Alkaloids, widespread in plants, have a series of pharmacological activities and have been widely used to treat various diseases. Because alkaloids are usually presented in multicomponent mixtures and are deeply low in content, they are very difficult to extract and separate by traditional methods. High-speed counter current chromatography(HSCCC) is a kind of liquid-liquid chromatography without solid support phase, which has the advantages of large injection volume, low cost, and no irreversible adsorption. Compared with the traditional methods of extraction and separation of alkaloids, HSCCC can ensure the separation of many different alkaloids at one time, with a high recovery and large amount. In this paper, the advantages and disadvantages of HSCCC compared with traditional separation methods were discussed and the solvent system and elution mode of HSCCC used to separate alkaloids in recent years were summarized by referring to the relevant literature to provide some references for the separation of alkaloids by HSCCC.
Biological Products ; Countercurrent Distribution/methods* ; Chromatography, High Pressure Liquid/methods* ; Alkaloids/analysis* ; Solvents/chemistry*

OBJECTIVES: To establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: The blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18, 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol (V_acetonitrile∶V_methanol=2∶3) were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring. RESULTS: The linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients (r) greater than 0.995 6. The limits of detection were 3.00, 0.40 and 1.30 ng/mL, respectively. The limit of quantitation were 8.00, 1.00 and 5.00 ng/mL, respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL, respectively. CONCLUSIONS This method has high sensitivity and good selectivity, which is suitable for the detection of carbamazepine and its metabolites in blood samples, and can be used for carbamazepine-related forensic identifications.
Chromatography, Liquid/methods* ; Tandem Mass Spectrometry ; Methanol ; Carbamazepine/analysis* ; Benzodiazepines/analysis* ; Solvents ; Chromatography, High Pressure Liquid ; Solid Phase Extraction

Hexane is a widely used organic solvent in industry, and chronic hexane poisoning is the main occupational toxic lesion in China. In particular, axonal and myelin lesions in the distal thick fibers of the peripheral nervous system may be caused by 2, 5-hexanedione (2, 5-HD), an intermediate metabolite of n-hexane in humans. Hexane has toxic effects not only on the nervous system but also on the liver, kidneys, and reproductive organs. In this paper, we review the progress of research on the mechanism of n-hexane toxic neuropathy.
Humans ; Hexanes/toxicity* ; Hexanones ; Industry ; Solvents

With the continuous exploration of microemulsions as solvents for traditional Chinese medicine extraction, polyoxyethy-lene(35) castor oil(CrEL), a commonly used surfactant, is being utilized by researchers. However, the problem of detecting residues of this surfactant in microemulsion extracts has greatly hampered the further development of microemulsion solvents. Based on the chemical structures of the components in CrEL and the content determination method of castor oil in the 2020 edition of the Chinese Pharmacopoeia(Vol. Ⅳ), this study employed gas chromatography(GC) and single-factor experiments to optimize the preparation method of methyl ricinoleate from CrEL. The conversion coefficient between the two was validated, and the optimal sample preparation method was used to process microemulsion extracts of Zexie Decoction from three batches. The content of methyl ricinoleate generated was determined, and the content of CrEL in the microemulsion extracts of Zexie Decoction was calculated using the above conversion coefficient. The results showed that the optimal preparation method for CrEL was determined. Specifically, 10 mL of 1 mol·L~(-1) KOH-methanol solution was heated at 60 ℃ for 15 min in a water bath. Subsequently, 10 mL of boron trifluoride etherate-methanol(1∶3) solution was heated at 60 ℃ for 15 min in a water bath, followed by extraction with n-hexane twice. CrEL could stably produce 20.84% methyl ricinoleate. According to this conversion coefficient, the average mass concentration of CrEL in the three batches of Zexie Decoction microemulsion extracts was 11.94 mg·mL~(-1), which was not significantly different from the CrEL mass concentration of 11.57 mg·mL~(-1) during microemulsion formulation, indicating that the established content determination method of this study was highly accurate, sensitive, and repeatable. It can be used for subsequent research on microemulsion extracts of Zexie Decoction and provide a reference for quality control of other drug formulations containing CrEL.
Polyethylene Glycols/chemistry* ; Castor Oil ; Methanol ; Surface-Active Agents/chemistry* ; Solvents ; Water/chemistry* ; Emulsions/chemistry*

