ICP-MS is a well established technique capable of giving highly reliable results day after day for years together. It only requires good care and sound training in sample preparation and handling practices which you can acquire easily over a period of time. ICP-MS involves heavy initial investment and running costs but the costs can be recovered easily due to its high sensitivity and un-paralleled performance features. Every single day lost on account of down time can mean a substantial revenue loss in terms of laboratory output and product manufacturing losses in manufacturing industries.
Preventive maintenance plays a major role in effective utilization of ICP-MS technique. It can be divided into daily and periodic checks based on guidelines provided by the manufacturer. However, a daily check on some critical components can prevent prevent major breakdowns and save your valuable time as well as repair or parts replacement costs. Daily inspections are mostly visual inspections and will not take more than 15-20 minutes of your time. It is important to take corrective action at your end whenever possible and also to keep logs of such checks as these will help the engineer in diagnosing the problem faster.
Components to be inspected daily
Argon Gas supply
Check for sufficient gas cylinder pressure which should be in the 70-120 psi range. A standby spare tank should be available for quick replacement.
Sample Drain container
Observe the level of liquid level in the liquid drain container. Do not allow the liquid level to exceed and overflow from the vessel.
Inspect daily the plumbing and connections from the coolant supply for any leaks or corrosion damage. Sufficient quantity of coolant should be present always to prevent damage to torch assembly due to overheating.
Torch and Rf Coil
Visually check for freedom from melting, cracking or solid deposits. In case necessary immerse in 1%nitric acid solution in an ultrasonic bath followed by rinsing with deionized water. It is advisable to replace torch if signs of damage are observed.
Inspect the peristaltic pump tubing before start of operation and every few hours of use for flat spots. It is best to replace tubing when flat spots or kinks develop in the tubing. Flat spots can be prevented by releasing pressure cams when pump is not in use. It is advisable to flush the tubing and system with deionized water at the end of the day.
Inspect the level of pump oil through the glass window. Also check the colour of the oil. In case oil is dirty or turns to coffee brown colour then replace the oil.
Air filters should be clean. Cooling efficiency of fans can get affected by dirty filters. A drop in efficiency of air flow can result in overheating and shut-down of the system.
Check the vacuum system daily before starting the analysis and keep a record in the logbook. This will give you an idea of the condition of the cones. If the cone orifice is clogged the pressure is lower and if the orifices become worn out the running pressure is higher. At time of removal of cones for inspection inspect all O-rings for wear and replace if found necessary. The cones can be cleaned in 1%nitric acid in an ultrasonic bath followed by deionized water rinsing as in the case of the torch.
Apart from inspection of peristaltic pump tubing check for roller pressure and freedom of rotation. Pump rollers should be clean and there should be no sticky movement. Leakages can result in deposits which can inhibit roller movement.
The sample introduction system comprises of the spray chamber and nebulizer. The spray chamber should be inspected for deposits, if any, and leaks near nebulizer and drain fittings. Similarly, the nebulizer tubing should be free of any blockages due to solid deposits. If required cleaning can be carried out in an ultrasonic bath with 1%nitric acid followed by deionized water rinsing. A damaged spray chamber or nebulizer should be replaced immediately without further delay.
The suggested inspections at most can take only a fraction of time of what it can take in carrying out expensive repairs in addition to loss of valuable time due to instrument downtime. Make it your daily habit and maintain your inspection records.