Currently, the main sample pretreatment methods for forensic toxic analysis are liquid-liquid extraction （LLE） and solid-phase extraction （SPE）. As a simple, convenient, and low-cost LLE method, dispersion liquid-liquid microextraction （DLLME） has high enrichment factor and good extraction efficiency, and therefore has attracted the attention of many researchers in the field of toxicology analysis in recent years. As a multi-functional microextraction method, DLLME has been widely used in the analysis of pesticides, sleeping sedatives, drugs and heavy metal poisons in forensic toxic analysis. Meanwhile, it can also be used in combination with such a variety of analytical instruments as gas chromatography-electron capture detectors （GC-ECD）, high performance liquid chromatography-diode array detectors （HPLC-DAD）. As a sample pretreatment method, DLLME has the advantages of simple operation, less use of organic solvent, reliable results and good reproducibility, thus can meet the requirements of modern court toxic analysis.
Forensic Toxicology ; Liquid Phase Microextraction ; Reproducibility of Results ; Solid Phase Extraction ; Solvents

Objective: A method for the determination of acetochlor and its metabolites in urine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established. Methods: After cleaned-up by a HLB extraction cartridges, the urine was eluted with 1% acetic acid acetonitrile solution. The target compounds were separated by ACQUITY UPLC®HSS T3 Column (2.1 mm×100 mm×1.8 μm) by using 1% formic acid solution and acetonitrile as mobile phase with gradient elution program, and analyzed in positive electrospray ionization mode by liquid chromatography tandem mass spectrometry. Results: All the target compounds showed good linear relationships in the range of 1-50 μg/L, and the correlation coefficients (r) were higher than 0.997. The recoveries rates at three different spiked levels for all target compounds in blank matrices were 107.6%-129.1%, and the relative standard deviations (RSD) were 1.5%-9.9% (n=6) . The limits of detection and quantitation of the method were 0.04-0.11 μg/L and 0.15-0.42 μg/L, respectively, and target substances were detected in all urine samples from occupational exposure workers to acetochlor. Conclusion: This method is suitable for rapid screening and analysis of acetochlor and metabolites in urine with the advantages of accuracy, rapidity, simplicity, high sensitivity and good specificity.
Acetonitriles ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Humans ; Solid Phase Extraction ; Tandem Mass Spectrometry ; Toluidines

Suitable pretreatment of biological samples can truly reflect the role of law of the measured components played in the body and will provide experimental evidence for the studies on metabolic process, material basis of efficacy, mechanism of action, pharmacology, toxicology and the others. Biological samples include blood, urine, hair, tears, etc. There are also many samples processing methods, such as the direct protein precipitation, liquid-liquid extraction and solid phase extraction and so on. These methods could be used alone or combined.
Animals ; Body Fluids ; chemistry ; Chemical Precipitation ; Chemistry Techniques, Analytical ; methods ; Humans ; Liquid-Liquid Extraction ; Proteins ; isolation & purification ; Solid Phase Extraction

To obtain ginsenoside Rg1 molecularly imprinted polymer (MIP) separating materials with high selectivity, enrichment and adsorption performance through directional separation of ginsenoside Rg1 and analogues. In this study, MIPs were respectively prepared by precipitation polymerization and surface imprinted polymerization. Their adsorption performances were compared. The results showed that ginsenoside Rg1 MIPs prepared by the above two methods had a high adsorption performance to template molecules, with the maximum apparent adsorbing capacity of up to 27.74, 46. 80 mg x g(-1), respectively. Moreover, MIPs prepared by surface imprinted polymerization showed higher adsorption capacity than that by precipitation polymerization. The experimental results indicated that as for ginsenoside Rg1 with higher polarity, MIPs prepared by surface imprinted polymerization showed higher selectivity and adsorption performance, which provides provide important reference for preparing imprinted polymers with good adsorption performance with active molecules with strong polarity.
Adsorption ; Chemical Fractionation ; methods ; Chemical Precipitation ; Ginsenosides ; chemistry ; isolation & purification ; Molecular Imprinting ; Polymerization ; Polymers ; chemical synthesis