Objective: To explore the mechanism of reactive oxygen species/thioredoxin-interacting protein/nucleotide-binding oligomerization domain-like receptor 3 (ROS/TXNIP/NLRP3) pathway in the skin injury of trichloroethylene (TCE) sensitized mice. Methods: In August 2020, 40 female BALB/c mice were randomly divided into control group (n=5) , solvent control group (n=5) , TCE treatment group (n=15) and TCE+(2-(2, 2, 6, 6-Tetrameyhylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride (Mito TEMPO) treatment group (n=15) . The TCE sensitization model was established. Mice in the TCE treatment group and TCE+Mito TEMPO treatment group were divided into the sensitized positive group and the sensitized negative group according to the skin erythema and edema reactions on the back of the mice 24 h after the last stimulation. The mice were sacrificed 72 h after the last stimulation, the back skin of the mice was taken, and the skin lesions were observed. Immunohistochemistry (IHC) was used to detect the expression level of NLRP3, and the Western Blot was performed to detect the expression levels of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC) , cysteinyl aspartate specific proteinase 1 (Caspase 1) , Interleukin-1β (IL-1β) and TXNIP proteins in the skin of the mice, the reactive oxygen species (ROS) kit was used to detect the level of intracellular ROS in the back skin tissue. Results: The sensitization rates of TCE treatment group and TCE+Mito TEMPO treatment group were 40.0% (6/15) and 33.3% (5/15) , respectively, and there was no significant difference between the two groups (P>0.05) . The back skin of the mice in the TCE sensitized positive group was thickened and infiltrated by a large number of inflammatory cells. The number of mitochondria in the epidermis cells was significantly reduced, the mitochondrial crest disappeared and vacuolar degeneration occurred. TCE+Mito TEMPO sensitized positive group had less damage, more mitochondria and relatively normal cell structure. Compared with the solvent control group and corresponding sensitized negative groups, the expression levels of NLRP3, ASC, Caspase 1, IL-1β, TXNIP proteins and the content of ROS in the TCE sensitized positive group and TCE+Mito TEMPO sensitized positive group were significantly increased (P<0.05) . Compared with TCE sensitized positive group, the expression levels of NLRP3, ASC, Caspase 1, IL-1β, TXNIP proteins and the content of ROS in the TCE+Mito TEMPO sensitized positive group were significantly decreased (P<0.05) . Conclusion: ROS/TXNIP/NLRP3 pathway was activated and then encouraged the release of IL-1β, finally aggravated the TCE-induced skin injury.
Animals ; Carrier Proteins ; Caspase 1/metabolism* ; Female ; Inflammasomes/metabolism* ; Mice ; Mice, Inbred BALB C ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Reactive Oxygen Species/metabolism* ; Solvents ; Thioredoxins/metabolism* ; Trichloroethylene/toxicity*

Objective: To detect the expression levels of M1-type polarization and autophagy-related indicators in the liver of trichloroethylene (TCE) -sensitized mice, and to explore the role of liver tumor necrosis factor-α (TNF-α) and tumor necrosis factor receptor 1 (TNFR1) in regulating M1-type Kupffer cells autophagy in liver injury in TCE-sensitized mice. Methods: In November 2019, according to simple random grouping, 45 SPF grade BALB/c female mice (6-8 weeks old) were divided into 4 groups: blank control group (n=5) , solvent control group (n=5) , TCE treatment group (n=18) , TCE+R7050 (inhibitor) treatment group (n=17) . Transdermally sensitized mice, 24 h after the last challenge, the mice were divided into TCE sensitized group and TCE non-sensitized group according to the skin reaction score. The livers of mice were harvested, and the pathological changes of the livers were observed under light and electron microscopes. Western blotting was used to detect the expressions of TNF-α, TNFR1 and autophagy-related indexes. The expression of inducible nitric oxide synthase (iNOS) , a marker of M1-type Kupffer cells, was detected by immunohistochemistry, and the occurrence of autophagy in M1-type Kupffer cells was detected by immunofluorescence double-labeling method. Results: The sensitization rate of TCE treatment group was 38.9% (7/18) , and TCE+R7050 treatment group was 35.3% (6/17) , with no significant difference between the two groups (P=1.000) . Compared with the blank control group, mice in the TCE sensitized group had abnormal liver ocytes, obvious liver injury, reduced mitochondria and broken endoplasmic reticulum. Western blotting results showed that the expressions of TNF-α and TNFR1 protein in the liver of the mice in the TCE sensitized group increased, the expression of iNOS protein in M1-type Kupffer cells increased, and the expressions of autophagic microtubule-associated protein 1 light-chain 3 (LC3B) and Beclin1 protein were decreased (P<0.05) . The results of immunohistochemistry showed that iNOS was not significantly expressed in the blank control group and solvent control group, and a small amount of expression was found in the TCE non-sensitized group, the positive staining area was obvious in TCE sensitized group, and the expression of iNOS was significantly increased (P<0.05) . Immunofluorescence results showed that the iNOS protein levels in the blank control group, solvent control group and TCE non-sensitized group were lower, and only partially colocalized with P62; the colocalization of iNOS with P62 in the TCE sensitized group was significantly increased. Conclusion: TNF-α/TNFR1 signaling pathway may promote liver injury in TCE-sensitized mice by inhibiting autophagy of M1-type Kupffer cells.
Animals ; Autophagy ; Female ; Kupffer Cells ; Liver ; Mice ; Mice, Inbred BALB C ; Receptors, Tumor Necrosis Factor, Type I ; Solvents ; Trichloroethylene/toxicity* ; Tumor Necrosis Factor-alpha

