Submitted to: North Dakota Academy of Science Proceedings
Publication Type: Other
Publication Acceptance Date: September 15, 1997
Publication Date: N/A
Interpretive Summary: Interest in the trace element analysis of hair has increased since discoveries have shown relationships between trace elements in hair and certain demographic variables such as, age, sex, race, diet, etc. Multiple chemical elements of clinical, epidemiological, and nutritional interest were measured in the hair of a man over two decades to hopefully determine seasonal variations or time trends. Hair obtained was washed with copper and zinc free shampoo at regular intervals. Twenty samples of hair collected between 1968 and 1986 were prepared by washing with organic solvent followed by a detergent. Samples were digested with acid at low temperature and then analyzed for 23 different elements by using emmission and absorption spectroscopy. A random analysis of the samples was done to avoid bias. The variability of some of the trace elements in the hair over time indicated that more than a single analysis maybe neccesary if hair is used for clinical evaluation. Preliminary data obtained, so far have shown no trends and further supports the conclusion that the use of hair analysis for medical diagnosis is limited. Similar analysis of various hairpools was used to assess analytical variability. Trace element values obtained were similar to published values.
Technical Abstract: Chemical elements often are measured in hair samples with the hope of obtaining useful clinical, epidemiologic, forensic, nutritional or toxicologic information. Analytical methods are sufficiently accurate and precise; medical utility remains largely unproven because of insufficient clinical validation and ignorance of potential variability. Hair samples (250-300 mg) were extracted with acetone and ether, washed with sodium lauryl sulfate and demineralized water, dried over CaSO4 and digested with sub-boiling HNO3 and clean-room grade hydrogen peroxide. Low temperature digestion in Teflon tubes (140 deg) minimized sample loss, and contamination from glass tubes. Elements measured were: Al, As, B, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Se, Si, Sn, V, Zn by using either atomic absorption spectroscopy or inductively coupled plasma spectroscopy. Replicate analyses were done on blanks and various pooled hair samples prepared similarly to the samples of subject hair. Coefficients of variation of the pools ranged from 4% for Zn to 34% for Al. The trace element values presented in this paper are similar to published values. Mean values, ug/g(SD), for some hair elements were; Cu,17.7 (14.4); Cd,0.185 (0.152); Lead,19.7 (27.1); Zn,170 (18.0). Usually several trace elements are measured in a single sample of hair; the within person variability found here reveals that a single analysis may be inadequate for diagnostic purposes or status assessment. Medical intervention based on a single analysis probably is undesirable without supporting data. Neither seasonal effects nor time trends have been found so far; evaluation of data on other elements is in progress with the hope of defining biological variability of hair trace elements better.