Gastec 111LL Methanol Detector Tube Operating Instructions

Quick guide for Gastec 111LL

The Gastec 111LL Methanol Detector Tube is designed for the detection of Methanol in air or industrial areas. It must be used in conjunction with a Gastec Gas Sampling Pump. This guide outlines the necessary steps for operation, safety precautions, and environmental correction factors.

Safety precautions

• Glass breakage: When breaking the tube tips, keep them away from your face. Do not touch broken glass or the reagent with bare hands.
• Toxic reagent: The tube contains a reagent with hexavalent chromium. Handle with care and follow local regulations for disposal.
• Compatibility: Use only Gastec detector tubes with a Gastec pump. Using non-Gastec parts may result in damage, injury, or voided warranties.

Specifications and performance

• Measuring Range: 2-20 ppm (requires 4 pump strokes) or 20-62 ppm (requires 2 pump strokes).
• Sampling Time: 2 minutes per pump stroke.
• Detection Limit: 0.2 ppm.
• Operating Conditions: Temperature 0-30°C (32-86°F); Relative Humidity 0-90%.
• Reaction Principle: CH3OH + Cr6+ + H3PO4 → Cr3+ (Color change: Pale yellow to Pale bluish green).

Measurement procedure

1. Check the pump for leaks before starting.
2. Break the tips off a fresh detector tube using the tube tip breaker on the pump.
3. Insert the tube into the pump inlet with the arrow pointing toward the pump.
4. Ensure the pump handle is pushed all the way in. Align the guide mark on the handle.
5. Pull the handle all the way out until it locks at one pump stroke (100 mL). Wait two minutes and confirm the completion of the sampling. Repeat the sampling procedure as required (2 or 4 strokes total).
6. Read the concentration level at the interface where the stained reagent meets the unstained reagent.
7. If necessary, apply correction factors for temperature, humidity, and atmospheric pressure.

Correction factors

If the measurement conditions deviate from standard, apply the following:

• Temperature: Use the provided temperature correction table to adjust the reading.
• Pressure: Multiply the tube reading by (1013 / Atmospheric Pressure in hPa).
• Humidity: No correction is required.

Interferences

Be aware that coexisting gases may interfere with the reading. Specifically, Alcohols and Aromatic hydrocarbons may cause interference. Refer to the interference table in the full documentation if you suspect the presence of these substances.

Disposal

The reagent contains hexavalent chromium. Dispose of the tubes, whether used or unused, in accordance with local government rules and regulations regarding hazardous waste.