Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1034
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
A qualitative analytical method of liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-Q-TOF-MS) was developed for identification of multi-constituents and an analytical method was developed for simultaneously determining 4 major compounds (rutin, isoquercitrin, kaempferol-3-0-rutinoside, and astragalin) in Tetrastigma hemsleyanum Diels et Gilg. The HPLC-Q-TOF-MS assay was performed on a Welch Ultimate XB-C18 column (4.6 mm x 150 mm, 5 microm) with the mobile phase consisting of acetonitrile (A) and water containing 0.1% Formic acid (B) in gradient mode at a flow rate of 0.8 mL x min(-1). The column temperature was at 30 degrees C, and negative ion mode was used for TOF-MS. The UPLC-QqQ-MS assay was performed on a Waters CORTECS C18 (2.1 mm x 100 mm, 1.6 microm) with the mobile phase consisting of acetonitrile (A) and water containing 0.1% formic acid (B) in gradient mode at a flow rate of 0.25 mL x min(-1). The column temperature was at 45 degrees C, and MRM mode was used for QqQ-MS. Based on the retention time and MS spectra, 24 compounds were identified or tentatively characterized by comparing with reference substances or literatures. For quantitative the linear range of 4 detected compounds were good (r > 0.9966), and the overall recoveries ranged from 98.27% to 101.58%, with the RSD ranging from 3.15% to 5.88%. The results indicated that new approach conbined HPLC-Q-TOF-MS and UPLC-QqQ-MS was applicable in qualitative and quantitative quality control of Tetrastigma hemsleyanum.
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