Phosphonic acid assay

What is phosphonic acid?

Phosphonic acid (CAS 13598-36-2) is an organophosphate compound used as an antifungal agent or as a degradation product of phosphonates. It is notably present in fosetyl-aluminum-based plant protection formulations, used to control fungal diseases such as downy mildew on grapevines, fruit trees, and vegetable crops.

Although its effectiveness is recognized, phosphonic acid persists in plants, soils and the environment after treatment, which necessitates rigorous monitoring of its residues.

Why measure phosphonic acid?

Phosphonic acid analysis is crucial in several contexts:

• Monitoring of pesticide residues in plant-based foodstuffs
• Verification of compliance with MRLs (maximum residue limits) defined by European regulations (EC Regulation No. 396/2005)
• Quality control of plant-based raw materials intended for human or animal consumption or for processing
• Assessment of environmental pollution related to the use of phosphonates (irrigation water, agricultural soils)
• Securing exports to demanding markets such as Japan or the United States

Many retail chains now impose stricter limits than European regulations, particularly for grapes, citrus fruits, salads or products intended for children.

Available analytical methods

YesWeLab offers several dosage techniques depending on the matrix and the thresholds to be reached:

• LC-MS/MS (liquid chromatography coupled with mass spectrometry): reference method, sensitive and specific, suitable for fruits, vegetables, extracts, powders, etc.
• Ion chromatography: recommended for the analysis of water, fertilizers and inorganic matrices
• GC-MS (in some cases, after derivatization), less used but complementary for certain complex matrices

The detection limits obtained are compatible with the lowest MRLs, typically in the order of mg/kg (ppm) or µg/kg (ppb) depending on customer requirements.

Matrices involved

The phosphonic acid assay test is applicable to a wide range of agricultural and environmental matrices:

• Fresh fruits and vegetables: grapes, apples, citrus fruits, salads, tomatoes, melons…
• Processed products: juices, purees, plant extracts
• Dietary supplements of plant or algal origin
• Animal feed: forage, silage, plant concentrates
• Phosphonate-based fertilizers or foliar formulations
• Drainage water, irrigation water, groundwater
• Cultivated soils or contaminated substrates

Regulatory context

Phosphonic acid is regulated as a residue of plant protection products. It is subject to specific MRLs for each crop, published in the annexes to Regulation (EC) No 396/2005. It may also be monitored within the framework of:

• Official control plans for plant protection product residues (DGCCRF, DGAL)
• Certification audits (AB, GlobalG.AP, Demeter, etc.)
• Export requirements for batches of plant-based food

Its dosage is also relevant in soil remediation or environmental monitoring processes in agricultural areas.

Why go through YesWeLab?

At YesWeLab, we collaborate with ISO 17025 accredited laboratories specializing in pesticide residue analysis and environmental monitoring. Our services include:

• Selecting the analytical method best suited to your matrix
• Validation of results according to applicable standards (EU regulation, Codex, export requirements)
• Comprehensive reports, usable for your quality controls, customer audits, or regulatory files
• Personalized scientific support for non-conformities or out-of-standard results

Our digital platform allows you to efficiently manage your samples, quotes, results and history.

Need to analyze phosphonic acid in your products or soils?

YesWeLab helps you ensure the safety, regulatory compliance, and traceability of your agricultural products or plant-based ingredients.
Contact us now for a personalized assessment or a quick quote.