🌿 Acetic acid in workplace air — gas chromatography, PN-Z-04323

Environment PN-Z-04323

Overview

WHAT THIS STANDARD DESCRIBES. The scope from the PKN catalogue card: "Podano metodę polegającą na adsorpcji par kwasu octowego na żelu krzemonionkowym, desorpcji związku roztworem kwasem mrówkowego w metanolu i analizie otrzymanego roztworu metodą chromatografii gazowej. Najmniejsze stężenie kwasu octowego, jakie można oznaczyć tą metodą, wynosi 0,5 mg/m3" [A method is given consisting in the adsorption of acetic acid vapours on silica gel, desorption of the compound with a solution of formic acid in methanol and analysis of the resulting solution by gas chromatography. The lowest concentration of acetic acid that can be determined by this method is 0.5 mg/m3]. The standard was published on 9 July 2004 in a Polish-language version, has six pages and is maintained by KT 159. The card has neither a "Withdrawn" header nor a "Withdrawal date" row (checked on 23.09.2026).

THREE SHEETS REPLACED BY ONE — WHAT THIS SAYS ABOUT THE CHANGE OF TECHNIQUE. In the "Replaces" field the card gives three items at once: PN-Z-04061-01:1971, PN-Z-04061-02:1971 and PN-Z-04061-03:1971, all in a Polish-language version. The 1971 series split the determination of acetic acid into three separate sheets, because each technique of the time required its own procedure — typically they differed in the concentration range or in the method of absorption. One standard from 2004 replaced them all, because gas chromatography covers the whole range with a single determination. **The "Replaces" field can therefore be read as a record of a technological change, not only as a cross-reference for the sake of order** — and that is why we quote it, even when it has no connection with today's procedure.

A LIMIT OF QUANTIFICATION WITH A LARGE MARGIN — AND WHY THIS IS NOT OBVIOUS. The limit value for acetic acid is **NDS 25 mg/m³ (10 ppm) and NDSCh 50 mg/m³ (20 ppm)** — item 346 of the list in the wording given by the regulation of 26 March 2026 (Journal of Laws 2026 item 447). The lowest determinable concentration is 0.5 mg/m³, i.e. **one fiftieth** of the limit value. PN-EN 482 requires one tenth — so this method has a fivefold margin over the requirement. For comparison: hydrogen chloride (PN-Z-04450) has exactly one tenth, potassium hydroxide (PN-Z-04436) one twelfth and tin (PN-Z-04488) one twelfth. The reason lies in the technique — gas chromatography with solvent desorption goes lower than absorption spectrometry or turbidimetry, because it concentrates the analyte on the sorbent throughout the sampling time.

TWO VALUES IN TWO UNITS — AND WHY BOTH ARE IN THE LIST. For acetic acid the list gives values both in mg/m³ and in ppm: NDS 25 mg/m³ and 10 ppm, NDSCh 50 mg/m³ and 20 ppm. The ppm columns are filled in only for substances that occur in air in the form of a VAPOUR or a GAS, because conversion between the units requires knowledge of the molar mass and of the normal conditions; for aerosols — such as dust, hydroxides or metals — these columns remain empty. A reader of an accreditation scope can therefore tell from the units alone which physical state of the agent is involved.

NO TRANSITIONAL PROVISION — CHECKED ON THE TEXT OF THE ACT. § 2 of the amending regulation does not mention acetic acid, so both values apply directly from the entry into force of the annex.

SCALE OF CITATIONS (reading of 23.09.2026, copy of the database of accreditation scopes). Matching by the BEGINNING of the notation: 21 entries at 17 laboratories; across all forms of the core "04323" — 22 at 18. Four forms of notation, the balance of occurrences agrees: "PN-Z-04323:2004" 18 times, "PN-Z-04323:2004-07" 2, "PN-Z 04323:2004" without a hyphen 1 and "PN-Z-04323/2004" with a slash instead of a colon 1.

AND HERE TWO REMARKS THAT MEET IN ONE PLACE IN THIS ONE ENTRY. First: the notation "PN-Z 04323:2004" without a hyphen after the letter element is the sixth sample in this database of a phenomenon counted in this database — **194 laboratories have in their scope a standard under which the search engine will not find them**; this laboratory is one of them. Second: the notation "PN-Z-04323:2004-07" with a month element is a NEWER notation than the designation on the card, which reads simply "PN-Z-04323:2004". The laboratory added a month that is not in the designation — the reverse of hydrogen chloride (PN-Z-04450, a separate entry in this database), where two laboratories omitted the month. **The same difference of one element gives once a notation that is too short and once one that is too long, and the search key must cover both.**

Method principle

Air from the workplace is drawn through a tube with silica gel, on which the acetic acid vapours are adsorbed. After sampling, the analyte is desorbed with a solution of formic acid in methanol, and the resulting solution is analysed by gas chromatography. The formic acid in the eluent acts as a modifier: it prevents broadening of the acetic acid peak on the column and improves recovery from the sorbent. The concentration in air is calculated from the mass of acetic acid in the solution and the volume of air drawn.

Applications

• Periodic measurements of occupational exposure required by the regulation of the Minister of Health on tests and measurements of agents harmful to health in the working environment
• Production and packaging of food vinegar and technical-grade acetic acid
• Tanneries, dye works and textile plants — acetic acid as a pH regulator of baths
• Production of cellulose acetate, solvents and adhesives

Key parameters

Standard

Standard number

PN-Z-04323:2004 (wersja polska)

Title (PL)

Ochrona czystości powietrza -- Oznaczanie kwasu octowego na stanowiskach pracy metodą chromatografii gazowej

Title (EN)

Air purity protection — Determination of acetic acid at workplaces by gas chromatography

Step-by-step procedure

1. Sampling

   Draw a known volume of air from the worker's breathing zone through a tube with silica gel.

2. Desorption

   Transfer the sorbent to a vial and desorb with a solution of formic acid in methanol.

3. Analysis

   Analyse the solution after desorption by gas chromatography; read the concentration from the calibration curve.

4. Calculation

   Calculate the concentration of acetic acid in air from the mass in the solution and the volume of air drawn.

5. Reference to the limit values

   Compare the exposure index for the work shift with the NDS of 25 mg/m³, and the results of short-term measurements with the NDSCh of 50 mg/m³. When giving the result in ppm, remember that the conversion applies to normal conditions.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• At working concentrations acetic acid irritates the eyes and respiratory tract; when concentrated, it is corrosive
• Methanol is toxic and highly flammable — carry out the desorption in a fume hood, away from sources of ignition
• Formic acid is corrosive — work in gloves and safety goggles

Frequently asked questions