138mm, below electrode holder
D-PAS - for UV pKa measurement
Please note: We have discontinued production of new D-PAS systems due to the launch of its successor, the new SiriusT3.
Service and support for existing D-PAS customers will remain available until further notice.
Overview
Advanced UV pKa measurement on GLpKa and PCA200
- Typical sample weight: 150 micrograms
- Typical assay concentrations: 0.05mM
- Single- or multi-protic molecules
- Macro- and micro-constants
- Measures molar extinction coefficients
- Diode Array detector measures 220 to 700nm in a single pulse
- Full, real-time computer control
- Easily fitted to Sirius GLpKa or PCA200
- Adds Turbidity Detection for pH-metric pKa assays
D-PAS is an accessory for Sirius' GLpKa and PCA200 instruments. With D-PAS, the multiwavelength UV spectrum is measured while the sample is titrated, and pKa is determined by RefinementPro software from the changes in UV absorption that occur as a function of pH whilst the molecule undergoes ionization. This pH-UV method for pKa measurement is preferred by most customers because it's faster than pH-metric pKa measurement, works at much lower concentration (very helpful for poorly soluble compounds), and also because the calculation of results from the data is faster and much easier to perform.
Spec with GLpKa
Length of dip-probe
Probe body and barrel material
Stainless steel
Type of miror
Quartz
Path length
10mm
Length of fibres
1115mm for GLpKa
Fibre material
Quartz
Lamp type
Pulsed deuterium fitted with 215nm cut-off filter
Lifetime of lamp
1000h (500h warranty)
Detector type
Diode array, 256 diodes
Detector wavelength range
190-735nm
Integration time
Minimum 10.5ms, maximum 655 ms
Typical sample concentration range
0.001- 0.1mM
pKa detection range
0-6 - 12.0
Signal-to-noise
0.0005 absorbance units @250nm
Services required
One mains power inlet (110, 130, 220, or 240V)
Computer
Windows 2000 or XP operating system Minimum 128MB RAM, recommended 512MB RAM for Windows XP One free full height PCI expansion slot for data collection card dimensions are 175mm (L) x 107mm (W) x 15mm (H). Note that a low profile PCI 2.2. standard slot is unsuitable.
Connection to the PC
Cable to data collection board (800mm maximum length) Note: the PC must be next to the D-PAS
Connection to the GLpKa
Attaches to the left-side of the GLpKa and via dip-probe optical fibres
Software
RefinementPro version 2.0.1.1 or later
GLpKa requirements
On-line connection to PC during assay GLpKa firmware revision 1.129 or later with D-PAS option selected
Reagent requirements
Phosphate buffer for mid-range titrations (0.2g dipotassium hydrogen orthophosphate (AR grade, FW 136.09) in 100mL ISA Water)
Dimensions
150 x 253 x 655mm (W x D x H)
Weight of unit
12.8kg
Dimensions of packaging
445 x 475 x 755mm
Weight of packed unit
20kg
Spec with PCA200
Length of dip-probe
138mm, below electrode holder
Probe body and barrel material
Stainless steel
Type of miror
Quartz
Path length
10mm
Length of fibres
830mm for PCA200
Fibre material
Quartz
Lamp type
Pulsed deuterium fitted with 215nm cut-off filter
Lifetime of lamp
1000h (500h warranty)
Detector type
Diode array, 256 diodes
Detector wavelength range
190-735nm
Integration time
Minimum 10.5ms, maximum 655 ms
Typical sample concentration range
0.001- 0.1mM
pKa detection range
0-6 - 12.0
Signal-to-noise
0.0005 absorbance units @250nm
Services required
One mains power inlet (110, 130, 220, or 240V)
Computer
Windows 2000 or XP operating system Minimum 128MB RAM, recommended 512MB RAM for Windows XP One free full height PCI expansion slot for data collection card dimensions are 175mm (L) x 107mm (W) x 15mm (H). Note that a low profile PCI 2.2. standard slot is unsuitable.
Connection to the PC
Cable to data collection board (800mm maximum length) Note: the PC must be next to the D-PAS
Connection to the PCA200
Attaches to the left-side of the PCA200 and via dip-probe optical fibres
Software
RefinementPro version 2.0.1.1 or later
PCA200 requirements
On-line connection to PC during assay PCA200 firmware revision 2.107 or later with D-PAS option selected
Reagent requirements
Phosphate buffer for mid-range titrations (0.2g dipotassium hydrogen orthophosphate (AR grade, FW 136.09) in 100mL ISA Water)
Dimensions
150 x 253 x 655mm (W x D x H)
Weight of unit
12.8kg
Dimensions of packaging
445 x 475 x 755mm
Weight of packed unit
20kg
Latest product news
PCI card
PCI card A PCI card must be installed in the PC to receive the spectral data from D-PAS. The cases
of some modern computers are so small that there is no room inside them to accommodate the PCI
card, even though the PCI slot is available. We therefore recommend that the PC chosen to use with
D-PAS has one free full height PCI expansion slot for D-PAS data collection size 175 x 110 x 15 mm.
A low profile 2.2 standard slot is unsuitable.
Added: 2006
Literature
Electronic copies of our D-PAS brochure and technical specifications are available for download:
> D-PAS Brochure> D-PAS Technical Specifications
New Scientific Paper Published
07.12.09
New paper from Sirius explains how our solubility measurements work, and introduces new methods for evaluating supersaturation.
New Scientific Paper Published
01.07.10
New paper - Study of pH-dependent solubility of organic bases. Revisit of Henderson-Hasselbalch relationship.
Physchem Forum 9, Barcelona
17.09.10
Sirius will exhibit at and sponsor the next Physchem Forum meeting in Barcelona