If the parts are separated by period (and periods don't appear in the sub-parts) then use the SCAN() function.
* When the letter part is first ;
barcode = 'ADC.15462ds32';
L_part = scan(barcode,1,'.');
N_part = scan(barcode,2,'.');
* When the letter part is last ;
barcode = '56sdg56348.ADC';
L_part = scan(barcode,2,'.');
N_part = scan(barcode,1,'.');
Then you can rebuild the code from the two parts.
new_barcode=catx('.',L_part,N_part);
If the "number" part is always longer than 3 characters and the "letter" part is always three characters then you could convert a random stream into a consistent format.
if length(scan(barcode,1,'.')) > 3 then
barcode=catx('.',scan(barcode,2,'.'),scan(barcode,1,'.'))
;