[Determination of 15 carbonyl compounds in soil using improved solid phase extraction-high performance liquid chromatography].

An improved solid phase extraction (SPE)-high performance liquid chromatography method was established to determine 15 carbonyl compounds, namely, formaldehyde (FOR), acetaldehyde (ACETA), acrolein (ACR), acetone (ACETO), propionaldehyde (PRO), crotonaldehyde (CRO), butyraldehyde (BUT), benzaldehyde (BEN), isovaleraldehyde (ISO), n-valeraldehyde (VAL), o-methylbenzaldehyde (o-TOL), m-methylbenzaldehyde (m-TOL), p-methylbenzaldehyde (p-TOL), n-hexanal (HEX), and 2,5-dimethylbenzaldehyde (DIM), in soil. The soil was ultrasonically extracted with acetonitrile, and the extracted samples were derivatized with 2,4-dinitrophenylhydrazine (2,4-DNPH) to generate stable hydrazone compounds. The derivatized solutions were cleaned using an SPE cartridge (Welchrom® BRP) packed with N-vinylpyrrolidone/divinylbenzene copolymer. Separation was performed on an Ultimate® XB-C18 column (250 mm×4.6 mm, 5 µm), isocratic elution was performed with acetonitrile-water (65∶35, v/v) as the mobile phase, and detection was performed at a wavelength of 360 nm. The 15 carbonyl compounds in the soil were then quantified using an external standard method. The proposed method improves the sample processing method described in the environmental standard HJ 997-2018: Soil and sediment-Determination of carbonyl compounds-High performance liquid chromatography. A series of experiments revealed the following optimal conditions for soil extraction: acetonitrile as the extraction solvent, extraction temperature of 30 ℃, and extraction time of 10 min. The results showed that the purification effect of the BRP cartridge was significantly better than that of the conventional silica-based C18 cartridge. The 15 carbonyl compounds showed good linearities, and all correlation coefficients were above 0.996. The recoveries ranged from 84.6% to 115.9%, the relative standard deviations (RSDs) ranged from 0.2% to 5.1%, and the detection limits were 0.02-0.06 mg/L. The method is simple, sensitive, and suitable for the accurate quantitative analysis of the 15 carbonyl compounds in soil specified in HJ 997-2018. Thus, the improved method provides reliable technical support for studying the residual status and environmental behavior of carbonyl compounds in soil.

[Preparation and evaluation of a new type of amino-bonded silica chromatographic stationary phase for the determination of lactose].

A method for the separation and determination of lactose and sucrose using high performance liquid chromatography-refractive index (HPLC-RI) detection base on the prepared amino-bonded silica gel chromatographic stationary phase was established. The method was accorded to the content determination method in Pharmacopoeia of the People's Republic of China (2015). Then, a series of chromatographic behaviors of lactose and sucrose such as the retention times, resolutions and peak area stabilities were investigated on three different types of amino-bonded silica columns (300 mm×4.6 mm, 5 µm). The mobile phase was acetonitrile-water (70:30, v/v) with isocratic elution, the flow rate was 1.0 mL/min and the injection volume was 10 µL. The resolution of lactose and sucrose was 3.03 by isopropyl side chain protected amino column, and the peak shape of each target compound was good. The relative standard deviation (RSD) of peak area of lactose was 1.14%, less than 2.0% prescribed in the Pharmacopoeia of the People's Republic of China (2015). Therefore, this method meets the requirements of lactose content determination, and is suitable as the quality control method in the above mentioned Pharmacopoeia.

Facile Synthesis and Chiral Separation of Chiral Mesoporous Silica Microspheres.

Mesoporous silica microspheres were synthesized by an acid-catalyzed sol-gel method using tetraethoxysilane (TEOS) as a precursor. The hydrochloric acid was used as a catalyzer to induce the hydrolysis of TEOS, while the cyclohexane acted as a stabilizer of the sol. The addition of polyethylene glycol can introduce the uniform mesoporous structure into the microspheres by phase separation. The as-prepared mesoporous silica microspheres possess a narrow particle size distribution, a mesopore size of 5.0 nm and a Brunauer-Emmett-Teller specific surface area as high as 230 m2·g-1. The resultant silica microspheres were used for packing chiral high-performance liquid chromatography (HPLC) columns, after activated by hydrochloric acid and modified by amylose-tris(3,5-dimethylphenylcarbamate), respectively. The flurbiprofen axetil as a typical chiral drug with two stereocenters can be successfully separated by the as-obtained chiral HPLC columns using different mobile phases.

[Determination of triterpenoic acid isomers in Eriobotryae folium using high performance liquid chromatography on C30 column].

A rapid and easy assay method for four triterpenoic acid isomers in Eriobotryae folium was established. The sample was extracted with methanol, then separated on a C30 column (250 mm x 4.6 mm, 5 microm) at 20 degrees C using acetonitrile-water (95 : 5, v/v) as the mobile phase at a flow rate of 1.0 mL/min. The target compounds were simultaneously detected at 210 nm, and the injection volume was 10 microL. The validation was carried out and the resolution (R > or = 2.2), the precision (RSD < or = 1.1%), the linearity (r > or = 0.999 2), the repeatability (RSD < or = 4.4%), and the recovery (range from 95.4% to 101.7%, RSD < or = 4.8%) were acceptable. The method is reliable for the quantification of the four triterpenoic acid isomers by HPLC on C30 column.

Determination of oleanolic acid and ursolic acid in Chinese medicinal plants using HPLC with PAH polymeric C18.

BACKGROUND: The RP-HPLC resolution of two triterpenic acid isomers was unstable. OBJECTIVE: To separate the oleanolic acid (OA) and ursolic acid (UA) simply within RP-HPLC. MATERIALS AND METHODS: The separation ability of five stationary phases was studied with the retention effect of their carbon loads. Also the resolution effects of mobile phase composition and different column temperatures were systematically investigated by using Drylab(®) (Rheodyne LLC.) after evaluating chromatograms automatically. RESULTS: The best available resolution of two bioactive isomers was achieved (r = 3.4) via using PAH (polycyclic aromatic hydrocarbons) polymeric C18 bonded phase column. The chromatographic system was applied to the quantification in ten Chinese medicinal plants and the validation was carried out and the precision (RSD ≤1.34%), the linearity (r ≥ 0.9998) and the recovery (range from 92.1% to 102.6%) were acceptable. CONCLUSION: It is clear that the method was simple, rapid and reliable for the quantification of two compounds in new HPLC method within PAH polymeric C18.