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DAx Data Acquisition and Data Analysis

Presentation of features

DAx Data Acquisition
Data Analysis Algorithms
Automatic Parameters
Shoulder Peak Detection
Manual Editing
Peak Qualification
Peak Quantification
Peak Comparison Sheets
Data Arithmetic
Fourier Filtering
Optimum Fourier Filtering
Analysis Assays
DNA Fragment Analysis
SNP Base Call Sheets
HPLC / GC Gradient Correction
Capillary Electrophoresis
Calibrations: DNA Base Pair Count Determination
Calibration Curves in DAx
Gel Permeation Chromatography
Data Presentation
Data Lists
Command Line Use
Good Laboratory Practice

DAx is a general purpose peak analysis program, yet includes specialised support for
  • Capillary Electrophoresis
  • Gel Permeation Chromatography
  • Calibrations (e.g. DNA Base Pair Count determination)
  • HPLC (with Gradient Correction)
  • Gas Chromatography
  • RFLP analyses (with automatic size calibration)
  • SNP analyses


  • DAx is highly customisable: unused options can be hidden from the user
  • Measurements are typed (HPLC, GC, CE, GPC, Generic). Options that are not relevant to a certain data type will not be shown

DAx Data Acquisition

  • Hardware options include PCI boards and USB solutions
  • Multi channel data acquisition
  • Hierarchical measurement linking
  • Measurement sequences using sample changers
  • Automatic re-calibrations during measurement sequences
  • Various measurement triggering methods

Data Acquisition

Data Analysis Algorithms

  • Baseline construction and subtraction
  • Peak finding … and refusal
  • Automatic peak shoulder detection
  • Tangent skimming
  • Spike removal
  • RMS and “Trumpet” noise calculation


Automatic Parameters

Analysis parameters are derived from data

original signal
Baseline construction filter width derived from highest number
of consecutive data points with high derivative values
Construct and subtract baseline
baseline subtracted
Sort by absolute value
sorted by absolute value
The red lines are extrapolated to give the "Trumpet Noise Level".
This is then used to set up a threshold to find peaks.

Shoulder Peak Detection

Automatic shoulder peak detection based on up to 4 criteria

Shoulder detection by slant
Degree of slant
Shoulder detection by skim ratio
Skim ratio
Shoulder detected when ratio

Shoulder detection legend

exceeds boundary value
Shoulder detection by relative width
Relative width
Shoulder detection by relative area
Relative area

Manual Editing

  • Sizing data (for instance to compare / overlay them)
  • Baseline corrections
  • Adding, changing, removing peaks
  • Marking shoulder peaks (shown)
All edit operations have 20 levels of undo.

equal peaks The many equal peaks in the plot at left are turned into shoulder
peaks using a single click and drag operation.
shoulder peaks

Peak Qualification

Peaks are identified using an Identification Database

  • Various qualifying parameters:
    • peak top time, first peak moment
    • peak begin or end time [ion chromatography]
    • peak top elution volume
    • molecular weight
    • apparent mobility, effective mobility
    • base pair count (calibrated value)
    • coordinate relative to other peak(s)
  • Various qualifying methods:
    • near coordinate
    • in interval (with or without area limit)

Peak Quantification

  • Various quantifying parameters:
    • peak top height
    • peak area
    • normalised peak area
    • migration time corrected peak area
    • migration time corrected normalised peak area
  • Various calibration curve types:
    • multi-linear
    • spline
    • polynomial

         Calibration Curves

  • Configurable per component or for entire database

Peak Comparison Sheets

Comparing duplicate measurements
  • Various qualifying parameters to determine which peaks correspond
    • peak top time, first peak moment
    • peak top elution volume
    • molecular weight
    • apparent mobility, effective mobility
    • base pair count
  • Sheets can be one dimensional (list) or two dimensional (binning sheet)

Comparing peaks

Data Arithmetic

  • Add, subtract, multiply, divide data by constants
  • Add, subtract, multiply, divide data by other data
  • Fourier (optimal) filtering (see below)
  • Moving average filtering
  • Savitzky-Golay filtering
  • Convolution and Deconvolution

