Infrared-enhanced multiphoton ionization detection of aromatic molecules in solution

Abstract

the ringer solution. These interferences include peaks B and F, and the negative deflections found at ca. 5.1, 7-7, 8.2, and 13 min. Schemes are being developed to eliminate these interferences. Peaks A, C, D, E, and G appear to be "real" peaks. Peak G is presumably an anionic compound, possibly a metabolite of dopamine, and has been seen in larger quantities in other samples. Future work will involve determination of the identity of solutes detected in these experiments. ACKNOWLEDGMENTThe authors wish to thank Jennifer Chien for her assistance with the snail dissections.

Ultraviolet and infrared laser excited two-color multiphoton ionization for determination of molecules in solution

“…The slope of the logarithmic plots of PC(355) or PC(355 + 1064) versus the concentration was nearly unity in the 10"10 to 1CT7 M region. Below about 10~9 M, APC/ PC(355) tended to be constant; PC(355 + 1064) was 6-7-fold larger than PC(355), as was the case in the previous result (18).…”

“…The UV (355 nm) and IR (1064 nm) two-color laser photoionization detection system is almost identical with the previous one (18). A Nd:YAG laser (Quantel YG 580A, pulse duration 10 ns) was operated at a repetition rate of 5 Hz.…”

“…In recent multiphoton ionization of aromatic molecules in nonpolar alkane solvents, the cooperative action of both ultraviolet (UV) and visible (vis) nanosecond pulses at relatively low temperatures (16,17) or of both UV and infrared (IR) picosecond pulses (10)(11)(12)(13) enhanced the photocurrent signal compared to that produced by a UV pulse acting alone; the result is attributed to an increase in the quantum yield of charge carriers due to photoexcitation of geminate electrons by a vis or IR pulse. Even the simultaneous action of both UV and IR nanosecond pulses at room temperature enhanced the photocurrent signal and the detection sensitivity (18).…”

A submicroliter transparent cell for laser multiphoton ionization detection in solution

“…Interfadal Electrochem. Laser multiphoton ionization spectrometry based on photocurrent measurement is sensitive for the determination of organic molecules in solution (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). The detection sensitivity in this method depends on laser power (9)(10)(11)(12)(13), excitation wavelength (8,9), molar absorptivity of an analyte (4, 7-9), and the polarity of a solvent (3,7).…”

Applications of Strong Interactions between Photons and Molecules to Analytical Sciences

“…From these viewpoints, we have attempted to increase the yield of free ion pairs generated from geminate ion pairs by irradiating the geminate ion pairs with the near-infrared laser light synchronized with the ultraviolet laser light. 24,25 The results for 9-phenylanthracene dissolved in heptane are presented in Fig. 4(b).…”