The dummy template molecularly imprinted polymers not only has such characteristics of normal imprinted polymers as rapid identification, easy preparation, stable structure and multiple reuse, but also can imprint the compounds in natural products that are not suitable as direct template. Therefore, it has drawn more and more attention in the field of the study of natural products. This paper summarizes the methods for the selection of dummy template molecules by investigating the relevant literatures in the past ten years, analyzes the advantages and disadvantages of dummy template molecules in the practical application, and based on the types of natural products active ingredients, this paper is the first to review of the latest progress in extraction and separation of dummy template molecularly imprinted polymers. We believed that this paper could provide references for better applications of the dummy template molecularly imprinted polymers to extract and separate natural products.
Biological Products/chemistry* ; Chemical Fractionation ; Molecular Imprinting ; Polymers

OBJECTIVETo develop a rapid hilic ultra performance liquid chromatography (UPLC)-mass spectrum (MS)/MS method for determination of tetrodotoxin in seafood.

METHODSThe sample of muscle and liver of puffer fish and nassarius were extracted with aqueous solution containing 0.2% (V/V) acetic acid (the extract of liver must be purified through HLB cartridge), and then cleanup of extract was accomplished by solid-phase extraction with a graphitized carbon black cartridge. The analysis of tetrodotoxin was carried out on a chromatographic column (Acquity UPLC BEH Amide, 100 mm×2.1 mm×1.7 µm) with gradient elution of 95% (V/V) acetonitrile-H2O both containing 0.1% (V/V) formic acid and 2.0 mmol/L ammonium formate, and detected by positive electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (MRM) mode, and quantified by matrix-match standard solution.

RESULTSThe calibration curves were linear in the range of 30 - 10 000, 50 - 10 000 and 30 - 10 000 µg/kg of tetradotoxin in muscle and liver of puffer fish and in muscle of nassarius, respectively. The correlation coefficients were within 0.9963 - 0.9990. The limits of detection were 10, 20 and 10 µg/kg, and that of quantitation were 30, 50 and 30 µg/kg for muscle and liver of puffer fish and muscle of nassarius, respectively. The average recoveries were 81.5% - 93.1%, 82.3% - 106.0% and 83.5% - 95.2% for tetrodotoxin spiked in muscle and liver of puffer fish and in muscle of nassarius, respectively, with relative standard deviation (RSD) of 2.3% - 11%, 4.3% - 14.0% and 3.5% - 13.0% (n = 6).

CONCLUSIONThe method was simple, accurate and sensitive, and could be successfully applied to the measurement of tetrodotoxin in puffer fish and nassarius.

A method of ultra-high performance liquid chromatography coupled with quadrupole/electrostatic field Obitrap high-resolution mass spectrometry(UHPLC-Q-Exactive MS) was established to comprehensively identify the metabolites of carnosic acid in rats. After oral gavage of carnosic acid CMC-Na suspension in rats, urine, plasma and feces samples were collected and pretreated by solid phase extraction(SPE). Acquity UPLC BEH C_(18 )column(2.1 mm×100 mm, 1.7 μm) was used with 0.1% formic acid solution(A)-acetonitrile(B) as the mobile phase for the gradient elution. Biological samples were analyzed by quadrupole/electrostatic field Obitrap high-resolution mass spectrometry in positive and negative ion mode. Based on the accurate molecular mass, fragment ion information, and related literature reports, a total of 28 compounds(including carnosic acid) were finally identified in rat samples. As a result, the main metabolic pathways of carnosic acid in rats are oxidation, hydroxylation, methylation, glucuronide conjugation, sulfate conjugation, S-cysteine conjugation, glutathione conjugation, demethylation, decarbonylation and their composite reactions. The study showed that the metabolism of carnosic acid in rats could be efficiently and comprehensively clarified by using UHPLC-Q-Exactive MS, providing a reference for clarifying the material basis and metabolic mechanism of carnosic acid.
Abietanes ; Animals ; Chromatography, High Pressure Liquid ; Mass Spectrometry ; Rats ; Solid Phase Extraction

