OTS Gas Analyzer based on TDLAS laser spectroscopy

Measure trace gases with confidence

OTS-100-The affordable laboratory trace gas analyzer for detection water, CO2, methane, or other gases.
The OTS-100 is a diode laser-based analyzer for laboratory and industrial gas measurement applications and is available for several different small molecule gases. This affordable instrument is ideal for monitoring gas concentration at part-per-million sensitivities, or better, depending on the gas.


This instrument is a self-contained analyzer for measuring trace amounts of a selected gas using diode laser optical absorption with wavelength modulation spectroscopy (wms) detection. The analyzer is fully automated upon power-up. A LabView-based program is supplied to read, display, and log gas concentration, temperature and pressure measurements, and instrument diagnostic codes on the user's computer. Readout is via a USB port configured for serial transmission and is available for user-customized data acquisition programs. The basic unit requires user-supplied sampling lines. An internal pump to flow the gas through the absorption cell is standard. If the sampled gas is also present in the background air, an additional port is provided so that the enclosure and path external to the absorption cell can be purged.

In addition to this bench top analyzer, Southwest Sciences also makes rugged, specialized instruments for measuring gases in industrial, outdoor and airborne applications. To discuss special requirements, please contact Kris Peterson at (505) 984-1322 ([email protected]).

List of Gases
Standard Gases* Lower Detection Limit (LDL) Part number
Acetylene 20 ppb OTS100-C2H2
Carbon dioxide 20 ppm OTS100-CO2
Carbon dioxide-Enhanced 150 ppb OTS100-CO2-ES
Carbon Monoxide 10 ppm OTS100-CO
Carbon Monoxide-Enhanced 40 ppb OTS100-CO-ES
Methane 100 ppb OTS100-CH4
Oxygen 30 ppm OTS100-O2
Water Vapor 100 ppm OTS100-H2O
Hydrogen Chloride Please inquire OTS100-HCl
Hydrogen Fluoride Please inquire OTS100-HF
Nitrous Oxide Please inquire OTS100-N2O

* Nitrogen purge required to measure concentrations less than 3 times the concentration in ambient air. ‡LDL is defined as the concentration for which S/N = 1. The concentration measurement range is gas dependent. Contact Southwest Sciences for the expected concentration range for a selected gas.  Modifications to accommodate other gases, concentrations, or conditions may be possible.  Please contact us regarding your needs.


Item Min Typical Max Comments
Dynamic Range
Precision (±1 stnd dev)
Greater of ±2 % of reading or ± LDL
See list of gases for lower detection limit (LDL)
Operating Temperature Range:

  Instrument (°C)
  Inlet Gas (°C)
Operating Pressure Range(Torr):**
  Standard Internal Pump
Cell must not be overpressured or damage will result
  External pump (user supplied)
Time response:
  0 – 90% step response
  Standard Internal Pump
~ 10 sec
  Time to replace one full cell volume with 760 Torr input

*Instrument is not rated for outdoor operation. **For operation below 500 Torr, consult Southwest Sciences.


Item Value Comment
  Size 8.3 x 13.0 x 41.9 cm  
3.5 kg  
Cell Volume 325 cm3  
Gas Fittings ¼ “ OD tube fitting Kynar or 316 Stainless steel (mating fittings included)
Electrical 100 - 240 VAC, 50/60 Hz, 0.3 A  

Data Logging Software

Item Value Comment
Readout rate 1 Hz  
Data Format ASCII strings Available to user via USB connector as RS-232 [38400 baud, 8,N,1,N]
Logged File Format Text
Data transmitted concentration,cell T and P, system health parameters  
On Screen Display concentration,cell T and P, system health parameters  


To order the OTS gas analyzer

Please contact Kris Peterson at 505-984-1322 or [email protected] for additional information or to request a quotation. Orders may be placed by email ([email protected]) or fax (505 988 9230). Please include the following:

  • Part number of the product.
  • Your Purchase Order (PO) Number.
  • The delivery address, billing address, your contact name & phone number.
  • A quotation number (if applicable).
  • Specify shipping method (paid by purchaser). If not specified, standard is UPS or FED-EX ground.
  • Delivery time is 6 – 10 weeks for standard gases, depending on laser availability.


Southwest Sciences, Inc. (SWS) warrants each OTS series instrument to be free from defects in material and workmanship for one year after the shipping date of the instrument, excluding the laser light source.  The laser light source warranty is as specified by the laser manufacturer’s warranty.  SWS's sole obligation under this warranty shall be to repair or replace any part of the instrument which SWS's examination determines to have been defective in material or workmanship without charge and only under the following conditions:

  1. The defects are called to the attention of SWS in writing within one year after the shipping date of the instrument, by email at [email protected] or by mail at Southwest Sciences Inc., 1570 Pacheco St., Suite E-11, Santa Fe, NM 87505.
  2. The instrument's case has not been opened nor has the instrument been adjusted, repaired, or altered by anyone who was not approved by SWS.
  3. The instrument was used in the normal, proper, and ordinary manner and has not been abused, altered, misused, neglected, involved in an accident or damaged by act of God or other casualty.
  4. The purchaser, whether it is a distributor or direct customer of SWS or a distributor's customer, packs and ships or delivers the instrument to SWS (at SWS's main office in Santa Fe, NM, USA) within 30 days after SWS has received written notice of the defect. Unless other arrangements have been made in writing, transportation to SWS is at customer expense.
  5. No-charge repair parts may be sent at SWS's sole discretion to the purchaser for installation by purchaser.
  6. SWS's liability is limited to repair or replace any part of the instrument without charge if SWS's examination determined that part to have been defective in material or workmanship.
  7. SWS will replace, with no labor charge, a laser that is still under the laser manufacturer’s warranty.  Laser replacement parts and labor for a laser not covered by the laser manufacturer’s warranty will be at the purchaser’s expense.

The laws of some locations may not allow the exclusion or limitation on implied warranties or on incidental or consequential damages, so the limitations herein may not apply directly. This warranty gives you specific legal rights, and you may already have other rights which vary from location to location. All warranties that apply, whether included by this contract or by law, are limited to the time period of this warranty which is a twelve-month period commencing from the date the instrument is shipped to a user who is a customer or eighteen months from the date of shipment to SWS authorized distributor, whichever is earlier. Further information concerning this warranty may be obtained by writing or telephoning Southwest Sciences, Inc. 

Warranty Returns

To return a product under warranty, please contact [email protected] to request a Return Material Authorization (RMA) number. Warranty requests cannot be processed without a valid RMA number. The RMA number must be prominently displayed on the return package. No returns will be accepted "collect" or "C.O.D." On all warranty returns, SWS will pay the shipping charges on the return of the merchandise to the customer. Please have the following information available when requesting an RMA number:

  • Model Number
  • Serial Number
  • Description of the Problem


Contact Information

Southwest Sciences, Inc.
1570 Pacheco St., Suite E-11, Santa Fe, NM 87505
tel. (505) 984-1322
e-mail [email protected]



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