When elements in a liquid are analyzed by X-ray fluorescence (XRF) spectrometry, the direct liquid analysis method, where a liquid sample is poured into a liquid cell with sample film and measured under helium, is usually used.

However, the wavelengths of the element lines of boron (B-Kα) and fluorine (F-Kα) are so long that they are absorbed by the sample film. This means that boron and fluorine in water cannot be analyzed by the direct liquid analysis method by XRF.

The micro-droplet method using "Ultra Carry®" enables boron and fluorine analysis in water. Ultra Carry (Figure 1) is designed to analyze trace elements in water solution. Since the paper pad and film are very thin, the observed background during measurement is very low, which significantly improves the peak-to -background ratio (signal/noise). The paper pad captures water on the pad, which enables a drop of 500 μL at a time. After drying, the specimen is measured under vacuum. Since water analysis with Ultra Carry can be conducted under vacuum without sample film, boron and fluorine in water can be analyzed by XRF using Ultra Carry.

Ultra Carry and trace element analysis in water solution with Ultra Carry were introduced in Application Note (XRF1084). In this report, boron (B) and fluorine (F) analysis in water with Ultra Carry is demonstrated.