This study aims to identify and analyze the metabolites of imperatorin in rats by UHPLC-Q-Exactive Orbitrap MS. Specifically, after rats were treated(ig) with imperatorin, the plasma, urine, and feces were collected, and the samples were processed by solid phase extraction. Then, UHPLC-Q-Exactive Orbitrap MS was performed. In MS, 0.1% formic acid water(A)-acetonitrile(B) was applied as mobile phase for gradient elution and the data of MS in both positive and negative ion modes were collected. The metabolites of imperatorin in blood, urine, and feces of rats were analyzed to explore the metabolic pathways of imperatorin in rats. According to accurate molecular weight, multistage MS data, MS fragmentation rule of the standard substance, and previous reports, a total of 51 metabolites were identified, with 35, 40, and 16 from plasma, urine, and feces, separately. The main metabolic pathways were oxidization, glucuronidation, isopentenyl removal, sulphation, carboxylation, among others. The conclusion in this study is expected to serve as a reference for the further development and the further pharmacodynamics study of imperatorin.
Animals ; Chromatography, High Pressure Liquid ; Feces ; Furocoumarins ; Plasma ; Rats ; Solid Phase Extraction

Objective: A method to determine chlorobenzene metabolite-p-chlorophenol in urine by solid phase extraction-gas chromatography was established. Methods: In May 2021, the urine sample was hydrolyzed at 100 ℃ for 1.5 h with 2 ml concentrated hydrochloric acid. After cooling and filtering, the sample was enriched and purified by Oasis(®)MAX 6cc SPE column. Drip washing with 0.01 mol/L hydrochloric acid solution and elution with acetonitrile, the eluent was volumized to 5 ml with acetonitrile and determined by gas chromatography, and quantify by standard curve method. Results: Calibration curve of the method was linear within the range of 1.61-80.30 μg/ml and showed good linearity with r=0.9997, the regression equation was y=1.51602x-0.10234. The determination limit was 0.17 μg/ml, and the limit of quantitation was 0.55 μg/ml. Recovery rates were between 89.3%-104.4%, the relative standard deviation (RSD) of intra-day measurements ranged from 4.3% to 6.7%, and the RSD of inter-day measurements ranged from 4.5% to 6.7%. Conclusion: This method could optimize sample pretreatment, and eliminate the interference of impurities, which is sensitive, efficient and accurate for the determination of chlorobenzene metabolite-p-chlorophenol in urine.
Acetonitriles ; Chlorophenols ; Chromatography, Gas ; Chromatography, High Pressure Liquid ; Hydrochloric Acid ; Solid Phase Extraction/methods*

Objective: To establish a method for rapid determination of bongkrekic acid (BA) in plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods: In November 2020, plasma samples were extracted by methanol and acetonitrile (1∶1) and purified directly. The samples were separated by C18 column. Gradient elution was carried out with 5 mmol/L ammonium acetate water acetonitrile solution as mobile phase. Under the optimized instrument conditions, the electrospray ionization multiple reaction monitoring (MRM) mode was used, and the external standard method was used for quantitative analysis. Results: The linear relationship of BA in plasma was good in the concentration range of 2-100 μg/L, the correlation coefficient was 0.9998, the average recovery was 83.7%-112.0%, the relative standard deviation within and between batches was less than 10%, the detection limit of the method was 0.7 μg/L and the lower limit of quantification was 2.0 μg/L. Conclusion: The method is simple, rapid, accurate and sensitive, and can meet the requirements for the determination of BA in blood samples of poisoning patients.
Bongkrekic Acid ; Chromatography, High Pressure Liquid ; Humans ; Solid Phase Extraction ; Tandem Mass Spectrometry