The OMA-300-CL2 showcases the seamless dynamic range of the OMA Series from low ppm up to high % concentrations of chlorine and chlorine-based compounds. This is achieved by the nova-II spectrophotometer, which makes automatic, real-time wavelength shifts to optimize the light signal in step with volatile concentrations.
Standard Analyte(s): Cl2
Frequent Extensions: ClO2 FeCl3 NCl3 TiCl4 vanadium VOCl3


Ethylene dichloride (EDC) is the first intermediate in the manufacturing of the versatile plastic PVC from raw materials. Heated to 500 °C in a cracking furnace, EDC splits into VCM (the precursor to PVC) and recyclable HCl. The EDC entering the furnace sometimes contains ferric chloride, the catalyst used to chlorinate ethylene in creating EDC; this contamination is far from trivial as trace FeCl3 is known to foul the furnace. Furthermore, PVC made from EDC with impurities (i.e. low-level FeCl3 and chlorine) does not meet the specifications of high-quality PVC.

Most chlorine and caustic soda is produced through electrolysis of sodium chloride brine. Chloride ions in the solution become elemental chlorine at the cathode and caustic soda and hydrogen are produced at the anode. Subsequent liquefaction of chlorine involves scrubbing and cooling to purify the chlorine from various contaminants; among these contaminants is NCl3 (nitrogen trichloride), formed from reactions between chlorine and nitrogen compounds in salts and additives.

As an explosive sensitive to light, heat, and organic compounds, NCl3 presents an enormous safety concern within chlorine production. Plants typically control NCl3 concentrations to well below 1%, which is the lower explosive limit (LEL) of NCl3 in air. In the scrubbing and cooling process, chlorine gas is added to essentially distill the solution of NCl3 in liquid chlorine such that the liquid chlorine vaporizes and leaves NCl3 accumulation in solution. This contaminant-rich solution is sent to the thermal decomposer, where NCl3 is dissolved in CCl4 and broken down.

The traditional NCl3 concentration monitoring method is Kjeldahl analysis, a lab method with origins in the 19th century; features include slow and infrequent measurements, high costs, and labor-intensive operation. The OMA-300 Chlorine is an always-online monitor of real-time NCl3 concentration in the headspace (gaseous phase). This multi-component system continuously measures the UV absorbance of NCl3 and Cl2 (accounting for chlorine absorbance interference) in a CCl4 background. Built around the rugged nova-II diode array spectrometer, the OMA-300 Chlorine brings the precision and automated performance necessary for tight, uninterrupted control of NCl3 levels.

Engineered for NCl3 analysis in feed forward, feedback, and elsewhere, this turn-key system immediately establishes the security of round-the-clock safety and optimized CCl4-as-solvent usage. Choose the OMA-300 Chlorine for proactive insurance against accidents.


Known in painting as the "whitest white," TiO2 is a widely used pigment. In the chloride production method, titanium ore is converted to TiCl4, from which metallic chloride impurities are discarded; oxidation of purified TiCl4 yeilds bright, finish-ready TiO2. Two yeild-critical points in this process require online analysis:

1) ensuring that the TiCl4 is vanadium-free to protect pigment quality, and
2) monitoring effluent from the oxidation vessel for unreacted TiCl4 to very the efficiency of conversion to desired TiO2.

Used as a reagent in organic synthesis, vanadium oxytrichloride (VOCl3) has traditionally made for difficult analysis. VOCl3 hydrolyzes upon contact with any form of water (including air moisture) and thus must be contained under a blanket of inert gas. The wide toxicity and sensitivity of the compound tend to complicate regular measurement and sample grabs.

Measuring by UV absorbance-in which VOCl3 shows distinct structural features-the OMA-300 Chlorine provides an elegant, automated alternative to these clumsy and delicate procedures. Analyzing the sample using a light signal transmitted via fiber optic cable, this system allows online VOCl3 concentration monitoring in a moisture-free environment.

General Performance

Measurement Technology

nova-II™ UV-VIS diode array spectrometer

Light Source

Pulsed xenon lamp (~5 year lifespan); deuterium and tungsten sources available

Sample/Analyzer Interface

Flow cell (various materials and path lengths available)

Sample Conditioning

If required; customized per chlorine application


Custom measurement ranges available for all components; typical ranges specified below.

Cl2 (chlorine)
0-100 ppm: ±5 ppm
0-10,000 ppm: ±2% full scale or 5 ppm**
0-100%: ±2% full scale

TiCl4 (titanium tetrachloride)
0-2,000 ppm: ±15 ppm
0-10,000 ppm: ±1% full scale

FeCl3 (ferric chloride)
0-300 ppm: ±1% full scale
0-10,000 ppm: ±1% full scale

NCl3 (nitrogen trichloride)
0-100 ppm: ±5 ppm
0-10,000 ppm: ±1% full scale
0-5%: ±1% full scale

0-5 ppm: ±0.3 ppm

**whichever is larger

Photometric Accuracy

±0.004 AU

Multi-Component Capability

Up to 5 stream chemicals measured simultaneously


For many applications, factory calibrated with certified calibration gases; for safety reasons, some applications require on-site calibration


Easy verification/validation with standard certified gas samples and neutral density filters
Operating Conditions

Ambient Temperature

0 to 55 °C (32 to 131 °F)
[Optional upgrade: -20 to 55 °C (-4 to 131 °F)]

Sample Temperature

Using immersion probe: -20 to 150 °C (-4 to 302 °F)
Using flow cell: -20 to 150 °C (-4 to 302 °F)

Sample Pressure

Using immersion probe: 100 bar (1470 psig)
Using flow cell: 206 bar (3000 psi)

Analyzer Environment

Indoor/outdoor (no shelter required)


Analyzer enclosure (standard): 24" H x 20" W x 8" D (610mm H x 508mm W x 203mm D)
Sample conditioning system enclosure (standard): 24" H x 30" W x 8" D (610mm H x 760mm W x 200mm D)


Analyzer (standard): 32 lbs. (15 kg)
Sample conditioning system: highly variable

Wetted Materials

Analyzer (standard): Teflon; K7 glass; Kalrez; Hastelloy C-276
Sample conditioning system (standard): Teflon; quartz; Kalrez; Hastelloy C-276


one galvanically isolated 4-20mA output per component; modbus TCP/IP (optional); RS232 (optional); Fieldbus, Profibus, and HART (all optional); two digital outputs for fault and sampling system control (user programmable)

Electrical Requirements

85 to 264 VAC 47 to 63 Hz

Power Consumption

45 watts

Area Classification

General Purpose (standard) / Class I, Div. 2 (optional) / Class I, Div. 1 (optional) / ATEX Exp II 2(2) GD (optional)
For your convenience, we offer two types of quotations. Based on the current completeness of your project information, please select from the RFQ options below:
  • Provides budgetary quote only (non-binding)
  • Requires only basic contact information and a measurement description