--- title: Choosing an Oxygen Analyser: Trace, Percent or Purity url: https://www.sarveshanalytics.com/learn/choosing-an-oxygen-analyser-trace-percent-or-purity.html description: How to choose an online oxygen analyser: trace ppm, percent or purity ranges, sensor types, sample conditions and the ACCURRA-S models for each. updated: 2026-11-02 source: html --- Learn · Measurement principles # Choosing an online oxygen analyser: trace, percent or purity Oxygen is the most commonly measured gas in industry, and the range decides almost everything about the analyser. Beginner 3 min read Lesson 14 of 15[Measurement principles](https://www.sarveshanalytics.com/learn/track-measurement-principles.html) Helpful first: [Gas analysis technologies compared: which sensor for which gas](https://www.sarveshanalytics.com/learn/gas-analysis-technologies-compared.html) Quick answer Choose by range. Trace oxygen (0 to 1000 ppm) uses ACCURRA-S 3015. Percent oxygen (0 to 25 % or 0 to 100 %) uses 3030 or 3130. Purity above 95 % uses 3090 or 3190 with pressure compensation. Hot flue gas uses ACCURRA-Zr, and classified areas use ACCURRA-Hz or INFINITY-Tx. Updated 2 November 2026 · Figures from Sarvesh datasheets **After this lesson you can** - Pick the oxygen analyser family from the range you need - List the sample questions that change the choice - Know when to involve an engineer ## Step 1: the range - Trace, ppm: nitrogen and argon purity, blanketing, furnace atmospheres. ACCURRA-S 3015, 0 to 1000 ppm, minimum range 0 to 100 ppm - Percent, 0 to 25 % or 0 to 100 %: process monitoring, fermenters, inerting, PSA oxygen. ACCURRA-S 3030 or 3130 - Purity, 95 to 100 %: air separation, medical and industrial oxygen. ACCURRA-S 3090 or 3190, pressure and temperature compensated - Flue gas, percent: boilers and furnaces. ACCURRA-Zr in situ ## Step 2: the sample ACCURRA-S expects a dry, non-corrosive, non-toxic, non-flammable sample at 2 to 10 psig and about 1 LPM. Hot, wet or dusty gas needs a probe and conditioner. Flammable or classified locations need ACCURRA-Hz or INFINITY-Tx. Liquid or cryogenic samples need a vaporiser. ## Step 3: the options Trace oxygen model 3015 has a sensor bypass valve, but no auto-calibration or internal pump. Models 3130 and 3190 are supplied without an internal sample pump, which suits pressurised lines. Dual-channel versions pair oxygen with dew point, CO or CO2. ## Step 4: confirm with an engineer Send us the gas, background, range, pressure, temperature, dew point, dust and area classification. Our pre-order input sheet asks for the same items. You can also use the analyser selector to get an indicative recommendation and send it to us with one click. **In short** - Range comes first: ppm, percent or purity. - Hot flue gas points to zirconia; classified areas point to hazardous-area units. - Pressure compensation matters for purity above 95 %. - Confirm the sample before you order. ## Check your understanding Answer in your head or on paper first, then open the answer. Recalling an answer teaches more than rereading. **Which oxygen analyser family suits 0 to 500 ppm in nitrogen?** The trace oxygen model, ACCURRA-S 3015 (0 to 1000 ppm, minimum range 0 to 100 ppm). **Which suits 99 % cryogenic oxygen?** A purity model with ambient pressure and temperature compensation, ACCURRA-S 3090 or 3190. **What information changes the choice besides range?** Sample temperature and pressure, dust, area classification and the output you need. ## Key terms - [Range](https://www.sarveshanalytics.com/learn/glossary.html#t-range) - [Purity analyser](https://www.sarveshanalytics.com/learn/glossary.html#t-purity-analyser) - [Trace measurement](https://www.sarveshanalytics.com/learn/glossary.html#t-trace-measurement) ## Frequently asked questions **Which analyser for 99.99 % nitrogen?** Trace model 3015. Residual oxygen up to 100 ppm is the measurement. **Which for PSA oxygen at 93 %?** The percentage models 3030 or 3130, which cover 0 to 100 %. The purity models start at 95 %. **Which for cryogenic oxygen at 99 %?** Purity model 3090 or 3190, with ambient pressure and temperature compensation. **Which for boiler flue gas?** ACCURRA-Zr, an in-situ zirconia analyser. ## Related products [ ### ACCURRA-S Online analyser for trace, percent and purity O2, CO, CO2, CH4 and dew point; can measure two gases from one sample. View ACCURRA-S ](https://www.sarveshanalytics.com/safe-gas-analyser.html)[ ### ACCURRA-S 3090 Oxygen purity analyser for 95 to 100 % O2 with ambient pressure and temperature compensation. View ACCURRA-S 3090 ](https://www.sarveshanalytics.com/oxygen-gas-analyser.html)[ ### ACCURRA-Zr Zirconia percent O2 analyser for furnaces and boilers, single-point air calibration, options to 1400 C. View ACCURRA-Zr ](https://www.sarveshanalytics.com/flue-gas-analysers.html) ## Where this applies - [Oxygen purity in air separation plants](https://www.sarveshanalytics.com/applications/oxygen-purity-air-separation-plant.html) - [Nitrogen purity and trace oxygen](https://www.sarveshanalytics.com/applications/nitrogen-purity-trace-oxygen.html) - [Medical oxygen plant purity monitoring](https://www.sarveshanalytics.com/applications/medical-oxygen-plant-purity-monitoring.html) - [ACCURRA-S oxygen analysers](https://www.sarveshanalytics.com/oxygen-gas-analyser.html) ## Where to go next - [How to specify a gas analyser: A practical checklist](https://www.sarveshanalytics.com/learn/how-to-specify-a-gas-analyser.html)