The topological evolution of the cleavage surface of a gypsum single crystal during its dissolution in a flowing undersaturated aqueous solution has been observed with an atomic force microscope. The matter transfer from solid to liquid proceeds through the migration of atomic steps. The step velocity has been measured and appears to depend on the force applied by the tip on the surface. Wherea...

A paper disc flameless atomic absorption spectroscopy (AAS) method is described for the determination of cadmium (Cd) in blood, enabling difficulties in sample preparation to be minimized. By control of the ashing step the matrix can be removed without loss of cadmium. Problems with the fast signal response during atomization can be met by spectral band width and temperature control. At the 106...

THE INITIAL STUDIES BY WILLIS (2, 3) and the more recent work of Zettner and Seligson (i) and others (4-7, 9-11) have proven the utility of atomic absorption spectrophotometry (AAS) in the clinical laboratory. However, until very recently there has been very little if any published information dealing with normal serum calcium values by atomic absorption spectrophotometry (11). The primary purp...

The direct chelation-extraction method, originally developed by Hessel (1968) for blood lead analysis, has been successfully applied to urinalysis for manganese. The analyses of 35 urine samples containing up to 100 microgram/1 of manganese from manganese-exposed workers showed that the data obtained by this method agree well with those by wet digestion-flame atomic absorption spectrophotometry...

Atomic absorption spectrophotometry (AAS) was applied to the determination of serum calcium. A special diluent was developed to abolish the effect of absorption depressors. This made possible measurement of calcium in directly diluted serum samples without prior removal of any serum constituents. Values obtained by AAS on calcium oxalate precipitates from serum were identical with those found b...

Zinc in pooled human serum, diluted 10-fold with demineralized water, was determined by flame atomic absorption spectrophotometry. Recoveries of zinc added to the serum were calculated by use of standards prepared in water, physiological saline, synthetic serum, or dilute HNO3 (10 ml/liter). The flow rates were essentially the same (9.1 to 9.3 ml/min) for water, diluted synthetic serum or act...