Kemtrak NIR Analyzers

The Kemtrak DCP007-NIR is designed to detect and report water in just about anything! Simple to use, the DCP007-NIR will measure trace and bulk water content in flows such as:

  • Alcohol
  • Ethanol
  • Methanol
  • Gasoline
  • Sugar solutions

 

The DCP007-NIR generates stable levels of NIR wavelength light that is passed through the flow stream and measures intensity changes due to absorbance of that light from varying water content. A temperature input is also optionally available to allow compensation of the measurement to a standard temperature – removes variations due to temperature – if necessary for the application.

 

Two versions of the DCP007-NIR are available:

  • LED source – Bulk water content across a range of 0 – 100%
  • Thermopile source – Trace water content down to ppm levels

 

The analyzer can be connected to any one of the many styles of flow through cell Kemtrak offers. For tank or large pipe applications, a third party fiber optic probe can also be used, usually without any special configuration or calibration requirements.

 

Typical applications for the DCP007-NIR are:

  • Solvent concentration
  • Moisture content analysis
  • Alcoholic beverage content monitoring & control
  • Water in alcohol monitoring
  • Chromatography control – solvent mixing
  • Residual solvent concentration in pharmaceuticals
  • Solvent recovery
  • Residual moisture concentration
  • Replace Karl-Fischer titration
  • Sugar concentration

Is Kemtrak Right for Your Application?

Let Kemtrak give you a solution – download an application data sheet, fill in your process specifications and send it to us. We’ll come back to you with a configuration that will suit your needs.

Water in Solvent Measurement

Water has a strong absorption throughout the entire NIR band with absorption peaks at approximately 1440nm and 1930nm.

  • 1440nm is recommended for water measurements from 0-100% water with approximately 0.1% precision.
  • 1930nm is recommended for trace (ppm) water measurements.

NIR is a preferred technique for accurately determining water in solvent concentrations, primarily because of the high degree of accuracy achievable due to the large difference between the water and solvent absorption, For instance, it is possible to accurately determine alcohol in water from concentrated solutions (100% Alcohol) all the way down to trace ppm amounts.

The following spectrum taken from a laboratory NIR spectrophotometer shows the absorption of water in alcohol.

NIR Absorption – Water in Alcohol (Ethanol)

With a wavelength of 1430nm, calibration of a Kemtrak DCP007-NIR photometer from 0-100% water in alcohol is possible with excellent linearity, as shown in the following calibration curve:

Water in Alcohol (Ethanol) Calibration

1430nm, 30°C

Traceable Validation Accessory

The optional Kemtrak NIST-traceable validation filter holder is supplied either fitted to the optical flow cell or as a standalone accessory in the optical fiber chain. It permits the use of either NIST traceable reference standards or liquid samples to quickly check instrument performance on a regular basis to ensure the photometer is operating within satisfactory parameters without having to remove the flow cell from the process line.

The Kemtrak NIST-traceable validation filter holder is designed to use industry standard 10mm cuvette style NIST-traceable absorbance filters, the same type as used on many standard laboratory spectrophotometers.

Benefits of using a Kemtrak NIST-traceable validation filter holder include:

  • Fast verification of measurement accuracy
  • Industry standard 10mm cuvette size
  • Same set of standard NIST filters as used in the laboratory
  • Cross validation between laboratory spectrophotometer and Kemtrak in-line industrial process photometers
  • Liquid samples can be measured
  • Recognized by international quality systems such as GLP, ISO 9000 and ISO/IEC 17025

Technology Overview

The Kemtrak DCP007-NIR photometer measures at two wavelengths. A primary “absorbing” wavelength is used to measure the concentration of the chemical being monitored while a “non absorbing” reference wavelength is used to compensate for turbidity, air bubbles and/or fouling.

The Kemtrak DCP007-NIR photometer uses precision fiber optics to shine a precisely focused monochromatic light through the process medium and back to a photo-detector.

The attenuation of the transmitted light beam caused by NIR absorbing substances in the process medium is mathematically described by the Beer-Lambert law.

Applying the Beer-Lambert law (below), the concentration of the sample can be calculated.

A = ε l c

where:

A = absorbance (= – log transmittance)

ε = molar absorptivity coefficient

L = optical path length

C = concentration of absorbing species