This review article expands on the previous one (S. Selvaraju and Z. El Rassi, Electrophoresis 2012, 33, 74-88) by reviewing pertinent literature in the period extending from early 2011 to present. As the previous review article, the present one is concerned with proteomic sample preparation (e.g., depletion of high abundance proteins, reduction of the protein dynamic concentration range, enrichment of a particular sub-proteome), and the subsequent chromatographic and/or electrophoretic pre-fractionation prior to peptide separation and identification by LC-MS/MS. This review article is distinguished from its second version published in Electrophoresis 2012, 33, 74-88 by expanding on capturing/enriching sub-phosphoproteomes by immobilized metal affinity chromatography and metal oxide affinity chromatography. Seventy-seven papers published in the period extending from mid 2011 to the present have been reviewed. By no means this review article is exhaustive, given the fact that its aim is to give a concise treatment of the latest developments in the field.
A green chemistry experiment is presented
for teaching an undergraduate
quantitative analysis/analytical chemistry laboratory class through
the use of black tea leaf extract for the determination of iron in
supplement tablets. Dried tea leaf is a safe, low cost, and widely
available source of natural extract that can be used in place of more
toxic chemicals (for example, 1,10-phenanthroline) or other uncommon
natural reagents that may be hard to obtain outside their native lands.
Various student learning outcomes accommodated within this experiment
include the principles and hands-on operation of a spectrophotometer,
the construction of a calibration graph and obtaining a linear regression
equation using Microsoft Excel, the determination of figures of merit
(limit of detection, limit of quantitation, and linear working range),
and sampling and preparation of supplement tablets with acid digestion.
Students were trained in quality control and quality assurance through
statistical data analysis for precision (SD) and accuracy (t test, percent recovery, and percent error) for the experiment.
They were asked to discuss not only advantages but also limitations
of using natural reagents for chemical analysis. Critical thinking
and a deep understanding of the experiment were assessed through the
students’ ability to answer follow-up questions in their report
and on the exam. Class management and modification of the experiment
to suit a laboratory with limited facilities are discussed. This robust
tea-Fe experiment was successfully demonstrated for teaching both
large and small laboratory classes at two institutions, one in the
U.S. and one in Thailand.
Two different neutral nonpolar monolithic columns series (designated as A and B columns series) each consisting of three columns at varying n-alkyl chain length were prepared by the copolymerization of the functional monomers C8-methacrylate, C12-acrylate, or C16-methacrylate with the cross-linking monomer pentaerythritol triacrylate (PETA) to yield monoliths with surface bound C8, C12, and C16 chains. In the A columns series, the composition of the functional monomers and crosslinker was adjusted to yield comparable chromatographic retention regardless of the alkyl chain length. In the B columns series, the composition of the functional monomers and crosslinker was kept constant yielding chromatographic retention, which increased as expected in the order of increasing the n-alkyl chain length. Due to their direct influences on the monolith porosity and retention energetic, the nature and composition of the monomers at a given porogen composition have largely affected the solute's mass transfer characteristics and sorption kinetics, as assessed by the van Deemter plots and separation efficiencies. The C16-monolith of the A series yielded the highest separation efficiency toward small solutes, but the A columns series were inadequate for protein separation. The C8-monolith of the B series provided the best separation efficiency for proteins while for tryptic peptide mapping, the C16-monolith of the A series seems to provide the best separation. For large protein molecules, the energetically "softer" C8 surface allowed faster sorption kinetics and in turn improved efficiency, while an energetically "harder" C16 surface favored better separation of the smaller size peptide solutes.
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