F.W.M. van der Wielen

Determination of alkylphenol ethoxylates in industrial and environmental samples

Abstract Degradation products of nonionic surfactants, which are used in large quantities in several industrial applications, have been shown to elicit estrogenic effects in the laboratory as well as in the environment. This has prompted the monitoring of such products, in particular the alkylphenols (AP) and alkylphenol ethoxylates (APE), in the environment. This study presents a relatively simple method for the determination of AP and APE in industrial and environmental samples by HPLC and GC-MS. It discusses some of the inherent analytical issues concomitant with the determination of the complicated mixtures these analytes are composed of. The method was applied to marine and estuarine sediments as well as wastewater and sewage sludge samples taken from industrial plants. In all marine and estuarine samples APE were found with a predominance of oligomers containing 1–3 ethoxylate units.

Optimization of a matrix solid-phase dispersion method with sequential clean-up for the determination of alkylphenol ethoxylates in biological tissues.

A modified Matrix Solid-Phase Dispersion (MSPD) method with sequential clean-up has been developed to isolate and purify alkylphenol ethoxylates (APEs) and alkylphenols in biological tissues. Elution profile, sequential clean-up adsorbent and experimental set up were optimized. Octadecylsilica was used as the solid-phase for matrix dispersion. Methanol was found to be the optimal eluting solvent for APEs. Aluminium oxide was quite efficient for removing the coeluting interferences. Quantitative analysis was done by reversed-phase HPLC with fluorescence detection. The optimized procedure was applied to analyze both fish and mussel samples. Average recoveries for all spiked tissue samples were greater than 90%. Typical limits of detection amount to tens of ppbs on a wet weight basis.

Uptake and elimination of PCDD/PCDF congeners by fish after aqueous exposure to a fly-ash extract from a monicipal incimerator

Abstract After aqueous exposure of fish to a fly-ash extract only a few highly chlorinated dibenzo-p-dioxins and dibenzofurans are accumulated. The estimated uptake rate constants of the accumulated congeners are comparable to those of PCBs or other hydrophobic chemicals. The elimination rate constants however seem to be relatively high. For the 2,3,7,8 TeCDD and 2,3,7,8 TeCDF a slow elimination is found if compared to other PCDDs and PCDFs.

Gas chromatographic determination of liquid vapour pressure and heat of vaporization of tetrachlorobenzyltoluenes

Abstract (Subcooled) liquid vapour pressures and heat of vaporization of low-volatility isomeric organic compounds (tetrachlorobenzyltoluenes, TCBTs) were determined by two gas-liquid chromatographic (GLC) methods. By the first method vapour pressures and temperature-independent heats of vaporization of nine TCBTs were obtained at experimental temperatures (433.15–493.15 K) and linearly extrapolated to 298.15 K. By the second method vapour pressures and temperature-dependent heats of vaporization were measured for the same TCBTs and, in addition, for diphenylmethane and p , p ′-DDT employing nonlinear extrapolations. It was concluded that the second method has several advantages over the first with respect to scope, sensitivity for selection of reference compounds and accuracy.

Determination of n-octanol/water partition coefficients of tetrachlorobenzyltoluenes individually and in a mixture by the slow stirring method.

Experimentally obtained n-octanol/water partition coefficients (Kow) are presented for nine TCBT isomers individually and in an eight isomers mixture. The Kow values were determined with the slow stirring method, which can provide Kow values for very hydrophobic compounds. The log Kow values of isomers determined individually ranged from 6.725 to 7.538 with standard deviations between 0.089 and 0.356. The log Kow values of TCBTs determined in the mixture ranged from 6.030 to 6.435 with standard deviations between 0.083 and 0.334. Reproducibility, isomer resolution and differences between mixture and individual measurements are discussed.

Derivation of solubility parameters of chlorinated dibenzofurans and dibenzo[p]dioxins from gas chromatographic retention parameters via SOFA

Molar heat of vaporization, molar liquid volume and Scatchard-Hildebrand solubility parameters of chlorinated dibenzofurans (PCDFs) and dibenzo[p]dioxins (PCDDs) were derived from (semi-)empirical values of heat of vaporization, (subcooled) liquid density and gas chromatographic Kovats retention indices. To this end a thermodynamic prediction model (SOFA), recently developed, was extended by an exchange entropy contribution representing molecular orientational disorder. The parameters derived were validated using experimental values of relative retention times on stationary phases of different polarities. Accurate to extremely accurate results were obtained with standard errors of regression close to experimental inaccuracy and high correlation coefficients comparing favourably to existing methods of prediction. The parameters derived performed quite well for apolar to moderately polar stationary phases. For polar phases inaccuracy increased significantly. The method has several advantages compared to other methods used for the prediction of chromatographic retention.

Comparison of bioconcentration factors of tetrachlorobenzyltoluenes in the guppy (Poecilia reticulata) and zebra mussel (Dreissena polymorpha)

Preliminary bioconcentration factors (BCFs) were determined of six tetrachlorobenzyltoluenes (TCBTs) in guppies (Poecilia reticulata). BCFs and rate constants were derived by an iterative integration method. With this method BCFs and rate constants can be derived from experimental data of a bioconcentration test, even if the concentration in the water is not constant and steady state has not been reached. Log BCF values of TCBTs in guppies ranged from 1.67 to 2.68 L.kg-1 on a wet weight basis. These values are much lower than the reported log BCF values of TCBTs in zebra mussels (Dreissena polymorpha) determined with the same method. Biotransformation of TCBTs in guppies as an explanation for the higher log BCF values in zebramussel is discussed.

Determination of vapour pressure and related thermodynamic properties of polycyclic aromatic compounds

Abstract A gas-liquid chromatographic (GLC) method is presented for determination of (sub-cooled) liquid vapour pressure, heat of vaporization and gas-liquid heat capacity differences of low-volatility organic compounds. Values obtained for unsubstituted and chlorine on-ring plus nitrogen in-ring substituted polycyclic aromatic compounds compare favourably with those obtained via other experimental and theoretical methods. The method allows for the determination of properties of large numbers of compounds and the distinction between isomers.

Determination of aqueous solubilities of tetrachlorobenzyltoluenes individually and in a mixture by a modified generator column technique

Aqueous solubilities of nine tetrachlorobenzyltoluenes (TCBTs) were determined at 25 °C using a generator

Synthesis of Some Non-Conjugated Dienones in the Retro-α-Ionone Series1

Abstract In the course of a study on the photochemical and thermal behaviour of β,γ-δ,e-dienones1-4, (E)-retro-α-ionone (2a) and a series of methylated (3, 4) and desmethyl analogues (2b-2e) have been synthesized by a simple deconjugative isomerization of the corresponding conjugated dienones in strong alkaline solution. 3-Methyl- (3) and 3,3-dimethyl-retro-α-ionone (4) have been prepared by addition of methyl chloride to a strongly alkaline solution of β-ionone (1a).5