ASTM D7742-17 is a standard practice that describes the determination of nonylphenol polyethoxylates (NPnEO, 3 = n = 18) and octylphenol polyethoxylates (OPnEO, 2 = n = 12) in water by Single Reaction Monitoring (SRM) Liquid Chromatography/ Tandem Mass Spectrometry (LC/MS/MS). The practice is a screening method for the presence of longer chain ethoxylates in a water sample. The primary source of NP and OP, which have toxic effects on aquatic organisms, is commercial surfactants that contain longer chain APEOs like nonylphenol polyethoxylate (NPnEO).
The standard uses direct injection liquid chromatography (LC) and detected with tandem mass spectrometry (MS/MS) detection to determine the concentration of the longer chain APEOs in the water sample. However, since neat standards of each alkylphenol ethoxylate (APEO) are not available and the synthesis and characterization of these neat standards is expensive, Igepal2 brand standards that contain a mixture of various chain lengths of the alkylphenol ethoxylates were used. This assumption is used to determine qualified amounts of each ethoxylate in the standards. The n-Nonylphenol diethoxylate (n-NP2EO) surrogate was available as a neat characterized standard, so concentration and recovery data was not estimated.
The estimated screening range for the concentration of APEOs shown in Table 1 was calculated from the concentration of the Level 1 and 7 calibration standards. The standard is used as a practice rather than a test method. A comparison between samples is possible using this practice to determine which has a higher concentration of APEOs. However, the APEOs are not regulated by the EPA, but nonylphenol, a breakdown product of NPnEOs, is regulated for fresh and saltwater dischargers. A request was made to make this practice available through ASTM in order to screen for the influent or effluent from sources of APEOs coming into the STP to meet effluent guidelines. This practice, therefore, screens for the longer chain APEOs which may enter the STP at elevated levels and may cause a STP to violate its permitted discharge concentration of nonylphenol.
single reaction monitoring liquid chromatography, liquid chromatography-tandem mass spectrometry, nonylphenol polyethoxylates, octylphenol polyethoxylates, alkylphenols,Monohydric Phenols,Water,Hyphenated Techniques,Liquid Chromatography,Non-Ionic Surfactants
