.alpha.-L-Aspartyl-L-phenylalanine methyl ester (.alpha.-APM) is prepared by catalytic hydrogenation of N-benzyloxycarbonyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester (Z-.alpha.-APM). The catalytic hydrogenation is conducted in an aqueous suspension containing the Z-.alpha.-APM in the form of particles whose average particle size is not greater than 800 .mu.m. The starting Z-.alpha.-APM may contain up to 30 wt. % of its .beta.-isomer provided that the process additionally includes recrystallization of the .alpha.-APM, collection of the .alpha.-APM by filtration and recycling of the filtrate for use in the aqueous suspension of Z-.alpha.-APM.

A process for obtaining dry crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a water content of about 2 wt. % to about 6 wt. % based on the weight of the wet crystals is disclosed. This process comprises exposing wet crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester, having a water content not greater than 50 wt. % based on the weight of the wet crystals and obtained by the crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester from an unagitated solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester, to a flow of air having a temperature of 80.degree. C. to 200.degree. C.

A multiple analyte assaying device includes a casing having a pocket portion adapted to capture or contain a predetermined volume of fluid specimen to be assayed. Disposed within the casing is a sample receiving pad and one or more reagent test strips. The pocket portion of the casing includes a feed element having multiple feed inlets, or alternatively, a single feed slot. The feed element provides pressure against the sample receiving pad. The pressure against the pad and a small size of the inlet or inlets are effective in controlling a rate of fluid release of the specimen to the sample receiving pad. The casing includes observation windows or alternatively a clear plastic view area for enabling observation of reagent zones of the test strips. The device is structured and adapted to enable a technician to capture the appropriate volume of fluid specimen in the pocket portion by submerging or dipping a portion of the device into a fluid-filled collection container for a brief period of time. The device includes a rail depending from the casing for elevating the dampened portion of the casing when the device is placed on a level surface.