How two identical Instruments can provide different results.
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Even identical HPLC systems from the same manufacturer can produce different chromatographic results. Differences in system sensitivity, extra-column volume, dwell volume, detector performance, and overall instrument condition can affect method transfer, system suitability, limits of detection, and analytical results.
The example below shows actual performance qualification data from two identical HPLC instruments operating in the same GMP laboratory. A stability-indicating method was successfully developed on one system, but when transferred to the second instrument, several peaks were not detected as expected. Using the MICROSOLV HSQ Kit standard qualification protocol, the laboratory identified measurable performance differences between the two instruments despite having the same model, configuration, and similar usage history.
This example demonstrates why instrument characterization is important for method development, method transfer, troubleshooting, and ongoing laboratory quality assurance.
By routinely measuring key system performance characteristics such as sensitivity, dwell volume, extra-column dispersion, injection precision, retention-time precision, and flow-rate accuracy, laboratories can better understand instrument-to-instrument variability and make more informed analytical decisions.
The MICROSOLV HSQ Kit provides a practical and standardized approach for evaluating and documenting HPLC system performance across multiple instruments, departments, and laboratory locations.
| Instrument: | Agilent 1100 LC System #9 | Agilent 1100 LC System #2 | |
| Performance Characteristic: | Test Conditions: | Performance: | Performance: |
| System Extra-Column Dispersion: | Rs test mix extrapolated N | 5 uL | 3 uL |
| Gradient Dwell Volume: | Dwell Volume: | 1.20 mL | 1.07 mL |
| Delivery Accuracy: | All circuits <5% of nominal | All circuits <5% of nominal | |
| % Injector Carryover: | No Wash Vial: | 0% | 0% |
| With Wash Vial: | 0% | 0% | |
| Injection Precision: | 10 replicate inj. | 0.07% RSD | 0.07% RSD |
| Ret. Time Precision: | 10 replicate inj. | 0.21% RSD | 0.06% RSD |
| System Sensitivity: | caffeine @ 273nm normalized for column efficiency peak to peak noise @ 273 nm |
Sens. = 363.9 mAU/µg LOD = 0.032 µg/mL Noise = 0.04 mAU |
Sens. = 400.6 mAU/µg LOD = 0.058 µg/mL Noise = 0.077 mAU |
| Pump Flow Rate Accuracy: | 0.5 mL/min | 100.3% | 100.0% |
| 1.0 mL/min | 100.3% | 100.3% | |
| 5.0 mL/min | 99.7% | 99.7% | |
| Pump Max Press: | BPR, leak check | Qual: to 5,000 psi, 345 bar | Qual: to 5,000 psi, 345 bar |
| Column Oven: | oven air temp <5°C of normal |
Qual: 20-50°C, <5°C of normal | Qual: 20-50°C, <5°C of normal |