🌱 Determination of trace elements in solid biofuels (PN-EN ISO 16968)
In short
Determination of thirteen trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, V, Zn) in all solid biofuels: digestion of the sample and determination in the solution. The test is performed according to PN-EN ISO 16968:2015-07 (wersja angielska; wprowadza EN ISO 16968:2015 [IDT], ISO 16968:2015 [IDT]); STATUS (state of the PKN card on 22-09-2026): CURRENT — the card of PN-EN ISO 16968:2015-07 has neither the "Wycofana" [Withdrawn] header nor a "Data wycofania" [withdrawal date] row. Publication date 21-07-2015, 24 pages, price group M. The procedure comprises 5 steps; it is used for: Assessment of biomass and pellets for metal content before combustion in an energy plant, Testing of wood, wood-based materials and packaging for trace element content, Reading an accreditation scope in which this standard stands alongside a document from outside the PN collection.
At a glance
- Standard: PN-EN ISO 16968:2015-07 (wersja angielska; wprowadza EN ISO 16968:2015 [IDT], ISO 16968:2015 [IDT])
- Category: Petrochemistry and fuels
- Procedure steps: 5
- STATUS (state of the PKN card on 22-09-2026): CURRENT — the card of PN-EN ISO 16968:2015-07 has neither the "Wycofana" [Withdrawn] header nor a "Data wycofania" [withdrawal date] row. Publication date 21-07-2015, 24 pages, price group M
- Elements covered by the standard (according to the scope on the card): arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, molybdenum, nickel, lead, antimony, vanadium and zinc — in ALL solid biofuels. The scope also allows selenium, tin and thallium ("określenie … jest również możliwe" [determination of … is also possible])
- What it replaced — a chain confirmed from TWO cards: PN-EN 15297:2011, withdrawn 21-07-2015. The card of the new standard: "Zastępuje PN-EN 15297:2011" [Replaces]; the card of the old one: "Wycofana i zastąpiona przez PN-EN ISO 16968:2015-07" [Withdrawn and replaced by]. Both sides agree — with withdrawn standards this is not the rule
Overview
WHAT THE STANDARD COVERS — ACCORDING TO THE CATALOGUE CARD. The scope quoted from the PKN card (reading of 22.09.2026): "Niniejsza norma międzynarodowa jest przeznaczona do oznaczania pierwiastków śladowych arsenu, kadmu, kobaltu, chromu, miedzi, rtęci, manganu, molibdenu, niklu, ołowiu, antymonu, wanadu i cynku we wszystkich biopaliwach stałych. Opisuje metody rozkładu próbek i proponuje odpowiednie metody instrumentalne dla oznaczenia pierwiastków w próbkach roztworzonych. Określenie innych pierwiastków jak selen, cyna i tal jest również możliwe z zastosowaniem metod opisanych w tej normie międzynarodowej." [This International Standard is intended for the determination of the trace elements arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, molybdenum, nickel, lead, antimony, vanadium and zinc in all solid biofuels. It describes methods of sample decomposition and proposes suitable instrumental methods for the determination of the elements in the digested samples. The determination of other elements such as selenium, tin and thallium is also possible using the methods described in this International Standard.]
THE LIST OF ELEMENTS HAS DISAPPEARED FROM THE TITLE — AND THAT MATTERS WHEN SEARCHING. The predecessor was called "Biopaliwa stałe — Oznaczanie pierwiastków śladowych — As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, V i Zn" [Solid biofuels — Determination of trace elements — As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, V and Zn]: the symbols stood in the TITLE. The current standard has a general title, and the elements are listed only in the scope. Anyone searching for the document by the name of an element — "a standard for mercury in biomass" — found it by the old title, but will not find it by the new one.
