What is the difference between Pico-Tag and AccQ-Tag? - WKB59621

ENVIRONMENT

• column
• AccQ-Tag
• Pico-Tag
• Amino Acids
• comparison
• advantage

ANSWER

The main advantage of AccQ-Tag vs. Pico-Tag is that AccQ-Tag Ultra is the only tagging technique Waters currently has with a fully supported total solution approach involving chemistry and system.  The Total Solution option allows for faster up-time and largely avoids chromatographic method development for four major types of amino acid separations: Food and Feed, Hydrolysate, Cell Culture and the Alkylation and Reduction of Cysteine.

Many of the system components used to run Pico-Tag methods to separate the amino acids are now obsolete or are no longer sold through Waters.

The AccQ-Tag reaction is much quicker and requires less glassware than the Pico-Tag reaction.

The Pico-Tag reaction is typically used with glassware associated with a biotechnology method called the Edman degradation. The Pico-Tag reaction requires several vacuum steps with the final step remove any excess un-reacted reagent. If you do not complete these steps, no peaks are detected.

AccQ-Tag is performed in a largely aqueous environment and excess salts do not interfere with the reaction. Samples are derivatized and injected directly.

Pico-Tag reaction is performed in a more organic environment and excess salts do interfere. Samples are derivatized, vac dried, reconstituted, and injected.

The historical advantage in HPLC with AccQ-Tag, was associated with use of a fluorescence detector that allows expansion of the linear range below 1 pmole. The one exception is Tryptophan. AccQ-Tag method requires a UV detector to see Tryptophan because the tagged AA quenches the fluorescent signal.

The current ACQUITY UPLC based AccQ-Tag Ultra chromatography conditions can be used with TUV, PDA and Fluorescence detector and provide similar linear detection range for each detector option.  AccQ-Tag Ultra method requires a UV detector to see Tryptophan because the tagged AA quenches the fluorescent signal.

The Pico-Tag amino acids are detected by UV and the detection limit is 1 pmol.

The other advantage of ACQUITY UPLC based method over the traditional Pico-Tag HPLC method, is the savings in solvent usage.  The AccQ-Tag Ultra UPLC based solution uses approximately 3x's less solvent  per injection, than the Pico-Tag HPLC methods.

ADDITIONAL INFORMATION