Active galactic nuclei (AGN) show a great diversity of optical and UV emission line properties. Dynamical and physical models should be built accordingly. The presence of strong FeII emission suggested the existence of a region shielded from high energy photons, where the low ionization lines are emitted. However, due to the complexity of the FeII emission features, the physical conditions and the location of this shielded region have remained an open issue for a long time. In the near-infrared region two low ionization lines the CaII triplet 8498, 8542, 8662 and the OI 8446 remains almost unexplored in intermediate/high z quasars. We carried out a spectroscopic survey of luminous (-26>Mv>-29) and intermediate redshift (0.60<z<1.85) quasars, covering the CaII triplet and OI 8446 region using the Infrared Spectrometer and Array Camera (ISAAC) at the ESO Very Large Telescope (VLT). We found that CaII profiles are narrower than the ones of Hbeta, suggesting that CaII is emitted in an outer region, further from the continuum source than the Hydrogen lines. We built photoionization models which indicate that CaII and FeII emission is favored in similar physical conditions while hydrogen line emission is possible under a broader range of physical condition. We conclude that the low ionization lines may be preferentially emitted in the outer zone of the accretion disk, while the hydrogen lines can be also emitted by less dense, less optically-thick clouds/filaments within the broad line region (BLR). In addition, we found that the CaII/FeII is systematically higher relative to a low-z sample. If the ratio CaII/FeII is considered as a chemical clock, this result may imply a significant enrichment of the BLR gas by a recent burst of circumnuclear star formation in the luminous quasars of our sample.