CE · Calibration procedure
Temperature and voltage verification
Checks the capillary cartridge temperature and the high-voltage output of the CE system against calibrated tools or the manufacturer's verification kit.
PURPOSE
Why this is checked
Mobility rises by about 2% for every 1 °C, so temperature errors shift migration times and can change resolution. Voltage errors change field strength and therefore migration time and heating. Both must be within specification for validated CE methods to transfer between instruments.
Frequency
Typically every 6–12 months and after repair, as defined in your SOP.
Learn how the CE worksYOU WILL NEED
Standards & tools
- Calibrated temperature probe or manufacturer's cartridge temperature verification tool
- Calibrated high-voltage measurement device or manufacturer's voltage verification kit (often a high-voltage divider)
- Test capillary and buffer as described in the kit, if a current check is included
BEFORE YOU START
Prerequisites
- Only trained engineers or analysts perform the high-voltage check
- Interlocks working; covers closed during measurement
- Tools within calibration date
PROCEDURE
Step by step
- 1Fit the temperature verification tool in the cartridge position.
- 2Set the cartridge to several temperatures (for example 20, 25 and 40 °C), allow it to stabilise and record measured values.
- 3Install the voltage verification kit as instructed.
- 4Apply several voltages (for example 10, 20 and 30 kV) and record measured values.
- 5Where required, run buffer at increasing voltages and plot current against voltage (Ohm's law plot) to confirm heat removal.
- 6Calculate differences from set values.
RECORD
Example observation table
| Parameter | Set | Measured | Difference | Result |
|---|---|---|---|---|
| Temperature | 20 °C | 20.3 °C | +0.3 °C | Pass |
| Temperature | 25 °C | 25.2 °C | +0.2 °C | Pass |
| Temperature | 40 °C | 39.6 °C | −0.4 °C | Pass |
| Voltage | 10 kV | 10.05 kV | +0.5% | Pass |
| Voltage | 20 kV | 19.88 kV | −0.6% | Pass |
| Voltage | 30 kV | 29.85 kV | −0.5% | Pass |
CALCULATION
How to calculate the result
Formula
Temperature difference = measured − set; Voltage error (%) = (measured − set) ÷ set × 100
Worked example
- 1
40 °C: 39.6 − 40.0 = −0.4 °C
- 220 kV: (19.88 − 20) ÷ 20 × 100 = −0.6%
- 330 kV: (29.85 − 30) ÷ 30 × 100 = −0.5%
ACCEPTANCE CRITERIA
Pass if
- Cartridge temperature typically within about ±1 °C of set point (or the manufacturer's specification)
- Voltage typically within about ±1–2% of set value (or the manufacturer's specification)
- Ohm's law plot linear over the method's voltage range, where tested
IF IT FAILS
What to do
- Label the system out of use for GMP analyses.
- Check coolant level and cartridge seating for temperature failures; call service for adjustment.
- Call service for high-voltage supply repair or calibration.
- Assess analyses run since the last passing check (migration time and resolution trends).
In LimsPulse · Calibration Management
LimsPulse schedules this calibration, records the result against limits, and blocks the instrument everywhere if it fails or goes overdue.