Chemical environments of 6.7 GHz methanol maser sources

6.7 GHz methanol masers are the brightest of class II that regarded as excellent signposts in formation young massive stars. We present here a molecular line study 68 maser hosts chosen from MMB catalogue, have MALT90 data available. performed (1) pixel-by-pixel 9 sources high signal-to-noise ratio and (2) statistical taking into account entire sources. estimated column densities abundances N$_2$H$^+$(1-0), HCO$^+$(1-0), HCN(1-0) HNC(1-0) lines. The derived found to be congruence with typical values towards mass star forming regions. density abundance ratios between these species an attempt unveil evolutionary stage HCN HNC increase N$_2$H$^+$ HCO$^+$ decline source evolution, suggested by chemical models. HCN/HNC, N$_2$H$^+$/HCO$^+$, HNC/HCO$^+$ N$_2$H$^+$/HNC consistent them being at later state than quiescent phase possibly protostellar phase, but earlier HII regions PDRs.