[X/H] abundances as a function of the pulsation phase. Each panel shows the abundances of α elements from neutral and ionized lines as listed in Tables 8 and 9. As explained in the text, the sulfur abundances were derived using the spectral synthesis method applied to one spectrum of each star (an exception are the stars ηAql, VY Sgr, and V340 Ara, for which the [S/H] abundances could not be derived due to the noisy profile of the sulfur line used).