🌿 Vapours of organic solvents (VOC) in workplace air — pumped sampling on a sorbent tube, solvent desorption (usually with carbon disulfide) and gas chromatography

Environment ISO 16200-1

Overview

Which document describes this method. The series ISO 16200 has two parts: Part 1 "Pumped sampling method" — sampling with forced flow through a pump — and Part 2 "Diffusive sampling method", that is diffusive (passive) sampling. Both end with SOLVENT desorption and gas chromatography; contrary to a widespread mental shortcut, Part 2 does not concern thermal desorption, only a different way of taking the sample. The full course of the test — the principle, the reagents, the apparatus, the sampling, the analytical procedure and the calculations — is contained in Part 1, and it is Part 1 that is the basis of this entry. Its layout is the classic layout of a method standard: 1 Scope, 2 Normative references, 3 Principle, 4 Reagents and materials, 5 Apparatus, 6 Sampling, 7 Procedure, 8 Calculations, 9 Interferences, 10 Precision and bias, 11 Storage and transport, 12 Test report, 13 Quality control, and in addition three informative annexes: A (description of the types of sorbents), B (equivalence of stationary phases for gas chromatography) and C (determination of the breakthrough volume). The standard was prepared by Technical Committee ISO/TC 146 "Air quality", Subcommittee SC 2 "Workplace atmospheres".

The national designation — checked: there is NO Polish adoption. We conduct the entry under the designation of the original ISO 16200-1:2001, because only that has been confirmed by a document. We checked the PKN catalogue on 11.09.2026 with two queries: "PN-EN ISO 16200" returns „Brak wyników wyszukiwania" [no search results], and "16200" alone returns only PN-EN 116200 in the Polish and the English version — that is, a standard with a different number caught by a partial match. There is therefore no PN item in the catalogue implementing ISO 16200-1, and for that reason the Polish title in the heading of this entry is our translation of the ISO title and not a title copied from the PKN catalogue. We add a finding from the ISO life-cycle card (id 30187), checked during the review of the batch: the standard stands at stage 90.92, that is "to be revised" — it is still the current version, but ISO has referred it for revision, so when citing it in a procedure it is worth checking whether a new edition has appeared: on the title page of the preview of the standard and in the metadata of the catalogue. A laboratory citing this method in its accreditation scope therefore refers to the ISO standard and not to its Polish counterpart — and should check the state of the catalogue for itself, because a national adoption may appear after the date of our check.

What this method serves for and what it does not cover. It is a general method for a whole class of volatile organic compounds, not a method for one substance: it is applied to hydrocarbons, halogenated hydrocarbons, esters, glycol ethers, ketones and alcohols, with the provisos which the standard states expressly — very polar compounds may require derivatisation, compounds with a very low boiling point are retained by the sorbent only partly and can be estimated only qualitatively, and semi-volatile compounds are retained in full but may be recovered only partly. The choice of the sorbent and of the desorbing solvent for particular pairs is referred by the standard to Tables 1 and 2 and to Annex A, which are not in the available preview — and which we do not reproduce here. For individual substances with their own NDS value in Poland there are separate substance standards (e.g. PN-Z-04016-10 for benzene), usually with a narrower measuring range adapted to the limit value; the general method does not release one from the obligation to check whether a dedicated method applies to the given compound.

The concentration range depends on the sample volume — and this is the commonest trap. The standard states: "the range of concentrations for which this part of ISO 16200 is valid depends on the volume of the sample taken. For example, for a 10 l sample the range is approximately from 1 mg/m³ to 1000 mg/m³ of a single organic compound; for a 1 l sample — from 10 mg/m³ to 10 000 mg/m³, and proportionally further". These figures concern a SINGLE compound, not the sum of the solvents, and they cease to apply when the volume of air changes. The upper limit is set by the sorption capacity of the sorbent and by the linear dynamic range of the column and the detector (or by the possibility of splitting the sample), and the lower limit by the noise level of the detector and by the levels of the analyte blanks and artefacts on the tubes or in the desorbing solvent. For the assessment of exposure one more conversion is needed: the result calculated from the formula in clause 8.2 is the mass concentration of the analyte IN THE AIR SAMPLE TAKEN, that is the average over the sampling time of that sample; the exposure indicator for the working shift is derived from it by conversion to a time-weighted average concentration (the standard itself indicates that a time-weighted average concentration for 8 h can be derived from the results of two or more consecutive samples), and the measurement strategy is described by PN-EN 689+AC:2019-06. The requirements placed on the procedure itself are given by PN-EN 482:2021: a measuring range of 0.1–2.0 of the limit value and a total relative uncertainty of ≤ 30 % in the range 0.5–2.0 and ≤ 50 % in the range 0.1–0.5 of that value. The range from the ISO standard does not guarantee these requirements automatically — it has to be compared with the NDS value of the particular compound and the sample volume chosen accordingly.

