Selective trace level analysis of phenolic compounds in water by flow injection analysis--membrane introduction mass spectrometry.
Flow injection analysis coupled with membrane introduction mass spectrometry (FIA-MIMS) with on-line derivatization is shown to allow fast, accurate, nearly interference-free, and sensitive (low microgram/L) quantitation of phenolic compounds in water. On-line FIA derivatization of the phenolic compounds is performed by acetic anhydride acetylation in a K2CO3-buffered alkaline medium. The phenol acetates so formed efficiently permeate a silicone membrane and are directly transferred to the mass spectrometer, in which they are analyzed with selectivity and high sensitivity via selected ion monitoring. FIA-MIMS analysis was performed for aqueous solutions of phenol, 2-methylphenol, 4-chlorophenol, 4-chloro-3-methylphenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, and detection limits in the 0.5-20 micrograms/L (ppb) range were observed for an analytical frequency of six samples/h. FIA-MIMS for phenolic compound analysis is considerably less time-consuming and labor intensive than most chromatographic methods based on liquid-liquid extraction and preconcentration procedures and is therefore applicable for on-line and in-situ monitoring of phenols in wastewaters and in the environment. FIA-MIMS employing acetic anhydride derivatization is also virtually free of interferences since it combines chemical, membrane, and enhanced MS selectivity; hence quantitation of phenolic compounds can be performed in the presence of congeners.
Alberici
R M
RM
Institute of Chemistry, State University of Campinas-UNICAMP, CP 6154, 13083-970, Campinas, SP, Brazil.
Sparrapan
R
R
Jardim
W F
WF
Eberlin
M N
MN
D000085:Acetates / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D010636:Phenols / Q000032:analysis*; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
D000085:Acetates; D010636:Phenols; D014874:Water Pollutants, Chemical