Based on the Hantzsch-reaction, a stabilization (fixation) of small concentrations of formaldehyde in aqueous solutions (<0.4vq CH20/ml) can be performed, allowing a storaqe of these solutions for 1 week in darkness. (Aex = 410 nm, Xem = 510 nm), formed as a result of the Hantzsch-reaction, CH20-concentrations down to 0.02 vq/ml can be determined fluorimetrically up to 7 days after preparation (sampling). at room temperature, Usinq the fluorescent nature of 3,5-diacetyl-l,4-dihydrolutidine In the determination of formaldehyde according to the Hantzsch-reaction, other aldehydes, amines and ketocompounds, at the same time present in the air, may cause interference.1073

An enzymatic, fluorometric method for kinetic assay of serum alpha-amylase (1,4alpha-D-glucan 4-glucanohydrolase, EC 3.2.1.1) is described. A soluble starch is used as substrate, in tris(hydroxymethyl)methylamine buffer. All measurements are made in Pyrex cuvettes at 37 degrees C, with a reaction volume of 1.16 ml. The assay is based on the following reaction sequence: (see article) The rate of appearance of fluorescence of NADH (lambdaex = 365 nm, lambdaem = 460 nm), developed in the indicator reaction (4), is measured and equated to the activity of alpha-amylase in serum. A calibration plot of the change of fluorescence per min vs. enzyme concentration shows a good proportionality in the range of 0.50-5.0 kU/liter.

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An enzymic, flurometric method is described for determination of triglycerides (and glycerol) in blood serum, a modification of the method of Bucolo and David [Clin. Chem. 19, 476 (1973)]. Commercially available reagent kits are used. The rate of disappearance of NADH fluorescence at 460 nm (excitation wavelength, 365 nm) is monitored and related to serum triglyceride concentration, corrected for the content of free glycerol. We compared the results obtained fluorometrically to the ultraviolet spectrophotometric Boehringer Neutral Fat method used at Gentofte Hospital, Copenhagen. Instrument response and concentration were linearly related in the range 0.27 to 2.7 mmol of triglycerides per liter of serum with the fluorometric method. The CV was 0.9% for the fluorometric method, 3.7% for the spectrophotometric procedure. The fluorometric method requires less reagents, time, and calculations than does the spectrophotometric method.

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