Rapid determination of octanol–water partition coefficient using vortex-assisted liquid–liquid microextraction

Vortex-assisted liquid–liquid microextraction (VALLME) coupled with high-performance liquid chromatography (HPLC) is proposed here for the rapid determination of octanol–water partitioning coefficients (Kow). VALLME uses vortex agitation, a mild emulsification procedure, to disperse microvolumes of octanol in the aqueous phase thus increasing the interfacial contact area and ensuring faster partitioning rates. With VALLME, 2 min were enough to achieve equilibrium conditions between the octanolic and aqueous phases. Upon equilibration, separation was achieved using centrifugation and the octanolic microdrop was collected and analyzed in a HPLC system. Six model compounds with log Kow values ranging between ∼0.5 and 3.5 were used during the present investigations. The proposed method produced log Kow values that were consistent with previously published values and the recorded uncertainty was well within the acceptable log unit range. Overall, the key features of the proposed Kow determination procedure comprised speed, reliability, simplicity, low cost and minimal solvent consumption.EP is grateful to the Region of Crete (Perifereia Kritis) for funding. Financial support from the Spanish Government (Project CTQ2011-23968) is also acknowledged. I.P.R. also thanks “Caja de Ahorros del Mediterraneo (CAM)” for his predoctoral grant and financial support

Chemometric comparison of almond oxidation rates using kinetic parameters obtained by infrared spectroscopy

BACKGROUND: The study of almond fat stability is essential from a quality control perspective meanly because, in most of the cases, almonds are sold skinned and thermally treated. In this work an alternative method to Rancimat test based on attenuated total reflectance‐Fourier‐transform infrared (ATR‐FTIR) spectrometry was adapted for checking the induced degradation at 75 °C of seven almond oil cultivars, three of the top Californian producing varieties, and, four traditional cultivars harvested in Spain. RESULTS: The thermal oil degradation evolution was followed by measuring the changes in the absorbance of the selected FTIR spectra bands (3470, 3006, 1730, 1630, 988 and 970 cm−1). A first‐order kinetic behaviour was observed, after an induction time in all bands. CONCLUSIONS: Kinetic coefficients and induction times were easily obtained as the absorbance values (from difference spectra) fitted to pseudo‐first‐order kinetics after the induction time. Principal component analysis was applied to the kinetic parameters to visualize which variables could be useful to classify the almond cultivars based on their resistance to thermal oxidation processes. It was found that selecting only the induction times corresponding to the bands 3470, 3006, 1630 and 970 cm−1 a separate classification of the Californian cultivars from the Spanish ones was possible. Finally, a linear discriminant analysis was assayed using only the four induction times previously selected. Validated classification and correct in 100% of the cases was obtained for all the samples based on their Spanish or Californian origin

Ionic liquids used as a green approach in headspace single drop microextraction and GCMS determination of organotin compounds

Gas chromatography with MS detection was applied for simultaneous determination of six of the most toxic organotin compounds (OTs): monobutyltin, dibutyltin, tributyltin, monophenyltin, diphenyltin, triphenyltin. Headspace single drop microextraction (HS-SDME) in Ionic liquids (ILs) was proposed as Green alternative to the traditional one. Three different ILs ([C8MIM][PF6]; [C6MIM][PF6]) and [C4MIM][PF6]) were evaluated as a collector phase. The first one was found as the most appropriate for a group microextraction of the tested OTs. Analytes were evaporated from the IL microdrop by means of thermal desorption. ILs possess some advantages as an extraction phase in comparison with traditionally used organic solvents. They are more stable during the analytical process and are considered as environmentally friendly compounds. Moreover HS-SDME procedure was performed in a single drop of only 5μl IL. The time needed for the extraction was proved to be only 20 min. Therefore the proposed method could be related to the Green chemistry methods.The current study has been financially supported by: NSF of Bulgaria (Project DO 02-70 (GAMA)); EC 7FP Project 245588 (BioSupport); MICINN of Spain (Project CTQ2008-06730-C02-01) and Regional Government of Valencia (Project ACOMP2010/047). LG thanks Erasmus program and Ministry of Education for her fellowship. IPR also thanks “Caja de Ahorros del Mediterraneo (CAM)” for his Ph.D fellowship

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially