Table 1. Cross-ReactivIty of Cyclamate and Cyclohexylamine In TDx Amphetamine Assay

Inulin is a natural fructose polymer, widespread in gut flora. Determination of inulin clearance is considered the method of choice when precise determination of the glomerular filtration rate is required (1). Classically, inulin determination has been performed after acid hydrolysis by complexing the liberated fructose with resorcinol or diphenylamine in concentrated sulfuric acid (2). However, the latter assays are time consuming, not suited for automated analysis, and potentially subject to interference from other carbohydrates such as glucose (2). Moreover, acid hydrolysis of inulin may result in the formation of other compounds, e.g., difructosedianhydride (3). The technical difficulty of inulin analysis is considered one of the main disadvantages of the method (4). Enzymatic analysis of inulin has been performed (5, 6); a blank reaction, however, is still needed because of glucose interference. Even at physiological concentrations, fasting serum (or amphetamin, class) concn measured, mg/L