A TRANSITION THAT HAS REALLY TAKEN PLACE — A RARE CASE. The chain is confirmed from BOTH CARDS: the card of PN-EN ISO 16968:2015-07 gives "Zastępuje PN-EN 15297:2011" [Replaces], and the card of PN-EN 15297:2011 has the header "Wycofana i zastąpiona przez PN-EN ISO 16968:2015-07" [Withdrawn and replaced by], the row "Data wycofania: 21-07-2015" [withdrawal date] and the "Zastąpiona przez" [Replaced by] field. THE MEASUREMENT CONFIRMS THE SAME: in the database of accreditation scopes PN-EN 15297 does not appear EVEN ONCE — zero entries, zero laboratories (22-09-2026). It is worth comparing this with PN-88/B-04481 (testing of soil samples, a separate entry), withdrawn eleven years ago and still present in 168 entries — a number from THE SAME MEASUREMENT as above (all forms of notation, copy of the database of 22-09-2026), so both sides of the comparison are counted with one measure: THE WITHDRAWAL OF A STANDARD SAYS NOTHING ABOUT WHETHER LABORATORIES HAVE STOPPED USING IT. This is decided by measurement, not by the date.
THE NUMBER OF ROWS IN THE DATABASE IS NOT A MEASURE OF PREVALENCE — WITH THIS STANDARD THIS IS PARTICULARLY STRIKING. The standard is cited by EIGHT laboratories. In the scope database (copy of 11.09.2026) there are 135 rows with it, of which 123 at one laboratory (AB 053, Łukasiewicz Research Network, Poznań) — but its scope, reprocessed in September 2026, is SPLIT in the database: each scope entry is made up of several rows (the header "Zawartość pierwiastków śladowych" [content of trace elements], the elements in Polish, the same elements in English and a separate row with the technique). Counted by headers, it has NINE entries. The other seven laboratories have twelve entries together, five of them one each. The number 123 therefore speaks of the way of recording in the database, not of the prevalence of the method — which is why we always give the number of entries together with the number of laboratories and with how it was counted.
A STANDARD ON FUELS USED FOR PACKAGING AND WOOD COATINGS. At AB 053, the nine scope entries with this standard concern three test objects: "Paliwa stałe: biopaliwa stałe" [solid fuels: solid biofuels] — five, "Materiały opakowaniowe, Drewno i materiały drewnopochodne" [packaging materials, wood and wood-based materials] — two, and "Powłoki i pokrycia materiałów drzewnych" [coatings and coverings of wood materials] — two. In the last four, the standard ALWAYS stands paired with a document from outside the PN collection (IOS-MAT-0010:2022 for packaging materials and wood, IOS-MAT-0066:2017 for coatings). WHAT THE IOS-MAT DOCUMENTS ARE, WE HAVE NOT ESTABLISHED — in the scope database they appear at two laboratories (AB 053 and, once, AB 244) and they are not PN standards; we have not checked the publisher or the content, and we do not guess.
WHAT WE DO NOT GIVE. We did not have the text of the standard (24 pages, English-language version, Mining Sector, KT 144 Coke and Processed Solid Fuels, ICS 75.160.40). WE DO NOT GIVE: the method of digesting the sample, the composition of the digestion mixtures, the mineralisation conditions, the indicated instrumental techniques with their conditions, the limits of quantification or the repeatability requirements. The card states only that the standard "opisuje metody rozkładu próbek i proponuje odpowiednie metody instrumentalne" [describes methods of sample decomposition and proposes suitable instrumental methods] — and that is all we say about them.
Method principle
The solid biofuel sample is brought into solution (digestion), and the elements are determined in the solution by an instrumental technique. The standard describes decomposition methods and proposes determination techniques — we do not quote their conditions, because we did not have the text of the standard. In accreditation scopes with this standard the following appear: inductively coupled plasma optical emission spectrometry (ICP-OES — at six of the eight laboratories), inductively coupled plasma mass spectrometry (ICP-MS — at two), and at one laboratory also flame and electrothermal atomic absorption spectrometry, the cold vapour technique and, for mercury, amalgamation. We give the techniques from the accreditation scopes; the card says only that the standard "proponuje odpowiednie metody instrumentalne" [proposes suitable instrumental methods].
