Lidocaine analogs, latex particle-analog conjugates, and methods of making and using the same. The analogs have the formula: ##STR00001## wherein Z comprises a nucleophilic group and optionally a protecting group; L is a linker; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 are each independently H, a protecting group, or C.sub.1 to C.sub.6 alkyls, provided that R.sup.1 and R.sup.3 may form a six membered ring with the nitrogen and carbon atom to which R.sup.1 and R.sup.3 are attached; R.sup.6 and R.sup.7 are each independently H or C.sub.1 to C.sub.20 alkyls; and including salts thereof. The analogs are immobilized on latex particles and prepared for use in assays for lidocaine.