Water Analysis by X-ray Fluorescence Spectrometry using UltraCarry

UltraCarry improves sensitivity by combining a highly adsorptive hydrophilic collection area with a thin polymer support. Larger liquid volumes can be deposited onto the collection area, concentrating dissolved elements after drying while minimizing X-ray scattering from the substrate. This increases fluorescence intensity and reduces background noise, resulting in significantly lower detection limits than conventional liquid sample cells or standard droplet filter papers.

Many elements can be detected at concentrations in the tens of parts per billion. Heavy elements such as arsenic, chromium, selenium, manganese, nickel, copper, zinc, and molybdenum exhibit ppb-level detection limits, while many light elements analyzed with the light-element version of the filter also achieve detection limits ranging from approximately 10 to 50 ppb. These sensitivities represent more than a tenfold improvement over conventional XRF liquid analysis methods.

Sample preparation is simple and requires only dispensing a measured volume of liquid onto the filter, followed by drying using ambient air, a low-temperature dryer, or a dedicated vacuum dryer. After drying, the concentrated residue is analyzed under vacuum using standard XRF instrumentation. The minimal preparation reduces operator variability while maintaining analytical reproducibility.

The technique supports quantitative analysis of a wide range of dissolved mineral elements, including sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, chromium, manganese, iron, and strontium. The choice between the standard and light-element versions of the filter allows optimization for either heavy-element sensitivity or broader elemental coverage.

Calibration curves exhibit excellent linearity across the measured concentration ranges. Analyses of commercial mineral waters produce elemental concentrations that closely match the mineral compositions reported by the manufacturers, demonstrating that the method provides reliable quantitative results for trace mineral analysis.

Yes. Standardless analysis using the fundamental parameter method (SQX) produces results that closely agree with calibration-based quantitative analysis while requiring no sample-specific calibration standards. This makes it well suited for rapid screening applications where approximate elemental concentrations are needed quickly.

The method is non-destructive, generates no chemical waste, requires minimal sample preparation, and avoids instrument contamination because the sample never directly contacts the measurement system. These characteristics make it attractive for routine environmental monitoring, industrial process control, and laboratory workflows where rapid, high-throughput elemental analysis is important.

Some volatile elements may be lost during drying if no stabilizing reagent is used, so retention agents can be added when necessary. Additionally, if dried residues become unevenly distributed across the filter, incorporating an internal standard with a characteristic X-ray energy close to the analyte can improve quantitative accuracy by compensating for variations in sample distribution.