Aquarius UV/Visible  Spectrophotometers

Further Information

System Functions



Double Beam Optical System

The fully symmetrical optical system measures sample and reference simultaneously for ultimate accuracy, precision and baseline flatness. Long term stability is up to ten times better than single beam systems.


Integral Control System

All control software is within the instrument, tamper proof, providing easy menu driven operation with massive safe storage for scans, plots, curves etc. PC control and data transfer to a PC are provided.


Equal Sample and Reference Facilities

Identical and generous sample and reference sampling facilities widens the scope of measurement, for example, to enable multi-cell sampling in both beams and accommodate bulky accessories in the reference beam.


Method Operation and Storage

Up to 30 sets of instrument parameters, including concentration curves may be stored, security code protected. When recalled, instrument parameters are automatically set, avoiding errors.


Alpha Numeric Entry

Full Alpha Numeric entry is provided so that results may be fully documented for GLP. Formula entry enables the creation of a wide range of formulae for automatic calculations using many wavelengths.


Software Enhancement By E-SEF

E-SEF - Encoded Software Enhancement Facility - allows software modules to be enabled using encoded numbers provided by telephone, fax or E-mail. Software requirements may be tailored, at any time, as required.


Data Storage and Protection

Data, including 100 spectra, concentration curves , kinetics and time course plots may be stored in safe memory, security code protected against tamper or deletion using a four digit password.


Reprocessing

Scans, time course plots, and reaction curves may all be reprocessed to any required format on the display screen and then plotted on the integral or an external printer.


Performance Validation

Software and certified standards enable wavelength accuracy, Absorbance accuracy, bandwidth etc. to be validated. A timed and dated report includes the serial number of the instrument.

Quantification


Powerful Quantification

Many quantitative methods are available including band area computation with background correction, differencing and stripping of spectra, wine and colour assays, mathematical calculations between several wavelengths, protein and DNA assays.


Curve and Line Fitting

A linear, quadratic or cubic concentration curve may be fitted to up to 30 standards, with or without an intercept at the origin. Standards may be deleted and replaced and a new curve fitted.


Reaction Kinetics

Single cell kinetic measurements are possible with plots and data displayed on screen. Data may be reprocessed, regression analysis applied and curves stored, security code protected against tamper or deletion.


Multi-Cell Reaction Kinetics

Up to four or six cells are automatically measured with all reaction curves displayed on screen. Each curve may be selected for processing with the results of regression analysis printed.


Multi Wavelength Assays

Assays are provided using either two or three wavelengths. A wine colour assay is provided which may use up to ten different wavelengths. Computations at up to four wavelengths are also provided.


DNA and Protein Assays

Protein assays may be made using either the 2 or 3 wavelength methods of Warburg and Christian. Also programmed are techniques and analytical procedures for assays by Lowry, Bradford, Biuret and BCA methods.


Band Area and Height Computation

Band areas with correction for sloping background absorption are readily quantified, with all details and construction displayed. Band areas may also be computed for derivative spectra to facilitate difficult quantification.


Wavelength Program

Using the various cell changers, measurements may be made on up to 4, 6 or 8 cells at a single wavelength with cycle time and number of cycles entered by the operator. A cell and wavelength program may be combined.


Cell Program

Measurements may be programmed for 10 different operator selected wavelengths with the cycle time and number of cycles selected by the operator. A wavelength and cell program may be combined.

Scanning


Double Beam Wavelength Scans

cans at up to 4000nm/min are presented on screen or printed with all peaks annotated with wavelength and absorbance. Tables are also presented listing all peaks and troughs with values.


Display Scrolling

Use of the display scrolling facility enhances the effective screen size and enables spectra and data up to 550nm wide to be viewed.


Dynamic Scan Recall

The last eight scans are automatically retained for recall by entering their scan sequence number and may be reprocessed, overlayed or transferred to protected memory for future recall.


Overlayed Spectral Scans

Up to eight scans, including stored scans, may be overlayed, with or without offsets for convenient comparisons or further manipulation.


Difference Spectra

New wavelength scans or scans from store may be presented on screen and the difference spectra produced. The scans may be normalised enabling spectral stripping to reveal impurities or additives.


Derivative Spectra

Derivative spectra, up to fourth are readily produced, with selectable smoothing, either alone or superimposed on the fundamental, with or without an offset. Scaling is automatic with all peaks and troughs quantified.


Scan Storage

Up to 100 spectra may be stored in 10 safe memory banks for future recall. Each spectrum is automatically allocated a recall number, when stored, and may be security code protected against tamper or deletion.


Programmed Scans

Automatic scans, single or repeat may be made of a cell program of up to 4, 6 or 8 cells. A programmed sequence of scans may also be made of a single sample.


Time Course Plots

Changing samples or flows may be examined and displayed by making a time course plot. Data may be reprocessed and stored, security code protected, with an automatically assigned recall number.

