Quantitative Determination of Total Molar Concentrations of Bioaccumulatable Organic Micropollutants in Water Using C18 Empore Disk and Molar Detection Techniques

Abstract

A highly sensitive and quantitative group parameter to determine total molar concentrations of organic micropollutants that can bioaccumulate in the lipid phase of aquatic organisms from effluents, surface water, and drinking water has been developed. C₁₈ empore disk was used as a surrogate lipid phase. The partition process between water and C₁₈ empore disk was employed to simulate the bioaccumulation process. After partition extraction of the water sample, the empore disk was extracted with cyclohexane, and total molar concentrations were determined in these extracts using vapor pressure osmometry (VPO) and gas chromatography/mass spectrometry (GC/MS), respectively. Total molar concentrations bioaccumulated in aquatic biota were estimated from the cyclohexane concentrations. Good accuracy for the total molar determination was obtained using VPO, due to the practically constant molar response factors (43.1 ± 1.7 V/M) for a wide compound range and to excellent additivity of individual compound responses. Satisfying reproducibility (0−8.3%) of VPO was obtained for sample extracts. The detection limit of VPO in cyclohexane extracts corresponded to 0.60 mM in the lipid phase of aquatic biota. A minimal separation GC/MS system was developed, which enabled highly sensitive and sufficiently accurate total molar determinations. The reproducibility of the GC/MS determination for samples ranged from 0.7 to 22%. The detection limit of GC/MS in cyclohexane extracts corresponded to 0.044 mM in the lipid phase. The determined total molar concentrations in the lipid phase of aquatic biota were in the range of 0.139−168 mM for effluents, 0.26−1.34 mM for surface water systems, and <0.044 mM for drinking water.