TY - JOUR
T1 - Cloud-point extraction of nodularin-R from natural waters
AU - Yu, Hong Xia
AU - Man, Ben Kwok Wai
AU - Chan, Lily Lee Ni
AU - Lam, Michael Hon Wah
AU - Lam, Paul K.S.
AU - Wang, Liansheng
AU - Jin, Hongjun
AU - Wu, Rudolf S.S.
N1 - Funding Information:
This work was jointly funded by the Research Grants Council of the Hong Kong Special Administrative Region, China (Central Allocation Grant 8730011 and Earmarked Research Grant City U 1103/00M), National Major Project for Initially Fundamental Research, China (No. 200150) and a grant from City University of Hong Kong (Project No. 7001392).
PY - 2004/4/29
Y1 - 2004/4/29
N2 - A cloud-point extraction (CPE) technique for the determination of a cyanobacterial hepatotoxin, nodularin-R, in aqueous media using a cationic surfactant, tricaprylmethylammonium chloride (Aliquat-336), was developed. Cloud-point phase separation of Aliquat-336 at ambient temperature was induced by the addition of sodium sulfate. The Aliquat-336/Na2SO4 CPE system displayed large preconcentration factor, FC, for nodularin-R. At the operational CPE conditions, FC of 709.2 was achieved. Distribution constant, KD, of the distribution of nodularin-R between the surfactant-rich and aqueous phases of the CPE system was estimated to be (4.94±0.8)×103. Coupled to liquid chromatography with UV detection, the CPE method offered a detection limit of 330pgml-1 (in freshwater)/1.3ngml-1 (in seawater) and a repeatability of 6.4% (in freshwater) (n=7, P<0.05) for nodularin-R in a sample of 25ml. The CPE is a rapid process and no cleanup step is required. Effects of pH, natural abundant anion (chloride) and dissolved organic matters (DOM, humic acid, HA) on the extraction efficiency were evaluated. A double CPE technique was developed to overcome interferences encountered in the analysis of environmental samples. Applicability of the new method to the determination of nodularin-R in real coastal marine water samples has also been demonstrated.
AB - A cloud-point extraction (CPE) technique for the determination of a cyanobacterial hepatotoxin, nodularin-R, in aqueous media using a cationic surfactant, tricaprylmethylammonium chloride (Aliquat-336), was developed. Cloud-point phase separation of Aliquat-336 at ambient temperature was induced by the addition of sodium sulfate. The Aliquat-336/Na2SO4 CPE system displayed large preconcentration factor, FC, for nodularin-R. At the operational CPE conditions, FC of 709.2 was achieved. Distribution constant, KD, of the distribution of nodularin-R between the surfactant-rich and aqueous phases of the CPE system was estimated to be (4.94±0.8)×103. Coupled to liquid chromatography with UV detection, the CPE method offered a detection limit of 330pgml-1 (in freshwater)/1.3ngml-1 (in seawater) and a repeatability of 6.4% (in freshwater) (n=7, P<0.05) for nodularin-R in a sample of 25ml. The CPE is a rapid process and no cleanup step is required. Effects of pH, natural abundant anion (chloride) and dissolved organic matters (DOM, humic acid, HA) on the extraction efficiency were evaluated. A double CPE technique was developed to overcome interferences encountered in the analysis of environmental samples. Applicability of the new method to the determination of nodularin-R in real coastal marine water samples has also been demonstrated.
KW - Cloud-point extraction
KW - Cyanobacterial toxin
KW - Natural waters
KW - Nodularin-R
UR - http://www.scopus.com/inward/record.url?scp=1542509421&partnerID=8YFLogxK
U2 - 10.1016/j.aca.2003.12.019
DO - 10.1016/j.aca.2003.12.019
M3 - Article
AN - SCOPUS:1542509421
SN - 0003-2670
VL - 509
SP - 63
EP - 70
JO - Analytica Chimica Acta
JF - Analytica Chimica Acta
IS - 1
ER -