What this description does not contain. The preview of the standard covers the pages up to and including clause 8.2 (8 out of 27). Clauses 9 "Interferences", 10 "Precision and bias", 11 "Storage and transport", 12 "Test report" and 13 "Quality control", Tables 1–3 (the list of compounds, the recommended sorbents and desorbing solvents, the retention indices on the BP-1 and BP-10 phases) and Annexes A, B and C we have not seen and none of their content is here — in particular we give no data on the precision and bias of the method and no recommended sorbent–solvent pairs for particular substances. A second source with the same substantive content is the British method HSE MDHS 96 (March 2000), available in full; its principle, scope and description of the sorbent tube are practically identical with ISO 16200-1, but the figures entered below in the course of the test come from ISO 16200-1 and not from MDHS.

Method principle

A measured volume of the air under test is drawn through one or several tubes connected in series containing a sorbent chosen to suit the compound or mixture to be sampled. With a properly chosen sorbent the volatile organic constituents are retained in the tube and removed from the stream of air passing through. The vapours collected are desorbed with a solvent — typically carbon disulfide — and the solution obtained is analysed by a gas chromatograph fitted with a flame ionisation detector, a mass spectrometer or another selective detector. The tube has two layers of sorbent: a collecting layer and a back-up layer; the back-up layer, analysed separately, serves as a check on breakthrough — if more than 10 % of the sample or more than 10 % of any constituent is found in it, the sample is rejected as unreliable. The amount of analyte read from the calibration curve is corrected for the blank and divided by the desorption factor D, determined separately for each kind of sorbent and each analyte in the concentration range of the sample — without this correction the result is systematically too low.

Applications

• Assessment of occupational exposure to solvent vapours in painting, varnishing, gluing, degreasing and cleaning of parts
• Measurement of solvent mixtures, where a single chromatographic injection has to separate from a few to a dozen or so constituents (thinners, paints, adhesives, cleaning fluids)
• Personal dosimetry in the worker’s breathing zone — the result is the average concentration over the sampling time of the sample, the basis for calculating the exposure indicator
• Static measurements in order to establish the distribution of concentrations in a hall and to assess the effectiveness of local exhaust ventilation
• Control of the effectiveness of technological changes — comparison of series of measurements before and after a change of solvent or a modernisation of the extraction system
• Testing for accredited reports on tests and measurements of harmful agents, carried out according to the strategy of PN-EN 689

Key parameters

Standard

Standard number

ISO 16200-1:2001

Title (PL)

Jakość powietrza na stanowiskach pracy — Pobieranie próbek i oznaczanie lotnych związków organicznych metodą desorpcji rozpuszczalnikiem i chromatografii gazowej — Część 1: Metoda pobierania próbek z przepływem wymuszonym

Title (EN)

Workplace air quality — Sampling and analysis of volatile organic compounds by solvent desorption/gas chromatography — Part 1: Pumped sampling method

Step-by-step procedure

1. Choosing the sorbent and planning the sample

   Choose a sampler suitable for the compound or mixture; guidance on sorbents is given by the standard in Annex A, and the references to source methods with flows and sampling times for particular VOCs — in Tables 2 and 3. The sample volume must be smaller than the breakthrough volume. For most VOCs at least 10 l can be taken on a standard tube without breakthrough; for more volatile compounds the safe volume is sometimes considerably smaller and a standard tube may not suffice for a full 8 h — two or more consecutive samples or a larger tube are then used.

2. Checking the volume flow of the pump

   Set the flow with a representative tube fitted in the train, so that the recommended sample volume is taken within the time available. The flow should not exceed 200 ml/min. Carry out the calibration with an external calibrated flow meter; one end of the flow meter is to be at atmospheric pressure.

   ⏱ Time: before every series

3. Fitting the tube and starting the sampling

   Break off both ends of the tube so that each opening has at least half the internal diameter. Put the tube into a holder and connect it to the switched-off pump with tubing so that the back-up layer (50 mg) is on the pump side. In personal dosimetry fix the sampler in the breathing zone; for a static measurement choose a suitable place. In both cases the tube is to be set vertically, so as to limit channelling of the flow in the sorbent layers. Switch on the pump and record the time and the flow (or the counter reading).

4. Ending the sampling and calculating the volume

   At the end record the time and the flow (or the counter reading) and switch off the pump. Calculate the volume taken usually as the mean of the initial and the final flow multiplied by the time, or from the counter reading multiplied by the stroke volume. If the difference between the initial and the final flow exceeds 10 % — reject the sample. During sampling record the air temperature and the barometric pressure periodically, if the result is to be converted to definite conditions or expressed in volume fractions.

5. Securing and labelling the samples, field blanks

   Disconnect the tube and close both ends with caps, pressing them on firmly. Label the tubes unambiguously, for example by engraving — paints and markers containing solvents and adhesive labels must not be used. Prepare field blanks: tubes identical with those used for sampling, subjected to the same treatment except the sampling itself, labelled as blanks.

