The multielemental analysis of bone. A review

Numerous elements, especially metals, possess biological activity. But until now, they were of interest mainly as ingredients of foods. This caused the grouping in essential and nonessential elements, and characteristic changes of their concentrations in tissues and body fluids of man are often accompanied by pathologic alterations. The growing interest in environmental influences on human, animal, and plant health has focused our view on the toxicity of certain elements. Often it depends on concentration (1) or chemical form (e.g., Cr3+ is essential whereas Cr6+ is venomous) if an element is vital or poisonous.

An application of gas chromatography mass spectrometry to the quantitation of substances and their labelled variants

A method is proposed for the quantitative estimation of a substance and its labelled analogue using the selected ion monitoring technique of gas chromatography mass spectrometry, in which estimation is achieved without a third labelled analogue as internal standard. In a first measurement the ratio of natural to labelled substance is established. Then a known amount of either labelled or natural compound is added, the isotope ratio is determined a second time and from these two measurements the mass amounts can be calculated. When applied to the heptafluorobutyrates of androstenedione and progesterone about 10 pg of 14C labeled compounds can be determined in the presence of 1 ng of the natural substances.