Quantitative laboratory experiments based on reactions of cyclamates

Abstract

Quantitative Laboratory ExperimentsBased on Reactions of Cyclamates The importance of creating experiments for quantitative and instrumental analysis laboratories which demonstrate both fundamental chemical measuring principles and practical industrial or commercial analysis cannot be too strongly emphasized in today's chemistry curriculum (1).Consistent with this philosophy, this report outlines a series of cohesive experiments based upon reactions of cyclamates for use in an introductory instrumental analysis laboratory. Cyclamates were of particular value because of recent wide public interest and publicity ( 2) and what appeared to be a lack of characterization of cyclamate reactions and determinations.The approach taken in the design of these experiments was to employ directly or with modification previously published cyclamate analyses, and to devise open-ended "developmental" experiments based upon analyses which "should work" for cyclamates because of analogy to known methods. The goals of this series of experiments were to develop a more-than routine student interest in the chemical reactions of the analysis, to apply a variety of instrumental measuring techniques, and to lay the ground-work for further research studies. The same approach and goals can be equally well applied to a variety of industrial or commercial products, and this report may serve as an outline for others interested in devising consistent, sequential experiments. Experimental Methods SelectionThe analytical chemistry of cyclamates prior to 1967 •was reviewed extensiv ly by Richardson (3) who has also developed two rapid cyclamate determinations (4, 5). A number of new determinations have been developed since Richardson's review {6-9). Cyclamates are sodium and calcium salts of N-alkyl-substituted sulfamates in which the alkyl substitution is cyclohexane {10). The chemical analyses are based upon relatively few different chemical reactions. In addition to classical elemental, gravimetric, volumetric, and separation techniques, cyclamates or cyclamate reaction products have been determined by spectrophotometric, electrochemical, and chromatographic methods. This variety of alternate approaches is ideal for the generation of a coherent series of laboratory experiments.

Electroanalysis and coulometric analysis

“…Apparatus for regenerating coulometric cells has been constructed (32) as have a detector for gas analysis ( 150), a coulometric calibrator for GC detectors (276), and a device to study surface reaction rates (248). CN _ free and coordinated (191) Cyclamates (26) Gold (30) Phenol (105)…”