Applications
- Assessment of biomass and pellets for metal content before combustion in an energy plant
- Testing of wood, wood-based materials and packaging for trace element content
- Reading an accreditation scope in which this standard stands alongside a document from outside the PN collection
- Checking whether an older report citing PN-EN 15297 concerns the same test
Key parameters
| Parameter | Value |
|---|---|
| STATUS (state of the PKN card on 22-09-2026) | CURRENT — the card of PN-EN ISO 16968:2015-07 has neither the "Wycofana" [Withdrawn] header nor a "Data wycofania" [withdrawal date] row. Publication date 21-07-2015, 24 pages, price group M |
| Elements covered by the standard (according to the scope on the card) | arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, molybdenum, nickel, lead, antimony, vanadium and zinc — in ALL solid biofuels. The scope also allows selenium, tin and thallium ("określenie … jest również możliwe" [determination of … is also possible]) |
| What it replaced — a chain confirmed from TWO cards | PN-EN 15297:2011, withdrawn 21-07-2015. The card of the new standard: "Zastępuje PN-EN 15297:2011" [Replaces]; the card of the old one: "Wycofana i zastąpiona przez PN-EN ISO 16968:2015-07" [Withdrawn and replaced by]. Both sides agree — with withdrawn standards this is not the rule |
| In what language the document we refer to exists | PN-EN 15297:2011 — the predecessor to which we refer the reader in the case of older reports — existed in the PKN catalogue ONLY IN THE ENGLISH-LANGUAGE VERSION; the catalogue has no Polish-language version of this edition. The same applies to the current standard: PN-EN ISO 16968:2015-07 is English only. Anyone who reaches for the text of either of them will get a document in English (reading of the cards on 22.09.2026) |
| Has the transition taken place — a measurement | YES, completely: PN-EN 15297 appears in accreditation scopes ZERO times (22-09-2026). For comparison, PN-88/B-04481 (testing of soil samples), withdrawn in 2015, has 168 entries at 45 laboratories counting ALL forms of notation (the same measure and the same copy as for the number above; by prefix, that is, the way the tab searches, the result is 124 entries at 33 laboratories). The withdrawal date settles nothing — the measurement settles it |
| Change of title and the consequence for the searcher | the old title listed the symbols of the elements (As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, V and Zn), the new one is general. Anyone searching by title for "a standard for mercury in biomass" will not find it; the elements are only in the scope |
| Scale of citations — a number WITH ITS BREAKDOWN, not the number alone | EIGHT laboratories (copy of the database of 11.09.2026). One of them (AB 053) has nine scope entries, split in the database into 123 rows (Polish, English and a separate row with the technique); the other seven — 12 entries together, five of them one each |
| Forms of notation in the scopes | "PN-EN ISO 16968:2015-07" on its own, with IOS-MAT-0010:2022 or IOS-MAT-0066:2017 added (both at AB 053), and without a year "PN-EN ISO 16968" (AB 550). The laboratories tab searches with the prefix "PN-EN ISO 16968" and covers all these forms |
| Matrices — a fuel standard beyond fuels | at AB 053: solid biofuels — five scope entries, packaging materials and wood — two, coatings of wood materials — two; for these four, always a joint citation with an IOS-MAT document |
| IOS-MAT documents — what they are, we STILL HAVE NOT ESTABLISHED, but the scopes say more about them than we gave | we have not checked the publisher or the content, and we do not guess. FROM THE SCOPES THEMSELVES, however, four things are visible (measurement of 22-09-2026, after applying the rule "the answer is sometimes in the neighbouring column"): (1) it is a SERIES with a number and a year — IOS-MAT-0010:2022, -0066:2017, -0076:2024, -0076:2025, -0137:2023, -0181 — and the same number 0076 appears in two years, so the documents are updated; (2) they ARE NOT tied to one method: they stand alongside PN-EN ISO 16968 (trace elements in biofuels), ISO 1171 (ash), PN-EN 717-1 and PN-EN 16516 (formaldehyde emission), PN-EN ISO 3385 (foam tests); (3) they always stand TOGETHER with a standard, never instead of it; (4) they appear at two laboratories — at AB 053 and once at AB 244. This does not answer the question of what they are — but it is enough for the reader to know that it is not a document replacing the standard, but the laboratory's own document used alongside it |
