Extract Duplicates

Use the Geochem Import > Duplicates > Extract Duplicates menu option (CHDUP GX) to extract duplicates from a new laboratory database and add the duplicates to the end of a duplicates database.

Extract Duplicates dialog option

Assays database

Assay database that contains duplicates to be extracted

Application Notes

Duplicate samples can be taken during sample collection (field duplicates), during sample preparation in the laboratory (coarse duplicates, pulp duplicates), and at other times during the life cycle of a sample. The expected results for any duplicate sample is that the concentrations of the various elements measured are very similar to that of the "original sample."

Duplicates can be identified in numerous ways which can vary greatly depending on the methodology of the sample collection team & the laboratory analysis staff. Each pair of samples should be identified in one of two ways - the "Sequence Method" or the "Sample IDs Method", both described below. This identification is stored in the "Duplicate channel."

Triplicates or higher are not supported at this time.

Identifying Duplicates using 1,2 sequences

This is the original CHDUP GX method for identifying pairs of duplicate samples.  The Duplicate channel contains a pair of integers (e.g. pair of "1" and "2", "3" and "4", etc.) for Duplicate samples, with the "original" sample containing the odd value (e.g. 1, 3, 5, etc.) and the "duplicate" sample containing the even value - one higher than the original's value.

For instance:

Sample	Duplicate
S1005	1
S1005A	2
S1006
S1007	3
S1007A	4

In the above example, S1005 and S1007 have duplicate samples, but S1006 does not.

If you are using the "Sequence method" (e.g. 1,2,3,4,5,6) to identify duplicates, always ensure that the Duplicate column is being imported as NUMERIC format (e.g. Data Type parameter is set to "Floating Point").

Identifying Duplicates using Sample IDs

As of v7.3, the duplicated samples are identified using the Sample ID of the original sample, written in the duplicates "Duplicate" channel. Only the duplicated sample contains a reference to the Sample ID. Do NOT "cross-reference" by including the Sample ID of the duplicated sample in the original's Duplicate channel.

Sample	Duplicate
S1005
S1005A	S1005
S1006
S1007
S1007A	S1007

This GX will go through a lab assay database (after merging with the field database) and extract all Duplicate samples.  For each Duplicate sample in the assay database, the sample assay results will be removed and added to the end of a Duplicates database. The Duplicates database may be located either in the GEOSOFT directory or the local directory.

If a Duplicates database does not exist, one will be created in the local directory.

In addition to the assay results, the batch name, Lab ID, sample number, assay order and assay weight are entered in separate channels of the Duplicate database. A channel "Seq", for sequence, will indicate the sequence of this set of Duplicates in the Duplicates database.

Duplicates are always added to the end of the Duplicates database. This allows a Duplicates database to accumulate Duplicate results over time.

After extracting Duplicates, the Duplicates database or databases are opened and you can use the spreadsheet tools to view the Duplicate results. The CHDUPREP GX can be used to graphically summarise Duplicate results.

With the Duplicates Report as the active map, and the View of interest selected in the Map Manager Tool, use the Shadow Cursor Tool from the toolbar to dynamically link to samples in the Duplicates database. Alternatively, click a sample in the database to see the corresponding point in the report.

If you are using the newer "Sample ID's" method to identify duplicates, always ensure that the Duplicate column is being imported as STRING (e.g. Data Type parameter is set to "String").