How to ensure high uptime of your AAS

Preventive maintenance is the key to ensure high uptime of your Atomic Absorption Spectrometer. It is a rugged instrument which can provide you high quality results for years together provided its maintenance schedules are followed religiously.

It is a good practice to make general visual inspection of the system before starting your day’s work Such observations will not take more than 10 – 15 minutes but will save you from frustrating time loss during operation.

Checks and corrective actions are required mainly on following components of the instrument:

• Hollow cathode lamps
• Burner head and spray chamber
• Nebulizer
• Drain System
• Gas Cylinders, hoses and fittings
• Exhaust system

Hollow cathode lamps

Hollow cathode lamps should be inspected regularly for freedom from damage or cracks. The quartz end window should not be touched by hand and should be cleaned with lint free issue only. The end window should be free from darkening and the energy meter should be routinely inspected for residual life of the lamp.

Burner head and spray chamber

Burner Head

Visually inspect burner head slots for cleanliness and freedom from solid deposits. Use cleaning tool to carefully work through the slot taking care not to nick the edges. Rinse head with de-ionized water to remove any scrapings that may result from cleaning from both inside and outside the slots. The burner head can be dried by blowing dry air from oil free compressor width.

If slot has become wide due to solution abrasion or corrosion damage then replace the burner head.

Spray chamber

Open the spray chamber and inspect for wear and tear of O-rings and the end cap. Also ensure that the spray chamber lining is free from any cracks or damage. Clean the spray chamber, end cap and flow spoiler with a soft brush and a mild laboratory detergent. Rinse with de-ionized high purity water and after drying
re- assemble the burner chamber.

Special cleaning procedure needs to be adapted after use of organic solvents. Aspirate for about 5 min with an organic solvent that is miscible with the original solvent and water. Next aspirate with 1% nitric acid for 5 min followed by rinsing with de-ionized water.

Nebulizer

Nebulizer efficiency will ensure high reproducibility of results.Aspirate with dilute surfactant solution such as 0.1% Triton X 100 for a few minutes. Use a cleaning wire to clean the capillary tube followed by iso- propanol. Running one or more standard will confirm if the nebulizer has been properly cleaned

Drain System

The drain vessel should not be allowed to overflow. Inspect drain pipes for damage or obstructions. The drain system maintenance can be carried out by slowly pouring about 500 ml of water into spray chamber after removing the burner. The drain vessel should be emptied regularly and never allowed to fill up completely. Replace drain tubing if kinks develop or damage is seen.

Gas Hoses and Fittings

Before checking hoses and fittings monitor gas cylinder residual pressures. Nearly empty gas cylinders should be replaced before starting the day’s work. Inspect hoses and fittings for freedom from leaks. Fuel supply, in particular, should be free of leaks as these can lead to changes in flow rates and result in errors in measurements.

Exhaust System

The exhaust system should be inspected for proper evacuation .If there are leakages or exhaust fan needs repair the necessary action should be taken before making use of the instrument.

Regular inspections and preventive maintenance can you save you from major breakdowns and can even ensure a safe workplace for yourself and your co-workers.