“…Examples for valid trace determination by TXRF cover a broad variety of different biological samples, from isolated proteins and nuclei acids to fluids, cells, bacteria, hair, and tissues such as the liver, placenta, chest, kidney, lung, prostate, or colon [2,13,[20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Besides the above-mentioned advantages, highly convenient and reliable multi-element quantification can be performed by adding an internal standard for a one-point calibration [20,21,27,30,31]. In addition, trace element determination by TXRF requires only minute sample amounts providing detection limits in the picogram range [19,30].…”