⛽ Hydrogen sulfide in liquefied petroleum gas (LPG) — detection with paper saturated with lead(II) acetate: vaporized sample at 2.3 l/min for 2 minutes, assessment of the stain after 5 minutes; PN-EN ISO 8819

Petrochemistry PN-EN ISO 8819

Overview

WHAT THE STANDARD COVERS. ISO 8819:1993 (clause 1) specifies a method for the detection of hydrogen sulfide in liquefied petroleum gases (LPG). The lower limit of detection is 4 mg of hydrogen sulfide in 1 m³ of liquefied gas. Methyl mercaptan, if present, produces a transitory yellow stain on the lead acetate paper which fades completely in less than 5 minutes; other sulfur compounds present in LPG do not interfere. Note 1 gives the reason for the test: LPG and its combustion products should not be unduly corrosive or reactive with materials they come into contact with, and hydrogen sulfide is a very reactive substance; in some applications (e.g. lighter gas) its odour is also unacceptable. The "Scope" field of the PKN card of PN-EN ISO 8819:2000 (Polish version): "A method is specified for detecting hydrogen sulfide in liquefied petroleum gas. The test conditions, the necessary apparatus, the test procedure and the preparation of the test report are specified. The lower limit of detection is 4 mg of hydrogen sulfide in 1 m3 of liquefied petroleum gas" (our translation; the misspellings of the card are not reproduced).

PRINCIPLE AND APPARATUS (clauses 2–3). The vaporized sample is passed under controlled conditions over moistened lead acetate paper; hydrogen sulfide reacts with lead acetate to form lead sulfide, and the stain on the paper — from yellow to black — depends on the amount of hydrogen sulfide. Apparatus (Figure 1): a glass cylinder 44.5 mm in diameter and 203 mm long with stoppers, inside a glass rod with a hook for the paper and a watch glass 25.4–38 mm in diameter; the gas enters from the sample side through stainless steel tubing via a needle valve and a section immersed in water at 60–80 °C, and leaves to a flow indicator. Paper: strips of smooth filter paper immersed in an aqueous lead acetate solution of 50 g/l, with the excess solution removed with clean blotting paper, or commercial paper if it has been shown to give similar results; a strip of approx. 51 mm × 9.5 mm with a 3.5 mm hole near the end so that it hangs freely. Flow indicator: wet gas meter or rotameter for the range 2–3 l/min.

PROCEDURE (clauses 4–6). The apparatus is connected to the sample source with tubing of clean stainless steel as short as possible (note 2: avoid rubber hoses and stoppers, because hydrogen sulfide has an affinity for rubber and the result will be wrong), the line and apparatus are purged with gas for approx. 1 minute, the reservoir is filled with water at 60–80 °C, and the needle valve is used to set a flow of 2.3 l/min ± 0.2 l/min (note 3: restricting the flow downstream of the apparatus or opening the valve suddenly can cause overpressure in the cylinder). A strip of paper moistened with distilled water is hung midway between the watch glass and the lower edge of the upper stopper and exposed to the flow for exactly 2 minutes. It is then compared with a moistened but unexposed paper: no distinct stain — result "hydrogen sulfide absent"; distinct stain — the comparison is repeated after 5 minutes: stain retained — "hydrogen sulfide present", initially yellow and faded — "methyl mercaptan present". Note 4: for "pass / fail" type results there is no generally accepted method for determining precision. The report contains at least the identification of the product, reference to the standard, the result, any deviations from the procedure and the date of the test.

SAMPLING (Annex A, informative). Hydrogen sulfide is chemically active and adsorbs, which is why connecting the apparatus directly to the sample source and testing on site is strongly recommended, instead of transferring the sample to a cylinder and testing in the laboratory. Experience has shown that in carefully cleaned cylinders (including stainless steel ones) the hydrogen sulfide content decreases, while in insufficiently cleaned cylinders, previously used for samples containing hydrogen sulfide, it can increase in a sample that did not contain it — according to the annex, data from hydrogen sulfide tests on samples tested in the laboratory are unreliable.

STATUS (PKN card as of 27.10.2026). The card of PN-EN ISO 8819:2000 (Polish version) has no withdrawal label: publication 03-07-2000, 6 pages, Chemistry Sector, KT 223 Technical Gases, "Adopts: EN ISO 8819:1995 [IDT], ISO 8819:1993 [IDT]", ICS 75.160.30; the card has no "Replaces" field. PKN search, search term "ISO 8819" (27.10.2026): this is the only item with this number. In the iTeh catalogue (read on 27.10.2026) ISO 8819:1993 has the status "Published" (stage "9060 – Close of review"), and EN ISO 8819:1995 — "Published" (stage "9093 – Decision to confirm").

