“EXPORT” is a standardized chromatography ASCII data file
available after integration of the raw data.

This file contains only the “reduced” raw data:  retention time (tms), peak width in half height (b05), peak height, peak area, and - as far as already available - retention index data.

“EXPORT” allows strict data reduction without loss of information. It offers new modes to read, compare, improve and understand chromatograms.


“EXPORT” contains only “reduced raw data” as they become available by and after integration. The “EXPORT” file allows a nearly unlimited use of qualitative and quantitative chromatographic evaluations. The file structure written exclusively in ASCII contains the retention time in seconds, the peak width in seconds, the peak height in volt or ampere (milli-, micro-, nano-..), the peak area in volt x seconds, one to two 255 characters long data line(s) containing all relevant information like place of sample taking, sample pretreatment, sample giving, instrument type and number, method, time of analysis, analyst, all separation system data and remarks.

These are the possibilities offered by the “EXPORT” standard chromatography
data file - available automatically with special software:

1. Auto removal of false data like spikes or removal of solvent peaks upon a given command.
2. Auto analysis about data “runaways” like false integrated peak areas because of
   signals are outside the linear or calibrated detector working range.
3. Removal of peak signals with excessive broadness but giving an ALERT.
4. Correction of retention time in case of temperature (GC) or flow (HPLC)
   problems during the analysis or for other purposes like precise chromatogram comparison.
5. Calculation of the retention index for all peaks (GC isothermal, temperature or
   pressure programmed and integration of the index values into the EXPORT chromatogram file).
6. Calculation of the k-values or, if phase programmed, of LC-index values and
   integration of the k-, or index values into the EXPORT chromatogram file.
7. Correction of selected peak areas by correction factors for quantitation purposes.
8. Calculation of specifically selected data like the n-alkane content in a hydrocarbon mix.
9. A new fully quantitative and well organized qualitative graphics display of the
   chromatogram allowing immediate understanding if two runs are compared or
   one run is seen relative to a standard chromatogram. This new look displays “line chromatograms”.

Many more other chromatogram “manipulation” is possible like seen in a command file field as given below but here is a strict statement:

The original raw chromatogram data file (binary) is NOT in any way touched,
it remains as it was.
The EXPORT data file however is a “reduced raw data” file as result of an integration run. Its correction, adaptation or enlargement is REVERSIBLE.

The integration program extracts from the binary RAW data file with thousands of signal data (intensity over time) the following values:

a) the retention time in seconds, found by 5th polynomial interpolation of seven raw data points around the peak top. This allows to take retention time data by +- 0.001 sec through interpolation. A quartz clock driven signal converter storing raw data however is necessary, otherwise high time precision is not available.

b) the peak width in half height in seconds, found automatically by mathematical statistical approaches and NOT based on the (false) assumption, the peak has a Gaussian shape. It has not: the variance of real peaks differs from the variance of a real GAUSS function easily by 20 to 40 and more percent even in capillary gas and capillary liquid chromatography. The peak width data are found by +- 0.001 sec. precision but see under a) above.

c) the peak height in amperes or volt (nano-, micro-, milli-...  depending on the electronics)

d) the integrated peak area based on the best possible baseline positioning, given in volt x seconds or in amperes x seconds.

Into this reduced raw data file there is one column integrated, which contains zeros, or already some retention index values, or k-data or substance specific codes. At the end of the EXPORT data set there are two 255 positions long ASCII lines attached containing 12 data fields. Each has 20 characters capacity and is enclosed in “semicolon” delimiters. This line portions of 20 characters capacity each contain information like
   - year / month / day / hour / minute / second of sample injection;
   - institution / laboratory / instrument;
   - sample code taken where, when, by whom, how, after which treating and sampling mode;
   - analytical mode / chromatographic and physical conditions / special remarks;
   - raw data code / raw data storage place;
   - reduced raw data (EXPORT) file name... and all the other (regulated)  information necessary. The specific info portion is always at the same position in this TEXT line and is enclosed by semicolons. This makes it possible to standardize the reporting procedure.

