scholarly journals Subcritical Water Chromatography with Electrochemical Detection

Molecules ◽  
2017 ◽  
Vol 22 (6) ◽  
pp. 962
Author(s):  
◽  
Keyword(s):  
Electrochemical Detection ◽  
Subcritical Water ◽  
Subcritical Water Chromatography

Carbon dioxide modified subcritical water chromatography

2008 ◽  
Vol 1200 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Michael O. Fogwill ◽  
Kevin B. Thurbide
Keyword(s):  
Carbon Dioxide ◽  
Subcritical Water ◽  
Subcritical Water Chromatography

A comparison of hydrocarbon and alkali metal response in the flame ionization detector used in subcritical water chromatography

2015 ◽  
Vol 93 (7) ◽  
pp. 784-789 ◽  
Author(s):  
Andrea F. Scott ◽  
Kevin B. Thurbide ◽  
Danica Quickfall
Keyword(s):  
Formic Acid ◽  
Alkali Metals ◽  
Gas Flow ◽  
Subcritical Water ◽  
Pure Water ◽  
Flame Ionization Detector ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Mobile Phases ◽  
Subcritical Water Chromatography

The flame ionization detector (FID) response toward alkali metals and hydrocarbons was compared. Optimal hydrogen flame gas flow rates were found near 40 mL/min for hydrocarbon response and 80 mL/min for alkali response. While each displayed a linear FID response, alkali metals produced several orders of magnitude greater detector sensitivity than hydrocarbons. Of note, KCl, NaCl, LiCl, and ethanol yielded respective FID sensitivity of about 7500, 980, 130, and 1 mV/μg analyte. This was subsequently demonstrated to greatly alter the FID response of organic salts. For example, while formic acid is normally unresponsive in an FID, its potassium salt could be readily detected here at picogram levels. Conversely, this phenomenon also rendered the FID unsuitable for use with buffered mobile phases containing such salts. In particular, FID background and baseline noise levels for formic acid – sodium formate buffers were about 10 times larger than equivalent experiments with methanol–water and up to two orders of magnitude larger than pure water. Overall, the results show that alkali metals respond much stronger in the FID than do hydrocarbons. Accordingly, their presence in organic analytes or mobile phases must therefore be accounted for when using this detector, particularly in areas such as subcritical water chromatography where it is commonly employed.

scholarly journals Separation and Analysis of Aspirin and Metformin HCl Using Green Subcritical Water Chromatography

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2258 ◽  
Author(s):  
Ninad Doctor ◽  
Yu Yang
Keyword(s):  
Organic Solvents ◽  
High Performance ◽  
Subcritical Water ◽  
Antidiabetic Drug ◽  
Chromatographic Separations ◽  
Pharmaceutical Ingredients ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Subcritical Water Chromatography ◽  
Metformin Hcl

Organic solvents are widely used in pharmaceutical and chemical industry for chromatographic separations. In recent years, subcritical water chromatography (SBWC) has shown ability in replacing hazardous organic solvents used in traditional high-performance liquid chromatography (HPLC). In this work, a pain killer—aspirin—and an antidiabetic drug—metformin HCl—were successfully separated on an XBridge C18 column using no organic solvents in the subcritical water chromatography mobile phase. Both traditional HPLC and subcritical water chromatography were used for comparison purposes. SBWC separation of metformin HCl and aspirin were achieved at 95 °C and 125 °C, respectively. The recovery for both active pharmaceutical ingredients (APIs) obtained by SBWC is 99% in comparing with the stated content of each drug. The relative standard deviation is less than 1% for SBWC assays developed in this work. This level of accuracy and precision achieved by SBWC is the same as that resulted by the traditional HPLC analysis.

Retention mechanism of phenolic compounds in subcritical water chromatography

2015 ◽  
Vol 31 (1) ◽  
pp. 103-106 ◽  
Author(s):  
Yichao Wu ◽  
Xiuqing Deng ◽  
Yinchun Mao ◽  
Yan Zhang ◽  
Jiaqin Liu ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Subcritical Water ◽  
Retention Mechanism ◽  
Subcritical Water Chromatography
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