| In recent decades, the development of traditional Chinese medicine (TCMs) has become a trend, due to their lower side effects, significant effect on many common diseases and the treatment of difficult cases and infectious diseases. With the wide application of TCMs, the extraction of the bioactive components is one of the key points. Traditional extraction methods are usually time-consuming and laborious. Application of modern extraction technique, such as matrix solid-phase dispersion (MSPD) which is convenient, makes the analytical progress more rapid. At the same time, the solvent and sample consumption was reduced.With the social development, public concern about food safety has grown considerably. Extraction procedures adopted in many standardized analytical methodologies for determining contaminants in food, are time-consuming and solvent consuming. In order to obtain satisfactory analyte recoveries, repeated extractions and centrifugation were required. In many cases, the combination of sample and solvent produces emulsions that may decrease the extraction efficiency and lengthen the analytical time. Because the generally employed organic solvents do not selectively extract the target compounds, and tedious and time-consuming cleanup procedures are needed to partially isolate analytes from the sample matrices. Matrix solid-phase dispersion can solve these problems well, and it is especially suitable to extract target analytes from a solid, semi-solid and liquid of food samples.The arctiin and arctigenin in fruit of Arctium lappa L. were extracted by matrix solid-phase dispersion and determined by high-performance liquid chromatography (HPLC). The experimental conditions for the MSPD were optimized. When silicon gel was used as dispersion adsorbent, the mass ratio of silicon gel to sample selected in the work is 3:1 and methanol was used as elution solvent, the extraction yields of analytes were highest. The extraction yields of arctiin and arctigenin in fruit of Arctium lappa L. obtained from four different cultivated areas are 18.5-74.6 mg g-1 and 2.8-8.9 mg g-1, respectively. The limits of quantification for arctiin and arctigenin are 0.01 and 0.025μg mL-1, respectively. The calibration curve showed good linear relationship (r>0.9998) in the concentration range of 0.01-5.0μg mL-1 for arctiin and 0.025-7.5μg mL-1 for arctigenin. The good accuracy (the recoveries of analytes are between 74.4%-100%) and precision (RSD of inner-day and inter-day are 1.9%-9.6%) were obtained. The proposed method consumed less sample, time and solvent compared with conventional methods including ultrasonic and Soxhlet extraction.A method based on matrix solid-phase dispersion has been developed for the extraction of indirubin in the leaves of Isatis indigotica Fort. The sample was blended with silicon gel, placed in small column and eluted with methanol. Analysis was performed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). Several dispersion adsorbents and elution solvents were tested during the optimization of the process in order to obtain the highest yields. The responce of the active component is linear in concentrations ranging from 0.0151 to 12.5μg mL-1, the correlation coefficient is 0.9999. the precision (the relative standard deviation) is lower than 3.2%, and mean recoveries range from 93.97% to 100.9%. The extraction yields of indirubin in the leaves of Isatis indigotica Fort. obtained from four different cultivated areas are 11.89-1129μg g-1.The proposed method was compared with the ultrasonic and Soxhlet extraction. The results proved that the content of indirubin obtained by MSPD is comparable to that obtained by Soxhlet extraction.Matrix solid-phase dispersion is used to extract three fluoroquinolone (FQ) residues, including fleroxacin (FLE). ciprofloxacin (CIP) and enrofloxacin (ENR) in chicken muscle sample. The experimental conditions for the MSPD were studied and optimized. Diatomaceous earth was selected as dispersion adsorbent, the mass ratio of diatomaceous earth to sample was selected as 1:1 and 8 mL of acetic acid-methanol (4:96,v/v) was selected as elution solvent. The solvent containing acetic acid-ammonium acetate (pH 3.0) and acetonitrile was used as mobile phase. The column temperature was 30℃. The fluorescence excitation and emission wavelengths were 280 and 450 nm respectively. Three fluoroquinolone residues can be separated and detected. Linearity is from 0.0026 to 2.5 for FLE, from 0.014 to 2.5μg g-1 for CIP and from 0.0022 to 2.5μg g-1for ENR. The calibration curve of each FQ showed good linearity with correlation coefficient (r) more than 0.9990. This method has good accuracy (the recoveries of analytes were from 83.8% to 109%), precision (RSDs were 0.33%-9.09%). The proposed method was effective and suitable for the determination of the fluoroquinolone residues in biological sample. |
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