Microwave-assisted headspace solid-phase microextraction to quantify polycyclic aromatic hydrocarbons in pine trees

Abstract

A methodology for the extraction and quantification of 16 polycyclic aromatic hydrocarbons (PAHs) based on microwave-assisted extraction coupled with headspace solid-phase microextraction followed by gas chromatography/mass spectroscopy was validated for needles and bark of two pine species (Pinus pinaster Ait. and Pinus pinea L.). The limits of detection were below 0.92 ng g(-1) (dry weight) for needles and below 0.43 ng g(-1) (dw) for bark. Recovery assays were performed with two sample masses spiked at three levels and the overall mean values were between 70 and 110 % for P. pinaster and 75 and 129 % for P. pinea. In the first species, the increase in sample mass lowered the recoveries slightly for most PAHs, whereas for the second, the recoveries were higher for the needles. Naturally contaminated samples from 4 sites were analysed, with higher levels for urban sites (1,320 and 942 ng g(-1) (dw) vs. 272 and 111 ng g(-1) (dw) for needles and 696 and 488 ng g(-1) (dw) vs. 270 and 103 ng g(-1) (dw) for bark) than for rural ones and also for P. pinaster samples over P. pinea. It is also shown that gas-phase PAHs are predominant in the needles (over 65 % of the total PAHs) and that the incidence for particulate material in bark, reaching 40 % as opposed to a maximum below 20 % for the needles. The method has proved to be fit and improved some of the existing approaches, on the assessment of particulate PAHs and bark levels.

Levels and sources of polycyclic aromatic hydrocarbons (PAHs) near hospitals and schools using leaves and barks of Sambucus nigra and Acacia melanoxylon

“…Moreover, leaves of S. nigra collect a higher proportion of HMW PAHs than bark (33.8% vs. 23.6%), and bark captures a higher proportion of LMW PAHs than leaves (18.7% vs. 9.7%). This is opposite to that observed in the work of Ratola et al ( 2012 ) on the use of needles and barks of two pine species ( Pinus pinaster Ait. and Pinus pinea L.) as biomonitors, which showed that LMW PAHs are predominant in needles, while HMW PAHs are predominant in bark.…”

“…Accumulation of PAHs on vegetative parts is plant species dependent, mainly to the chemical, morphological and physiological characteristics of each tree species (Fellet et al, 2016 ; Pereira et al, 2019 ; Rodriguez et al, 2012 ). The vegetative parts of a same tree species have also shown to have different abilities to accumulate PAHs (Ratola et al, 2009 , 2012 ; Yin et al, 2011 ). Identification of tree species, and different vegetative parts of a same tree species, with the best ability to accumulate air pollutants is still poorly known and constitutes an important research topic, mainly because data can allow to choose the most appropriate for a specific purpose and can also help to identify which factors control the PAH accumulation.…”

Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Leaf and Bark Samples of Sambucus nigra Using High-Performance Liquid Chromatography (HPLC)

“…Regarding PAHs extraction, ultrasonic extraction [ 11 , 18 , 20 ], Soxhlet extraction [ 18 , 21 , 23 ], accelerated solvent extraction [ 18 , 22 , 24 ], and microwave-assisted extraction [ 11 , 25 ] are the most used techniques, which involve the use of different organic solvents for better yields.…”

“…Regarding pre-concentration, the rotary evaporator [ 17 ] and the nitrogen stream [ 32 ] are the common techniques used. For instrumental analysis, gas chromatography coupled to mass spectrometry (GC-MS) is the most widely used equipment for the detection and quantification of PAHs [ 14 , 22 , 23 , 24 , 25 , 33 ]. High-performance liquid chromatography with diode array (HPLC-DAD) and/or fluorescence detectors (HPLC-Fl) is another technique used, although to a lesser extent than GC-MS [ 20 , 21 , 32 ].…”

Voltammetric analysis of Pinus needles with physiological, phylogenetic, and forensic applications

“…The chemoecological importance of Pinus species has motivated a continuous interest for developing methods devoted to the determination of inorganic [14,15] and organic [16][17][18] pollutants. Remarkably, the great variability of climates and microclimates where the Pinus species grow, as well as the appearance of a wide range of morphological, chemical, and biochemical characters, has complicated the delimitation of the different species and the establishment of their taxonomic relationships [19][20][21].…”