oSIST prEN 17767:2026

oSIST prEN 17767:2026 is the Slovenian version of the CEN draft European Standard for extracting phosphorus from organic and organo-mineral fertilizers with 2 % formic acid. The method is used before a later phosphorus determination to indicate the amount of soft natural phosphates. It also applies to certain fertilizing product blends, so laboratories can decide which extraction method fits a mixed product.

What does oSIST prEN 17767:2026 specify?

oSIST prEN 17767:2026 specifies a laboratory procedure for extracting phosphorus from organic and organo-mineral fertilizers with 2 % formic acid. The extracted solution is then used for a phosphorus determination that reflects soft natural phosphates.

The document is organized into scope, normative references, terms and definitions, principle, sampling and sample preparation, reagents, apparatus, procedure, and test report, followed by a bibliography. In practice, that structure takes the user from product selection and sample handling through to the extract and the reporting record.

A key scope point is the treatment of fertilizing product blends. The method applies when the blend contains at least two specified component types and the organic fertilizer or organo-mineral fertilizer is the highest percentage component; otherwise, the standard for the highest-percentage component applies. When components are present in equal quantity, the user decides which standard to apply.

What are the key requirements of oSIST prEN 17767:2026?

The core requirement is to extract phosphorus under defined conditions with 2 % formic acid and then determine the phosphorus in the extract according to the companion analysis method. That separation step is what makes the result relevant to soft natural phosphates rather than to all phosphate forms.

Principle and analytical follow-up

Clause 4 uses the formic acid extraction to help distinguish hard natural phosphates from soft natural phosphates. The extract is analysed according to prEN 17774, so the extraction and the phosphorus measurement must be treated as one linked workflow.

Sampling and sample preparation

Clause 5 makes clear that sampling is handled separately from the extraction itself. The laboratory needs a representative sample that has not been altered in transport or storage, and sample preparation is carried out according to EN 1482-2. Recommended sampling methods are given in EN 1482-1 and EN 1482-3.

Reagents and apparatus

Clause 6 requires water with low conductivity and free from the elements to be determined, plus a 2 % formic acid solution prepared from concentrated formic acid and distilled water. Clause 7 calls for standard laboratory equipment, a 500 ml wide-neck graduated flask, an overhead shaker, and phosphate-free filter paper. In practice, clean reagents and phosphate-free materials help prevent false results.

Test portion and extraction

Clause 8 starts with a 5 g test portion weighed to the nearest 0.01 g, although 1 g to 5 g may be used if the 1:100 sample-to-final-volume ratio is kept constant. The flask is filled with formic acid at 20 ± 2 °C, closed, vented to release gas, then shaken for 30 min at 20 ± 2 °C. The solution is filtered and the first portion of filtrate is discarded. These control points matter because time, temperature, ratio, and filtration affect the extract quality.

Timing, storage, and reporting

The phosphorus determination is carried out on the same day as the extraction according to prEN 17774. If needed, extracts may be kept at 4 ± 2 °C for up to two days before analysis. Clause 9 requires the report to identify the sample, state the method used, record sampling information if known, note when extraction finished, and list any deviations or incidents that could affect the result.

What terms does oSIST prEN 17767:2026 define?

• Fertilizing product blend - a mix of at least two listed component types, such as fertilizers, liming materials, soil improvers, growing media, inhibitors, and plant biostimulants.
• Organic fertilizers - one of the product categories covered by the scope when it is the dominant component of a blend.
• Organo-mineral fertilizers - another covered product category, also within the method’s scope when it is the dominant blend component.
• Soft natural phosphates - the phosphate fraction targeted by the extraction and subsequent determination.
• Hard natural phosphates - the contrasting phosphate fraction used in the principle of the method.
• Test portion - the weighed amount of laboratory sample used for the extraction step.

Who uses oSIST prEN 17767:2026?

This standard is used by fertilizer laboratories, quality control teams, and conformity assessment bodies that need a repeatable way to prepare extracts for phosphorus determination. It is also relevant to fertilizer producers, blend formulators, and buyers who need to classify organo-mineral products or compare batches. In practice, it supports routine testing, product release checks, and laboratory reporting for mixed fertilizing products.

What changed in oSIST prEN 17767:2026 from the previous edition?

oSIST prEN 17767:2026 supersedes CEN/TS 17767:2022. The stated changes are:

• the CEN Technical Specification was adopted as a European Standard;
• an introduction was added;
• the scope was updated, including clarification for fertilizing product blends and method selection;
• Clause 9 on the test report was added;
• the bibliography was updated.

Which standards are used with oSIST prEN 17767:2026?

What does the oSIST prEN 17767:2026 document contain?

The document contains a short laboratory method built around one extraction principle, one reagent system, and one linked analytical step. It gives the preparation of the test portion, the extraction conditions, the filtration step, and the timing rules for carrying the extract into phosphorus analysis.

It also contains the required reporting items for traceability, including sample identification, method reference, sampling information, extraction completion date, and any incidents during testing. The foreword records its relationship to CEN/TS 17767:2022 and the technical changes introduced in this edition.