Determination of cadmium in biological samples

Even though normal exposure levels to Cd may be small, the human body is inefficient at excreting the heavy metal, so it slowly accumulates over the period of a lifetime. Eventually, the Cd level in the body may become toxic and give rise to harmful effects. Cadmium exposure could therefore be linked to diseases associated with aging such as osteoporosis, prostate cancer, and pancreatic cancer. These potential links have driven the development of a myriad of analytical techniques for the determination of Cd in biological samples. Natural biological Cd concentrations are typically low, so preconcentration steps and sensitive instruments are frequently a necessity. In addition, the complex matrices of biological specimens such as blood, urine, serum, and tissue often require a form of matrix modification or separation. This review provides an overview of these methods with 200 references from the literature published between 1995 and 2005. The analytical methods for the determination of Cd in biological samples include: spectrophotometry, atomic emission spectrometry, atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma mass spectrometry, and electrochemistry. In addition, Cd speciation techniques, using high-performance liquid chromatography and capillary electrophoresis, are briefly discussed.