Table 2. Long-term stability of the measurement of the plasma extract standard containing borneol, isoborneol, camphor, and the internal standard naphthalene (250 nmol/L for each compound). The data are expressed as the mean±standard deviation (relative standard deviation).
| Compound |
Response (×104) |
Chromatographic parameters |
||
|---|---|---|---|---|
| Column efficiency (×104) | Retention time (min) | Asymmetry factor | ||
| Injection Nos: 1–30 | ||||
| Borneol | 130±6 (4.6%) | 19.5±2.4 (12.3%) | 9.18±0.01 (0.1%) | 1.00±0.13 (12.7%) |
| Isoborneol | 88±6 (6.8%) | 20.4±2.5 (12.3%) | 9.02±0.01 (0.1%) | 1.02±0.08 (7.4%) |
| Camphor | 50±3 (6.0%) | 24.1±2.5 (10.4%) | 8.72±0.01 (0.1%) | 0.97±0.11 (11.7%) |
| Naphthalene | 142±7 (4.9%) | 12.2±1.5 (12.3%) | 9.52±0.01 (0.1%) | 1.30±0.19 (14.7%) |
| Injection Nos: 31–60 | ||||
| Borneol | 130±10 (7.7%) | 21.0±2.1 (10.0%) | 9.21±0.01 (0.1%) | 0.98±0.08 (8.4%) |
| Isoborneol | 85±7 (8.2%) | 20.9±2.0 (9.6%) | 9.04±0.01 (0.1%) | 1.04±0.07 (6.5%) |
| Camphor | 49±3 (6.1%) | 23.1±3.1 (13.4%) | 8.74±0.01 (0.1%) | 1.02±0.10 (9.8%) |
| Naphthalene | 140±12 (8.6%) | 13.0±1.7 (13.1%) | 9.54±0.01 (0.1%) | 1.22±0.15 (11.9%) |
| Injection Nos: 61–100 | ||||
| Borneol | 137±8 (5.8%) | 21.8±2.6 (12.0%) | 9.21±0.01 (0.1%) | 0.96±0.13 (13.5%) |
| Isoborneol | 90±6 (6.7%) | 20.5±2.6 (12.7%) | 9.05±0.01 (0.1%) | 0.97±0.09 (9.4%) |
| Camphor | 49±4 (8.2%) | 23.0±3.0 (13.0%) | 8.75±0.01 (0.1%) | 0.96±0.12 (12.1%) |
| Naphthalene | 140±11 (7.9%) | 12.2±1.7 (13.9%) | 9.55±0.01 (0.1%) | 1.19±0.16 (13.3%) |
Number of theoretic plates=5.54×(retention time÷peak width at 1/2 height)2. Peak asymmetry factor was defined as the distance from the center line of the peak to the back slope divided by the distance from the center line of the peak to the front slope, with all measurements made at 10% of the maximum peak height.