Analytical Methods see also Part V, Chapter

The facile formation of a yellow, sparingly soluble complex salt of the composition K3[Co(N02)6] has been used as a simple qualitative test for cobalt ions in solution. A more sensitive test is based on the formation of the intensely blue cobalt aluminate, CoO AI2O3, a pigment also known as The-nard s Blue. A spot-test utilizing a-nitroso-a-naphthol allows detection of 0.05 pg of Co at a dilution of up to 1 1000000. 

Methods for quantitative analysis of Co indude flame and graphite-furnace atomic absorption spectrometry (AAS e.g., Welz and Sperling 1999), inductively coupled plasma emission spectrometry (ICP-AES e.g., Schramel 1994), neutron activation analysis (NAA e.g., Versieck etal. 1978), ion chromatography (e.g., Haerdi 1989), and electrochemical methods such as adsorption differential pulse voltammetry (ADPV e.g., Ostapczuk etal. 1983, Wang 1994). Older photometric methods are described in the literature (e.g.. Burger 1973). For a comparative study of the most commonly employed methods in the analysis of biological materials, see Miller-Ihli and Wolf (1986) and Angerer and Schaller 

---