Photoionization Fast-Conductivity Technique for Analysis of Traffic Contaminated Soils

Abstract

A time-resolved detection of the multiphoton ionization induced photocurrents was developed and applied to map a near-field contamination profile of a year-around-active traffic road. Main advantages of the proposed method are in its simplicity and rapidity. No chemical sample preparation is required: analysis is carried out in ambient conditions and the technique can be easily automated. A fast screening of contaminated soils is feasible. The soil samples collected at various radial distances, R, have produced, as method's readout, the photoionization charges, Q.These originate from combustion by-products and were found to decrease according to 1/Q -R. This finding is supported by a straightforward contamination model that largely avoids an obvious complexity associated with the precise mathematical treatment of such a pollution source. We estimate that, at R=50 m the concentration of organic contamination is as high as O.lpg/g.

Authentication and Testing of Banknotes Using Laser Multiphoton Electron Extraction Spectroscopy (MEES)

“…A rather new and uncommon analytical technology is Multiphoton Electron Extraction Spectroscopy (MEES), which has been based of previous analytical applications of multiphoton ionization under ambient conditions: starting with gas phase applications [5][6][7][8], liquids [9], aerosols [10][11][12], and solid surfaces [13][14][15][16][17][18][19][20][21]. MEES is a quantitative analytical spectroscopy, based on detection of photoelectrons extracted in multiphoton process, as a function of laser irradiation wavelength.…”

Multiphoton Ionization Spectroscopy as a Diagnostic Technique of Surfaces Under Ambient Conditions

“…MPI has also been tested under ambient conditions. − It has been found that the resulting photocurrent can be used for quantitative estimation of the concentration of an easily ionized compound in a hardly ionizable matrix. − In its resonant mode, the method can be used for detection of gaseous organic compounds. , …”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] It has been found that the resulting photocurrent can be used for quantitative estimation of the concentration of an easily ionized compound in a hardly ionizable matrix. [1][2][3][4][5][6][7][8][9][10][11][12][13] In its resonant mode, the method can be used for detection of gaseous organic compounds. 14,15 We succeeded, for the first time, to utilize MPI spectroscopy for direct chemical analysis of solids under ambient conditions.…”

Simultaneous Laser-Induced Multiphoton Ionization and Fluorescence for Analysis of Polycyclic Aromatic Hydrocarbons

“…Thus, the LMPI-based techniques are now ready for numerous analytical applications. In particular, some of the recently reported approaches are related to LMPI-based mass spectrometry of airborne particulates, [24][25][26][27][28] to environmental samples, [29][30][31][32][33] and to direct PAH analysis in air by LMPI-induced mirror charges. [34][35][36][37][38] The LMPI method has been extensively investigated 4-5,39-41 and shown to provide extremely sensitive detection systems.…”

“…Thus, the LMPI-based techniques are now ready for numerous analytical applications. In particular, some of the recently reported approaches are related to LMPI-based mass spectrometry of airborne particulates, − to environmental samples, − and to direct PAH analysis in air by LMPI-induced mirror charges. − …”