Sampling


Sampling Flexibility

The design of the double beam optical sampling allows exactly similar space and facilities in both the sample and reference beams.  Full size accessories and multi-cell reference sampling, with temperature control is therefore possible.  Operation is not limited to a single standard cell in the reference beam as in some other instruments.


Reflectance/Gel Scanning

Accessories include fixed angle and variable angle reflectance units and a gel scanning system for gels up to 100mm long.


Multi-User Convenience

Aquarius double beam instruments were designed for the greatest convenience in a laboratory where multi user operation is required.  All methods, stored scans, plots, curves and data remain in secure integral memory, tamper protected by passwords, readily accessible to all operators without the possibility of mislaid disks or plug in card modules.


Cells and Flowcells

As well as 10mm cells and flowcells, holders are available for rectangular and cylindrical cells up to 100mm pathlength. A microsampling system measures to 50ml or below.


Automatic Cell Changers

Automatic changers are available for 4, 6 or 8 cells, providing rapid sample changing or the facility for full programming.


Sipette Sampling

Samples down to 300 microlitres may be measured in a 10mm cell. Sampling is under control of the instrument's microprocessor system. Samples may be saved or pumped to waste.


Ultra-Micro Sampling

Valuable samples, such as biological samples prepared with costly reagents, may be measured using a special ultra-microcell and holder. With the system, samples of 50µl or even less may be accurately measured.  Third party nano cells may also be used.


Sample Temperature Control

Water and thermoelectric temperature control are available for single cells and automatic cell changers. Temperature is set from the control panel and displayed on the screen.


Dissolution Testing

Versions of the instruments fitted with a special cell compartment with piping port, are available for dissolution testing using Cecil TD software and a PC. Six and eight cell changers are available.


Batch Sampling

Automatic batch sampling for up to 100 samples is available. The pump fits within the sample compartment and volume etc is set from the control panel and displayed on screen. Batch number entry is provided.


Specular Reflectance

Special accessories enable specular reflectance measurements to be made. Both fixed angle and variable angle reflectance accessories are available. The latter is particularly useful for film thickness measurements.


Gel Scanning

A gel scanner enables gels up to 100mm long to be measured. An autoradiograph film holder is also available.


Micro - Sipette Sampling

Small samples or multiple samples are conveniently measured using the micro-sipette system, with very low cross contamination.  All measurements are made in the same cell, enhancing accuracy.  The pump, which is mounted in the sample compartment, operates under the control of the instrument's micro-processor system.

Assay Programmes


Reaction Kinetics

Both single cell and multi cell Kinetics are available with reaction plots to screen and printer. Regression analysis is applied to the user selected portion of reaction curves and results are reported in Units/Litre. Data may be reprocessed as required and curves stored. Sample temperature control is available for single cells and four and six cell changers.


Advanced Kinetics

An example of advanced kinetics is shown below where time based reaction data generated by the spectrophotometer, has been transferred into Grafit, fitted to a curve and transformed into a more suitable format for mathematical interpolation and calculation. In this particular example, the basic data plot can yield the limiting rate (Vmax), the Michaelis constant (Km) and the initial linear portion (Vmax/Km).


This has been transformed into the Eadie-Hofstee format and plotted to give better precision in the calculation of these important factors and constants.


Other transformations are available such as Lineweaver-Burk and the Hill plot for allosteric enzyme systems.


PC Data Manipulation

Using DataStream software, data may be transferred to a PC for use with spread sheets and other mathematical software packages.


More advanced reaction kinetics data manipulation may be readily performed with Grafit software. Linear, non-linear or polynomial curve fitting is easily accomplished together with non-linear regression analysis. A wide selection of standard equations are provided, together with an equation editor for customised equation fitting.


Data may also be transformed into other mathematical formats for plotting and calculation.



Band Quantification

Accurate quantitative assays using band area or height, corrected for background absorption, are exceptionally easy to carry out with the Series 7000 Aquarius instruments.


Analytical results are displayed on the screen with construction lines enabling the quality of the parameters to be assessed.


The procedure may be stored as a method with security code protection in the integral memory of the instrument.

Validation



Assessment of instrument performance is readily carried out using the validation software module built into all Aquarius instruments and released by E-SEF, 'encoded software enhancement facility'. Laboratories subject to regulatory control, or following G.L.P. are provided with a range of Pharmacopoeia (EP) tests as well as tests using filters traceable to national standards with certificates of calibration issued by Cecil Instruments. A selection of the tests are shown here.


Absorbance Accuracy

The Pharmacopoeia (EP) test for Absorbance accuracy, using a 60mg/L solution of Potassium Dichromate in a 10mm pathlength cuvette, is shown here.



Optical Bandwidth

The optical bandwidth of the instrument may be validated by measuring the half height width of the narrow deuterium emission line at 656.1nm. The measurement is carried out automatically.


Validation Using Filters

Absorbance accuracy is most conveniently measured using certified filter sets calibrated by Cecil Instruments against NPL certified standards. A validation printout for the procedure is shown here. Wavelength calibration is also carried out using certified filters.