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Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium

100%

Souza E., Cristante V., Padilha P., Jorge S., Martines M., Silva R., Carmo D., Castro G.

Polish Journal of Chemical Technology

2011

vol. 13

issue 4

28-33

A method was developed to attach 2,2-bipyridine (BP) onto a silica gel surface by a two-step reaction. The first step consisted of a reaction between the matrix and a silylating agent, 3-chloropropyltrimethoxysilane. In the second step of the reaction, a ligand molecule was attached onto Si-CPTS, yielding the product Si-BP. The modified material contained 0.431±0.01 mmol of 2,2-bipyridine per gram of modified silica, as confirmed by FT-IR spectra of the proposed structure. The surface modification was characterized by the BET technique, which revealed a decrease in the surface area from 614 to 450 m2 g-1. The series of adsorption isotherms for the metal ions were adjusted to fit a modified Langmuir equation. The maximum number of moles of copper, cadmium and lead ions adsorbed was 0.64, 0.53, and 0.54 mmol g-1, respectively. The surface saturation was calculated as φ fraction and the values obtained, Cu(II) = 1.160, Cd(II) = 1.044 and Pb(II) = 0.997, suggest a type 1:1 metal-ligand complex.

Selective determination of penicillin G from tap water and milk samples using surface molecularly imprinted polymers as solid-phase extraction sorbent

100%

Du W., Zhou H., Luo Z., Zheng P., Guo P., Chang R., Chang C., Fu Q.

Molecular Imprinting

2014

vol. 2

issue 1

In this study, a selective sample preparation method coupling surface molecularly imprinting polymers (SMIPs) with solid-phase extraction (SPE) was developed for the determination of penicillin G from tap water and milk samples. SMIPs for penicillin G were synthesized by using silica gel as supporting matrix, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the cross-linker, methanolacetonitrile (1:1,v/v) as the solvents and 2,2′-azo-bisisobutyronitrile (AIBN) as the initiator. Characterization and adsorption experiments revealed that SMIPs exhibited large adsorption capacity, high recognition ability and high rate of mass transfer. Application of SMIPs in SPE followed by HPLC was done to selectively determine penicillin G from tap water and milk samples. Under the optimal conditions, the proposed method demonstrated high linearity with the concentration of penicillin G ranging from 0.12 to 200 μg mL-1. The limits of detection (LOD) in tap water and milk were 0.05, 0.03μg mL-1, respectively. The limits of quantification (LOQ) in tap water and milk were 0.25, 0.12 μg mL-1, respectively. The recoveries of penicillin G at three spiked levels were ranged from 78.9 to 85.5 % with intra-day and inter-day relative standard deviation values below 4.8 %.

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1 Molecular Imprinting

1 Polish Journal of Chemical Technology

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1 Carmo D.

1 Castro G.

1 Chang C.

1 Chang R.

1 Cristante V.

1 Du W.

1 Fu Q.

1 Guo P.

1 Jorge S.

1 Luo Z.

1 Martines M.

1 Padilha P.

1 Silva R.

1 Souza E.

1 Zheng P.

1 Zhou H.

Search results

Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium

Selective determination of penicillin G from tap water and milk samples using surface molecularly imprinted polymers as solid-phase extraction sorbent