Mercury speciation by CE: A review

Abstract

CE methods for the speciation of inorganic and organomercury compounds are reviewed. Sample preparation, separation conditions and detection modes are discussed. Efficient separation and sensitive determination of mercury species by CE typically involves complexation with various thiols, chromogenic and other chelating agents; however, some methods do not require complexation. Spectrophotometric detection based on UV-visible absorption is by far the most commonly used. Hyphenated techniques, such as CE/inductively coupled plasma (ICP)-MS, hydride generation coupled to ICP-MS or atomic fluorescence spectrometry and CE/atomic absorption spectrometry are gaining popularity due to their high sensitivity and selectivity. Last, but not least, the potential and applications of electrochemical methods for detection of separated mercury species are outlined.

DNA binding in combination with capillary electrophoresis and inductively coupled plasma mass spectrometry for the rapid speciation analysis of mercury

“…2+ and CH 3 Hg + As we mentioned above, it is very difficult to directly separate Hg 2+ and CH 3 Hg + with CE since these mercury species in solution present as un-dissociated molecules, which makes their charge equals almost zero [19][20][21]. The way to solve this problem in previous studies is that complexing Hg 2+ and CH 3 Hg + with a thiol group-containing ionic agent, which makes the formed mercury complex possess different negative charges to create a difference in electrophoretic mobility [1,15,22,24].…”

“…For example, HPLC or GC or CE hyphenated with atomic fluorescence spectrometry (AFS) or inductively coupled plasma mass spectrometry (ICP-MS) [4][5][6][7][8][9][10][11][12][13][14][15][16]. Among all above hyphenated techniques, CE-ICP-MS has attracted increasing attention since CE has higher separation efficiency for all ionic and neutral species, tiny sample requirement, various separation modes and low operating cost [17][18][19], and ICP-MS has short detection time, broad dynamic range, multi-element capabilities, excellent mass resolution and high sensitivity for almost metallic ions. However, the CE separation of Hg 2+ and CH 3 Hg + is still a complicated problem since these mercury compounds in solution generally presented as un-dissociated molecules [20].…”

“…However, the CE separation of Hg 2+ and CH 3 Hg + is still a complicated problem since these mercury compounds in solution generally presented as un-dissociated molecules [20]. An effective way to solve this problem is to complex Hg 2+ and CH 3 Hg + with an ionic agent having thiol group or complexones [4,19,[21][22][23]. So far, nearly all of previous CE-ICP-MS methods for the speciation analysis of mercury used mercaptoacetic acid (MAA) or cysteine or dithizone as complexing agent [4,15,[22][23][24].…”

“…An effective way to solve this problem is to complex Hg 2+ and CH 3 Hg + with an ionic agent having thiol group or complexones [4,19,[21][22][23]. So far, nearly all of previous CE-ICP-MS methods for the speciation analysis of mercury used mercaptoacetic acid (MAA) or cysteine or dithizone as complexing agent [4,15,[22][23][24]. However, the CE-ICP-MS methods previously reported have a longer separation time and relatively low sensitivity when amplification strategy was not employed [4,15,[22][23][24].…”

“…So far, nearly all of previous CE-ICP-MS methods for the speciation analysis of mercury used mercaptoacetic acid (MAA) or cysteine or dithizone as complexing agent [4,15,[22][23][24]. However, the CE-ICP-MS methods previously reported have a longer separation time and relatively low sensitivity when amplification strategy was not employed [4,15,[22][23][24]. Lately, a rapid CE-ICP-MS method was developed for the speciation analysis of mercury by using a short CE capillary (only 16 cm) [25].…”