With the increasing production and use of fullerene nanomaterials, it is imperative that quantitative analytical methods be developed to study their occurrence and behavior in the natural environment so that the risks posed by these materials to ecosystem and human health can be addressed. Liquid-liquid extraction (LLE) and solid-phase extraction (SPE) coupled with HPLC-UV/vis analysis were identified as efficient quantitative methods, with detection limits as low as 4.21 mu g/L for C-60. The addition of MgCl2 in both LLE and SPE increased the extraction recovery of C-60 from 75% to 90% while humic acids and fulvic acids decreased recovery to less than 40%. Humic acid was more effective at lowering C-60 recovery than fulvic acid. The recoveries of fullerenes from surface water, treated wastewater and groundwater matrices were statistically equivalent but the recovery of fullerene from seawater was >90%. A method to correct for inconsistent C-60 extraction recovery using C-70 as a surrogate standard was also developed. (C) 2011 Elsevier B.V. All rights reserved.