Related Experiment Video
Updated: Oct 2, 2026

A Rapid and Chemical-free Hemoglobin Assay with Photothermal Angular Light Scattering
Published on: December 7, 2016
Determination of methemoglobin and total hemoglobin in toxicological studies by derivative spectrophotometry
A Cruz-Landeira1, M J Bal, Quintela
1Forensic Toxicology Service, Legal Medicine Institute, University of Santiago of Compostela, Spain.
Abstract:
A method for the determination of methemoglobin in the presence of other hemoglobin subforms (i.e., oxy-, deoxy-, and carboxyhemoglobin) by use of derivative spectrophotometry is proposed. The method, which uses the first-derivative of the spectrum at 645 nm, is straightforward and expeditious, so it is of special interest to forensic toxicology laboratories as it allows the simultaneous determination of the methemoglobin saturation percentage and the hemoglobin concentration. This facilitates interpretation of the results and provides a better understanding of the significance of methemoglobin saturation in specific cases. Based on an analysis of interferences, the presence of other hemoglobin subforms or of endogenous components of plasma does not detract in any way from the performance of the method.
Related Concept Videos
Effects of EDTA on End-Point Detection Methods
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
Flame Photometry: Lab
Therapeutic Drug Monitoring: Drug Analysis Methods
Precipitation Titration: Endpoint Detection Methods
In the Volhard method, a standard excess of AgNO3 is first added to the...

