Isomeric triterpenic acids of oleanolic acid (OA) and ursolic acid (UA) both have very low ultraviolet absorption and always exist in the same plant, so the separation and simultaneous determination of them have been a difficult task. In this study, a sensitive method combining dispersive liquid-liquid microextraction (DLLME) with HPLC-UV was developed for the extraction and determination of OA...

A novel dispersive liquid-liquid microextraction (DLLME) method followed by HPLC analysis, termed sequential DLLME, was developed for the preconcentration and determination of aryloxyphenoxy-propionate herbicides (i.e. haloxyfop-R-methyl, cyhalofop-butyl, fenoxaprop-P-ethyl, and fluazifop-P-butyl) in aqueous samples. The method is based on the combination of ultrasound-assisted DLLME with in si...

A methodology based on dispersive micro solid-phase extraction (DMSPE) using multiwalled carbon nanotubes (MWCNTs) as solid sorbent prior to measurement with energy-dispersive X-ray fluorescence (EDXRF) spectrometry is proposed. The procedure consists of chelating of nickel, cobalt, copper, and lead ions with ammonium pyrrolidinedithiocarbamate (APDC) and posterior adsorption of metal chelates ...

This paper describes a dispersive liquid–liquid microextraction (DLLME) procedure using room temperature ionic liquids (RTILs) coupled with flame atomic absorption spectrometry detection with microsample introduction system capable of quantifying trace amounts of lead. In the proposed approach, ammonium pyrrolidine dithiocarbamate (APDC) was used as a chelating agent and 1-hexyl-3-methylimmidaz...

Haloacetic acids are toxic organic pollutants that can be formed as by-products of disinfection of water by chlorination. In this study, we developed a fast and efficient method for the determination of six species of these compounds in water using dispersive liquid-liquid microextraction followed by GC-MS analysis. To be suitable for GC analysis, the acidic analytes were derivatized using n-oc...

Ionic liquid-based dispersive liquid–liquid microextraction (IL– –DLLME) coupled with high performance liquid chromatography (HPLC) with UV detection was developed for the simultaneous extraction and determination of nickel, cobalt, copper and zinc ions. In the proposed approach, salophen (N,N'-bis(salicylidene)-1,2-phenylenediamine) was used as a chelating agent, the ionic liquid, 1-hexyl-3-me...

Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for in...

Dispersive liquid-liquid microextraction (DLLME) and spectrofluorimetry, coupled with chemometrics methods, are proposed in this work for the pre-concentration and determination of ofloxacin concentration in spiked human urine. Chloroform and acetonitrile were selected as the extraction and dispersive solvents by the one-variable-at-a-time process. The Box-Behnken design was used to optimize th...

A comprehensive review is presented on the recent developments and trends in the QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation approach. This technique involves liquidliquid partitioning using acetonitrile and purifying the extract using dispersive solid-phase extraction (d-SPE). Originally, the QuEChERS was introduced for pesticides residues analysis in high moi...

in this work, an environmentally friendly sample pre-treatment method, ultrasound assisted surfactant enhanced emulsification microextraction (uaseme) followed with spectrofluorimetry was performed for determination of oxadiazon residues in water samples. after the determination of the most suitable extraction solvent and its volume, other parameters such as type and concentration of surfactant...