This study describes a sample preparation method for trace element analysis using total reflection X-ray fluorescence analysis. The procedure of this method is as follows: 1) a hydrophobic-coated sample holder whose hydrophobic film at around the center of the surface is partially dissolved by acetone is prepared; 2) a droplet of a sample solution is dropped on the sample holder; and 3) the sample droplet is heated and dried while vibrating it. This sample preparation method is effective for reducing the size of the dry residue of the sample solution and suppressing the coffee-ring formation. Furthermore, this method leads to an enhancement in the intensity of an X-ray fluorescence line from an analyte element in the sample residue. In this study, this sample preparation method led to an improvement in the detection limit for vanadium in commercially available bottled drinking water.
Keywords: Coffee ring; dry residue; total reflection X-ray fluorescence; vanadium; vibration.