Single bubble in-tube microextraction coupled with capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science
• Environmental Analysis

Background:

• Headspace (HS) extraction is a key sample pretreatment for volatile and semivolatile organic compounds.
• In-tube microextraction (ITME) coupled with capillary electrophoresis (CE) offers a powerful HS extraction method.
• Conventional HS-ITME requires larger volumes and longer extraction times.

Purpose of the Study:

• To introduce and evaluate a new single bubble (SB) ITME technique for headspace extraction.
• To assess the efficiency and speed of SB-ITME compared to conventional HS-ITME.
• To determine the applicability of SB-ITME for analyzing phenolic compounds in tap water.

Main Methods:

• Developed single bubble (SB) ITME using a submicroliter bubble (∼200 nL) at the capillary inlet.
• Analyte evaporation into the bubble, extraction into an acceptor phase, and subsequent CE analysis.
• Compared SB-ITME (5 min) with conventional HS-ITME (10 min) for enrichment factors.

Main Results:

• SB-ITME achieved comparable enrichment factors to HS-ITME in half the time due to a high surface-to-volume ratio.
• Enrichment factors for 2,4,6-trichlorophenol (TCP), 2,3,6-TCP, and 2,6-dichlorophenol were 53, 41, and 60, respectively, in tap water.
• Achieved limit of quantitation (LOQ) values of 5.6-8.3 ppb, significantly below the WHO guideline for 2,4,6-TCP.

Conclusions:

• Single bubble ITME is a rapid and efficient headspace extraction technique.
• SB-ITME offers significantly faster enrichment compared to conventional HS-ITME.
• The method is suitable for sensitive analysis of phenolic compounds in drinking water, meeting regulatory standards.