THE ELECTROMETRIC TITRATION OF VANADIUM.

The Electrometric Titration of Hemin and Hematin

It was shown 5 years ago (1) that the change from methemoglobin to hemoglobin could be studied by an electrochemical method. The reduction by means of sodium hydrosulfite and the oxidation of the reduced compound (hemoglobin) by ferricyanide were found to involve 1 equivalent. These results have been confirmed and extended in later work (2). An application of the same method to a study of the r...

The Electrometric Titration of Lecithin and Cephalin”

It has been recognized for some years that lecithin is an internally neutralized compound (1). The neutralization takes place between a strongly acidic group and a strongly basic group. Solutions of lecithin therefore may be expected to show no buffering power within the physiological range and this has been observed to be the case (24). The internal neutralization of lecithin has led to the pr...

Electrometric Titration of Chloride in Small Volumes

Electrometric titration of copper and zinc in biologic material.

C OLORIMETRIC ANALYSIS has been employed extensively in determination of copper and zinc in human serum and other biologic materials. Greenleaf (1) and Callan and Henderson (2) determined copper colorimetrically using dithizone and diethyldithiocarbamate, respectivelv. Zinc was determined colorinietricallv by Fischer and Leopoldi (4) and by Wolf (5), using dithizone. These procedures were evalu...

The structure of metaphase chromosomes. I. Electrometric titration, magnesium ion binding and circular dichroism.

Isolated mammalian metaphase chromosomes suspended in ion-free or 10d3 YN&l solution undergo an irreversible, pH-dependent structural change, as reflected by electrometric titrations, pH-stat experiments and measurements of circular dichroism spectra. Unmasking of titratable groups with pK’s lower than the isoionic pH of chromosomes in ion-free water, pH 66, accompanies the change in conformati...