| THE LIMITS OF QUANTIFICATION DO NOT COME FROM THE STANDARD | the card gives no limits of quantification or measuring ranges; every number in an accreditation scope comes from VALIDATION AT THE GIVEN LABORATORY, not from the standard. This is a statement about the standard and does not depend on any measurement in the database: a reader who sees "0,01 mg/kg" in someone else's scope cannot attribute this number to the standard |
| Who gives numerical limits at all (with the FIELD stated) | there are 8 laboratories with this standard; TWO give numerical limits. AB 053 — in the name of the test (notations such as "Kadm Cd (0,01 - 2,00) mg/kg" [Kadm = cadmium]; in the database each such notation stands twice, in Polish and in English); AB 688 — in the parameters field (notations such as "Cd - (0,015 - 10,0) mg/kg"). The other six laboratories give only the names of the elements, without limits. WE STATE THE FIELD BECAUSE THE RESULT DEPENDS ON IT: a query addressed only to the parameters field does not see the limits of AB 053 |
| OWN CORRECTION (22-09-2026): the spread of limits is mostly WITHIN one laboratory, not BETWEEN laboratories | originally we wrote here: "The spread of lower limits in the scopes: cadmium from 0.01 to 2.0 mg/kg (a hundredfold), mercury from 0.05 to 0.5 mg/kg (tenfold)… Two laboratories citing the same standard may therefore have incomparable methods". A REPEATED MEASUREMENT, MADE WITH A BREAKDOWN BY LABORATORY, DOES NOT CONFIRM THIS. For mercury, all notations with limits — from (0.0006 – 0.7500) to (0.5 – 30.0) mg/kg — come from ONE laboratory (AB 053), which has five different working ranges for the same element, depending on the matrix and the technique. For cadmium, lead, chromium, nickel and copper there are two laboratories, and the difference between them is small (cadmium: 0.01 versus 0.015 mg/kg). WE LEAVE THE ORIGINAL SENTENCE SO THAT IT IS VISIBLE WHAT WE ARE CORRECTING: the numbers were true, but the conclusion "different laboratories, incomparable methods" did not follow from these numbers — something else followed from them, and this too is worth knowing: one laboratory can have several different working ranges for the same element under one standard. |
| Techniques visible in the scopes with this standard | ICP-OES — at six of the eight laboratories (at AB 053 in a separate row "Method:", at the others in the technique field); ICP-MS — at two (AB 054, AB 713); only at AB 053 also FAAS, ETAAS, CVAAS and, for mercury, AAS with amalgamation. This is a reading from the scopes, not from the standard; the card says only that the standard "proponuje odpowiednie metody instrumentalne" [proposes suitable instrumental methods] — laboratories apply different techniques with it |
| Content of the standard | WE DO NOT GIVE IT — we did not have the text. This concerns the method of digestion, the composition of the mixtures, the mineralisation conditions, the measurement conditions, the limits of quantification and the repeatability requirements |
Standard
- Standard number
- PN-EN ISO 16968:2015-07 (wersja angielska; wprowadza EN ISO 16968:2015 [IDT], ISO 16968:2015 [IDT])
- Title (PL)
- Biopaliwa stałe — Oznaczanie pierwiastków śladowych
- Title (EN)
- Solid biofuels — Determination of minor elements
Step-by-step procedure
-
Checking which matrix the test concerns
The standard speaks of "wszystkich biopaliwach stałych" [all solid biofuels]. In accreditation scopes it is sometimes cited also for wood, packaging materials and coatings — there always together with a document from outside the PN collection. Citing the standard alone for such a matrix is incomplete.
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Preparation of the analysis sample
A solid biofuel is a heterogeneous material; the result concerns the portion actually digested, not the lot of material. This standard does not replace the rules for preparing the analysis sample.
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Digestion
The standard describes methods of sample decomposition. We do not quote the conditions — we did not have the text of the standard.
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Determination of the elements in solution
The standard "proponuje" [proposes] the instrumental technique, and the laboratory chooses it — that is why the accreditation scope gives it separately for each entry. Two laboratories citing the same standard may measure with different techniques, and both comply with the document.
