Chromium Determination
Leather testing laboratories employ EN ISO 17070 to quantify hexavalent chromium in finished articles derived from animal hides. Regulatory authorities enforce strict concentration limits on this specific oxidation state because hexavalent chromium causes allergic reactions and possesses toxic properties. The analytical procedure begins with aqueous extraction from the material sample under controlled pH conditions.
Technicians subsequently isolate the target compound using chromatographic equipment equipped with photometric detection.
Extraction Parameter
Analytical repeatability depends heavily on maintaining extraction solution acidity within a precise range during sample preparation. Slight deviations alter the reduction and oxidation equilibria governing chromium species stability within the liquid matrix. Laboratories maintain strict temperature control throughout the procedure to prevent thermal degradation of the extracted compounds during agitation.
Technicians measure the resulting extract using spectrophotometric methods calibrated against known reference standards.
Detection Limit
Equipment sensitivity dictates the lowest concentration of hexavalent chromium reportable under the protocol. Modern chromatographic instruments achieve quantification thresholds well below regulatory ceilings mandated for consumer goods. Sample interference from tanning agents and fatliquors occasionally complicates peak resolution during the analytical run.
Analysts apply secondary cleanup steps when complex dye formulations mask the target signal.
Compliance Threshold
Finished garments entering retail distribution must demonstrate hexavalent chromium content remaining underneath the maximum allowable limit. Brand auditors review laboratory certificates confirming adherence to these chemical restrictions prior to shipment approval. Manufacturing facilities adjust tanning auxiliary formulations to prevent trivalent chromium from oxidizing into restricted forms during storage.
Effective process control at the tannery level ensures that bulk production satisfies regulatory scrutiny at destination ports.
