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Quality evaluation of Codonopsis Radix through high performance liquid chromatography fingerprint combined with chemometrics and simultaneous determination of five characteristic ingredients

An Qi, Sun Hong, Wu Linzhi, Liu Liangliang, Chen Sue

Acta Chromatographica

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2023

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Vol. 35, no. 3

247--258

EN

Codonopsis Radix (CR) is recorded as the roots of Codonopsis pilosula, C. pilosula var. modesta and Codonopsis tangshen. It is difficult to evaluate the quality of CR because of the existence of many original plants. In this paper, a strategy integrating chromatographic analysis and chemometrics for the quality control of CR is proposed. Systematic analysis of the chemical composition of CR was achieved through high performance liquid chromatography (HPLC) fingerprinting. Based on the HPLC fingerprinting data, chemometrics, including unsupervised principal component analysis (PCA) and supervised orthogonal partial least squares-discrimination analysis (OPLS-DA), were applied to classify all CR samples. Components with variable importance in projection values higher than 1 in the OPLS-DA model were selected as potential chemical markers for distinguishing the origins of CR. Finally, an HPLC method was validated for determining the five characteristic ingredients in the CR samples. HPLC characteristic fingerprints showed 17 common peaks for C. pilosula, 13 for C. pilosula var. modesta, and 9 for C. tangshen, and all of them showed good similarity (>0.9). Additionally, there were 9 common peaks for all CR samples with relatively poor similarity, ranging from 0.607 to 0.970. PCA could differentiate CR from the three origins, except for a partial overlap between C. pilosula and C. pilosula var. Modesta, and the OPLS-DA model achieved excellent classification results. Eight components (peaks 12, 8, lobetyolin, 10, codonopsin І, syringin, 3, and 11) were selected as potential chemical markers. There was a large discrepancy in the contents of the five characteristic ingredients in all samples, with the relative standard deviation ranging from 36.0% (lobetyolin) to 85.9% (atractylenolide Ⅲ). The average contents of the five characteristic ingredients were similar between C. pilosula and C. pilosula var. modesta samples and notably higher than those of C. tangshen samples. Consequently, a rapid, precise, and feasible strategy was established for the discrimination and quality control of CR with different origins.

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Laser Welding of TA15 Titanium Alloy and Inconel 718 Dissimilar Metals

An Qi, Wu Dongting, Liu Peng, Zou Yong

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1267--1276

EN

This paper studied the effect of laser welding technology on dissimilar metal welding joints of TA15 titanium alloy and Inconel 718 nickel-based alloy. The research results indicate that the laser welding of TA15 titanium alloy and Inconel 718 nickel-based alloy directly was difficult to form well, which due to the intermetallic compounds caused the joint brittle. When the pure Cu foil was used as the filling layer, the quality of the welding joints can be improved effectively. The experimental results also indicate that there were brittle intermetallic-compounds in the laser welding seam, and the laser power had an important influence on the performance and mechanical properties of the dissimilar metal joint. The maximum average tensile strength of the welding joint of 2300 W was increased to 252.32 MPa. Scanning electron microscope(SEM) results show that the fracture morphology was river pattern, a typical morphological of cleavage fracture, and the mode was brittle fracture.

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Application of ultrasound-assisted deep eutectic solvent extraction combined with liquid-liquid extraction method to the extraction of three pesticide residues from fruit and vegetable samples

Chen Sue, An Qi, Sun Hong, Mao Mengqian

Acta Chromatographica

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2021

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Vol. 33, no. 1

30--36

EN

A simple, inexpensive and sensitive method was developed for the simultaneous determination of three pesticide residues (carbendazim, thiophanate-methyl, and imidacloprid) in fruit and vegetable samples using high performance liquid chromatography (HPLC) based on a combined pretreatment of ultrasoundassisted deep eutectic solvent extraction (UA-DES-E) and liquid-liquid extraction (LLE). In this study, various types of deep eutectic solvents (DESs) were synthesized and the extraction efficiency was compared as extraction solvents. Results showed that glycerol-proline 5 9:4 (GP-5) obtained the highest extraction efficiency among different types of DESs. Experiment conditions, including DES volume, extraction time and pH, were systematically optimized using single-factor experiment. Under the optimum conditions, the limits of detection (LODs) and quantification (LOQs) were in the ranges of 0.05– 0.2 mg$mL1 and 0.1–0.5 mg$mL1, respectively. The relative recoveries of the three pesticides in the fruit and vegetable samples ranged from 85.7 to 113.0% at two spiked levels. Meanwhile, the method achieved excellent linearity with determination coefficients (r) greater than 0.999. Furthermore, the method was successfully applied to the analysis of the pesticides in real fruit and vegetable samples (apple, tomato, and grape).