The Gastec 123TP Xylene Detector Tubes are designed for measurement of xylene (C6H4(CH3)2) in workplace air using a compatible automatic air sampling pump.

The 123TP provides a quantitative measuring range of 2 to 80 ppm, with a detection limit of 1 ppm under the specified sampling conditions. The detector system produces a white-to-brown color change for visual determination of xylene concentration.

IMPORTANT: The Gastec 123TP uses two connected tubes for each measurement. Each box contains 10 tubes for a total of 5 tests.

Automatic Air Sampling Pump Required

IMPORTANT: Gastec 123TP Xylene Detector Tubes require a compatible automatic air sampling pump capable of maintaining a continuous 100 mL/min sampling rate.

Compatible Automatic Sampling Pump:
Gastec GSP-501FT Automatic Air Sampling Pump

The Gastec 123TP is an automatic air sampling pump detector tube and should not be treated as a standard hand-pump detector tube.

Accurate measurement requires drawing 1,000 mL of air through the connected detector tube system at 100 mL/min for 10 minutes.

Do not substitute a standard manual Gastec detector tube pump for the required automatic sampling method.

Measurement & Sampling Specifications

Measurement Range	Sampling Rate	Sample Volume	Correction Factor	Sampling Time
2–80 ppm	100 mL/min	1,000 mL	1	10 Minutes

The Gastec 123TP requires a continuous sampling rate of 100 mL/min for 10 minutes, producing a total sample volume of 1,000 mL.

The correction factor is 1, allowing the xylene concentration to be read directly from the detector tube scale under the specified sampling conditions.

Product Specifications

Brand: Gastec
Tube Type: Xylene Detector Tube for Automatic Air Sampling Pump
Part Number: 123TP
Gas/Vapor Measured: Xylene
Chemical Formula: C6H4(CH3)2
Measurement Range: 2–80 ppm
Detection Limit: 1 ppm at 1,000 mL (minimum detectable concentration; not part of the quantitative measuring range)
Sampling Rate: 100 mL/min
Sample Volume: 1,000 mL
Correction Factor: 1
Sampling Time: 10 Minutes
Color Change: White → Brown
Operating Temperature: 0–40°C (32–104°F), temperature correction not required
Operating Humidity: 0–90% RH, humidity correction not required
Relative Standard Deviation: 10% for 2–20 ppm; 5% for 20–80 ppm
Quantity: 10 Tubes
Tests per Box: 5 Tests
Shelf Life: 24 Months
Pump Requirement: Gastec GSP-501FT or Compatible Automatic Air Sampling Pump

Two-Tube Measurement System

The Gastec 123TP requires two tubes to be connected together during each measurement.

Prepare and connect the tubes according to Gastec's official instructions before attaching the assembled detector tube system to the automatic air sampling pump.

Because two tubes are consumed for each measurement, one box containing 10 tubes provides 5 complete tests.

Always follow the official Gastec 123TP instruction manual for correct tube preparation, connection, orientation, and sampling procedure.

Xylene Measurement

The Gastec 123TP provides quantitative measurement of xylene concentrations from 2 to 80 ppm in workplace atmospheres.

The 1 ppm detection limit represents the minimum concentration capable of producing a detectable reaction under the specified 1,000 mL sampling conditions. It is not part of the quantitative measuring range and should not be interpreted as a 1–80 ppm measurement range.

During sampling, xylene reacts with the detector tube reagent, producing a visible white-to-brown color change.

Common Applications

Gastec 123TP Xylene Detector Tubes may be used for applicable xylene vapor monitoring applications including:

• Industrial Hygiene & Occupational Exposure Monitoring

• Workplace Xylene Monitoring

• Paint, Coating & Solvent Operations

• Printing & Manufacturing Facilities

• Chemical Manufacturing & Processing

• Adhesive & Chemical Handling Areas

• Laboratory & Research Applications

• Industrial Process Air Monitoring

• Leak & Release Investigations

• Solvent Vapor Monitoring

Operating Conditions

The Gastec 123TP can be used from 0 to 40°C (32 to 104°F) without temperature correction.

The specified operating humidity range is 0 to 90% relative humidity, and humidity correction is not required.

Atmospheric pressure correction may still be required according to Gastec's official measurement procedure.

Possible Interferences

Certain coexisting substances may affect Gastec 123TP measurements.

Carbon Monoxide: At concentrations of 75 ppm or greater, the stain demarcation may become unclear. Carbon monoxide itself may produce a brown color at concentrations of 50 ppm or greater.

Ethyl Benzene: At concentrations of 1/3 or greater relative to the xylene concentration, may produce a positive interference and brown color.

Ethyl Acetate: At concentrations of 400 ppm or less, Gastec identifies no interference and no independent color change.

Dichloromethane: At concentrations of 30 ppm or less, Gastec identifies no interference and no independent color change.

N,N-Dimethylformamide: At concentrations of 25 ppm or less, Gastec identifies no interference and no independent color change.

Trichloroethylene: At concentrations of 1/2 or greater relative to the xylene concentration, may produce a positive interference.

Toluene: At concentrations of 1/3 or greater relative to the xylene concentration, may produce a positive interference and brown color.

n-Hexane: At concentrations of 200 ppm or greater, the stain demarcation may become unclear.

Methanol: At concentrations of 200 ppm or less, Gastec identifies no interference and no independent color change.

Coexisting gases and vapors should always be considered when interpreting detector tube measurements.

Important

A Gastec GSP-501FT or compatible automatic air sampling pump is required for correct use of the Gastec 123TP Xylene Detector Tubes.

Compatible Automatic Sampling Pump:
Gastec GSP-501FT Automatic Air Sampling Pump

Sampling is performed at 100 mL/min for 10 minutes, producing a total sample volume of 1,000 mL.

Two detector tubes must be connected for each measurement. Therefore, 10 tubes provide 5 complete tests.

Do not use a standard manual Gastec detector tube pump in place of the required automatic sampling method.

Always follow Gastec's official instructions for tube connection and orientation, sampling rate, sample volume, sampling time, atmospheric pressure correction, environmental conditions, possible interferences, and interpretation of results.

Choose Instrument Depot for dependable Gastec 123TP Xylene Detector Tubes, C6H4(CH3)2 detector tubes, xylene vapor testing, workplace xylene monitoring, Gastec automatic air sampling pumps, Gastec GSP-501FT sampling pumps, industrial hygiene air monitoring, solvent vapor testing, gas detector tubes, and industrial gas detection equipment.