US EPA

1960921 

Journal Article 

Quantitative Determination of PAHs in Biochar: A Prerequisite To Ensure Its Quality and Safe Application 

Hilber, I; Blum, F; Leifeld, J; Schmidt, HP; Bucheli, TD 

2012 

Yes 

Journal of Agricultural and Food Chemistry
ISSN: 0021-8561
EISSN: 1520-5118 

60 

12 

3042-3050 

22397545 

10.1021/jf205278v 

WOS:000301969300013 

Biochar is increasingly promoted as a beneficial soil conditioner. However, it may contain residues of polycyclic aromatic hydrocarbons (PAHs) as a result of its production by pyrolysis. To date, analytical methods to analyze PAHs in biochar quantitatively are hardly available. This study presents an optimized and validated procedure to quantify the 16 U.S. EPA PAHs in biochar. PAHs were best extracted with Soxhlet for 36 h using 100% toluene. Average absolute recoveries of isotope labeled internal standards used for each analyte from three different biochars ranged from 42% to 72%, and relative recoveries were between 71% and 105%. The limits of detection were biochar-dependent, but on average a factor of >50 lower than quantified PAH concentrations (9-355 mg kg(dry weight)(-1)). The established method prepares the ground for a harmonized protocol for PAH analysis of biochars, a necessity for biochar quality control, registration, and legislation. 

biochar; charcoal; polycyclic aromatic hydrocarbons; total concentrations; extraction method