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Recording the result with the element and the technique stated
Citing the standard alone does not say which of the thirteen elements was determined or by what technique. In accreditation scopes the elements are sometimes listed with separate measuring ranges.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Sample digestion system | The standard "opisuje metody rozkładu próbek" [describes methods of sample decomposition] — which ones and under what conditions, we do not give: we did not have the text | — |
| Spectrometer for determining the elements in solution | In the scopes with this standard: ICP-OES (six laboratories), ICP-MS (two), at one also FAAS, ETAAS and CVAAS. Which techniques the standard itself proposes HAS NOT BEEN ESTABLISHED — we did not have the text | — |
| Mercury analyser with amalgamation | In the scopes, a separate technique with amalgamation appears for mercury (one laboratory, AB 053) | — |
| Digestion vessels of known purity | In determinations at the mg/kg level, contamination of the vessel gives a TOO HIGH result that does not stand out in any way | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Digestion reagents | — | WE DO NOT GIVE the composition of the digestion mixtures — it is in the text of the standard, which we did not have. The purity grade of the reagents in trace determinations is part of the method, not a procurement detail |
| Element standard solutions | — | For the instrumental determination; their type and method of preparation HAVE NOT BEEN ESTABLISHED — we did not have the text of the standard |
Health and safety (OHS)
- The digestion reagents HAVE NOT BEEN ESTABLISHED (we did not have the text of the standard) — the safety data sheets of the reagents used in the laboratory apply
- Biomass dusts are combustible and irritating to the respiratory tract; use extraction during size reduction
- Mercury and its vapours — proceed according to the safety data sheet, also with standards
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN ISO 16968:2015-07 (wersja angielska; wprowadza EN ISO 16968:2015 [IDT], ISO 16968:2015 [IDT]) — “Solid biofuels — Determination of minor elements”.
How does this method work?
The solid biofuel sample is brought into solution (digestion), and the elements are determined in the solution by an instrumental technique. The standard describes decomposition methods and proposes determination techniques — we do not quote their conditions, because we did not have the text of the standard.
What is the measuring range and accuracy?
STATUS (state of the PKN card on 22-09-2026): CURRENT — the card of PN-EN ISO 16968:2015-07 has neither the "Wycofana" [Withdrawn] header nor a "Data wycofania" [withdrawal date] row. Publication date 21-07-2015, 24 pages, price group M; Elements covered by the standard (according to the scope on the card): arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, molybdenum, nickel, lead, antimony, vanadium and zinc — in ALL solid biofuels. The scope also allows selenium, tin and thallium ("określenie … jest również możliwe" [determination of … is also possible]); What it replaced — a chain confirmed from TWO cards: PN-EN 15297:2011, withdrawn 21-07-2015. The card of the new standard: "Zastępuje PN-EN 15297:2011" [Replaces]; the card of the old one: "Wycofana i zastąpiona przez PN-EN ISO 16968:2015-07" [Withdrawn and replaced by]. Both sides agree — with withdrawn standards this is not the rule; In what language the document we refer to exists: PN-EN 15297:2011 — the predecessor to which we refer the reader in the case of older reports — existed in the PKN catalogue ONLY IN THE ENGLISH-LANGUAGE VERSION; the catalogue has no Polish-language version of this edition. The same applies to the current standard: PN-EN ISO 16968:2015-07 is English only. Anyone who reaches for the text of either of them will get a document in English (reading of the cards on 22.09.2026).
How long does the test take?
The procedure comprises 5 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Sample digestion system, Spectrometer for determining the elements in solution, Mercury analyser with amalgamation, Digestion vessels of known purity.
Where is this test used?
Assessment of biomass and pellets for metal content before combustion in an energy plant; Testing of wood, wood-based materials and packaging for trace element content; Reading an accreditation scope in which this standard stands alongside a document from outside the PN collection; Checking whether an older report citing PN-EN 15297 concerns the same test.
What safety precautions apply?
The digestion reagents HAVE NOT BEEN ESTABLISHED (we did not have the text of the standard) — the safety data sheets of the reagents used in the laboratory apply; Biomass dusts are combustible and irritating to the respiratory tract; use extraction during size reduction; Mercury and its vapours — proceed according to the safety data sheet, also with standards.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN ISO 16968.