REGULATIONS. Announcement of the Minister of Climate and Environment of 10 May 2024 on the publication of the consolidated text of the regulation on quality requirements for liquefied petroleum gas (LPG) (Journal of Laws 2024 item 744, "in force" in the ELI database of the Sejm, read on 27.10.2026), table of requirements, item 5: hydrogen sulfide — "none". Regulation of the Minister of Climate and Environment of 27 December 2021 on test methods for the quality of liquefied petroleum gas (LPG) (Journal of Laws 2021 item 2502, "in force"), annex, points 5–5.1: hydrogen sulfide is detected by the lead(II) acetate method, and the detection procedure, apparatus, procedure and report are determined in accordance with the current state of knowledge and best practice, in particular as in standard PN-EN ISO 8819.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database refreshed from the production server on 27.10.2026 and current PCA documents downloaded on that day). Number 8819 appears in 8 records at 6 Polish laboratories: AB 009, AB 079 (Fuel Laboratories in Gdynia and in Tychy), AB 103, AB 484, AB 1275 (two entries, including the Testing Laboratory in Małaszewicze Małe), AB 1278 (Saybolt Poland, Gdańsk). In all 6 current PCA documents the standard is in the same 8 rows; no entry is suspended. Forms: "PN-EN ISO 8819:2000" (AB 079, AB 103, AB 484, AB 1275) and "PN-EN ISO 8819" (AB 009, AB 1278). The "Laboratories" tab ("PN-EN ISO 8819") shows 7 laboratories: these 6 Polish ones and 1 Czech one (tab query on labcoda.pl, 27.10.2026).

WHAT THE LABORATORIES TEST (database copy and PCA documents). All entries: "presence of hydrogen sulfide", visual method, in liquefied petroleum gas LPG (liquefied hydrocarbon gases); AB 009 also in the biocomponent "bio propane-butane". No entry gives a concentration range — it is a qualitative test.

ALONGSIDE THIS STANDARD (database copy, 27.10.2026). AB 484 also has in its scope the entry "presence of hydrogen sulfide" in liquefied hydrocarbon gases according to PN-C-96008:1998 point 4.4.2 (visual method).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — methyl mercaptan: a yellow stain which fades within 5 minutes does not mean hydrogen sulfide; which is why with a distinct stain the comparison is repeated after 5 minutes (point 5.2.2). Second — rubber in the line: rubber hoses and stoppers absorb hydrogen sulfide and give a false negative result (note 2). Third — sample in a cylinder: hydrogen sulfide may disappear in it (clean cylinder) or appear (cylinder after samples with hydrogen sulfide), so according to Annex A a laboratory result is unreliable — testing on site, connected directly to the source, is recommended. Fourth — time and flow: exposure lasts exactly 2 minutes at 2.3 l/min ± 0.2 l/min; other conditions change the amount of gas passed over the paper. Fifth — the result is qualitative (present / absent, detection limit 4 mg/m³) and corresponds to the requirement "none" of the regulation; it is not a determination of concentration.

WHAT WE DO NOT GIVE. We read the full text of ISO 8819:1993 (4 pages); we do not give the text of the Polish edition of the standard or precision, which the standard — as it notes itself — does not specify for qualitative results.

Method principle

The vaporized sample of liquefied petroleum gas is passed under controlled conditions (2.3 l/min ± 0.2 l/min, exactly 2 minutes, gas through a section in water at 60–80 °C) over moistened lead(II) acetate paper. Hydrogen sulfide reacts with lead acetate to form lead sulfide, which stains the paper from yellow to black; a stain retained after 5 minutes means the presence of hydrogen sulfide, a fading yellow one — methyl mercaptan (ISO 8819:1993, clauses 2 and 5).

Applications

• Liquefied petroleum gases (LPG) — detection of hydrogen sulfide, detection limit 4 mg/m³ (ISO 8819:1993, clause 1)
• Quality control of LPG against the requirement "no hydrogen sulfide" (Journal of Laws 2024 item 744); method cited in Journal of Laws 2021 item 2502
• Testing on site, with the apparatus connected directly to the source — recommended instead of testing a sample in a cylinder (Annex A)
• In accreditation scopes: 6 Polish laboratories, visual method; AB 009 also bio propane-butane

Key parameters

Standard

Standard number

PN-EN ISO 8819:2000 (wersja polska; wprowadza EN ISO 8819:1995 i ISO 8819:1993 [IDT])

Title (PL)

Skroplone gazy węglowodorowe — Wykrywanie obecności siarkowodoru — Metoda z octanem ołowiu(II)

Title (EN)

Liquefied petroleum gases — Detection of hydrogen sulfide — Lead acetate method

Step-by-step procedure

1. Connection

   The apparatus is connected to the sample source with tubing of clean stainless steel as short as possible, without rubber; preferably directly to the source, without a sample cylinder (point 5.1, Annex A).

2. Purging and settings

   Purging of the line and apparatus with gas for approx. 1 minute, water bath at 60–80 °C, flow 2.3 l/min ± 0.2 l/min set with the needle valve; beware of overpressure when restricting the outlet.

3. Exposure

   Strip moistened with distilled water hung midway between the watch glass and the upper stopper, exposed to the flow for exactly 2 minutes.

4. Assessment

   Comparison with a moistened, unexposed paper: no distinct stain — "hydrogen sulfide absent"; with a stain, repeated comparison after 5 minutes — retained: "present", yellow faded: "methyl mercaptan present" (point 5.2).

5. Report

   Identification of the product, reference to the standard, result, deviations from the procedure, date of the test (clause 6). PN-EN ISO 8819:2000 — current (PKN card as of 27.10.2026).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The test is carried out with a flammable gas, often at the sampling point; the standard warns that its use may involve hazardous materials, operations and equipment, and that the user establishes the safety measures (warning before clause 1)
• Restricting the flow downstream of the apparatus or opening the needle valve suddenly can create overpressure in the glass cylinder (note 3)
• TECHNICAL NOTE: a yellow stain fading within 5 minutes is methyl mercaptan, not hydrogen sulfide

Frequently asked questions