# Elemental Composition Analysis of Sheep Tears Using Particle‐Induced X‐Ray Emission

## TL;DR

This study used a technique called PIXE to analyze the elemental composition of sheep tears and found consistent levels of elements like chloride and sodium.

## Contribution

The study introduces PIXE as a reliable method for analyzing elemental composition in small biological samples like sheep tears.

## Key findings

- Chloride and sodium were the most concentrated elements in sheep tears.
- Elemental concentrations remained consistent over a 5-day sampling period.
- PIXE is a viable method for tear analysis and potential biomarker research.

## Abstract

To identify the elemental composition of ovine tears using particle‐induced X‐ray emission (PIXE).

Ten physically healthy female sheep.

Tear samples were collected using Schirmer tear test strips. Tear samples were collected once daily over five consecutive days to assess reproducibility. Elemental analysis was performed with PIXE. Data were processed with GUPIX software. Median values of the elements identified were calculated and statistically analyzed with Kruskal–Wallis and post hoc Dunn's tests.

The analysis demonstrated consistent elemental concentrations over the 5‐day sampling period. Among the elements detected, chloride (Cl) and sodium (Na) exhibited the highest concentrations.

This study establishes PIXE as a valuable technique for detecting and analyzing the elemental composition of the tear film in sheep. By providing a precise method for elemental analysis in small biological samples, this approach lays the groundwork for future research exploring its reliability and sensitivity in tear analysis and potential as a biomarker for ocular and systemic health. The impact of variables including age, diet, and environmental exposure on tear film constituents should be studied, potentially extending the methodology to other species.