Proteus mirabilis lipase (PML) features tolerance to organic solvents and great potential for biodiesel synthesis. However, the thermal stability of the enzyme needs to be improved before it can be used industrially. Various computational design strategies are emerging methods for the modification of enzyme thermal stability. In this paper, the complementary algorithm-based ABACUS, PROSS, and FoldX were employed for positive selection of PML mutations, and their pairwise intersections were further subjected to negative selection by PSSM and G_REMLIN to narrow the mutation library. Thereby, 18 potential single-point mutants were screened out. According to experimental verification, 7 mutants had melting temperature (T_m) improved, and the ΔT_m of K208G and G206D was the highest, which was 3.75 ℃ and 3.21 ℃, respectively. Five mutants with activity higher than the wild type (WT) were selected for combination by greedy accumulation. Finally, the T_m of the five-point combination mutant M10 increased by 10.63 ℃, and the relative activity was 140% that of the WT. K208G and G206D exhibited certain epistasis during the combination, which made a major contribution to the improvement of the thermal stability of M10. Molecular dynamics simulation indicated that new forces were generated at and around the mutation sites, and the rearrangement of forces near G206D/K208G might stabilize the Ca²⁺ binding site which played a key role in the stabilization of PML. This study provides an efficient and user-friendly computational design scheme for the thermal stability modification of natural enzymes and lays a foundation for the modification of PML and the expansion of its industrial applications.
Enzyme Stability ; Lipase/chemistry* ; Molecular Dynamics Simulation ; Proteus mirabilis/metabolism* ; Solvents/chemistry*

Objective: To evaluate the occupational health risk of organic solvents in major posts of printing industry, and to provide technical reference to take targeted risk control measures. Methods: In January 2021, the contact ratio method was used to assess the occupational health risk of organic solvents in the major posts of 84 printing enterprises in Shantou, and Monte Carto method was used to estimate the probability distribution of risk levels in the majorpostsin January 2021. Results: The highest probability of risk assessment in printing and membranecovering post is Level 4 (high risk) , which are 76.2% and 67.6% respectively; the highest probability of simulation evaluation result in oil blending, dispensing and cleaning post is Level 3 (medium risk) ; and the simulation evaluation result in glueing post are mostly Level 3 (medium risk) and Level 4 (high risk) , the probability of which are 45.7% and 54.3% respectively. Conclusion: The occupational health risk of organic solvents in the major posts is generally middle-high risk level, and then the occupational health risk control of organic solvents in major posts of printing industry should be strengthened.
Air Pollutants, Occupational/analysis* ; Industry ; Occupational Exposure/analysis* ; Occupational Health ; Risk Assessment ; Solvents

Objective: To establish a method for the determination of acetylacetone in the air of workplace by gas chromatography. Methods: In August 2020, acetylacetone in the air of workplace was collected by silica gel tube, eluted with methanol, separated and detected by gas chromatography with flame ionization detector. The detection limit and precision of the method were also analyzed. Results: The linear range of acetylacetone was 1.95-1950.60 μg/ml with the regression equation of y=0.815x-3.667, and the correlation coefficient was 0.99993. The limit of detection of the method was 0.18 μg/ml and the minimum detection concentration was 0.12 mg/m(3) (collected sample volume was 1.50 L). The within-run precisions were 1.08%-4.11% and the between-run precisions were 1.98%-2.80%. The desorption rates were 99.68%-100.45%. The sealed samples could be kept at least 15 days at room temperature without significant loss. Conclusion: The solvent desorption-gas chromatography method for the determination of acetylacetone has good precision, high sensitivity and simple operation, and is suitable for the determination of acetylacetone in the air of the workplace.
Solvents ; Air Pollutants, Occupational/analysis* ; Chromatography, Gas/methods* ; Workplace

Objective: To understand the volatile organic components in the organic solvents used by enterprises in Baoan District, Shenzhen. Methods: From January to December 2020, a total of 541 organic solvent samples used by 86 companies were collected for volatile organic component analysis, and the main volatile components and high-risk occupational hazards in organic solvents used in different industries were analyzed. Results: A total of 201 volatile organic components were detected in 541 organic solvents. The top 5 components detected include xylene (29.76%, 116/541), toluene (21.81%, 118/541), methanol (20.70%, 112/541), n-hexane (14.79%, 80/541) and ethylbenzene (14.23%, 77/541). The detection rates of benzene, trichloroethylene, n-hexane, and 1, 2-dichloroethane, which were high-risk occupational hazards, were 2.40% (13/541), 3.70% (20/541), 14.79% (80/541), and 1.66% (9/541), respectively. The volatile components in organic solvents used in different industries was different. Benzene is more frequently detected in organic solvents used in the printing industry, trichloroethylene was more frequently detected in organic solvents used in the electronics industry, and n-hexane was more commonly found in organic solvents used in the electronics industry, printing and other industries, and 1, 2-dichloroethane has been more frequently detected in organic solvents used in the machinery industry. Conclusion: There are many types of organic solvents used by enterprises in Bao'an District, with complex components and differences in different industries.
Benzene/analysis* ; Hexanes ; Solvents ; Industry ; Trichloroethylene