TOC-Vw

Benchtop laboratory total organic carbon analyzers with chemical oxidation of the sample combined with UV irradiation

The TOC-Vw benchtop laboratory analyzers use the principle of the so-called «wet» decomposition of organic molecules, which involves a chemical reaction with an oxidizing reagent in combination with UV radiation and heating. The use of such analyzers is especially effective for samples with extremely low concentrations of organic carbon (at the level of 0.5 – 1 μg/l). Such high sensitivity in comparison with analyzers operating on the principle of thermocatalytic oxidation is due to the increased volume of the sample contained in the reactor volume.

Possible models of TOC-Vw series analyzers

TOC-Vw series analyzers are available in two models:

  • TOC-VWP total organic carbon analyzer (control of the instrument using a PC)
  • TOC-VWS total organic carbon analyzer (control using a built-in microprocessor).

Determined indicators

Total Carbon (TC). The sample is oxidized to convert TC to carbon dioxide using a persulfate solution in combination with UV irradiation and heating. The area of ​​the carbon dioxide peak, measured using a non-dispersive IR detector, is converted to the TC concentration using a previously constructed calibration curve.

Total inorganic carbon (IС). The sample is acidified with phosphoric acid and purged to convert the IC in the sample to carbon dioxide, the latter content of which is determined using a non-dispersive IR detector. IC concentrations are measured in the same way as TC.

Total organic carbon (TOC). The total organic carbon content is calculated as the difference (TC – IC).

Total Non-Purgeable Organic Carbon (NPOC). The sample is pre-acidified with phosphoric acid in order to convert the carbonates and bicarbonates present in it into carbon dioxide, which is removed by purging, and then the NPOC indicator is determined in the same way as the TC.

Areas of application

The increased sensitivity of the TOC-Vw series analyzers is of great interest to the electronics industry, as well as to instrument-making companies that produce devices for obtaining especially pure water.

Technical specifications

ASI-V automatic sampler

Combining the ASI-V automatic sampler with the TOC-VWS/TOC-VWP series TOC analyzers allows you to create a fully automated analysis system.

Features:

  • Possibility of working with vials of two different volumes (in case of TOC-VWS/TOC-VWP).
  • You can choose the optimal type of vial and their holder.
  • All types of vials have well-sealing, easily replaceable gaskets with screw caps.
  • The dosing needle is optimized for both sample extraction from a capped vial and for bubbling.
  • It is very easy to add a sample vial or change the analysis conditions during the analysis. The system operation and the flow of carrier gas can be automatically stopped after the analysis is completed.
  • Building several calibration curves simultaneously and selecting the optimal curve for samples with significantly different concentrations allows you to analyze these samples within the same series.
  • Rinsing both the outer and inner surfaces of the needle prevents cross-contamination of samples.

Two types of vials with different volumes are available:

  • 40ml Vials × 68 (maximum quantity)
  • 125ml Vials × 24 (maximum quantity)

OCT-1 automatic sampler

The OST-1 8-port sampler is the path to ultra-simple automatic analysis.

  • The design based on the 8-port tap is simple and compact.
  • It is convenient to use, since the auto-doser does not require a special vial.
  • 2 OST-1 automatic samplers can be installed on each TOC-V series total organic carbon analyzer. If each OST-1 holds 8 samples, then the total capacity of two OST-1 is 16 samples.
  • Standard stirrers can be used.

SSM-5000A attachment for solid sample analysis

  • The combination of the SSM-5000A with the TOC-VWS/WP carbon analyzers allows the analysis of many solid samples, such as soils, sludges and sediments, in addition to liquid samples. This attachment allows the analysis of samples obtained by the «scraping» method from any surface to confirm the cleanliness of this surface.
  • The ability to analyze a sample weighing up to 1 g with a carbon content of up to 30 mg reduces weighing error and the error associated with the inhomogeneity of the carbon distribution in the sample.
  • The use of dual measuring cells, combining a long cell for liquid analysis with a short cell for solid sample analysis, allows a single TOC analyzer to operate in the range from several tens of ppb (μg/L) in ultra-pure water to several tens of percent in solid samples.
  • Water samples with a large number of suspended particles can be analyzed by dosing the sample into a solid sample boat.
  • The transition from liquid sample analysis using TOC-VWS/WP analyzers to solid sample analysis is extremely simple.
  • The SSM-5000A can be added to a TOC-VWS/WP, analyzer equipped with an auto-doser, but automatic solid sample analysis is not possible.