PCA200

Overview

Entry level automation for pKa, logP/D, Solubility and Dissolution measurement

  • pH-metric pKa, logP and logD
  • Optional Solubility module
  • Optional Dissolution module
  • pH range of 1.8 - 12.2 (for standard titrations)
  • Measurements down to 0.5mM
  • Built-in traceability and reminders
  • Supports D-PAS for spectrophotometric pKa
  • Temperature controlled sample position

PCA200 is a semi-automated instrument for high-quality measurement. It is ideal for laboratories with a low sample throughput, or for academic research applications.

In pH-metric methods, pKa is measured by titrating a solution of the sample in water or solvent with acid and base, and calculating the pKa from the shape of the titration curve. In principle they will always find the pKas of a sample, provided the concentration is adequate (e.g. >0.0005M). In practice it may be necessary to work at a lower concentration using a pH/UV method and the D-PAS accessory. LogP is also measured by a pH-metric method, based on a two-phase acid- base titration in a mixture of water and octanol. It works well for poorly water-soluble samples, because they tend to dissolve in the octanol phase.

PCA200 can be used with D-PAS for spectrophotometric pKa measurement. Results are calculated by RefinementPro 2 software. PCA200 can also be upgraded to perform Solubility measurements. Since its introduction in 2000, PCA200 has become the instrument of choice for measurements of ionisable compounds in low-throughput environments such as formulation and regulatory support departments in pharmaceutical research and in universities.

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specification

pH electrodes

Ag/AgCI, double junction reference

Stirrer

Overhead, variable speed

Temperature probe

PT100, allows automatic temperature compensation

Precision dispensers

Acid and Base, minimum of 0.4µL with 5mL syringe

DualTip dispenser

Two quartz dispenser tubes

Probe movement

Fully automated X-Y axis

Washes

Two water washes and one special wash station provided

Electrode storage/calibration

Two pH7 buffer positions, one storage and one calibration

Single sample holder

Glass temperature control vessel (external circulating bath required)

Purge gas

Nitrogen or argon required

Partition solvents

Supports 7 including Octanol and a generic solvent

CoSolvents

Supports 10 including MeOH and DMSO

Keypad

Liquid-crystal 16-line display for text and graphics, 22-buttons for numeric data entry

System standardisation

Sirius Four-Plus(TM) procedure

Sample concentration

>0.5 mM (depending on the pH range)

pH-range

1.8 - 12.2

Assay volume

Minimum 5mL, maximum 20mL

Spectroscopy

Supports D-PAS

Services required

One mains power inlet (110 or 240 V)

Connection to the PC

Cable from PCA200 to PC serial comm port

Computer

Windows 2000 or XP

Software

PCA200 Firmware Version 2.107. RefinementPro Version 2.0.1.1

Reagent requirements

See 'pH-metric reagents' sheet

Dimension

600 x 440 x 520mm (WxDxH)

Weight of unit

25kg

Dimensions of packaging

900 x 800 x 750mm (WxDxH)

Weight of packed unit

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Services required

You will need a computer, which is required to run the software that accompanies the instrumentation. The minimum specification as shown below.

PC specification

Pentium processor Minimum 128 MB RAM Hard disk, CD ROM, floppy drive

1024 x 768 screen display One free PCI expansion slot for data collection card (for D-PAS if required later) of size 175 x 110 x 15mm (LxWxH). Graphics card that supports OpenGL One free serial port

PCA200 connection to the PC

Cable to serial port (no limit to length)

Software required

Windows 2000 or Windows XP operating system PCA200 firmware revision 2.107 RefinementPro version 2.0.1.1

Sirius will supply all the necessary cables between the instrumentation and the PC. You will also require access to a colour printer, either local or networked.

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Services required D-PAS

You will need a computer, which is required to run the software that accompanies the instrumentation. The minimum specification as shown below.

PC specification

Pentium processor Minimum 128 MB RAM Hard disk, CD ROM, floppy drive

1024 x 768 screen display One free PCI expansion slot for data collection card (for D-PAS if required later) of size 175 x 110 x 15mm (LxWxH). Graphics card that supports OpenGL One free serial port

D-PAS connection to the PC

Cable to serial port (800mm maximum length) Note: hence the PC must be next to the D-PAS

GLpKa connection to the PC

Cable to serial port (no limit to length)

D-PAS connection to the PCA200

Attaches to the left side of the PCA200 and via-dip pro

Software required

Windows 2000 or Windows XP operating system PCA200 firmware revision 2.107 RefinementPro version 2.0.1.1

Sirius will supply all the necessary cables between the instrumentation and the PC. You will also require access to a colour printer, either local or networked.