Fourier Filtering

low pass filter
Low pass filter results
                              high pass filter
High pass filter results

detail view
Detail view             
original signal
          Original signal

Optimum Fourier Filtering
original signal
Original signal
     optimum filtered
Optimum filtered
Derive characteristics: signal to noise ratio as function of filter width characteristics Use optimum filter width

  • Reports can contain the following items:
    • Logos (bitmaps or metafiles)
    • Texts
    • Variables (e.g. "filename)
    • Data plots
    • Peak lists
    • Various calibration curves
    • Lines &Rectangles
  • Report editor is fully featured drawing program
  • Multi page reports
  • Several measurements on a single report page
  • Automatic report printing when measurement ends

Analysis Assays
Automatically determine quality of analysis
  • Baseline quality (interval, drift, noise)
  • Peaks quality (maximum skew, number and area of unrecognised peaks)
  • Presence of required peaks
  • Presence of unwanted peaks
  • Calibration quality (steepness, curvature)

DNA Fragment Analysis

  • Read ABI, Amersham, SCF files
  • Automatic size calibration details
  • Create binning sheets to compare hundreds of samples
  • Command line batch analysis enables processing of thousands of samples per day
  • Locate specified base sequences in multiple samples simultaneously



SNP Base Call Sheets
  • Specify base sequence with SNP locations
  • Read up to hundreds of trace files

  • Base Calls Sheet displays SNP locations in overview:
  •   Base Calls Sheet detail

  • Colour-view for alignment overview:
  •   Colour-view



HPLC / GC Gradient Correction

  • User entered or data derived gradients
  • Convenient manual editing of gradients
  • Gradient Percentages or Temperature Programme displayed as curve
  • Subtracting Gradients

not gradient corrected

The signal value Gradient Nodes can be dragged using the mouse.
(Gradient shown exaggerated here for clarity.)
    Subtract signal gradient      
after gradient correction

The second vertical axis is for the gradient level plot.

Capillary Electrophoresis

  • Apparent and Effective mobility calculations
    • Mobility axis
    • Mobility tracking
    • Recognising components by mobility
    • Recognising components by peak begin / end coordinate
  • Normalised (corrected) peak areas
    • Can be used to quantify components
  • Reference peaks mark EOF
  • Reads ABI Genescan and Amersham MegaBACE files

Calibrations: DNA Base Pair Count Determination

  • Calibration Curves   (see below)
  • Saving and Loading Calibrations
  • Calibrated value axes:
Base Pair Count

Calibration Curves in DAx

Calibration curves are used:
  • for quantitative analysis
  • to derive molecular weights in GPC    Gel Permeation Chromstography
  • to derive calibrated values, such as DNA base pair counts    Calibrations

All calibrations can take several forms:
  • poly-line (connecting data points with straight lines)
  • cubic spline
  • polynomial
    • linear and logarithmic calibrations (not for quantitative analysis)

calibration curve
Example of a calibration curve. The calibration is a first order polynomial.
The two points at the extreme left have been excluded from the calibration (they are marked with circles rather than dots).

Gel Permeation Chromatography

  • Calibration curves relating molecular weight to elution volume
    • multi-linear
    • cubic spline
    • polynomial
    • linear or logarithmic

  • Recognising components by Mp, Mn, Mw or Mz

  • Tracking molecular weight

  • Molecular weight axes
  • Elution volume axes


Data Presentation
  • Data set overlaying (with or without normalising)
  • Extensive peak labeling and annotation
  • Fully customisable reports (including logos)
  • Copying graphs to clipboard using metafiles
  • Exporting data
    • Several ASCII based files
    • Andi (AIA) files

Data Lists
Quick Reference Overview of Data Files
  • Data Lists list numerous properties:
  • File name
  • File date & time
  • File type
  • Data set name
  • Operator name
  • Measurement time
  • Number of data points
  • Frequency
  • Ordinate name
  • Description
  • Data type
  • Sort by any property
  • Search for property values
  • Select all files that meet one or more search criteria
  • Display component concentrations overview for all data files in list

Command Line Use

Direct analyses entirely from the command line for very high through-put applications
For details click here

Big computer

Good Laboratory Practice

  • Name registration (with password login)
  • Error messages and warnings are logged
  • Operations on data are logged
  • Preservation of raw measurement data
  • File overwrite prevention