ISO 21264:2019 pdf download – Surface active agents – Detergents – Determination of alkylphenol ethoxylates
1 Scope
This document provides a method for the determination of alkylphenol ethoxylates (APEOs) in surfactants using high performance liquid chromatography (HPLC) and detected with diode array detector (DAD) or fluorescence detector (FLD).
This method is appropriate for the detection and quantification of APEOs in surfactants.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 607, Surface active agents and detergents — Methods of sample division
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Principle
The sample is weighed into a vial and extracted in methanol using an ultrasonic bath. Subsequently the extract is filtered and analysed using high performance chromatography system with diode array detector (DAD) or fluorescence detector (FLD). Quantification is achieved by external quantification method and using the relationship chromatographic peak through its unique its retention time.
5 Reagents and materials
During the analysis, use only reagents of recognized analytical grade and the water of quality for HPLC analysis.
7.1.1 Prepare 1 000 mg/l stock solutions of each APEOs from standard materials or certified solutions in methanol. 100 mg of the OP n EO (5.2) and NP n EO (5.3) are dissolved in different 100 ml volumetric flasks with methanol and filled up to the mark respectively. Depending on the stock concentrations prepared, the solubility at that concentration will have to be ensured.
7.1.2 Prepare calibration curve for samples of each APEO stock standard solution at required concentrations by adding aliquots of stock solutions to a 100 ml volumetric flask and then diluted with methanol to the desired calibration level. If lower reporting limit is required, lower concentration of calibration standard shall be prepared to cover the reporting limit. Each calibration curve is prepared using the respective stock solution. The preparation of the Level 5 standard can be accomplished using different volumes and concentrations of stock solutions as is accustomed in the individual laboratory. The calibration vials shall be used within 24 h to ensure optimum results. Stock calibration standards are routinely replaced every 14 days if not previously discarded for quality control failure.
7.3.2 Qualitative determination
Injection volumes of all calibration standards and extraction solutions at concentration gradient are made at 10,0 μl volume by autosampler under selected conditions. An aliquot of the extraction solution is automatically ejected onto a reverse phase column (6.6) for sample component separation. Under the chromatographic conditions given, the detection and identification of the chromatogram peaks can be identified by comparison with the retention times of the substances contained in the chromatogram of all the pure substances.