Startup & Shutdown

Pre-Startup Checklist

Before powering on the instrument, complete the following safety and readiness checks:

1. Argon Gas Supply: Verify the argon cylinder pressure is adequate (typically > 100 psi / 7 bar). Ensure the regulator outlet pressure is set to approximately 80–100 psi. Check for any gas leaks at connections.
2. Drain Vessel: Inspect the drain vessel (waste container) beneath the spray chamber. Empty it if it is more than half full. Ensure the drain tube is properly connected and has a liquid seal to maintain the spray chamber pressure.
3. Exhaust System: Confirm that the laboratory exhaust/extraction system is running with positive extraction at the instrument exhaust duct. The ICP-MS generates hot plasma gases that must be vented properly.
4. Peristaltic Pump Tubing: Inspect all pump tubing (sample, internal standard, drain) for flat spots, cracks, or loss of elasticity. Replace if deteriorated. Ensure the tubing is correctly seated in the pump rollers.
5. Spray Chamber & Torch: Visually inspect the spray chamber, torch assembly, and bonnet for cracks, deposits, or damage. Clean if deposits are visible (see Chapter 6: Maintenance).
6. Interface Cones: Check that the sampler and skimmer cones are correctly installed and seated. Verify the orifices are clear of debris (use the Agilent magnifier tool if available).
7. Sample Uptake Line: Place the sample uptake line into a container of 2% HNO₃ rinse solution (or your standard rinse blank).
8. Instrument Covers: Ensure all instrument panels and covers are closed and secured. Safety interlocks will prevent plasma ignition if covers are open.

Startup Procedure

Follow this sequence to power on the instrument and ignite the plasma:

Step 1 — Power On the Water Recirculator (Chiller)

Turn on the water recirculator/chiller first. It provides cooling water to the ICP-MS RF coil and interface region. Allow the chiller to stabilise for a few minutes until it reaches the set temperature (typically 15–20 °C). Verify water flow is established.

Step 2 — Power On the ICP-MS Instrument

Turn on the main power switch of the Agilent 8900 ICP-MS. The instrument will begin its initialisation sequence:

• The foreline (roughing) pump starts automatically and begins evacuating the vacuum chambers.
• The turbomolecular pump will ramp up to full speed — this takes several minutes.
• System self-diagnostics run, including checks on vacuum levels, temperatures, and gas flows.

Step 3 — Power On the Computer & Launch MassHunter

Turn on the workstation PC. Launch ICP-MS MassHunter Workstation software. The software will automatically connect to the instrument and display the current instrument status on the Home → Startup tab.

Check the status indicators for:

• ✅ Vacuum status — should show "Ready" (green)
• ✅ Temperature — chiller and interface temperatures within range
• ✅ Gas pressures — argon and cell gas pressures normal
• ⚠️ Any warning or error indicators — resolve before proceeding

Step 4 — Plasma Ignition

1. Engage the peristaltic pump: Lower the pump clamps onto the tubing. Start the pump to begin aspirating the rinse solution.
2. Wait for rinse flow: Allow 30–60 seconds for solution to reach the nebulizer and establish a stable aerosol.
3. Ignite the plasma: In MassHunter, click the "Plasma On" button (or use the Startup sequence). The RF generator will ignite the plasma. You should see a bright white/blue plasma glow through the viewing window.
4. Warm-up period: Allow the plasma to stabilise for at least 15–30 minutes before performing any analysis or tuning. This warm-up period ensures thermal equilibration of the torch, cones, and optics.

Step 5 — Autotune & Performance Check

After warm-up, run the Autotune procedure from MassHunter (covered in detail in Chapter 3). The autotune optimises plasma position (torch axis), ion lens voltages, and cell gas flows. After autotune, a Performance Report is generated — review it to confirm the instrument meets specifications.

Shutdown Procedure

Proper shutdown protects the instrument and extends component lifespan. Follow this sequence:

Standard (End-of-Day) Shutdown

1. System Rinse: Aspirate 2% HNO₃ (or appropriate rinse solution) for at least 5–10 minutes to flush residual sample from the sample introduction system, nebulizer, spray chamber, and torch.
2. Final Rinse: Switch to ultrapure deionised water and rinse for an additional 3–5 minutes to remove acid residue.
3. Turn Off Plasma: In MassHunter, click "Plasma Off". The RF generator shuts down, and the plasma extinguishes.
4. Release Pump Tubing: Release the peristaltic pump clamps to prevent tubing deformation. Lift the pressure bar off the tubing.
5. Drain the Spray Chamber: Allow any remaining liquid in the spray chamber to drain. Empty the drain vessel if needed.
6. Keep Vacuum Running: For overnight shutdown, leave the instrument powered on to maintain vacuum. This allows rapid startup the next day. Only turn off gases and plasma.

Full Shutdown (Extended Off / Maintenance)

For extended shutdown (weekends, holidays, maintenance):

1. Complete the Standard Shutdown steps above (rinse, plasma off, release tubing).
2. Vent the MS: In MassHunter, select "Vent" from the instrument control. This safely brings the vacuum chambers to atmospheric pressure. The software automatically shuts off heaters and voltages, sets gas flows to standby, and allows turbo pumps to spin down.
3. Wait for Venting: Wait until the software confirms venting is complete (turbo pump fully stopped, atmospheric pressure reached). This may take 20–30 minutes.
4. Close MassHunter: Close the MassHunter software.
5. Power Off PC: Shut down the workstation computer.
6. Power Off ICP-MS: Turn off the main power switch on the Agilent 8900.
7. Power Off Chiller: Turn off the water recirculator.
8. Close Gas Valves: Close the main valve on the argon cylinder and any cell gas cylinders.

Quick Reference — Startup/Shutdown Sequence