DETERMINATION OF CHLORINE IN CONCRETE BY LASER-INDUCED BREAKDOWN SPECTROMETRY IN AIR
The destruction of concrete is often associated with local chloride corrosion. The possibility of chlorine determination in concrete by the laser-induced breakdown spectrometry (LIBS) below the level resulting in the material destructive changes was demonstrated. Intensity of the analytical line Cl I 837.60 nm was found to increase significantly with the double-pulse LIBS use. For a combination of the second harmonics of Q-switched Nd:YAG and Nd:YALO lasers (532 nm+540 nm) the effect of the interpulse delay and of the plasma observation time after the second pulse were studied. The optimal temporal parameters of the double-pulse LIBS determination of chlorine were 4.0 and 0.5 µs, respectively. In these conditions, the detection limit of chlorine was 50 ppm.