Biomedical subjects

S Paytubi

Publications and source records attributed to S Paytubi.

3 recordsLinked to original sources

PubMed2003

Aggregation profile characterisation in dielectrophoretic structures using bacteria and submicron latex particles.

A novel quantitative characterisation method for the measurement of anomalous low frequency aggregation processes on dielectrophoresis electrodes has been developed. Experimental evidence is provided for the relationship between the aggregation effect and AC electro-osmotical fluid motion theory. The aggregation profile dependence for E.coli bacteria, as a function of frequency and applied field, has been quantitatively examined. Additional experimental observations of the aggregation profiles of latex particles with dimensions of hundreds of nanometres, also confirm the relationship between this aggregation effect and the mentioned fluid motion theory.

Journal Article↗

PubMed2001

Determination of aniline derivatives in oils related to the toxic oil syndrome by atmospheric pressure ionization-tandem mass spectrometry.

In 1981, an unknown disease appeared in Spain, the Spanish Toxic Oil Syndrome. Nowadays and despite all efforts, the etiological agent is still unknown. Early studies showed a link between this illness and the consumption of denatured rapeseed oil fraudulently processed and marketed as edible oil. Two families of aniline derivatives present in these oils (fatty acid anilides and acylated phenyl amino propanediol derivatives or PAPs) were found to be good chemical markers of toxic oils. In this work, a new method has been developed to analyze these aniline derivatives in oil samples by HPLC-MS and HPLC-MS/MS with an API source. For their quantification, three different internal standards were used, one for anilides and two for PAPs. Quantification limits were 8 ppm for anilides and 0.2 ppm for PAPs. Anilides and PAPs were found in marker-positive samples at levels up to 50,000 and 330 ppm, respectively. The relative abundance of the different fatty acid anilides and PAPs correlates with the fatty acid composition of the oils. More than 2,600 different samples were analyzed by this method in the most exhaustive screening of suspected toxic oils carried out to date.

Aniline Compounds↗

PubMed2001

Automated strong cation exchange extraction of fatty acid esters of 3-(N-phenylamino)-1,2-propanediol from oil samples for routine quantification by HPLC-APCI/MS/MS.

Fatty acid esters of 3-(N-phenylamino)-1,2-propanediol are currently considered the best chemical markers of toxic oils related to the Spanish toxic oil syndrome. Recent research in this area has undertaken the exhaustive and quantitative characterization of these compounds in oils collected during the epidemic outbreak. Current methods developed in this laboratory are based on solid phase extraction (SPE) using SCX cartridges followed by HPLC-APCI/MS/MS quantification. To circumvent the long and tedious extraction procedure, the SPE protocol was adapted for automatic extraction and the problems derived from the use of the immiscible solvents required for the SCX extraction were solved. Linearity of the analytical method was found in the same range as for the manual method. Extraction recoveries were 87 and 75% for 2-hydroxy-3-(N-phenylamino)propyl linoleate and 2-(linoleyloxy)-3-(N-phenylamino)propyl linoleate, respectively, and the corresponding coefficients of variation were approximately 1%, greatly improving reproducibility over manual procedures.

Cation Exchange Resins↗