Sorbent Tube VOC Air Sampler

What is the Sorbent Tube VOC Air Sampler?

A pump and sorbent tube set that collects VOCs from air for laboratory thermal desorption analysis. It is the right choice for time-integrated speciated sampling at many sites at relatively low cost.

Overview

This sampler consists of a calibrated low-flow pump, a sorbent tube and, often, a flow controller and timer. Air is drawn through the tube at 10 to 200 millilitres per minute for a set period, and VOCs are retained on Tenax TA, Carbopack, activated charcoal or a multi-bed combination chosen for the boiling range of interest. Sampling volumes are calculated to keep breakthrough below a defined fraction, so the amount collected stays proportional to concentration. After sampling, tubes are capped, stored cool and returned to the laboratory, where they are heated and the desorbed compounds are swept onto a gas chromatograph, usually with mass spectrometry. This gives speciated, time-integrated results at very low detection limits. Active sampling with a pump allows precise volume control, unlike passive diffusion badges, and can be used for personal exposure or fixed-point monitoring. Tubes are reusable after conditioning.

How does it work?

VOC analyzers rely on different detection principles. A photoionization detector uses a sealed ultraviolet lamp, usually at 10.6 eV, to ionize molecules with an ionization potential below the lamp energy, and measures the resulting current; it reports total VOC without speciation. Flame ionization detectors burn organics in a hydrogen flame and measure the ions produced, giving total hydrocarbon response calibrated as methane or propane. Gas chromatography with FID first separates compounds on a column, producing speciated results. Proton transfer reaction mass spectrometry ionizes VOCs with hydronium ions and identifies them by mass, giving fast speciated data. Sorbent tube sampling collects VOCs on Tenax or charcoal and delivers them to the laboratory for thermal desorption and GC analysis.

What are the key features?

• Calibrated pump gives precise, documented sample volumes.
• Multi-bed sorbent tubes cover a wide boiling range of VOCs.
• Time-integrated sampling captures exposure over hours to days.
• Tubes are reusable after conditioning and are widely available.
• Field and tube blanks support data quality assessment.
• Compatible with standard thermal desorption GC-MS laboratory methods.

What are the technical specifications?

A typical sorbent tube voc air sampler configuration offers sampling method of Active pumped sampling, flow rate of 10–200 mL/min, sorbent media of Tenax TA, Carbopack, charcoal or multi-bed, tube dimensions of 89 mm × 6.35 mm OD, sampling duration of 15 min to 8 h typical and sample volume of 1–100 L, method dependent. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Sorbent Tube VOC Air Sampler is used in indoor air quality investigations, personal exposure assessment, fence-line VOC documentation and odour and building material emission studies. Across the wider VOC Analyzers class, laboratories also deploy it for industrial fence-line and leak monitoring, indoor air quality and building surveys and workplace exposure assessment.

Which standards and certifications apply?

Relevant standards and methods include US EPA Method TO-15, US EPA Method TO-17, ISO 16000-6, ISO 16017-1, EN 14662-3 and HJ 644. Certification candidates for this model are CE, RoHS and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Calibrate photoionization detectors with the target gas where possible, because response factors differ widely between compounds, and check the lamp window for fouling. For GC systems, verify column performance with a standard mixture, check carrier gas purity and replace the FID jet or the mass spectrometer filament as needed. Sorbent tubes must be conditioned, capped, stored cool and analysed within the method holding time, with field and tube blanks included. For continuous fence-line monitoring, shelter the analyzer, condition the sample line to avoid condensation and provide suitable calibration gas delivery. Record detection limits, calibration dates and validity flags, and follow the applicable national method for reporting.

How do I select the right Sorbent Tube VOC Air Sampler?

Select pumped sorbent tube sampling when low detection limits and speciated time-integrated data are needed and laboratory analysis is available. Passive badges suit large-scale surveys where approximate averages from many sites are enough. In an RFQ, specify target compounds, sampling duration, sorbent type and the laboratory method to be used.

How does it compare with other VOC Analyzers variants?

Match the analyzer to the purpose. For leak detection, screening and rapid field checks, a portable photoionization detector is fast and easy, but it reports only total VOC and has compound-dependent response factors. For regulatory or speciated data, gas chromatography with FID or mass spectrometry is required, either online or in the laboratory after sorbent tube sampling. Total hydrocarbon analyzers suit continuous monitoring of hydrocarbon emissions against a single methane-equivalent limit. PTR-MS gives real-time speciated data for research on emission sources and reaction products. Consider the required detection limit, the target compound list, whether real-time or time-integrated data is needed, and the calibration gases and lamp or column consumables.