Part No: P021Issued year: 2008File size: 1.87mbFile type: pdf
It is well known that traditional liquid-liquid extraction (LLE) provides very clean extracts prior to LC/MS analysis. Supported liquid extraction is analogous to traditional LLE, however, analyte partitioning takes place using an inert support material, rather than two immiscible liquids. This provides excellent extraction efficiencies while alleviating
many of the tedious liquid handling issues associated with LLE.
1) Remember to add stir bar for efficient mixing. Catalysts, salts, or visible precipitate should be washed clear of head space and into solution. Particles adhering to glass head space could cause excessive heating increasing possibility of failure of vial. Stay within specified vial volume range (see diagram for proper filling).
Part No: P080Issued year: 2014File size: 0.88mbFile type: pdf
This poster describes the benefits of supported liquid extraction and highlights its use in removal of endogenous matrix components that cause ion suppression/enhancement (matrix effects) in LC-MS/MS analyses.
Part No: P118Issued year: 2015File size: 0.48mbFile type: pdf
This poster examines the use of ISOLUTE SLE+ columns as an alternative to SPE for the extraction and clean up of hair samples containing drugs of abuse. SLE was found to be a simple, faster alternative to SPE for this type of analysis.
Part No: P089Issued year: 2014File size: 0.79mbFile type: pdf
This poster presents a novel method for the simultaneous extraction, derivatization and subsequent detection of both the traditional 25-hydroxy and the biologically active 1α,25-dihydroxy vitamin D metabolites in serum.
Part No: Issued year: 2013File size: 0.35mbFile type: pdf
Leu-Enkephalin-amide (YGGFLNH2, Ca. MW = 554.65) was synthesized on the Rink amide ChemMatrix® resin at a scale of 0.5 mmol. Crude peptide (100 mg) was purified in duplicate using the Isolera Dalton equipped with a Biotage® SNAP KP-C18-HS 12g cartridge.
Part No: AN097Issued year: 2014File size: 0.73mbFile type: pdf
A branched peptidoglycan mimic and a tetra-branched antimicrobial peptide analogue were synthesized on a lysine scaffold using Biotage® Initiator+ Alstra™ microwave peptide synthesizer. These peptide modifications are challenging to synthesize and automate, however, the procedure was operationally simplified using Branches™.
Part No: AN053Issued year: 2010File size: 0.92mbFile type: pdf
It has recently been demonstrated that specific recognition of rhizobial bacteria by the signaling molecule Nod-factor receptor 5 (NFR5) relies on LysM domains. The LysM (lysine motif) domain is believed to be involved in the regulation of the interaction between plants and rhizobial bacteria to promote plant growth. The LysM domain is predicted to consist of two-α
helices and a two-stranded anti-parallel β-sheet in a β-α-α-β structure and has been identified in NFR5 by sequence alignment of the crystal structure with the LysM domain of Bacillus subtilis ykuD.2 The synthesis of the C-terminal and the N-terminal regions of LysM domains provide significant challenges, this is presumably due to the formation of β-sheet like structures, which are known to pose problems for peptide chain assembly.
Part No: AN055Issued year: 2012File size: 0.28mbFile type: pdf
C-terminal peptide aldehydes are key components in oxime and hydrazine ligations and their synthesis is therefore very desirable. A well established method for the synthesis of C-terminal modified peptides including peptide aldehydes, is the backbone amide linker (BAL) strategy (Scheme 1).1 In this strategy, the first amino acid is anchored by reductive amination followed by acylation of the newly formed secondary amine. Thus, the growing peptide chain is anchored not through the C-terminal carboxyl but through a backbone amide nitrogen giving access to, in principle, any C-terminal modification.
Part No: AN054Issued year: 2011File size: 0.39mbFile type: pdf
A number of biologically active natural products contain N-methyl amino acids. N-Methyl amino acid containing peptides are potentially useful therapeutics as they have improved pharmacological properties such as such as proteolytic stability, bioavailability, lipophilicity, enhanced potency and receptor selectivity. The synthetic challenges associated with the synthesis of peptides containing consecutive N-methyl amino acids are well known1,2 and often require coupling reagents such as PyBOP3, HATU4 or even triphosgene4 to obtain high coupling yields. Syro Wave.
Part No: AN052Issued year: 2010File size: 0.26mbFile type: pdf
One of the current challenges in peptide science is the assembly of long peptides and small proteins, which has to overcome the accumulation of side-reactions and the hurdles posed by so-called difficult sequences. During the synthesis of difficult sequences the peptide chain most likely becomes partially inaccessible typically due to the formation of secondary structures, especially β-sheets, which can inhibit acylation and deprotection during synthesis, resulting in truncated sequences. In addition, steric hindrance from β-branched amino acids can be a problem.
Part No: Issued year: 2014File size: 1.01mbFile type: pdf
We have demonstrated the capability of the Biotage® Initiator+ Alstra
microwave peptide synthesizer to fully synthesize branched and cyclic
peptides. The synthesis included specialized reactions of non-linear peptides and a high degree of purity was achieved. Furthermore, the Branches software feature provides an extensive overview for the scheduling and visualization of operations in order to make complex peptide modifications and is a great addition to the toolbox for the peptide chemist. Presented at EPS, Sofia, 2014.
Part No: Issued year: 2005File size: 0.29mbFile type: pdf
Microwave technology at ChemDiv
Standard procedure for Suzuki coupling:
Building block 1-25 (0.25 mmol), the correspondent boronic acid (0.50 mmol) was heated under microwave irradiation (180oC, 10-40 min) in the presence of catalyst [PdCl2(PPh3)2 or dichlorobis(triphenyl-phosphine)palladium(II) polymer bound and Cs2CO3 as a base in DME/Water (50/50) as solvent.