Comment on egusphere-2025-5295

Abstract. The study establishes an optimized, minimally invasive sampling protocol for water vapor – a semi-in situ method crucial to ecohydrology that addresses the limitations of destructive techniques. The key innovation is an integrated, multifactor assessment of how container type, flow rate, temperature, and storage time affect the isotopic stability of δ18O and δ2H. The optimal configuration uses 250 ml infusion glass bottles (ND 32), which provided the highest isotopic stability (±0.5 ‰ for δ18O and ±1‰ for δ2H over 24 hours), outperforming FlexFoil and aluminum-zip bags. The best results were obtained with flow rates of 100–125 ml/min and storage not exceeding 24 hours under ambient conditions (20–25 °C). δ18O was highly stable under nearly all conditions (