KULIM KHT CORTEST TCFC TRAINING

Kulim KHT MIMOS Dip Coater 2

Kulim Kht MIMOS Dip Coater Large

Kulim Kht ACM POT16 Potentiostatic & Galvanostatic Testing

DESCRIPTION 
Fixed potentials for parallel potentiostatic tests. 
This instrument provides 16 potentiostats for long term testing of electrodes at a fixed potential. Each channel has a fixed current measurement range, selected on purchase for the type of testing to be performed.  The standard range is 350 mA with a resolution of 5 micro Amps. Up to 4 fixed potentials may be ordered and allocated between the 16 channels at no extra cost.  For example channels 1 to 8 could be set to -1.5 V, channels 9 to 11 set to -3 V, channel 12 to 14 set to - 3.5 V and 15 to 16 set at -4 V.  These potentials are set on internal 25 turn trimming potentiometers and may be changed by the operator if the need arises. Measurement of the current flowing from each potentiostat and the voltage between RE and WE (as a check on operation) is performed by a pair of 24 bit converters, running at a maximum read rate of 4 channels per second. The software supplied allows for simple set up of data filename and read rate and displays the latest data recorded.  The data is stored on the PC's hard disc as the test progresses.  In the event of a power cut the data will be added to the earlier data on resumption of the power supply. An example of the use of a Pot 16 is in performing tests on coated steel to study the likelihood of cathodic disbondend at a fixed potential. 
A dedicated and powerful instrument offering very cost effective fixed potentiostats for long term measurement, each potentiostat is built to the same specification as supplied in the Gill AC.

APPLICATIONS 
• Cathodic Protection • Coating Disbondment • Cracking • Metal Leaching • Quality Control • Standard Tests

 

FEATURES 
• 16 Potentiostats • 500 mA per Channel • High Impedance RE • Fixed Potentials • Very Stable • Measure Current • Measure RE

Kulim Kht SPR BioNavis reflectometer for liquids

Surface plasmon resonance instrument as a refractometer for liquids and ultrathin films

A surface plasmon resonance (SPR) setup in Kretschmann configuration is being utilized as a refractometer for both liquids as well as ultrathin films. The SPR signal detection technology used is based on a goniometer approach providing a wide angular scan range which facilitates highly accurate liquid and gas phase measurements.

Attention was paid to improve sample handling and preparation. In order to avoid cross-contamination between measurements an easily removable and exchangeable molded PDMS flow cell was used during the measurements. By careful choice of components for liquid handling the dead volume of the system could be reduced down to some microliters.

The angular change and thus the refractive index for sucrose, ethylene glycol (EG) and ethanol solutions with different concentrations, the thickness and refractive index of deposited Langmuir-Blodgett (LB) films, and the interaction kinetics between a biotin containing self-assembled monolayer (SAM) and streptavidin were determined. The measured refractive indices of sucrose, EG and ethanol solutions corresponded well with literature values. LB films were characterized by measuring the complete SPR curve in an angular scan range from 40 to 78[degree sign]. A two-color SPR approach combined with two-media measurements was successfully employed for simultaneous and unambiguous determination of both refractive index and thickness of stearic acid monolayers. The thickness obtained for the stearic acid monolayer was 2.66 nm, and the refractive indices at 635 and 670 nm were 1.5800 and 1.4138, respectively. The developed sensor-plate holder enabled functionalization of the SPR gold chip outside the instrument, therefore making the sample handling more flexible. The affinity constant obtained for the streptavidin-biotin interaction was 1.01 x 10-8 M. The total angle SPR method used in this study clearly shows its potential to be used as a refractometer for both liquids and ultrathin films, as well as for traditional liquid phase biomolecular kinetic studies.