Bench space (min)

Width 780mm
Depth 440mm
Height 660mm

This excludes the space required for the PC and printer

Argon

Supply of argon ready to be connected to the right-hand side of PCA200. Your supply must be fitted with a pressure reducer that gives 0-5 bar. The standard working pressure required for PCA200 is 0.5 bar

Temp. circulator

PCA200 has only two dispensers so the ISA water, partition solvents, and co-solvents must be added manually. The volumes added have to be accurate so it is recommended to use positive displacement pipettes, e.g. Eppendorf, which have disposable tips. To cover the range of volumes required, use two variable volume pipettes, i/ 20µL-200µL and ii/500-5000µL

Set-up a constant temperature circulator that will supply temperature controlled water to the PCA200 temperature control unit. Sirius will supply two connectors that fit tubing with an internal diameter of 5mm. The customer is required to supply suitable tubing to fit between these connectors and the water circulator. Ensure that the circulator is below the height of the bench on which the PCA200 will be sited.

A suitable specfication is:

5-80°C +/-0.1°C
2 psi free flow pressure
Maximum pressure when outlet is blocked 10 psi
4L capacity
Cooling rate of 1 degree per 2-3 minutes

The customer is required to make up the following reagents:

Distilled/de-ionised water

This water is used for making up reagents and for rinsing. It should be freshly distilled or de-ionised, or purchased (e.g. HPLC-grade). The resistivity of the water should be more than 10MW cm.

ISA water (Ionic strength adjusted water): 0.15M Potassium Chloride

Volume required: 4L
This solution is distilled or deionised water with its ionic strength adjusted by the addition of inert "background electrolyte" salt. This ISA water is used as the matrix for all the titrations.

Acid titrant: 0.5M Hydrochloric acid

Volume required: 1L
We suggest that customers purchase this ready-made as a volumetric standard. Check that the solution does not contain mercury salts or other additives. Sirius recommend Aldrich 31,895-7 05027N HCI solution.

Base: 0.5M Potassium Hydroxide

Volume required: 1L
Must be made from CO2 -free ampoules of KOH solution. Do not use flakes or pellets of KOH, or ready-made volumetric standards, as these forms of KOH usually contain significant amounts of CO2-. The Sirius applications laboratory uses ampoules containing concentrated KOH solution. Suitable ampoules are supplied by Fisher and Merck. The KOH solution should not be stored in a glass container after preparation because KOH slowly dissolves silica from the glass, which interferes with pKa determinations.

Partition solvent

olume required: 1L
The partition solvent most commonly used is octan-1-ol (C8H17OH) which is the default partition solvent when GLpKa is installed. The octanol should be "water-saturated" (this can be done at the time of installation). We recommend "partition-grade" octanol.

CoSolvent solutions

Up to four CoSolvents can be connected to the 4-way valve. The customer should supply 1L of 80% methanol at the time of installation. Additional solutions can be made up during or after installation. To make up 80% methanol, weigh 11.18g of KCI, dissolve in 200mL of water and add methanol to make volume up to 1L in a volumetric flask.

Surfactant wash solution

Volume required: 1L
This is a 0.5% solution of Triton X-100 in water. Dissolve 5mL of Triton X-100 in 1L of water. (Triton X-100 is a Registered Trademark of Rohm and Haas)

Potassium Hydrogen Phtalate (KHP)

Weight required: 100g
High purity crystalline solid used for standardising base titrant.

Soda lime, self-indicating

Used to recharge the CO2 absorption tube which is fitted to the KOH reagent bottle.

Mid-range Phosphate buffer for D-PAS

Potassium dihydrogen orthophosphate, AR grade (Fisher p/no P/4800/60) 0.40g in 200mL ISA water

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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

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Literature

Electronic copies of our PCA200 brochure and technical specifications are available for download:

> PCA200 Brochure
> PCA200 Techinical Specifications
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Sirius appointed as distributors for Kibron Delta-8

24.7.08

Sirius are now the exclusive distributors in UK, USA and Canada for the Kibron Delta-8 system for measurement of surface tension and phospholipidosis.

Read more

Cambridge scientists set solubility challenge

11.8.08

A new paper from scientists using Sirius solubility techniques at the University of Cambridge asks "can you predict solubilities of 32 molecules using a database of 100 reliable measurements?".

Read more

AAPS Annual Meeting

16.11.08

Sirius will have a booth (#1460) at this years AAPS Annual Meeting in Atlanta, Georgia.

Read more

LogP2009

08.02.09

We are main sponsors of the logP2009 meeting in Zurich, Switzerland. We will have an exhibit booth showcasing our latest products and services.

Read more

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