Influence of dilution factors on detection capability and accuracy of total reflection X-Ray fluorescence analysis of seawater samples

Seawater analysis is crucial for monitoring marine ecosystem contamination, particularly that of heavy metals, which poses significant threats to marine life and human health. However, the matrix effect in seawater, caused by the presence of multiple compounds and interference, can lead to inaccurate results. Total reflection X-Ray Fluorescence (TXRF) is a highly sensitive technique for determining the elemental concentrations in samples; however, the high salt content in seawater can cause interference in the TXRF spectrum. This study aimed to evaluate the influence of dilution factors on the detection capability and accuracy of TXRF analysis of seawater. Surface seawater collected from Playa La Marinera, Tonosí, was filtered and diluted to $1: 5$, 1:10, and 1:20. Gallium was used as an internal standard, and the samples were analyzed using a S2 Picofox TXRF spectrometer. Statistical parameters, including detection limits, Poisson distribution, and deconvolution quality, were calculated for each sample to assess the optimal dilution. The results of this study will enhance the understanding of direct element measurements in liquids with high matrix content and contribute to the development of more accurate and reliable seawater analysis methods for monitoring marine ecosystem health.