Affinity of Compounds for Phosphatydylcholine-Based Immobilized Artificial Membrane-A Measure of Their Bioconcentration in Aquatic Organisms

Abstract

The BCF (bioconcentration factor) of solutes in aquatic organisms is an important parameter because many undesired chemicals enter the ecosystem and affect the wildlife. Chromatographic retention factor log k_w^IAM obtained from immobilized artificial membrane (IAM) HPLC chromatography with buffered, aqueous mobile phases and calculated molecular descriptors obtained for a group of 120 structurally unrelated compounds were used to generate useful models of log BCF. It was established that log k_w^IAM obtained in the conditions described in this study is not sufficient as a sole predictor of bioconcentration. Simple, potentially useful models based on log k_w^IAM and a selection of readily available, calculated descriptors and accounting for over 88% of total variability were generated using multiple linear regression (MLR), partial least squares (PLS) regression and artificial neural networks (ANN). The models proposed in the study were tested on an external group of 120 compounds and on a group of 40 compounds with known experimental log BCF values. It was established that a relatively simple MLR model containing four independent variables leads to satisfying BCF predictions and is more intuitive than PLS or ANN models.

Keywords: Immobilized artificial membrane; artificial neural networks; bioconcentration factor; liquid chromatography; multiple linear regression; partial least squares regression.

Figure 1

MLR1 model, Equation (22)—predicted vs. reference log BCF values.

Figure 2

MLR2 model, Equation (23)—predicted vs. reference log BCF values.

Figure 3

MLR3 model, Equation (24)—predicted vs. reference log BCF values.

Figure 4

PLS1 model (six components)—predicted vs. reference log BCF values.

Figure 5

PLS2 model—predicted vs. reference log BCF values.

Figure 6

ANN14 model—predicted vs. reference log BCF values.

Figure 7

ANN43 model—predicted vs. reference log BCF values.

Figure 8

ANN44 model—predicted vs. reference log BCF values.

Figure 9

Predicted vs. experimental log BCF values for models MLR2, PLS1 and ANN43.