CZE determination of submicromolar level of phenol in seawater using improved dynamic pH junction

Abstract

Using an improved dynamic pH junction as an on-line concentration procedure, we developed CZE for determining submicromolar phenol in seawater for chloride to phenol concentration ratios of 1 000 000. To enhance the effect of conventional dynamic pH junction, a saturated fatty acid solution was injected into the capillary after sample injection. We named the procedure an improved dynamic pH junction. The method requires no sample pretreatment. The following optimum conditions were established: BGE, 40 mM sodium tetraborate decahydrate adjusted to pH 9.8 containing 0.001% m/v hexadimethrine bromide; 190 nm detection wavelength; 18 s (370 nL) vacuum injection period of sample; a saturated fatty acid solution, 30 mM sodium n-hexanoate; 20 s (420 nL) vacuum injection period of the sodium n-hexanoate; and 15 kV applied voltage with the sample inlet side as the cathode. The LOD for phenol was 5.9 μg/L at S/N of 3. The respective values of the RSD (intraday) of the peak area, peak height, and migration time for phenol were 1.9, 2.9, and 0.46%. The recoveries of phenol (25-100 μg/L) spiked into the natural seawater sample obtained using the peak areas were 92-110%. The proposed method was applied to simple biodegradation experiments using natural seawater samples containing phenol.

Dynamic computer simulations of electrophoresis: 2010–2020

“…A simulation study performed with the same simulator dealt with the concentration of weak acids in a pH boundary formed between sodium borate pH 9.5 and sodium phosphate pH 2.5 electrolytes [140]. Other input data are given in [144]. From ref.…”

“…A 50 μm id capillary of 50 mm length divided by a mesh of 10 μm without EOF served as separation space. Other input data are given in[144]. From ref [144]…”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2016–2018)

“…Yasuno and Fukushi developed an improved dynamic pH junction to determine sub‐micromolar phenol in seawater. They used borate buffer at pH 9.8 (close to the p K a of phenol) and hexadimethrine bromide to reverse EOF.…”

Capillary zone electrophoresis determination of aniline and pyridine in sewage samples using transient isotachophoresis with a system-induced terminator

“…However, the concentration sensitivity of CE with conventional UV detection is not sufficiently high because of the-small sample-injection volume and the short light pathway. Therefore, various on-line concentration procedures have been developed to improve the sensitivity: field-amplified sample injection (FASI) [13][14][15][16][17], large volume sample stacking [18,19], dynamic pH junction [20][21][22], sweeping [23,24], electrokinetic supercharging (EKS) [25][26][27], and transient isotachophoresis (tITP) [17,28].…”