Study on the photoaging process and metal ion release of plastic films with two kinds of structures in marine environment: Aliphatic and aromatic polymers.

The prevalence of plastics in the oceans has significantly intensified microplastic pollution, contributing to broader marine secondary pollution issues. This paper examines how plastic structure affects the aging characteristics of plastics and the release of metal ions, to better understand this secondary source of marine pollution. This study simulate the photoaging of plastics in natural environments, focusing on aliphatic and aromatic polymers. The results showed that the photodegradation degree was higher for aliphatic than aromatic polymers. All polymers contained thirteen detectable metals, with their release increasing over time due to photoaging, The release dynamics of these metal ions correlated more strongly with the level of polymer degradation rather than with the polymer structure itself, adhering to a second-order kinetic model driven by surface and intraparticle diffusion processes. The results will help control and treat marine plastic pollution.

Microscopic dissolution process of cellulose in alkaline aqueous solvents and its application in CNFs extraction - Investigating temperature as a variable.

The target of this study is to gain a deeper understanding of the micro-dissolution process of cellulose in alkaline aqueous solutions and to develop a novel method for extracting cellulose nanofibrils (CNFs). Herein, the dissolution process of cellulose in alkaline aqueous solutions will be controlled by varying the temperature, and the undissolved cellulose will be analyzed to reveal the microscopic dissolution process of cellulose, and a novel process for extracting cellulose nanofibrils (CNFs) will be developed based on the findings. The crystalline structure of cellulose was gradually disrupted as the dissolution progressed, and the crystal form of cellulose changed gradually from cellulose I to cellulose II during the dissolution process, while all undissolved cellulose crystals remained as cellulose I. Cellulose, after its structure is disrupted during the dissolution process, will inevitably decompose into CNFs, and the microscopic dissolution process of cellulose follows a "top-down" dissolution sequence. The CNFs extraction method developed in this study can extract CNFs with high yield (>60 %) in a stable manner, as well as narrow particle size distribution, high crystallinity (>77 %), and good thermal stability. This study enhances the comprehension of the dissolution process of cellulose and paves a possible way for industrialization of CNFs production.

[Analysis on volatile components of Ficus carica fruit].

OBJECTIVE: To Analyze the volatile chemical components of Ficus carica fruits. METHODS: The volatile components of Ficus carica fruits were extracted by the three extraction methods such as SPME, SD and SE, and then analyzed by GC-MS. RESULTS: A total of 91 peaks were identified by GC-MS. 61 compounds came from the extraction methods of SPME, 7 compounds from SD, and 30 compounds from SE. CONCLUSION: The volatile components extracted by the three methods are not quite similar. Among of them, the volatile components extracted by SPME method are the most and have the highest resolution.

[Analysis of volatile constituents of Astragali Complanati semen by HS-SPME combined with GC-MS].

OBJECTIVE: To analyze the compositions of volatile constituents in Astragali Complanati Semen. METHODS: The volatile constituents were extracted with headspace solid phase micro extraction (HS-SPME), and identified by GC-MS. RESULTS: 51 compounds were separated from Astragali Complanati Semen and 25 of them were identified, which made up 78.85% of the total amount. The main components obtained from Astragali Complanati Semen were L-Bornyl acetate (14.1%), Camphor (5.98%) and L(-)-Borneol (4.27%). CONCLUSION: The compounds in Astragali Complanati Semen are firstly confirmed,which provides scientific evidence for the development of Astragali Complanati Semen.

[Fingerprint of Angelica polymorpha by HPLC].

OBJECTIVE: To establish the HPLC fingerprint of Angelica polymorpha. METHOD: The 10 batches of A. polymorpha were measured by HPLC with isoimperatorin as a reference substance and the chromatographic experients were performed on Kromasil 100A C18 column (4.6 mm x 250 mm, 5 microm), eluted with acetonitrile and water as mobile phase in gradient mode. The flow rate was 1.0 m x min(-1) and the detection wavelength was 254 nm. RESULT: The common mode of the HPLC fingerprints were set up. There were 8 common peaks in the fingerprint of 10 samples, and the similarity of the 10 samples was more than 0.9. CONCLUSION: The method is simple, accurate and have a good reaptability. The quality of A. polymorpha can be controlled effectively by the HPLC fingerprint.

