Gastec Hydrogen Sulfide Detector Tubes | 4TP are designed for sensitive, low-level measurement of hydrogen sulfide (H2S) in air using a compatible automatic air sampling pump.

The 4TP provides a primary measuring range of 0.1 to 1.6 ppm, with measurements extendable from 1.6 to 2.88 ppm using the specified sampling conditions and correction factor. The tube has a 0.02 ppm detection limit, allowing indication of H2S below the quantitative measuring range.

The tube uses a colorimetric reaction that produces a yellow-to-pink color change for visual determination of hydrogen sulfide concentration.

Each box contains 10 detector tubes for 10 tests.

Automatic Air Sampling Pump Required

IMPORTANT: Gastec 4TP Hydrogen Sulfide Detector Tubes require a compatible automatic air sampling pump capable of maintaining the specified flow rate and sampling time for proper measurement.

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

The 4TP is an automatic air sampling pump detector tube and should not be treated as a standard hand-pump detector tube. Accurate measurement depends on drawing the specified volume of air through the tube at the correct continuous flow rate for the full 10-minute sampling period.

Gastec's instructions specify automatic sampling at 100 mL/min or 50 mL/min, depending on the concentration range being measured.

Measurement & Sampling Specifications

The 0.1–1.6 ppm primary range requires a 100 mL/min sampling rate and 1,000 mL sample volume. Measurements from 1.6–2.88 ppm require a 50 mL/min sampling rate, 500 mL sample volume, and a correction factor of 1.8.

Product Specifications

Brand: Gastec
Tube Type: Hydrogen Sulfide Detector Tube for Automatic Air Sampling Pump
Part Number: 4TP
Gas Measured: Hydrogen Sulfide (H2S)
Primary Measurement Range: 0.1–1.6 ppm
Extended Measurement Range: 1.6–2.88 ppm
Detection Limit: 0.02 ppm at 1,000 mL (minimum detectable concentration; not part of the quantitative measuring range)
Sampling Rate: 50 or 100 mL/min, depending on measurement range
Sampling Time: 10 Minutes
Color Change: Yellow → Pink
Operating Temperature: 0–40°C (32–104°F)
Operating Humidity: 0–90% RH
Quantity: 10 Tubes
Tests per Box: 10
Shelf Life: 24 Months
Pump Requirement: Compatible Automatic Air Sampling Pump Required

Low-Level Hydrogen Sulfide Measurement

The Gastec 4TP is particularly suited for applications requiring sensitive measurement of relatively low hydrogen sulfide concentrations.

Its 0.1–1.6 ppm primary measuring range provides quantitative H2S measurements, while its 0.02 ppm detection limit indicates the minimum concentration capable of producing a detectable reaction under the specified conditions. The 0.02 ppm detection limit should not be interpreted as the bottom of the quantitative measurement range.

Hydrogen sulfide reacts with the tube reagent to form an intermediate material that stains the indicator pink.

Common Applications

The Gastec 4TP Hydrogen Sulfide Detector Tube is intended for detecting hydrogen sulfide in air, industrial areas, and environmental atmospheric conditions. Common applications may include:

• Industrial Hygiene & Workplace Air Monitoring — Measuring low concentrations of H2S in occupational environments.

• Wastewater & Sewage Treatment — Evaluating hydrogen sulfide in applicable treatment, collection, and processing areas.

• Oil & Gas Operations — Low-level H2S measurement in applicable petroleum, natural gas, and processing environments.

• Chemical & Petrochemical Processing — Monitoring areas where hydrogen sulfide may be produced, handled, or released.

• Pulp & Paper Operations — Checking applicable process areas where sulfur-containing gases may be present.

• Environmental Air Monitoring — Measuring low concentrations of hydrogen sulfide in applicable atmospheric investigations.

• Odor & Emission Investigations — Evaluating suspected H2S sources and low-level releases.

• Industrial Safety & Maintenance — Checking applicable work areas where H2S may be generated or released.

Operating Conditions

The Gastec 4TP can be used from 0 to 40°C (32 to 104°F) without temperature correction and at 0 to 90% relative humidity without humidity correction.

Gastec specifies a relative standard deviation of 10% from 0.1–0.4 ppm and 5% from 0.4–1.6 ppm.

Possible Interferences

Gastec identifies several substances that may affect 4TP measurements, including ammonia, other mercaptans, hydrogen chloride, hydrogen cyanide, nitric acid, sulfur dioxide, nitrogen dioxide, and hydrogen fluoride.

Several of these substances may produce a pink indication or otherwise interfere with the detecting layer. Their presence should therefore be considered when interpreting hydrogen sulfide measurements.

Important

A compatible automatic air sampling pump is required for correct use of the Gastec 4TP Hydrogen Sulfide Detector Tubes.

Accurate measurement depends on maintaining the specified 50 or 100 mL/min continuous sampling rate for 10 minutes. Do not substitute a standard manual detector tube pump for the required continuous automatic sampling method.

Always follow Gastec's official instructions for the 4TP detector tube and the sampling pump, including the required flow rate, sample volume, correction factor, sampling time, operating conditions, and procedures for interpreting results.

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

Choose Instrument Depot for dependable Gastec 4TP Hydrogen Sulfide Detector Tubes, H2S detector tubes, automatic air sampling pumps, low-level hydrogen sulfide testing, industrial hygiene air monitoring, environmental H2S testing, and industrial gas detection supplies.