The determination of S-nitrosothiols in biological samples--procedures, problems and precautions

Area of Science:

• Analytical Chemistry
• Biochemistry
• Physiology

Background:

• S-nitrosothiols (RSNO) play vital roles in biological processes.
• Accurate quantification of RSNO in biological matrices remains a significant analytical challenge.
• Existing methods face obstacles including RSNO lability and lack of reference standards.

Purpose of the Study:

• To highlight the analytical challenges in determining S-nitrosothiols (RSNO) in biological samples.
• To identify key factors compromising RSNO assay reliability.
• To emphasize the necessity of specific reagents for accurate RSNO determination.

Main Methods:

• Review of existing literature on S-nitrosothiol (RSNO) determination.
• Identification of artifactual RSNO formation pathways.
• Discussion of preanalytical steps critical for reliable measurements.

Main Results:

• RSNO determination is hindered by sample preparation complexity and RSNO instability.
• High concentrations of thiols and nitrites in biological samples can lead to artifactual RSNO formation.
• Metal-catalyzed decomposition, transnitrosylation, and GGT-mediated degradation compromise RSNO assays.

Conclusions:

• Preanalytical steps are critical for reliable RSNO measurements.
• Metal chelators, thiol reagents, and GGT inhibitors are essential for accurate RSNO quantification.
• Addressing these challenges is vital for resolving discrepancies in reported RSNO and GSNO concentrations.