title: Optimization of ultrasonic-assisted extraction for determination of polycyclic aromatic hydrocarbons in biochar-based fertilizer by gas chromatography-mass spectrometry.
abstract: Application of biochar-based fertilizers is increasingly being considered for its potential agronomic and environmental benefits. However, biochar may contain residues of polycyclic aromatic hydrocarbons (PAHs) as a result of its production by pyrolysis. The strong adsorption of PAHs to biochar makes extraction and analysis of biochar-based fertilizers difficult. This study optimizes the extraction of PAHs in biochar-based fertilizer samples by using an ultrasonic bath for quantification by gas chromatography-mass spectrometry. Among 12 solvents, acetone-cyclohexane (1:1) mixture was selected as the optimum solvent for extraction. Three variables affecting the extraction were studied by Box-Behnken design. The optimum conditions were 57 °C extraction temperature, 81 min extraction time, and two extraction cycles, which were validated by assessing the linearity of analysis, LOD, LOQ, recovery, and levels of PAHs in real biochar-based fertilizer samples. Results revealed that the 16 U.S. EPA PAHs had good linearity, with squared correlation coefficients greater than 0.99. LODs were low, ranging from 2.2 ng g(-1) (acenaphthene) to 23.55 ng g(-1) (indeno[1,2,3-cd]perylene), and LOQs varied from 7.51 ng g(-1) to 78.49 ng g(-1). The recoveries of 16 individual PAHs from the three biochar-based fertilizer samples were 81.8-109.4 %. Graphical Abstract Use of RSM to optimize UAE for extraction of the PAHs in biochar-based fertilizer.
authors.affiliation: Department of Environment and Resource, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Mingxing
authors.initials: M
authors.lastname: Sun
authors.forename: Zhixiu
authors.initials: Z
authors.lastname: Zhu
authors.forename: Jidong
authors.initials: J
authors.lastname: Zhang
authors.forename: Guoqing
authors.initials: G
authors.lastname: Shen
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D005591:Chemical Fractionation / Q000379:methods*; D005308:Fertilizers / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D057230:Limit of Detection; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000302:isolation & purification; D012997:Solvents / Q000737:chemistry; D013010:Sonication / Q000379:methods*
chemical_list: D005308:Fertilizers; D011084:Polycyclic Aromatic Hydrocarbons; D012997:Solvents; C540010:biochar; D002606:Charcoal