Contactless Conductivity Detection of 14 Inorganic Cations in Mineral and Phytotherapeutic Formulations after Capillary Electrophoretic Separation

Abstract

18-crown-6 ether, and 1 mmol L À1 citric acid (pH 6.0) as complexing additives for co-migrating cations. The methodology was evaluated and validated for the cations and it was found to be reliable for determining inorganic cations in samples of mineral fertilizers and medicinal plants used in the phytotherapy.

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

“…These agents are rather unstable and form alkylated and arylated phosphonic acids during their hydrolytic degradation, which can easily be determined using CE‐C 4 D . Silicate was determined in mineral water samples , inorganic and heavy metal cations in fertilizers and the determination of inorganic and organic anions and inorganic cations in biodiesel car fuel was demonstrated . Alkylcarbonates were determined in aqueous media and formation of monoalkyl carbonate from CO 2 and ethanol in deionized water was monitored .…”

A new CE with contactless conductivity detection method for the determination of complex cationic compositions: Application to the analysis of pen inks

“…According to de Carvalho et al. , Ni 2+ migrated very close to the EOF and in certain analyses they co‐migrated together, probably due to small changes in the EOF intensity, leading to the partial or complete peak loss. Cu 2+ and Co 2+ also co‐migrated under these conditions as well as Fe 2+ and Pb 2+ .…”

“…The particular case of the separation and determination of metal cations by CE‐C 4 D has attracted the interest of several researchers in the last decade. Many different kinds of samples have been studied, including waters , table salts , fertilisers , plant exudates , virgin olive oils , post‐blast explosive residues or fireworks among others. Alkali and alkali earth ions (always excluding Fr + , Be 2+ and Ra 2+ , and less frequently excluding Rb + and Cs + ) are the most commonly studied metal cations by CE‐C 4 D because some of them, such as Na + , Ca 2+ , Mg 2+ and K + , are widely present in a number of diverse samples.…”

“…Alkali and alkali earth ions (always excluding Fr + , Be 2+ and Ra 2+ , and less frequently excluding Rb + and Cs + ) are the most commonly studied metal cations by CE‐C 4 D because some of them, such as Na + , Ca 2+ , Mg 2+ and K + , are widely present in a number of diverse samples. Very often, background electrolytes BGEs based on 2‐( N ‐morpholino)ethanesulfonic acid/histidine (MES/His) (usually at equimolar concentrations) have been employed for the separation of these metal cations by CE‐C 4 D , because of the high ionic strength, low conductivity, and suitable migration velocities of the co‐ions and counter‐ions . However, these BGEs are suitable only for the analysis of samples in which Na + , Ca 2+ and Mg 2+ are in molar ratios close to 1, since they tend to co‐migrate when they are present at different ratios .…”

“…However, these BGEs are suitable only for the analysis of samples in which Na + , Ca 2+ and Mg 2+ are in molar ratios close to 1, since they tend to co‐migrate when they are present at different ratios . Another drawback is that Ni 2+ migrates very close to the EOF signal in this BGE . According to our experiences in the laboratory, this behaviour may produce the partial or absolute loss of this peak after small changes in the EOF intensity that naturally occur inside the capillary.…”