The H-point and generalized H-point standard additions methods for flow injection procedures

This paper establishes the fundamentals of the H-point standard additions method (HPSAM) and generalized H-point standard additions method (GHPSAM) in the flow injection technique. Two kinds of analytical signals can be employed, FIA peaks and spectra. Different analytical problems have been studied: determinations of one analyte in the presence or absence of matrix effect when different blank features are present, and determination of two analytes in the presence of blank bias error affecting the development of one of them. The determination of chloride with mercury thiocyanate which presents a matrix effect, and the determinations of calcium and/or magnesium with arsenazo III are examined. The methods were compared with conventional data treatment and proved able to isolate the analyte signal from the global one, thus providing accurate and precise results in the determination of the above mentioned species in bottled waters. No additional experimental work is needed to apply the methods.