Portable Total Reflection X-ray Fluorescence Spectrometer with a Detection Limit in the 100 ng/L Range

In this study, a method was presented for detecting low concentrations of elements in a high purity water sample using a portable total reflection X-ray fluorescence (TXRF) spectrometer. Preparing the dry residue of a sample droplet with large volume on a hydrophobic film coated sample holder was effective for improving the detection limit expressed as the concentration of a target element in a sample solution. When a TXRF spectrum of the dry residue of a 200 µL droplet of a solution containing 10 µg/L of Cr that was prepared by diluting a commercially available 1000 mg/L Cr standard solution with ultrapure water on a hydrophobic film coated sample holder was measured, a detection limit of 0.13 µg/L was achieved for Cr.