The HPLC-SPE-NMR technique was used for the analysis of a root-bark extract of Croton membranaceus. The components of the extract were separated on an analytical-size reversed-phase HPLC column, the chromatographic peaks were trapped on SPE (solid-phase extraction) cartridges after post-column dilution of the eluate with water and the compounds were eluted from the cartridges with acetonitrile-...

Seven liquid solvent systems--dichloromethane, dichloromethane-pentane (1:1), freon 113, diethyl ether-pentane (1:1 and 1:9), ethyl acetate-pentane (with and without an additional salting-out effect) (1:3 and 1:20), and seven solid-phase extraction (SPE) systems (Amberlite XAD-2, 4, 7, and 16; Porapak Q; C8; and C18)--are comparatively studied. The distribution coefficients between the extracti...

Two modifications of the HPLC-ED method with respect to extraction procedure used have been developed for psilocin, the active metabolite of psilocybin, in human plasma using either liquid-liquid extraction (LLE) or automated on-line solid-phase extraction (on-line SPE). Each type of the sample preparation required a different HPLC system followed by electrochemical detection at 650 to 675 mV. ...

A syringe-cartridge solid-phase extraction (SPE) method was developed for determination of patulin in apple juice. A 2.5 mL portion of test sample was passed through a conditioned macroporous SPE cartridge and washed with 2 mL 1% sodium bicarbonate followed by 2 mL 1% acetic acid. Patulin was eluted with 1 mL 10% ethyl acetate in ethyl ether and determined by reversed-phase liquid chromatograph...

Lead is an important constituent widely used in different industrial processes. For evaluation of workers' exposure to trace toxic metal of Pb (II), solid-phase extraction (SPE) was optimized. SPE using mini columns filled with XAD-4 resin was developed with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume, elution volume, the amount of resins, and sa...

In this paper, single wall carbon nanotube (SWCNT) suspensions were added dropwise to silica particles before volatising the solvent to prepare a core-shell composite adsorbent with SWCNTs wrapped around silica particles (SWCNTs@Silica). The composite adsorbent was used as packing for the solid phase extraction (SPE) and the enrichment of organophosphorus pesticides (OPPs) in water. The results...

The stereocontrolled synthesis of (E)-configured styrenes via Pd(0)-catalyzed cross-couping of (E)-alkenylgermanes with aryl bromides is described. The germanes employed have bis(naphthalen-2-ylmethyl) substitution to allow photooxidative activation toward coupling and a C8F17-fluorous tag to facilitate purification by fluorous solid-phase extraction (F-SPE). The selectivities obtained suggest ...

Pada penelitian ini telah dilakukan pembuatan karbon aktif kayu bakau sebagai Solid Phase Extraction (SPE) melalui aktivasi fisika dan kimia. Proses pada suhu 500⁰C selama 1 jam dengan furnace kimia menggunakan H 3 PO 4 10% 24 jam. Karbon yang diperoleh memenuhi standar mutu SNI 06-3730-1995 tentang aktif. Adsorben terbentuk dikarakterisasi SEM-EDX FTIR. Hasil pemekatan konsentrasi fenol SPE di...

A simple method for the routine determination of quercetin in biological samples was developed. The method consists of hydrolysis of bonded quercetin, its isolation and preconcentration on solid-phase extraction (SPE) column and a final analytical step using micellar electrokinetic capillary chromatography. The working range, linear range, the limit of quantification, and the measurement uncert...

Purification of peptides is often the most difficult part of the process used to obtain the compounds [1]. Several methods are used for isolation and subsequent purification of the post-synthesis mixture. Depending on the properties of the peptide and the types of impurity, commonly used techniques are ion-exchange chromatography and gel filtration [2,3]. The standard method for isolation is hi...