Sulfophenyl carboxylates

Eichhom P, Lopez O, Barcelo D (2005) Application of liquid chromatography-electrospray-tandem mass spectrometry for the identification and characterisation of linear alkylbenzene sulfonates and sulfophenyl carboxylates in sludge-amended soils. J Chromatogr A 1067 171-179... 

Main biodegradation products of LAS, sulfophenyl carboxylates (SPCs), were separated by CE using a-cyclodextrin as the chiral selector [6]. The best separation of enantiomers was achieved with 60 mM a-cyclodextrin in a 20 mM citrate buffer at pH 4.0 with an uncoated fused-silica capillary. The method was applied for the qualitative and quantitative analysis of SPC in primary sewage effluents with a detection limit of 1 p,g L-1. 

The recent use of HPLC for the analysis of sulfophenyl carboxylates (SPCs) has been one of the most interesting applications of this technique for the study of the environmental behaviour of anionic surfactants. SPCs are separated by reversed-phase ion-paired chromatography, in which a hydrophobic stationary phase is used and the mobile phase is eluted with aqueous buffers containing a low concentration of the counter-ion [19]. 

Novel metabolites from the fS-oxidation of sulfophenyl carboxylates. Besides the evidence from the repetitive cycles of (3-oxidation in C12-LAS biotransformation, further support for (3-oxidation could be gathered if other intermediates occurring via this pathway were detectable. (3-Oxidation, though known for decades, is still the subject of active research [101,102], The class of compound that has been identified to date, albeit in mammalian systems, is the a,(3-unsaturated carboxylate. 

Although a substantial body of data is available on the levels of linear alkylbenzene sulfonates (LASs) in rivers and estuaries, fewer studies have been conducted on their environmental behaviour, with reference to the mechanisms involved in their transport and to the reactivity they undergo. Studies of LAS in subterranean water and in the marine medium are scarce and have mainly been conducted in the last decade [2-6], coinciding with the development of new techniques of concentration/separation and analysis of LAS at ppb levels or less. Data on concentrations of sulfophenyl carboxylates (SPCs) are very scarce and the behaviour of these intermediates has hardly received any study. This chapter provides an overview of the current knowledge on behaviour of LAS and their degradation products in coastal environments. 

Behaviour of sulfophenyl carboxylates during drinking water production... 

The mitochondrial respiratory parameters have also been employed to determine the toxicity of surfactants, including anionic (LAS), nonionic (NPEO) and their metabolites, sulfophenyl carboxylates (SPCs), NP and nonylphenoxy carboxylate (NPECi) [37]. The system employed was the in vitro response of submitochondrial particles from beef heart. The EC50 toxicity calculated as the reduction rate of NAD+ ranged from 0.61 mg L-1 for a commercial LAS mixture to 18 000 mg L-1 for SPCs, and 1.3 mg L-1, 8.2 and 1.8mgL 1 for NPEOio, NPECi and NP, respectively. These results indicate that from the toxicity perspective, LAS is the compound demanding increased attention, while for NPEO, the parental compound and the metabolites must be quantified. 

In the E-Screen bioassay, LAS was not effective in promoting cell proliferation (Table 7.3.3). This compound was tested at concentrations of up to 100 pM with no evidence of cellular toxicity. The antiestrogenic effect of this compound was also measured but all samples tested were negative. Because it has been suggested that surfactants of the alkylbenzene sulfonate type are readily degradable and transformed into sulfophenyl carboxylates or SPCs, an important number of SPCs were assayed in the E-Screen test. These SPCs did not induce cell proliferation of MCF7 cells. 

The ecotoxicity of sulfophenyl carboxylates (SPC) to aquatic organisms (fish and Daphnia) was explored showing that the LC50 was increased by a factor of200—300 by carboxylation of one terminal methyl group of the alkyl chain and by another 10 to 20 times upon shortening of the alkanoate chain from 11 to 7 and to 5 [43]. This was attributed to the fact... 

Biosensors differ from bioassays mainly by the fact that in bioassays the transducer is not an integral part of the analytical system and biosensors can extract quantitative analytical information of single compounds in complex mixtures. One example is the determination of concentrations of dioxin-like compounds in the blood and environmental samples using the Calux assay, where within a complex matrix its levels are determined with great accuracy (see, e.g., Murk et al. 1997). Additionally, compounds that are difficult to detect (e.g., surfactants, chlorinated hydrocarbons, sulfophenyl carboxylates, dioxins, pesticide metabolites) can more easily be evaluated using biosensors. 

FIGURE 10.7 Separation of sulfophenyl carboxylates (SPC) by IP-RPLC and ESI-MS detection in the negative ion mode. The LAS elutes at 27.5 min (time window not shown). (From Eichhorn, P. and Knepper, T. P., Environ. Toxicol. Chem., 21, 1-8, 2002.)... 

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