Table 1. Retention times for guanosine and the guanine nucleotides GMP, GMPPN, GDP, GMPPNP and GTP.
The indicated ranges of peak retention times were defined by HPLC measurements over a 1+ year period using two identical Reverse-phase C18 columns. Retention time differences were noted between the two columns, and the retention time was also exquisitely sensitive to the precise composition and pH of the mobile phase. Retention times were highly reproducible from day-to-day using the same batch of mobile phase eluant. The ranges indicate the overall, long-term variability that can be expected between different columns and eluant batches. Importantly, such variability does not cause overlaps and thus has no impact on the resolution and assignment of the different nucleotide peaks.
| Nucleotide | Retention time (mins) |
|---|---|
| Guanosine | 1.8 |
| Minor peak | 2.3 |
| GMPPN | 2.9–3.0 |
| GDP | 3.8–4.0 |
| GMPPNP | 5.1–5.6 |
| GTP | 6.8–7.8 |