The document discusses how the author uses the VLOOKUP function in Microsoft Excel to filter raw measurement data and select only the relevant information. Specifically, it creates a lookup label column to identify sample peaks based on retention time. It then creates a new sheet where VLOOKUP looks up the labeled data, such as the filenames of chromatograms that contained a sample peak. This allows the desired data to be automatically selected rather than manually, saving time. Various other selections and filters are possible using VLOOKUP.

1. How I filter data with MS Excel’s
VLOOKUP() function
Anneke M. Batenburg

2. Rationale
This is what my raw
measurement data
usually look like, after I
export them from
Isodat.
This file includes six
peaks of each
chromatogram, whereas
I’m only interested in
one peak (sample peak)
per chromatogram.
Selecting the data I want
by hand is TEDIOUS.

3. Enter: VLOOKUP()
VLOOKUP searches for a value in the first column of
a table array and returns a value in the same row
from another column in the table array.
Syntax:
VLOOKUP(value_to_look_for, array_to_look_in,
column_number_to_return_value_from,
boolean_that_should_always_be_FALSE_in_my_ca
ses)
One complication: my data should have a first
column with lookup labels (value_to_look_for)

4. Create a lookup
label
I create a first column
with a formula that
detects
• if the peak is a sample
peak (based on
retention time),
• and if yes, gives it a
sequential number.
Ax=IF(AND(260 < Kx , Kx
< 625),
MAX(A$2:Ax)+1,"")

5. Create a sheet with
selected data
Now I create another
sheet where I use
VLOOKUP() to look up
the data I want
automatically.
Like the filename of the
chromatograms that
yielded a sample peak.
Ax=VLOOKUP(ROW()-1,
’SheetName'!A$2:Z$20
7, 2, FALSE)

6. And I can look up
more data, as
desired.
Many more variations are
possible, like selecting only
the measurements that have
“NAT334” or “BLANK” in the
filename, or selecting only
measurements from a
particular measurement day...