Sensitivity enhancement of thermal-lens spectrometry using laser-induced precipitation.
The possibility of thermal lensing of dynamically emerging light-absorbing layers at cell surfaces was investigated. Analyte accumulation at a cell surface determines long-term changes in the thermal-lens signal that was used as a source of analytical information to enhance sensitivity of thermal lensing. Considering the rate of accumulation as an additional analytical signal, we achieved a threefold decrease in the limits of detection for 4-aminoazobenzene to the level of 7 microM in a batch mode with the same level of reproducibility. The details of observed thermal-lens signal behavior in cells are discussed. The possibilities to use thermal-lens detection for 4-aminoazobenzene determination in quartz capillaries in flow mode were discussed and a drastic thermal-lens signal enhancement was discovered. The corresponding limit of detection for 4-aminoazobenzene in a flow mode is further decreased to the level of 3 microM.
Nedosekin
Dmitry A
DA
Chemistry Department, M. V. Lomonosov Moscow State University, Moscow 119991, Russia. tanarek@mail.ru
Faubel
Werner
W
Proskurnin
Mikhail A
MA
Pyell
Ute
U