Pressurized liquid extraction of toxins from cyanobacterial cells

Abstract

The suitability of pressurized liquid extraction (PLE) of cyanotoxins from cells was investigated. The stability of cyanotoxins (MCYST-RR, MCYST-LR, and anatoxin-a) was evaluated at nine combinations of pressure and temperature (7, 10, and 14 MPa and 60 degrees C, 80 degrees C and 100 degrees C) using 75% (v/v) methanol in water (MeOH) as solvent. Additional experiments investigated the stability of cyanotoxins when water was used as solvent (at a pressure of 14 MPa and a temperature of 40 degrees C, 50 degrees C, 60 degrees C, 80 degrees C, or 100 degrees C). Results using 75% MeOH showed that the MCYST-RR and MCYST-LR were stable under the tested pressures up to 80 degrees C. At 100 degrees C MCYST recovery decreased by 10% to 17%. When water was used as the solvent, no differences in recovery were observed for MCYST-LR, whereas for MCYST-RR, maximum recovery was obtained at 60 degrees C, and degradation occurred at 100 degrees C. In contrast, anatoxin-a was labile under all experimental conditions; the best recoveries (ca. 50%) were obtained at 60 degrees C at the three pressures using 75% MeOH. However, only 17%-23% recovery was obtained with water extraction at all temperatures. The extraction of MCYST-LR and variants from cells (Microcystis aeruginosa, UTCC299) was studied using two solvents, 75% MeOH and 100% water, at 14 MPa and 60 degrees C and 100 degrees C. PLE extracts were compared with extracts obtained with 75% MeOH and ultrasonication. Complete extraction was achieved in both solvents in one 5-min cycle (at 100 degrees C). Although lower recovery was obtained using PLE (79%-105%), shorter extraction time and automation are advantageous over ultrasonication.

Analysis of intracellular and extracellular microcystin variants in sediments and pore waters by accelerated solvent extraction and high performance liquid chromatography-tandem mass spectrometry

“…ASE conditions, originally developed for the analysis of cyanotoxins in culture [27], were used for microcystins in sediments. Each stainless-steel extraction cell (33 mL) was lined with a cellulose filter and packed with sediment mixed with Hydromatrix TM (Varian, Mississauga, ON, Canada).…”

Genotoxicity of crude extracts of cyanobacteria from Taihu Lake on carp (Cyprinus carpio)

“…The solution was then evaporated and pulled through a Sep-Pak C18 column and washed with 20% methanol. MCs were eluted with 90% methanol containing 0.1% TFA according to previously published methods (Harada et al 1988;Aranda-Rodriguez et al 2005;Qi et al 2009). Concentrations of MCs in the extracts were analyzed by high performance liquid chromatography (HPLC) (Agilent 1100 Series, Agilent Technologies, Waldbronn, Germany) equipped with a Zorbax Eclipse SB-C18 column (250 mm 9 4.6 mm, 5 lm, Agilent Technologies).…”

Time-dependent oxidative stress and histopathological changes in Cyprinus carpio L. exposed to microcystin-LR

“…Analyses of extracts were performed according to Aranda-Rodriguez et al (2005) using an HPLC (Agilent 1100 Series, Agilent Technologies, USA) with a Zorbax Eclipse SB-C18 column (250 mm 9 4.6 mm, 5 lm, Agilent Technologies). MC-LR concentration in test solutions was monitored periodically and the results indicated that there were no remarkable differences between the measured and added MC-LR concentrations in test solutions during the experimental period (Table 1).…”