Chemical composition of post-AGB star candidates
We present a high resolution detailed abundance analysis for a sample of six post-AGB candidate stars, five of them had not been studied spectroscopically in the optical region. All the analyzed objects are IRAS sources identified as possible post-AGB on the two-colours IRAS diagram. We find three objects with clear signs of evolved stars; IRAS 05338-3051 shows abundances similar to the RV Tauri V453 Oph; the lower-luminosity stars IRAS 18025 - 3906 is O-rich without s-process enrichment and IRAS 18386 - 1253 shows a moderate selective depletion of refractory elements generally seen in post-AGB stars, which show mid-IR excess; they may be evolved post-RGB objects, in which case these would be the first Galactic counterparts of post-RGB objects observed in the Large and Small Magellanic Clouds (Kamath et al. 2014, 2015). On the other hand, IRAS 02528 + 4350 seems to be a moderately metal-poor young object and IRAS 20259 + 4206 also seems to be a young object showing carbon deficiency; however, an analysis with better spectra might be in order to clarify its evolutionary state. Finally, our abundances calculations for the binary post-AGB star IRAS 17279 - 1119 are found in good agreement with those of De Smedt et al. (2016).