Before conducting flame atomic absorption spectrometric analyses, minute quantities of cadmium, cobalt, copper, and lead ions from environmental samples were concentrated and isolated utilizing an innovative and very sensitive enrichment membrane filtration method. A cellulose nitrate membrane filter was used to collect the analyte ions as (E)-4-(2-hydroxybenzylideneamino)-N-(pyrimidin-2-yl)benzenesulfonamide complexes. Nitric acid was then used to separate them. The concentration levels of cadmium, cobalt, copper, and lead ions in the final solutions were determined by flame atomic absorption spectrometry. A number of analytical factors were looked into because they affect the collection and identification of metal ions. These included pH, reagent amounts, sample volume, flow rates, matrix effects, and membrane filter type and size. The recovery values of the analyte ions, as determined through measurement, ranged from 95% to 102%. The accuracy of the proposed approach was evaluated by calculating the relative standard deviation (%), yielding a value of ≤4.0%. The method proposed exhibited detection limits ranging from 0.2 to 0.8 μg L−1. The preconcentration factors for each analyte examined were 100. The examination of authorized reference sources verified the accuracy of the proposed methodology. The analyte ions in water and food samples have been successfully separated and preconcentrated, yielding good outcomes.