Validation of an Analytical Method for the Determination of Manganese and Lead in Human Hair and Nails Using Graphite Furnace Atomic Absorption Spectrometry

Multi-Elemental Analysis of Hair and Fingernails Using Energy-Dispersive X-ray Fluorescence (ED XRF) Method Supported by Inductively Coupled Plasma Mass Spectrometry (ICP MS)

This work compared the multi-element analysis of human hair and nails using inductively coupled plasma mass spectrometry (ICP MS) with an easy, fast, cheap, non-destructive method using energy-dispersive x-ray fluorescence (ED XRF). The ICP MS-based method was more sensitive (over 30 elements could be quantified) and costly (requiring more time, samples, and chemicals). The EDX-based method required laboratory and certified reference materials made of hair for instrument calibration. It was less sensitive (16 elements could be quantified: S, Si, Ca, Br, Fe, Cu, Cr, Mg, Si, K, Mn, Ni, Zn, Se, Sr, Pb), but it allowed us to replace troublesome grinding with the dissolution of keratin-based material with an alkalic agent (tetramethylammonium hydroxide, TMAH) and the formation of stable-for-days pellets. This method is simple, enables automation, and, due to the modification of wells in the autosampler of the EDX system via the immersion of home-designed inserts, it requires smaller amounts of biological material and binder (down to 70 mg instead of 500 mg required by commercially available instrument) to perform analysis. It was concluded that the EDX-based method offers complementary selectivity and sensitivity to ICP MS with the possibility of sample reuse for further analysis.

Recent advances in instrumental techniques for heavy metal quantification

Heavy metals (HMs) are ubiquitous; they are found in soil, water, air, and all biological matrices. The toxicity, bioaccumulation potential, and deleterious effects of most of these metals on humans and the environment have been widely documented. Consequently, the detection and quantification of HMs in various environmental samples have become a pressing issue. The analysis of the concentrations of HMs is a vital component of environmental monitoring; hence, the selection of the most suitable analytical technique for their determination has become a topic of great interest in food, environment, and human health safety. Analytical techniques for the quantification of these metals have evolved. Presently, a broad range of HM analytical techniques are available with each having its outstanding merits as well as limitations. Most analytical scientists, therefore, adopt complementation of more than one method, with the choice influenced by the specific metal of interest, desired limits of detection and quantification, nature of the interference, level of sensitivity, and precision among others. Sequel to the above, this work comprehensively reviews the most recent advances in instrumental techniques for the determination of HMs. It gives a general overview of the concept of HMs, their sources, and why their accurate quantification is pertinent. It highlights various conventional and more advanced techniques for HM determination, and as one of its kind, it also gives special attention to the specific merits and demerits of the analytical techniques. Finally, it presents the most recent studies in this regard.