"BioNavis' SPR Navi system allows unique configurations for multiple concurrent research projects"

Prof. Orlando Rojas
North Carolina State University in Raleigh
United States

Kulim Kht SPR BioNavis CMC

Modification of cellulose films by adsorption of CMC and chitosan for controlled attachment of biomolecules

The adsorption of human immunoglobulin G (hIgG) and bovine serum albumin (BSA) on cellulose supports were investigated. The dynamics and extent of related adsorption processes were monitored by surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation monitoring (QCM-D). Amine groups were installed on the cellulose substrate by adsorption of chitosan from aqueous solution, which allowed for hIgG to physisorb from acid media and produced a functionalized substrate with high surface density (10 mg/m2). hIgG adsorption from neutral and alkaline conditions was found to yield lower adsorbed amounts. The installation of the carboxyl groups on cellulose substrate via carboxymethylated cellulose (CMC) adsorption from aqueous solution enhanced the physisorption of hIgG at acidic (adsorbed amount of 5.6 mg/m2) and neutral conditions. hIgG adsorption from alkaline conditions reduced the surface density. BSA was used to examine protein attachment on cellulose after modification with chitosan or carboxymethyl cellulose. At the isoelectric point of BSA (pI 5) both of the surface modifications enhanced the adsorption of this protein, when compared to that on unmodified cellulose (a two-fold increase from 1.7 to 3.5 mg/m2). At pH 4 the electrostatic interactions favored the adsorption of BSA on the CMC-modified cellulose, revealing the affinity of the system and the possibility of tailoring biomolecule binding and regeneration by choice of the surface modifier and pH of the medium.

info(a)bionavis.com.

SPR Kulim Kht Bionavis surface plasmon resonance

Langmuir-Blodgett film characterization in
air using surface plasmon resonance.



Introduction

The ability to assemble ordered molecular films with tailored
functionality over macroscopic lateral dimensions provides
exciting and unique opportunities in many practical and
commercial applications. Sensors, detectors, displays and
electronic circuit components are just a few examples. This
well known technique is referred to as Langmuir-Blodgett
(LB) deposition, where films of functional molecules,
nanoparticles, nanowires or microparticles are spread at the
air-water interface, compressed and transferred to a solid
substrate. Compared to other organic thin film deposition
techniques, such as thermal evaporation, sputtering,
electrodeposition, molecular beam epitaxy, layer-by-layer
or self-assembly, LB is much less limited by the molecular
structure of the functional molecule. This means that it
is often the only technique that can be used for bottom up
assembly in nanotechnology and functional materials
 The Langmuir-Blodgett (LB) technique, used to deposit single and multiple
 layers of molecules on a solid substrate.
applications. The aim of this note is to demonstrate that
SPR-Navi from BioNavis is ideal for the ex situ
investigation in air of mono- and multilayer films of stearic
acid deposited on a gold surface.
Experimental
The gold-coated glass slides used in the SPR
measurements were cleaned by immersion in a boiling
1:1:5 NH3OH:H2O2:H2O for ten minutes, flushed thoroughly
with ion exchanged water and blown dry with nitrogen.
Monolayers and multilayers of Cadmium Stearate (SACd,
(C17H35COO)2Cd) were deposited via the LB technique
(KSVNIMA LBtrough System 2) on cleaned gold slides,
. Complete SPR curves were
measured after depositing one, three and five layers of
SACd on separate gold slides.

Results
 illustrates SPR intensity versus angle curves for
the clean gold surface, and for surfaces with one, three and
five deposited layers of SACd. There are some differences
in the absolute minimum value in the SPR curves between
different samples. This difference stems from the use of
separate gold slides, and does not affect the validity of the
measurement.Fitting the experimental data with a theoretical model (solid
curves,  allows determination of the layer thickness
of the deposited LB layers (WinSPALL Software, Wolfgang
Knoll, MPI, Germany).  thickness increases linearly with layer number, as expected for this
system. Meanwhile, the slope of the thickness vs. layer
number plot is 2.45 nm/deposited layer, which is in very
good agreement