Validate Your VROC Chips
Tips to validate your chips prior to testing.
Application Brief
Chip Validation for m-VROC II & Initium One Plus
When validating your chip with a viscosity calibration standard (i.e., MGVS or oil), follow these steps:
- Measure the viscosity at five different shear rates corresponding to the five measured %FS (reported in software) ranges shown in the table below.
- For more robust validation, obtain at least 5 – 10 repeats for each shear rate using temp control.
- This is very easy to do with the m-VROC II or Initium One Plus because these give unlimited automatic measurements with only one sample volume, saving a lot of time and effort.
- This is time-consuming and more labor intensive with the old m-VROC I since you must load up the test syringe many times.
- The m-VROC II and Initium One Plus have built-in Peltier temp control, while the old m-VROC I requires an external water bath.
| Measured %FS | Passing % Error |
| 5 ≤ %FS < 25 | ≤ 5 |
| 25 ≤ %FS < 33 | ≤ 4 |
| 33 ≤ %FS < 50 | ≤ 3 |
| 50 ≤ %FS < 75 | ≤ 2 |
| 75 ≤ %FS ≤ 95 | ≤ 2 |
- The chip is validated if the calculated % error (equation shown below) ≤ passing % error (shown in table above) for segments with R2 ≥ 0.996.
- If the calculated % error is too high, the chip is not validated and may need to be appropriately cleaned, or serviced by RheoSense or a RheoSense-approved distributor.
- This cleaning can be automatically done using multiple solvents with the Initium One Plus, or with the mVROC II chip cleaning station.
- Cleaning is not automatic with the old m-VROC I, which requires the user to load cleaning solvent multiple times into the test syringe.
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