Real time and in situ determination of lead in road sediments using a man-portable laser-induced breakdown spectroscopy analyzer

摘要

In situ,real time levels of lead in road sediments have been measured using a man-portable laser-induced breakdown spectroscopy analyzer.The instrument consists of a backpack and a probe housing a Q-switched Nd:YAG laser head delivering 50 mJ per pulse at 1064 nm.Plasma emission was collected and transmitted via fiber optic to a compact cross Czerny-Turner spectrometer equipped with a linear CCD array allocated in the backpack together with a personal computer.The limit of detection(LOD)for lead and the precision measured in the laboratory were 190 mu g g~(-1)(calculated by the 3cr method)and 9% R.S.D.(relative standard deviation),respectively.During the field campaign,averaged Pb concentration in the sediments were ranging from 480 mu g g~(-1)to 660 mu g g~(-1)depending on the inspected area,i.e.the entrance,the central part and the exit of the tunnel.These results were compared with those obtained with flame-atomic absorption spectrometry(flame-AAS).The relative error,expressed as [100(LIBS result-flame AAS result)/(LIBS result)],was approximately 14%.