Rapid solubilization of human body tissues and tissue fluids for microdetermination of heavy metals

We evaluated the suitability of a liquid pressure technique for decomposing and liquifying several different human tissues as a pretreatment for atomic absorption spectroscopy. Samples of lead, mercury, copper, zinc, cadmium, nickel, and/or chromium in the ppm concentration range were used to spike samples of human liver, intestine, muscle, lung, brain, and/or teeth. All human tissue samples decomposed completely in a 23-ml capacity Teflon-lined decomposition vessel under the following standard conditions: 0.2 g tissue, 2.5 ml nitric acid (64%), 135 degrees C for 2 hr. Recoveries of the various added heavy metals under the above standard conditions by atomic absorption spectroscopy were high, with errors averaged over all the samples of 29.2% for a concentration of 1 ppm, 8.4% for 5 ppm, and 5.7% for 20 ppm. Thus liquid pressure technique was found to be a simple, rapid, and reliable method for decomposing both hard and soft human tissues for trace metal determinations by atomic absorptions spectroscopy.