Proficiency testing for inorganic acids

(HCl, HNO3 and H2SO4, H3PO4)

Test gas stream

Zoom Image

IFA's (former) test gas stream
Source: IFA

The proficiency testing (PT) is offered alternatively with and without own sampling. Participants may choose whether they wish to perform sampling for inorganic acids themselves, or to have the sample carriers supplied to them [1].

The concentrations to be measured for volatile and non-volatile inorganic acids will lie within the range between 1/10 and two times the AGW [2] value.

Since there is only a short-time limit value for nitric acid, the concentration of one test gas is in accordance with this limit value. The concentrations of the other two test gases are in accordance with the limit value of hydrochloric acid.

For HCl and HNO3, the IFA recommends the analysis method for hazardous substances described in IFA Folder No. 6172 [3], DFG [4] or NIOSH [5].

For H2SO4 and H3PO4, a procedure according to IFA Folder 6173 [6], DFG [7] method or NIOSH [8] is recommended.

Ion chromatography should be employed for analysis.

Proficiency testing scheme with own sampling

At the dynamic test gas stream at the IFA up to 25 participants can carry out parallel sampling.

  • When: 22/23 June 2021
  • Where:
    Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung (IFA)
    Alte Heerstr. 111
    53757 Sankt Augustin
  • Concentration range: between 1/10 and two times the AGW value [2]
  • Number of test series: 3
  • Duration per test series: 2 hours plus preparation time and run-in period (round three will be a short time measurement) (15 min).
  • Accomodations: Hotels in Sankt Augustin

Participants will receive detailed information on the PT scheme, a description of the apparatus, and the connections for the sampling devices in particular, in good time.

The participants will in addition receive the sample kit for H2SO4 and H3PO4 (see below).

Proficiency testing without own sampling

The PT for inorganic acids consists of two parts [1]:

Volatile inorganic acids: HCI, HNO3

Loading of the sample carriers for volatile inorganic acids is performed at the dynamic test gas stream of the IFA. Alkaline impregnated quartz fibre filters are employed as sample carriers.

Non-volatile inorganic acids: H3PO4, H2SO4

As sample carriers quartz-fibre filters are loaded with sulphuric acid and phosphoric acid. The samples are produced by means of piezoelectric microdispensing.

The loaded filter are stabilised with 4 mL desorption solution (c (Na2CO3) = 3,1 mmol/L / c (NaHCO3) = 0,35 mmol/L) [1].

Each participant receives two sampling kits comprising of:

One sampling kit for HCI and HNO3 comprising of

  • Three loaded sample carriers (quartz fibre filters), and
  • Two unloaded sample carriers for blank value adjustment.

In addition the participants will receive a sample kit for H2SO4 and H3PO4 comprising of

  • Three loaded filters stabilised immediately after loading
  • Two unloaded stabilised filters for blank value adjustment.


[1] Ringversuch Anorganische Säuren (Kennzahl 1630-2) In: IFA-Arbeitsmappe Messung von Gefahrstoffen. Lieferung: 02/2017

[2] GESTIS – Internationale Grenzwerte für chemische Substanzen

[3] Anorganische Säuren, flüchtig: Bromwasserstoff, Chlorwasserstoff, Salpetersäure (Kennzahl 6172). In: IFA-Arbeitsmappe Messung von Gefahrstoffen. 38. Lfg. IV/2007. Hrsg.: Institut für Arbeitsschutz der DGUV (IFA), Sankt Augustin. Erich Schmidt, Berlin 2011 - Losebl.-Ausg.

[4] Deutsche Forschungsgemeinschaft (DFG). Volatile inorganic acids (HCl, HBr, HNO3). In: Analyses of hazardous substances in air. Volume 6. Hrsg.: Kettrup, A. Wiley-VCH, Weinheim 2002

[5] Volatile Acids by Ion Chromatography (HCl, HBr, HNO3). Method 7907. In: NIOSH, Manual of Analytical Methods, Fifth Edition, Issue 1, 20 May 2014

[6] Anorganische Säuren, partikulär: Phosphorsäure, Schwefelsäure (Kennzahl 6173). In: IFA-Arbeitsmappe Messung von Gefahrstoffen. 46. Lfg. XII/2010.

[7] Deutsche Forschungsgemeinschaft (DFG). Inorganic acid mists (H2SO4, H3PO4). In: Analyses of hazardous substances in air. Vol. 6. Hrsg.: A. Kettrup. Wiley-VCH, Weinheim 2002

[8] Non-Volatile Acids (H2SO4, H3PO4). Method 7908. In: NIOSH, Manual of Analytical Methods, Fifth Edition, Issue 1, 20 May 2014


Division 2: Chemical and biological hazards

Brigitte Maybaum
Krista Gusbeth
Franziska Nürnberger