Biomedical subjects

C Mahugo Santana

Publications and source records attributed to C Mahugo Santana.

4 recordsLinked to original sources

PubMed2006

Development of a solid-phase microextraction method with micellar desorption for the determination of chlorophenols in water samples. Comparison with conventional solid-phase microextraction method.

A novel analytical method is presented for the determination of chlorophenols in water. This method involves pre-concentration by solid-phase microextraction (SPME) and an external desorption using a micellar medium as desorbing agent. Final analysis of the selected chlorophenols compounds was carried out by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Optimum conditions for desorption, using the non-ionic surfactant polyoxyethylene 10 lauryl ether (POLE), such as surfactant concentration and time were studied. A satisfactory reproducibility for the extraction of target compounds, between 6 and 15%, was obtained, and detection limits were in the range of 1.1-5.9ngmL(-1). The developed method is evaluated and compared with the conventional one using organic solvent as a desorbing agent. The method was successfully applied to the determination of chlorophenols in water samples from different origin. This study has demonstrated that solid-phase microextraction with micellar desorption (SPME-MD) can be used as an alternative to conventional SPME method for the extraction of chlorophenols in water samples.

Chlorophenols↗

PubMed2002

Use of non-ionic surfactant solutions for the extraction and preconcentration of phenolic compounds in water prior to their HPLC-UV detection.

A simple and rapid HPLC method with spectrophotometric detection to determine phenolic compounds in water, including the 11 priority phenolic pollutants, is described. As they are present in low concentrations, an extraction and preconcentration step is necessary prior to their determination. A methodology based on the cloud point phenomenon is applied using the non-ionic surfactant oligoethylene glycol monoalkyl ether (Genapol X-080) as extractant. The optimum conditions for the extraction and preconcentration of phenolic derivatives have been established and detection limits lower than 10 micrograms L-1 were obtained for all studied compounds. The method has been applied to their determination in sea water and depurated waste water samples.

Chemistry Techniques, Analytical↗

PubMedDate not supplied

Optimization of the separation selectivity of PCBs in a hydroorganic reverse-phase liquid chromatography in the presence of cetyltrimethylammonium bromide with fluorescence detection.

The retention of different PCBs of toxicological and environmental interest was studied in a hydro-alcoholic reverse-phase liquid chromatography in the presence of cetyltrimethylammonium bromide (CTAB). The influence of variables like type and percentage of alcohol, concentration of CTAB, temperature and mobile phase flow was determined. According to the aforementioned studies, the appropriate conditions for separation of PCBs in presence of CTAB in a hydro-alcoholic medium are: percentage of 1-Propanol 55% (v/v), concentration of CTAB 5.0 x 10(-3) M, temperature 50 +/- 1 degrees C and mobile phase flow 1 ml min-1.

Cetrimonium↗

PubMedDate not supplied

Extraction and determination of phenolic derivatives in water samples by using polyoxyethylene surfactants and liquid chromatography with photodiode array detection.

Methodology based on the cloud-point phenomenon was applied to the comparative study of 3 different polyoxyethylene nonionic surfactants in order to extract and preconcentrate a group of phenolic derivatives in water samples; these phenolic compounds, which were determined by liquid chromatography with UV detection, included 11 pollutants given priority by the U.S. Environmental Protection Agency. The optimum conditions for the extraction and preconcentration of phenolic compounds were established for each surfactant. The surfactant that gave the best extraction and preconcentration of the analytes under study was polyoxyethylene 6 lauryl ether (C12E6) with detection limits of <3.5 microg/L for all the phenolic compounds tested. The method was applied to seawater and depurated wastewater samples.

Calibration↗