Saltzman method

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The Saltzman method is a chemical-analytical measuring method for determining the concentration of nitrogen dioxide in gases. It is described in various standards .

description

The Saltzman process is based on the Griess-Ilosvay reaction. In this detection reaction for nitrites , a reagent made from sulfanilic acid and 1-naphthylamine turns red.

The sample air is passed through a reaction solution consisting of sulfanilic and acetic acid , among other things , so that a red azo dye is formed in the presence of nitrogen dioxide . The color intensity of the reaction solution is determined photometrically and provides information about the content of nitrogen dioxide in the sample air. The absorbance of the color solution must be measured after 15 minutes at the earliest, but a period of 20 hours between sampling and absorbance measurement must not be exceeded. The calibration curves of the method are not linear .

By using an oxidizing agent, the Saltzman method can also be used to determine nitrogen monoxide . If only nitrogen monoxide is to be determined in the presence of nitrogen dioxide, the gas to be sampled must first be passed through a solution that absorbs nitrogen dioxide .

When sampling indoors, tobacco smoke leads to a falsification of the measurement result because components of the smoke react with the reaction solution. Since the interference depends on the smoke density, it cannot be quantified.

standardization

The Saltzman process is described in the VDI guidelines VDI 2453 Part 1 and VDI 4301 Part 1 as well as the DIN 51864 standard . It is the German reference method for immission measurements of nitrogen dioxide.

A VDI guideline from 1974 for determining the nitrogen monoxide concentration using the Saltzman method was withdrawn in May 1992.

literature

  • VDI 2453 Part 1: 1990-10 Measurement of gaseous immissions; Measuring nitrogen dioxide concentration; Manual photometric basic method (Saltzman) (Gaseous air pollution measurement; determination of nitrogen dioxide concentration; photometric manual standard method (Saltzman)). Beuth Verlag, Berlin. ( Summary and table of contents online )

Individual evidence

  1. ↑ Hans Fuhrmann: The recording measurement of gaseous immission concentrations with a new analysis device. In: Dust - cleanliness. Air . 25, No. 7, 1965, pp. 266-269.
  2. ↑ Jürgen Falbe, Manfred Regitz (Ed.): Römpp Chemie Lexikon . Thieme Verlag, Stuttgart 1995, ISBN 3-13-102759-2 , p. 1653.
  3. ^ A b c Franz Joseph Dreyhaupt (Ed.): VDI-Lexikon Umwelttechnik. VDI-Verlag Düsseldorf 1994, ISBN 3-18-400891-6 , pp. 1005-1006.
  4. ↑ VDI 2453 sheet 2: 1974-01 measurement of gaseous immissions; Determining nitric oxide; Oxidation to nitrogen dioxide and measurement using the photometric method (Saltzman). VDI-Verlag, Düsseldorf, p. 2.
  5. ↑ VDI 4301 sheet 1: 1997-12 Measurement of indoor air pollution ; Measuring nitrogen dioxide concentration; Manual photometric method (Saltzman) (Indoor air pollution measurement; Determination of the concentration of nitrogen dioxide; Manual photometric method (Saltzman)). Beuth Verlag, Berlin, p. 15.
  6. ↑ VDI 4301 sheet 1: 1997-12 Measurement of indoor air pollution ; Measuring nitrogen dioxide concentration; Manual photometric method (Saltzman) (Indoor air pollution measurement; Determination of the concentration of nitrogen dioxide; Manual photometric method (Saltzman)). Beuth Verlag, Berlin, p. 2.
  7. ↑ DIN 51864: 1986-09 Testing of gaseous fuels and other gases; Determination of the content of nitrogen monoxide; Saltzman method. Beuth Verlag, Berlin, p. 2.
  8. ^ Association of German Engineers : VDI guideline: VDI 2453 sheet 2 Measurement of gaseous immissions; Determining nitric oxide; Oxidation to nitrogen dioxide and measurement using the photometric method (Saltzman) , accessed on September 5, 2017.