6. Storage and transport to the laboratory

   If the samples are not going to be analysed within 8 h, place them in a clean, uncoated, tightly closed metal or glass container. Store samples of very volatile substances (e.g. vinyl chloride) in dry ice or in a freezer — depending on the volatility; for less volatile substances cooling below 5 °C suffices.

   🌡 Temperature: < 5 °C (less volatile substances)

7. Desorption

   Analyse as soon as possible. Carry out the desorption in a clean atmosphere, in a fume cupboard. Pipette 1.0 ml of desorbing solvent into a vial with a septum and close it at once. Score the tube within the collecting (larger) layer and break it, take out and discard the glass wool, transfer the collecting layer into the solvent and close the vial again. Shake the vial intermittently for 30 min, so that the desorption is as complete as possible. Repeat the same separately for the back-up layer, in another vial. Desorb the blanks in the same way as the samples. With tubes containing more sorbent than 100 mg + 50 mg use a larger vial and a proportionally larger volume of solvent. With very volatile substances cool the vial with the solvent before adding the sorbent.

   ⏱ Time: 30 min

8. Calibration and chromatographic analysis

   Prepare the chromatograph for the analysis of volatile organic compounds; choose the column to suit what compounds may interfere with the separation. Inject a fixed, known volume (1–5 µl) of each standard solution, by a technique giving repeatable peak heights or areas (for a series of replicates the relative standard deviation should be better than ±2 %, autosamplers usually achieve better than ±1 %). Inject the same volume from the solution after desorption of the sample and read the analyte concentration from the calibration curve. Analyse the blank and the samples used for determining the desorption factor in the same way. Agreement of the retention time on a single column is not proof of the identity of a compound.

9. Determining the desorption factor D

   D is determined for each kind of sorbent and each analyte, in the concentration range corresponding to the sample. Prepare the standard tubes by passing an exactly known volume of a standard atmosphere (not greater than the breakthrough volume for the given analyte–sorbent pair) or by injecting 1–4 µl of standard solution onto a clean tube in a tee with a septum, with an inert-gas purge of 100 ml/min for 5 min. Desorb and analyse the standards so prepared like samples; D is the quotient of the amount recovered to the amount applied. If the set of D results is homogeneous, the pooled mean of the combined series is taken; otherwise it is checked whether it can be described by a smooth non-linear relationship in which D increases with the ratio of the mass of analyte to the mass of sorbent.

10. Checking breakthrough and the validity of the sample

    Compare the amount of analyte in the back-up layer with the amount in the collecting layer. If there is more than 10 % of the sample or more than 10 % of any constituent in the back-up layer — reject the sample as unreliable. Bear in mind that the breakthrough volume decreases as the ambient temperature, the relative humidity, the vapour concentration and the volume flow increase.

11. Calculating the concentration in the air

    Draw up the calibration curve in logarithmic form: the decimal logarithm of the peak height or area of the analyte, corrected for the blank level, against the decimal logarithm of the analyte concentration (in µg/ml) in the injected portion of standard solution. Calculate the concentration in the air from the formula cm = (mF + mR − mB) / (D · V) × 1000, where cm is the analyte concentration in the air sampled [mg/m³], mF the mass of analyte in the collecting layer [mg], mR the mass of analyte in the back-up layer [mg], mB the mass of analyte in the blank tube [mg], D the desorption factor at a tube loading corresponding to mF, and V the volume of the sample taken [l].

12. Relating the result to the assessment of exposure

    The cm obtained is the average concentration over the sampling time of the given sample. For comparison with the limit value convert it to the quantity to which that value refers: the time-weighted average concentration for 8 h with NDS (with several consecutive samples combine them), the average concentration for 15 min with NDSCh. Check whether the measuring range actually attained with the sample volume chosen falls within the requirements of PN-EN 482 (0.1–2.0 of the limit value). Establish the number, distribution and duration of the samples according to the strategy of PN-EN 689+AC:2019-06.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Carbon disulfide is flammable and toxic — the standard requires the desorption and all operations with this solvent to be carried out in a clean atmosphere in a fume cupboard; MDHS 96 additionally stipulates that work with carbon disulfide is to be confined to a well-ventilated fume cupboard.
• The substances determined are themselves sometimes toxic or carcinogenic (e.g. benzene) — exposure by all routes has to be limited, and the samples treated as material containing those substances.
• The standard states expressly that it does not cover all the safety questions connected with its application — establishing the proper health and safety practices and checking the regulatory limitations is the user’s responsibility.
• The glass tubes are flame-sealed and broken by hand when being fitted and during desorption — hold them in protective sleeves, and protect the hands and eyes when breaking and scoring them.
• A worker with a pump and a tube in the breathing zone works through the whole shift: the mounting must not hinder movement or catch on parts of machines; agree the sampling place with the person supervising the workplace.
• Markers and paints with solvents and adhesive labels must not be used for labelling the tubes — not only will they falsify the result, they also introduce additional vapours into the sampling zone.

Frequently asked questions