THM Analyzer 1501 providing continuous and accurate THM measurements in UPW
THM online process control

THM Analyzer 1501

Trihalomethanes (THMs) are critical contaminants in drinking water and Ultrapure water (UPW) and require monitoring as well as efficient removal.

Ovivo’s THM Analyzer 1501 provides real-time measurements in potable water, process water and UPW with the aim of controlling THM removal processes or water disinfection processes.

Contact an Expert

Ovivo’s THM Analyzer 1501 is a unique analyzer which is able to give measurements at real time in potable water, process and UPW with the aim to control THM removal processes or water disinfection processes.

The THM Analyzer 1501 is able to measure several common THMs such as: Trichloromethane (Chloroform) CHCl3, Bromodichloromethane CHCl2Br, Dibromochloromethane CHClBr2, Tribromomethane (Bromoform) CHBr3.

The THM Analyzer 1501 has the following important features:


  • No reagent required
  • Low maintenance
  • Typically, one calibration per month
  • Several measurements per hour
  • Up to four channels included for grabbing samples
  • Each component of THMs detected, quantified and recorded
  • Minimum utilities needed: Compressed air and power
  • Continuous automatic online sampling and analysis


  • Automatic operation after initial start
  • Data logging – reports can be generated daily, weekly or monthly showing min/max limits
  • Dedicated software saves all measurements and external signals (optional)
  • Automatic analysis cycle, from sampling to evaluation
  • Gas chromatography analysis
  • Customised sampling channel sequence
  • Calibration protocols available
  • Alarm outputs and input/output control signals

The application is for raw water, process water and UPW.

Headspace gas chromatography with highly reliable and sensitive PID/TID detectors

The THM Analyzer 1501 consists of a gas chromatograph (GC) with thermal ionisation detector (TID) and photo ionisation detector (PID) connected to an industrial computer equipped with analytical software for the evaluation and documentation of the measurements.

The water sample passes through a multiplexer to a sample preparation unit, which operation is based on a headspace method. The sample is heated for a defined period of time at a set temperature and the volatile substances from the sample enter the gas phase. When a balance between the liquid and the gas phase is reached, the resulting overpressure forces the gas towards the sample loop of the gas chromatograph.

The individual compounds are analysed using separation columns and detectors (PID and TID) which generate signals displayed on chromatograms. The concentration of the compounds are then calculated by evaluation software through determination of respective peak height and integration of peak surface.

Limit of detection 1 ppb for each component
Quantification Range THM GC-PID-TID 1…500 ppb THM
THM GC-TID 1…200 ppb THM
Sampling channels Up to 4
Average measurement time 15…30 min / sample
Volume per sample < 250 mL
Max. sample pressure 10 bar (145 psi)
Voltage 115 or 230 VAC / 50 or 60 Hz
Power consumption 500 Watt
Dimensions 656 x 653 x 1800 mm
(25.8 x 25.7 x 70.9 in)
Operation mode Automatic/selectable sequence or manual single measurements
Online or grab sample analysis