Analysis and Identification of Acid–Base Indicator Dyes by Thin-Layer Chromatography

2007 ◽  
Vol 84 (7) ◽  
pp. 1186 ◽  
Author(s):  
Daniel D. Clark
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Acid Base ◽  
Indicator Dyes ◽  
Layer Chromatography

Analytical chemistry students’ explanatory statements in the context of their corresponding lecture

2020 ◽  
Vol 21 (4) ◽  
pp. 1183-1198
Author(s):  
Ying Wang ◽  
Scott E. Lewis
Keyword(s):  
Analytical Chemistry ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Formal Education ◽  
Limited Information ◽  
Acid Base ◽  
Secondary Chemistry ◽  
Chemistry Students ◽  
Post Secondary ◽  
Layer Chromatography

Conceptually understanding chemistry requires the ability to transition among representational levels to use an understanding of submicroscopic entities and properties to explain macroscopic phenomena. Past literature describes student struggles with these transitions but provides limited information about upper-level post-secondary chemistry students’ abilities to transition among levels. This group is of particular interest as they are engaging in potentially their final training before entering a career as professional chemists, thus if students are likely to develop this skill during their formal education it should be manifest among this group. This study characterized analytical chemistry students’ responses to open-ended assessments on acid–base titrations and thin-layer chromatography for the use of sub-microscopic entities or properties to explain these macroscopic phenomena. Further, to understand whether explanatory statements were an expectation inherent in the instructional context of the setting, the analytical chemistry instructor's lectures on acid–base titrations and thin-layer chromatography were analyzed with the same framework. The analysis found that students seldom invoked explanatory statements within their responses and that congruence between lectures and responses to assessment was primarily limited to the use of macroscopic, descriptive terms. Despite the fact that the lecture in class regularly invoked explanatory statements in one context, this did not translate to student use of explanatory statements. To further test the hypothesis that analytical chemistry students struggle with explanatory statements, a follow-on study was also conducted among a second cohort of students reviewing their responses when specifically prompted to use sub-microscopic entities to explain a macroscopic phenomenon. The results suggest that fewer than half of the students showed proficiency on generating explanatory statements when explicitly prompted to do so. Instructional implications to promote explanatory statements are proposed in the discussion.

Thin-Layer Chromatography

1965 ◽  
Author(s):  
H. R. Bolliger ◽  
M. Brenner ◽  
H. Gänshirt ◽  
Helmut K. Mangold ◽  
H. Seiler ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Layer Chromatography

THE LESS-POLAR METABOLITES PRODUCED BY INCUBATION OF TESTOSTERONE-4-14C WITH RAT AND BOVINE BRAIN

1969 ◽  
Vol 61 (4) ◽  
pp. 641-648 ◽  
Author(s):  
Leon J. Sholiton ◽  
Emile E. Werk
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Paper Chromatography ◽  
Specific Activity ◽  
Bovine Brain ◽  
Polar Fraction ◽  
End Products ◽  
Polar Metabolites ◽  
Layer Chromatography ◽  
Constant Specific Activity

ABSTRACT Rat and bovine brain have been incubated with testosterone-4-14C under standard conditions. With use of paper chromatography, the extracted metabolites were noted to fall into less-polar, iso-polar, and more polar fractions. The components of the less-polar fraction were separated by acetylation and thin-layer chromatography and the major end-products identified by recrystallization to constant specific activity or constant 3H/14C ratios. Androst-4-enedione and 5α-dihydrotestosterone were formed consistently under the conditions utilized. Trace amounts of other less-polar metabolites were noted occasionally.

Sign in / Sign up

Export Citation Format

Share Document