Development and evaluation of gas and liquid chromatographic methods for the analysis of fatty amines

In contrast to the plethora of publications on the separation of fatty acids, analogous studies involving fatty amines are scarce. A recently introduced ionic‐liquid‐based capillary column for GC was used to separate trifluoroacetylated fatty amines focusing on the analysis of a commercial sample. Using the ionic liquid column (isothermal mode at 200°C) it was possible to separate linear primary fatty amines from C₁₂ to C₂₂ chain length in less 25 min with MS identification. The log of the amine retention factors are linearly related to the alkyl chain length with a methylene selectivity of 0.117 kcal/mol for the saturated amines and 0.128 kcal/mol for the mono‐unsaturated amines. The sp² selectivity for unsaturated fatty amines also could be calculated as 0.107 kcal/mol for the ionic liquid column. The commercial sample was quantified by GC with flame ionization detection (FID). An LC method also was developed with a reversed phase gradient separation using acetonitrile/formate buffer mobile phases and ESI‐MS detection. Native amines could be detected and identified by their single ion monitoring chromatograms even when partial coelution was observed. The analysis of the commercial sample returned results coherent with those obtained by GC–FID and with the manufacturer's data.     

Changing Assessment Practices in Science and Mathematics

One recommendation of the national reform movements in mathematics and science is to change the way students are assessed. In this article five formats of alternative assessment forms are described, and suggestions are given on how these methods can be implemented within science and mathematics classrooms. Benefits of each type of assessment are discussed and potential pitfalls are elucidated. Samples of the five formats, journal writing, open-ended problems, portfolios, interviews and performance assessments, are included.     

Nitric Acid on Silica Gel: A Useful Nitrating Reagent for Activated Aromatic Compounds

Phenols and arylmethyl ethers are rapidly mononitrated by nitric acid adsorbed in silica gel at room temperature in high yields.     

Natural Polymer Characterization

Summary : A review about the characterization of natural polymers is given, describing the polymers found in Nature, methods to distinguish natural from syntheticpolymers, and what modern Polymer Science can learn from Nature     

Expansive learning: lessons from one teacher’s learning journey

The provision of quality learning experiences for teachers is critical to mathematics reform agendas aimed at equitable and culturally responsive teaching. In this paper we use an activity theory framework to explore one teacher’s learning journey. Drawing on the teacher’s self-report of his journey 1 year after his participation in an intervention designed to support the introduction of mathematical inquiry practices we examine those factors that supported expansive learning. In seeking to understand our pedagogical stance within the intervention we gained new insights into the provision of research based tools to support learning, the provision of space for individual and collective learning, and the provision of a safe learning environment both within the programme, the class, and the wider professional community. These factors are important in understanding transformational changes associated with ambitious pedagogy.     

Middle Grade Students' Interpretations of Contour Maps

This study examined eighth graders' approach to three tasks implemented to assist students with learning to interpret contour maps. Students' approach to and interpretation of these three tasks were analyzed qualitatively. When students were rank ordered according to their scores on a standardized test of spatial ability, the Minnesota Paper Form Board Task ( Likert & Quasha, 1948 ), evidence emerged that spatial ability was related to how students interpreted the tasks. Students with the relatively lowest spatial ability scores had difficulty picking out the relevant features of the representations used for instruction and despite scaffolding attempts by peers remained unclear about their interpretation. Students with relatively higher spatial ability were able to pick out salient features of the representations used for instruction which resulted in their learning to read and interpret contour maps.