Application of unusual on/off electrochemical properties of a molecularly imprinted polymer based on an EDOT–thiophene precursor for the detection of ephedrine

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

Multi-phase extraction of ephedrine from Pinellia ternata and herbal medicine using molecular imprinted polymer coated ionic liquid-based silica

INTRODUCTION

Ephedrine is a typical compound found in lots of plant species that is used in several medicines for the treatment of asthma and bronchitis. However, excess amounts are harmful to humans, so it needs to be removed.

OBJECTIVE

This study developed a multi-phase extraction (MPE) method with a molecular imprinted polymer (MIP) coated ionic liquid (IL)-based silica (SiO₂ @IL@MIP) to simultaneously extract and separate ephedrine from Pinellia ternata, 10 medicines, and urine samples.

METHODS

IL was immobilized on silica. Subsequently, the IL was combined with the functional monomer, followed by the addition of the crosslinker and template. The resulting sorbent was applied to the MPE, and the extraction, washing and elution solvents were evaluated.

RESULTS

Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the synthesis of SiO₂ @IL@MIP. A maximum adsorption amount of 5.76 mg/g was obtained at 30°C at a neutral pH. In MPE, 10.00 mL of methanol could extract all the ephedrine from Pinellia ternata. The interference was removed by washing with 4.00 mL of water, ethanol, and acetonitrile. Finally, 8.00 mL of methanol/acetic acid (99:1, v/v) was applied as the elution solvent. The following were extracted: 5.50 μg/g of ephedrine from Pinellia ternata, 0.00-46.50 μg/g from the 10 herbal medicines, and 68.70-102.80 μg/mL in the urine samples.

CONCLUSION

The proposed method was applied successfully to the simultaneously extraction and separation of ephedrine from plants and medicines. These results are expected to provide important data for the development of new methods for the separation and purification of bioactive compounds.

Multiphase extraction of ephedrine from Pinellia ternata using bionic liquid-modified polymer

Multiphase extraction (MPE) was applied as a developed, convenient and efficient method in separation of ephedrine from Pinellia ternata. Firstly, in order to increase the adsorption efficiency, bionic liquid-modified polymer was created. Comparing the effects of all sorbents under variables conditions, the highest amount of 5.8 mg/g can be adsorbed on dual imidazole ionic liquid modified polymer (Im-Im-Poly) in methanol/water (70:30, v/v) solution at 25°C within 30.0 min. Then the Im-Im-Poly was applied in MPE, after 7 times repetition of extraction, around 1.0 mg/g of ephedrine from Pinellia ternata was detected. After washing by water, ethanol and methanol, and elution by methanol/acetic acid (99.0:1.0, v/v), ephedrine was successfully separated.