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Transcatheter arterial chemoembolization (TACE) is an effective method for the treatment of unresectable hepatocellular carcinoma. Although many embolic agents have been developed in TACE, there are few ideal embolic agents that combine drug loading, imaging properties and vessel embolization. Here, we developed novel magnetic embolic microspheres that could simultaneously load sunitinib malate (SU), be detected by magnetic resonance imaging (MRI) and block blood vessels. Calcium alginate/poly (acrylic acid) hydrogel microspheres (CA/PAA-MDMs) with superparamagnetic iron oxide nanoparticles (SPIONs) modified by citric acid were prepared by a drip and photopolymerization method. The embolization and imaging properties of CA/PAA-MDMs were evaluated through a series of experiments such as morphology, X-ray diffraction and X-ray photoelectron spectroscopy, magnetic responsiveness analysis, elasticity, cytotoxicity, hemolysis test, in vitro MRI evaluation, rabbit ear embolization and histopathology. In addition, the ability of drug loading and drug release of CA/PAA-MDMs were investigated by using sunitinib (SU) as the model drug. In conclusion, CA/PAA-MDMs showed outstanding drug loading capability, excellent imaging property and embolization effect, which would be expected to be used as a potential biodegradable embolic agent in the clinical interventional therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

We have developed a sample preparation method involving derivatization combined with headspace single-drop microextraction (HS-SDME) for the determination of short-chain fatty acids (SCFAs) in complex matrices. The derivatization of SCFAs was conducted using the BF3/ethanol method prior to HS-SDME. The HS-SDME extraction conditions for the derivatization products (ethyl esters) of SCFAs were optimized using 1.0μL of dibutylphthalate (DBP), 1000rpm stirring speed, 30% (w/v) NaCl, 20min extraction time, and 7mL of sample solution in a 12mL vial. Quantitative determination of ethyl esters was performed using gas chromatography (GC). Linear calibration curves and excellent reproducibility were obtained using these optimized extraction conditions. Compared with our previous work, the significantly lower detection limits (0.11, 0.017, 0.0060, and 0.0024μg/mL for C2 to C5 SCFAs, respectively) indicate that this new method is suitable for quantitative analysis of SCFAs in complex matrices, such as the RuO4 oxidation products of kerogen or asphaltene., (Copyright © 2013 Elsevier B.V. All rights reserved.)

In this study, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography-flame ionization detection (GC-FID), was employed to determine short-chain fatty acids (SCFAs) in ruthenium tetroxide (RuO(4)) oxidation products of asphaltenes. Several significant parameters, such as drop solvent type, drop volume, sample solution ionic strength, agitation speed, extraction time, and ratio of headspace volume to sample volume were optimized. Under optimum extraction conditions (i.e., a 3-microL drop of 1-butanol, 20 min exposure to the headspace of a 6 mL aqueous sample placed in a 10 mL vial, stirring at 1000 rpm at room temperature, and 30% (w/v) NaCl content), the reproducibility and accuracy of the method have been tested and found to be satisfactory. The analysis of a real asphaltene sample using this method proved that HS-SDME can be a promising tool for the determination of volatile SCFAs in complex matrices., (Copyright 2010 Elsevier B.V. All rights reserved.)