0000000000064103
AUTHOR
Paweł Dżygiel
Combination of supported liquid membrane and solid-phase extraction for sample pretreatment of triazine herbicides in juice prior to capillary electrophoresis determination
A possibility of a combination of supported liquid membrane (SLM) and solid-phase extraction (SPE) for the determination of atrazine at microgram level in different type of fruit juices is presented. In comparison to SPE extraction from juice samples, the application of SLM-SPE enrichment provides much cleaner extracts and the possibility of lowering the limit of detection as low as 30 microg/l. However, it was also shown that by appropriate manipulation of SLM extraction conditions mainly flow-rate of donor phase and volume ratio between donor and acceptor phase, the level of detection can be further decreased to 10 microg/l. The results suggest that the application of SLM extraction prior…
Supported liquid membrane extraction of glyphosate metabolites
Use of the supported liquid membrane (SLM) technique for (aminomethyl)phosphonic acid (AMPA) extraction is presented. For the extraction of this analyte a suitable SLM system involves a liquid membrane containing Aliquat 336 – a cationic carrier that facilitates AMPA transport. The extraction of this compound, as in the case of glyphosate, is dependent on the donor phase pH and the concentration and type of counter-ion in the acceptor phase, although some differences are also observed. In both cases the transport mechanism is counter-coupled transport in which the driving force of mass transport over the membrane is created by the gradient of chloride anions from the acceptor to donor phase.
Extraction of glyphosate by a supported liquid membrane technique.
The possible application of the supported liquid membrane (SLM) technique for the extraction of glyphosate is presented. For the extraction of this compound the SLM system has been applied with utilisation of Aliquat 336 as a cationic carrier incorporated into the membrane phase. The extraction efficiency of glyphosate [N-(phosphonomethyl)glycine] is dependent on the donor phase pH, carrier concentration in the organic phase and NaCl concentration in the acceptor phase. The optimal extraction conditions are: donor phase pH>11, acceptor phase of 2 M NaCl solution and the organic phase composed of 20% (w/w) Aliquot 336 solution in di-hexyl ether. Counter-coupled transport of chloride anions f…
Supported liquid membrane extraction of aromatic aminophosphonates
Abstract A fast and efficient supported liquid membrane (SLM) extraction system for the series of substituted aromatic aminophosphonates was elaborated. The mass transfer of solute was examined in terms of operator (pH and ionic strength of water phase, composition of membrane phase and the concentration of analyte) dependent parameters. Additionally, the influence of the aminophosphonates structure on the extraction efficiency was examined. From the results it can be concluded that the most effective conditions of membrane process are 10% (w/w) carrier concentration (Aliquat 336) in the liquid membrane, high pH of donor phase (pH=11) and moderate salt concentration (0.4 M NaCl) in the acce…
Enrichment of amino acids by supported liquid membrane extraction using Aliquat 336 as a carrier
Abstract The possible application of Aliquat 336 (trioctylmethyl ammonium chloride) as a carrier for liquid membrane extraction of amino acids was investigated. The extraction is performed from an aqueous donor phase with pH > 11 to an acceptor phase containing a salt solution through a supported liquid membrane with Aliquat 336 as a carrier in the membrane to facilitate amino acid transport. Counter-coupled transport of chloride anions from the acceptor phase to the donor phase is the driving force of the mass transfer in this system. The extraction efficiency depends on the donor phase pH, the carrier concentration in the liquid membrane, the composition of the acceptor phase and the hydr…
Enantiodifferentiation of N-benzyloxycarbonylaminophosphonic and phosphinic acids and their esters using cyclodextrins by means of capillary electrophoresis
Capillary electrophoresis was successfully applied for separation of the enantiomers of N-benzyloxycarbonyl-alpha-aminophosphonic and alpha-aminophosphinic acids as well as their ethyl and phenyl monoesters with the use of a range of commercially available cyclodextrins (alpha, beta and hydroxypropyl-gamma-cyclodextrins) as chiral selectors. The dependence of effectiveness of separation on type and concentration of these chiral selectors as well as on pH of background electrolyte was examined in some detail.
Supported liquid membrane separation of amine and amino acid derivatives with chiral esters of phosphoric acids as carriers
Studies on the possible use of phosphate and phosphonate esters bearing chiral menthol or nopol moieties as carriers for the transport of amines, amino acids, and amino acid esters through supported liquid membranes (SLM) are presented. Additionally, the enantioselectivity of the SLM transport of alkyl esters of aromatic amino acids and a non‐protein amino acid was also evaluated. It could be concluded that the extent of transport strongly depends on the hydrophobicity of the amino compound. Moreover, the carrier structure also influences the transport of those compounds through SLM: chiral phosphate and phosphonate esters appear to be poor or moderate carriers for enantioselective SLM tran…
Determination of optical purity of phosphonic acid analogues of aromatic amino acids by capillary electrophoresis with alpha-cyclodextrin.
A simple and efficient method for the determination of enantiomeric purity of structurally diverse phosphonic and phosphinic acid analogues of phenylalanine and phenylglycine using capillary electrophoresis is presented. These preliminary studies indicated that the enantiomer separation is strongly dependent on the structure of the aminophosphonic acid.
Supported Liquid Membranes and Their Modifications
Publisher Summary This chapter discusses the principle, kinetic and transport mechanisms, stability of supported liquid membrane (SLM) design followed by thier configuration. In the examples of SLM applications presented in this chapter, the possibility to separate high quantities of compounds using small volumes of organic phases shows that this method is still a very attractive choice when an efficient and selective method is necessary. Also, as a result of the development and commercialization of hydrophobic hollow-fiber membrane contactors, SLM might be applied successfully for industrial purposes. This is due to the high-membrane surface per unit of volume with satisfactory liquid memb…
Separation of aromatic aminophosphonic acid enantiomers by capillary electrophoresis with the application of cyclodextrins
The detailed studies concerning capillary electrophoresis separation of aminophosphonic acid enantiomers with various commercially available cyclodextrins are presented. The obtained results show that the separation of these stereoisomers is dependent on pH of background electrolyte, concentration of cyclodextrin as well as on the type of applied chiral selector. The separation mechanism is based on the co-operative effect of hydrogen bond type interactions enhanced by hydrophobic forces and sterical constrains between aminophosphonate and cyclodextrin. With application of elaborated method, enantiomeric baseline or partial separation of 18 alpha-aminophosphonic acids was achieved. This sep…
Enantiomeric separation of amino acids by capillary electrophoresis with α-cyclodextrin
A simple method for separation of underivatized aromatic amino acid enantiomers is presented. The influence of α-cyclodextrin concentration, applied voltage and background buffer pH on the separation were investigated to achieve the best conditions of separation.