[Analysis of the chemical constituents of essential oil from Anaphalis aureopunctata by GC-MS].

OBJECTIVE: The chemical components of essential oil from Anaphalis aureopunctata were analyzed by GC-MS. METHODS: Essential oil was extracted by stem distillation (SD). The chemical components of essential oil were analyzed by GC-MS. RESULTS: The main components in the oil were Eudesma-4(14), 11-diene, alpha-Bisabolol,6,10,14-trimethyl- 2-Pentadecanone,Caryophyllene oxide,alpha-Selinene and so on. CONCLUSION: This is the first time to adopt GC-MS to analyze the chemical components of volatile oil of Anaphalis au-reopunctata, and this study can provide science basis for further research development of Anaphalis aureopunctata.

[Studies on chemical constituents of Dendranthema indicum var. aromaticum].

OBJECTIVE: To study chemical constituents of Dendranthema indicum var. aromaticum. METHODS: The constituents were separated and purified by column chromatography with silica gel and Semi-preparative HPLC. Their structures were identified on the basis of physical-chemical properties and spectral data. RESULTS: Seven compounds were isolated and identified as acacetin, apignein, acacetin-7-O-beta-D-glucopy ranoside, apignein-7-O-beta-D-glucopy ranosids, luteolin, beta-sitosterol and daucosterol. CONCLUSION: Apigenin, acacetin-7-O-beta-D-glucopy ranoside and apignein-7-O-beta-D-glucopy ranoside are obtained from the plant for the first time.

[Analysis of the chemical constituents of essential oil from Magnolia biondii by GC-MS].

OBJECTIVE: The chemical components of essential oil from Magnolia biondii were analyzed by GC-MS. METHODS: Essential oil was extracted by steam distillation (SD). The chemical components of essential oil were analyzed by GC-MS. RESULTS: The chemical components in the oil were qualitatively and quantitatively analyzed by GC-MS. 63 components were separated and 50 components were identified. The main components were Eucalyptol (28.92%), P-pinene (12.39%), alpha-Terpineol (8.28%). CONCLUSION: This is the first time to adopt GC-MS to analyze the chemical components of volatile oil of Magnolia biondii, and this study can provide science basis for further research development of Magnolia biondii.

[Studies on the HPLC fingerprint spectrum of flavonoids in Gynostemma pentaphyllum].

OBJECTIVE: To establish the HPLC fingerprint spectrum of flavonoids from Gynostemma pentaphyllum. METHODS: The HPLC conditions with TURNER Kromasil C18 column (250 x 4. 6 mm, 5 microm) was used, the mobile phase consisted of 0.4% phosphoric acid-methanol-acetonitrile with gradient elution at flow rate of 0.5 ml/min and the detection wavelength was set at 360nm. RESULTS: Ten common characteristic peaks were taken as fingerprint peaks the presision and the retest are in accordance with the requirement. CONCLUSION: The method is stable, reliable, precision and provides a scientific basis for the quality standard of Gynostemma pentaphyllum.

[Study on HPLC-FPS of cortex magnoliae officinalis].

OBJECTIVE: To study the HPLC-FPS of Cortex Magnoliae Officinalis, the substitute species and counterfeits from different habitats, and to obtain the sameness and differences. METHOD: HPLC-FPS was used. RESULTS: There were sameness and differences between two certified Cortex Magnoliae Officinalis, which were easily distinguished from their substitute species and counterfeits. CONCLUSION: The HPLC-FPS can provide the useful information for the quality estimation and plant source of Cortex Magnoliae Officinalis.