Environmental Sample Stability for Pharmaceutical Compound Analysis: Handling and Preservation Recommendations.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Accurate detection of pharmaceutical compounds in environmental water samples is critical.
• Effective sample preservation techniques are needed for reliable quantitative analysis.

Purpose of the Study:

• To investigate the stability of key pharmaceutical compounds after preconcentration using solid-phase extraction (SPE).
• To establish optimal storage conditions for environmental water samples containing pharmaceuticals.

Main Methods:

• Stability assessment of 17α-ethynylestradiol (EE2), acetaminophen (ACM), oxytetracycline (OTC), sulfamethoxazole (SMX), and trimethoprim (TMP).
• Samples were preconcentrated in SPE cartridges and stored under various time and temperature conditions (4°C, -18°C, room temperature).

Main Results:

• Four pharmaceutical compounds showed stability for one month at 4°C and six months at -18°C in darkness.
• All five tested compounds (ACM, TMP, OTC, EE2, SMX) remained stable for three days at room temperature.
• Storage in SPE cartridges at -18°C proved effective for long-term preservation.

Conclusions:

• Developed guidelines for handling and storing pharmaceutical compounds preconcentrated from aqueous environmental samples.
• Demonstrated the feasibility of using SPE cartridges for sample preservation under specific temperature and time constraints.