Antonio M. Ruiz

A rapid method for peroxide value determination in edible oils based on flow analysis with Fourier transform infrared spectroscopic detection

The development of an automated, rapid and highly precise method for determination of the peroxide value in edible oils based on a continuous flow system and Fourier transform infrared (FTIR) spectroscopic detection is described. The sample stream was mixed with a solvent mixture consisting of 25% (v/v) toluene in hexanol which contained triphenylphosphine (TPP). The hydroperoxides present in the sample reacted stoichiometrically with TPP to give triphenylphosphine oxide (TPPO) which has a characteristic and intense absorption band at 542 cm-1. A 10% (m/v) TPP solution in the solvent mixture and a 100 cm reaction coil were necessary for complete reaction. FTIR transmission spectra were recorded using a flow cell equipped with CsI windows having an optical pathlength of 100 microns. By using tert-butyl hydroperoxide spiked oil standards and evaluation of the band formed at 542 cm-1 a linear calibration graph covering the range 1-100 PV (peroxide value; mequiv O2 kg-1 oil) was obtained. The relative standard deviation was 0.23% (n = 11) and the throughput 24 samples h-1. The developed system was also applied to the determination of PV in olive, sunflower and corn oils, showing good agreement with the official reference method of the European Community which is based on titration using organic solvents. The results obtained clearly show that the developed method is superior to the standard wet chemical method, hence suggesting its application in routine analysis and quality control.

Geodetic measurements of crustal deformation on NW–SE faults of the Betic Cordillera, southern Spain, 1999–2001

Abstract The Granada basin, located in the central sector of the Betic Cordillera, is one of the most seismically active zones of the Iberian Peninsula. For the first time, a geodetic network along the Padul fault and two levelling profiles (Genil and Viznar) crossing the Granada fault were operated to detect crust microdeformations in this area. Three years of terrestrial geodetic measurements are analysed to characterize the behaviour of these faults in a low to moderate strain rate environment. After the comparison of these three campaigns, we can conclude that there is no significant short-term movement of the Padul fault. Granada fault measurements show significant differences between 1999 and 2001 campaigns in Viznar profile. However, more data are needed to correlate this displacement to the tectonic activity.

Establishment of a Non-Permanent GPS Network to Monitor the Recent NE-SW Deformation in the Granada Basin (Betic Cordillera, Southern Spain)

The Granada Basin (Central Betic Cordillera), one of the most seismically active areas of the Iberian Peninsula, is currently subjected to NW-SE compression and NE-SW extension. The present day extension is accommodated by normal faults with various orientations but particularly with a NW-SE strike. At the surface, these active NW-SE normal faults are mainly concentrated on the NE part of the Basin. In this part we have selected a 15-km long segment where several active normal faults crop out. Using the marine Tortonian rocks as a reference, we have calculated a minimum extensional rate of 0.15-0.30 mm/year. The observed block rotation, the listric geometry of faults at depth and the distribution of seismicity over the whole Basin, indicate that this rate is a minimum value. In the framework of an interdisciplinary research project a non-permanent GPS-network has been established in the central sector of Betic Cordillera to monitor the crustal deformations. The first two observation campaigns were done in 1999 and 2000.

A GRAVIMETRIC GEOID COMPUTATION AND COMPARISON WITH GPS RESULTS IN NORTHERN ANDALUSIA (SPAIN)

Two new GPS surveys have been carried out to check the accuracy of an existing gravimetric geoid in a test area located in northern Andalusia (Spain). The fast collocation method and the remove-restore procedure have been used for the computation of the quasigeoid model. The Spanish height system is based on orthometric heights, so the gravimetrically determined quasigeoid has been transformed to a geoid model and then compared to geoid undulations provided by GPS and levelling at benchmarks belonging to the Spanish first-order levelling network. The discrepancies between the gravimetric solution and GPS/levelling undulations amount to ±2 cm for one survey and ±5 cm for another after fitting a plane to the geoid model.

Geodetic Control of the Present Tectonic Deformation of the Betic Cordillera (Spain)

The Betic Cordillera, located in the south of the Iberian Peninsula, is currently subjected to NW-SE compression and NE-SW extension. Until a few years ago, there were hardly any geodetic studies to quantify the tectonic deformation taking place in the Betic Cordillera. In 1999, in the framework of an interdisciplinary research project to monitor the deformation, several geodetic studies were initiated by the Universities of Jaen, Granada and Alicante. These studies were centred on the basins of Granada and the Bajo Segura (Alicante), sectors in which the last two destructive earthquakes in the Iberian Peninsula took place. This paper describes the geodynamic context of these study areas and the main features of the geodetic studies, focusing on the deformation analysis of the three observation surveys carried out in 1999, 2000 and 2001 over a non-permanent GPS network established in the Granada Basin. The results agree with the low rates of deformation previously calculated from geological data. To detect such small rates, observation over a longer time span will be needed.

A New Continuous GPS Network to Monitor Deformations in the Iberian Peninsula (Topo-Iberia Project). First Study of the Situation of the Betic System Area

Topo-Iberia is a project funded by the Spanish Research Council that shares interests with Topo-Europe project. Its objective is to understand the interactions in the Iberian Peninsula (SW Europe) between deep, shallow and atmospheric processes, through a multidisciplinary approach linking Geology, Geophysics and Geodesy. In order to achieve the observational goals of the project, three main working groups have been set up: seismic, magneto-telluric and geodetic. The first task of the GPS geodetic working group was to design the new Continuous GPS network to complement other GPS networks which are already operating under the supervision of different institutions. The Betic System is the most active tectonically area in the Iberian Peninsula. As this area in under a NNW-SSE to NW-SE compression regime, two station alignments (from NE to SW and NW to SE) were built, including continuous GPS (CGPS) stations in Northern Africa. Nowadays the Topo-Iberia GPS network includes twenty-six operational stations: 22 installed in different regions of Spain and 4 located in strategically chosen places in Morocco. In this work the state of the art of the CGPS network in the Betic System Area is presented.