Extraction of Maltol from Fraser Fir: A Comparison of Microwave-Assisted Extraction and Conventional Heating Protocols for the Organic Chemistry Laboratory

2014 ◽  
Vol 92 (1) ◽  
pp. 170-174 ◽  
Author(s):  
Andrew S. Koch ◽  
Clio A. Chimento ◽  
Allison N. Berg ◽  
Farah D. Mughal ◽  
Jean-Paul Spencer ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Chemistry Laboratory ◽  
Conventional Heating ◽  
Microwave Assisted Extraction ◽  
Fraser Fir ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Organic Chemistry Laboratory

scholarly journals Optimization of Ionic Liquid Based Simultaneous Ultrasonic- and Microwave-Assisted Extraction of Rutin and Quercetin from Leaves of Velvetleaf (Abutilon theophrasti) by Response Surface Methodology

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Chunjian Zhao ◽  
Zhicheng Lu ◽  
Chunying Li ◽  
Xin He ◽  
Zhao Li ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Extraction Time ◽  
Conventional Heating ◽  
Ultrasonic Power ◽  
Extraction Temperature ◽  
Microwave Assisted Extraction ◽  
Solid Ratio ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Influential Parameters

An ionic liquids based simultaneous ultrasonic and microwave assisted extraction (ILs-UMAE) method has been proposed for the extraction of rutin (RU), quercetin (QU), from velvetleaf leaves. The influential parameters of the ILs-UMAE were optimized by the single factor and the central composite design (CCD) experiments. A 2.00 M 1-butyl-3-methylimidazolium bromide ([C4mim]Br) was used as the experimental ionic liquid, extraction temperature 60°C, extraction time 12 min, liquid-solid ratio 32 mL/g, microwave power of 534 W, and a fixed ultrasonic power of 50 W. Compared to conventional heating reflux extraction (HRE), the RU and QU extraction yields obtained by ILs-UMAE were, respectively, 5.49 mg/g and 0.27 mg/g, which increased, respectively, 2.01-fold and 2.34-fold with the recoveries that were in the range of 97.62–102.36% for RU and 97.33–102.21% for QU with RSDs lower than 3.2% under the optimized UMAE conditions. In addition, the shorter extraction time was used in ILs-UMAE, compared with HRE. Therefore, ILs-UMAE was a rapid and an efficient method for the extraction of RU and QU from the leaves of velvetleaf.

Developing and Implementing a Specifications Grading System in an Organic Chemistry Laboratory Course

2020 ◽  
Author(s):  
William J. Howitz ◽  
Kate J. McKnelly ◽  
Renee Link
Keyword(s):  
Organic Chemistry ◽  
Chemistry Laboratory ◽  
Grading System ◽  
Traditional Grading ◽  
Final Grade ◽  
Laboratory Courses ◽  
Lower Division ◽  
Collaborative Learning Environment ◽  
Organic Chemistry Laboratory ◽  
Grade Uncertainty

<p>Large, multi-section laboratory courses are particularly challenging when managing grading with as many as 35 teaching assistants (TAs). Traditional grading systems using point-based rubrics lead to significant variations in how individual TAs grade, which necessitates the use of curving across laboratory sections. Final grade uncertainty perpetuates student anxieties and disincentivizes a collaborative learning environment, so we adopted an alternative grading system, called specifications grading. In this system each student knows exactly what level of proficiency they must demonstrate to earn their desired course grade. Higher grades require demonstrating mastery of skills and content at defined higher levels. Each students’ grade is solely dependent on the work they produce rather than the performance of other students. We piloted specifications grading in the smaller, third quarter course of the lower division organic chemistry laboratory series held during a summer term. Open-ended questions were chosen to gather student and TA perceptions of the new grading system. TAs felt that the new grading system reduced the weekly grading time because it was less ambiguous. Responses from students about the nature of the grading system were mixed. Their perceptions indicate that initial buy-in and multiple reminders about the bigger picture of the grading system will be essential to the success of this grading system on a larger scale.</p>

Orthogonal test in optimizing microwave-assisted extraction process of magnolin from Magnoliae Flos

2010 ◽  
Vol 30 (5) ◽  
pp. 567-568
Author(s):  
Xiao-li LI ◽  
Ming-yuan ZHANG ◽  
Wei-quan ZHAO ◽  
Man Li ◽  
Hai-ying TENG ◽  
...  
Keyword(s):  
Extraction Process ◽  
Orthogonal Test ◽  
Microwave Assisted Extraction ◽  
Microwave Assisted ◽  
Assisted Extraction
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