orders of magnitude was obtained.
= 257 nm (infused-silica capillaries with 75-m i.d.) via the near-fieldthermal lens effect. The detector was realized by using afrequency-doubled argon ion laser as pump laser and alaser diode (emission wavelength, 633 nm) coupled intoa monomode optical fiber as probe laser. Comparing theperformance of this detector to the performance of acommercial absorption spectrometric detector working at = 257 nm equipped with a unit for on-column detectionin fused-silica capillaries showed a substantial improvement in detection limits (up to 30-fold improvement) forthe near-field thermal lens detector (NF-TLD). The feasibility of the NF-TLD for sensitive detection of nonfluorescent analytes in real samples after separation by micellarelectrokinetic chromatography was shown taking thedetermination of nitroaromatic compounds in contaminated water from a former ammunition plant as anexample. Dependence of the thermal lens signal on pumplaser power, velocity of the mobile phase, and chopperfrequency was investigated. A linear calibration range over2 orders of magnitude was obtained.