It'll be difficult as well as time consuming  to get precise result without AAS for metal ions determination, but you can use ion exchange HPLC (IE-HPLC) or Capillary electrophoresis using conductomeric detection as a possible alternative. Moreover, complexometric titration using masking agent could be an option for the quantitation of metal ions.

I agree with you Subrata, Thank you very much. But kindly suggest the type of masking agent that can be used for the complexometric titration.