In situ Determination of Phenanthrene Adsorbed onto Surface of Mangrove Leaves Using a Laser-Induced Nanosecond Time-Resolved Fluorescence System

Abstract

Developing new methods for in situ determination of polycyclic aromatic hydrocarbons(PAHs) in plant leaves is of great significance to further achieve the field detection of PAHs in actual leaf samples.A set of laser-induced nanosecond time-resolved fluorescence(LITRF) system was employed to complete the in situ quantitative determination of the phenanthrene(Phe) that was adsorbed onto the leaf surfaces of three kinds of mangrove species,named Kandelia obovata(Ko),Bruguiera gymnorhiza(Bg) and Aegiceras corniculatum(Ac).Experimental results showed that the linear dynamic ranges for the in situ determination of the Phe that was adsorbed onto the leaf surfaces of Ko,Bg and Ac were 2-1400 ng/spot,1-1000 ng/spot and 4-2000 ng/spot,with the detection limits of 0.20,0.14 and 0.42 ng/spot,respectively.The relative standard deviations were less than 6.0%(n=9).The experimental recoveries for the Phe in Ko,Bg,and Ac were 89.6%-108.1%,78.2%-92.4% and 93.2%-112.9%,respectively.Satisfactory results were obtained for the in situ determination of the Phe that was adsorbed onto the surfaces of the lab-exposure mangrove leaf samples contaminated by the Phe.The sensitivity of the established method was much higher than that of the previously established fiber optical fluorimetry,and the linear dynamic range got improved.The LITRF method marked a significant step toward realizing the field detection of PAHs in vegetation.