The structure of this EXPORT data :

 time (tms)      width (b05)     area (%)        height         index
 28.423          0.8855           0.09477         14.7           0
 34.772          0.9221           0.04280           5.9          0
continued by about 170 or more data lines and ending with the above mentioned two information text lines: one which is made by the software transferring information already given prior the start of the analysis like:
the complete date and the precise time of the injection. This time value is a very powerful identifier. If given by the second there is no uncertainty about the strict correlation of a sample, the chromatographic instrument and the responsible chromatographer. An automatic dead time calculation program corrects a non precise “injection time value” up to the 0.001 second level.

Many further information are only relevant at the time of integration, thus the finish of the EXPORT file details may also need a last text line for remarks. As the EXPORT data file is written in ASCII, it is easily readable and can be transmitted error free under the very intensive quality control modes for e-mail transmission. We never had trouble in sending and exchanging EXPORT files globally. Security exists with e-mail and ASCII attachments.

How and where to get EXPORT standard chromatogram (reduced raw) data ?

All leading chromatography instrument companies could include into their integration software a small add-on program, which writes and stores the EXPORT ASCII data file after each integration run upon request Automatically the file name is given either with eight characters in a way, that the correlation with the binary raw data set is safe. This way all relevant sample, instrument, analyst name, date and method details etc. can also be written into the IDENT line of the EXPORT data file exactly as shown in “structure of the EXPORT data file” above. Additional data necesssary for an automatical treatment of the EXPORT file for instance to calculate working ranges etc. can be added with special delimiters into the second text line.

However still in the 50ties year of quantitative chromatography some companies do not offer the peak width values, thus in this case the EXPORT data file gets zeros into the peak width column and quite some error testing procedures fail. Some integration programs on the market even do not offer peak height values and some have no international peak area units. Some integration programs measure and store the retention time in minutes, others in seconds only. The less qualified the integrated chromatogram data are, the less qualified are evaluations based on those data. A quality oriented critical selection of integration software by the analyst is our proposal. It is obvious, that the chromatography EXPORT data structure is THE chromatography data standard offering all necessary and nearly all possible evaluation modes for the benefit not only of analysts but the users of analytical results for correct and complete decision making.

Why this Standard Data file is given in ASCII is due to the security, safety and good economy with which EXPORT data can be transmitted by e-mail attachments, for mass data analysis, for perfect mathematical statistical data analysis and especially for the immediate graphical inspection by the chromatographer. There are well informed users of analytical information which read chromatogram results often better than chromatographers when available graphically. The EXPORT graphics possibilities are nearly unlimited. The most useful graphics application of Standard EXPORT data are given in this site under
“line chromatograms”

Command file field in order to optimize the Standard Chromatography EXPORT file if necessary for optimal application especially in comparison or error checks:

In case two EXPORT data files are loaded for a qualitative / quantitative comparison, the first information for the chromatographer should tell him: can you really compare or must something be done first. Graphical comparison is best. A look into digital data will make clear, if the graphical comparison is acceptable. Thus it is helpful to get immediately after the file loading a minimum amount of data like the ones given below.

An example: Following data are available for graphical comparison of two chromatograms (and any further with the first - may be STANDARD one):

                                                   1. file C0000476.EXP      2. file C0000478.EXP

First conclusion: data files look similar, but definitively the chromatographic conditions differed. Look “careful” to the graphics display. Probably some corrections are necessary. May be retention index data should be calculated completely and a log / lin graphics selected. The linearized retention index display or the C-carbon number scale is a great help to understand up to now unknown qualitative results. The EXP file name starting with a C. as seen above indicates, that the EXPORT file contains retention index data. This finds the used software upon loading the data for comparison.

Second and all further conclusions as well as decisions:
They are immediately obvious after the graphics are seen but as line chromatograms only.
This statement is easy to understand: it is for (normal) human beings impossible to make quality decisions based on 171 or 153 peak data in four rows simultaneously. We quit after seven data sets are read. We do not quit after two graphics are seen as we automatically “scan” them into memory. Humans are since a very long time picture oriented just because of the survival base programs burned into the genes.

See in this site “new look” and “LOG-LIN line chromatogram”.

Reduced EXPORT files:
For several applications the EXPORT file can be saved in a reduced format, for instance as basis for the line chromatogram application.
There peak width data are not of importance. EXPORT files are easily accessible for comparison, completion, correction. The following two figures show screen shots of EXPORT file data for digital comparison prior analog presentation as line chromatograms: