Determination of ions in Caenorhabditis elegans by ion chromatography

The Caenorhabditis elegans (C. elegans) is a model organism that has been increasingly used in health and environmental toxicity assessments. The quantification of such elements in vivo can assist in studies that seek to relate the exposure concentration to possible biological effects. Therefore, this study is the first to propose a method of quantitative analysis of 21 ions by ion chromatography (IC), which can be applied in different toxicity studies in C. elegans. The developed method was validated for 12 anionic species (fluoride, acetate, chloride, nitrite, bromide, nitrate, sulfate, oxalate, molybdate, dichromate, phosphate, and perchlorate), and 9 cationic species (lithium, sodium, ammonium, thallium, potassium, magnesium, manganese, calcium, and barium). The method did not present the presence of interfering species, with R² varying between 0.9991 and 0.9999, with a linear range from 1 to 100 µg L^-1. Limits of detection (LOD) and limits of quantification (LOQ) values ranged from 0.2319 μg L^-1 to 1.7160 μg L^-1 and 0.7028 μg L^-1 to 5.1999 μg L^-1, respectively. The intraday and interday precision tests showed an Relative Standard Deviation (RSD) below 10.0 % and recovery ranging from 71.0 % to 118.0 % with a maximum RSD of 5.5 %. The method was applied to real samples of C. elegans treated with 200 uM of thallium acetate solution, determining the uptake and bioaccumulated Tl⁺ content during acute exposure.