6. Stimulant Detection Reagent

On-Column Chiral Derivatization Reagent for GC Separation of
Optical Isomeric Amphetamine & Methamphetamine


MTPA-Pyrazole is a reagent for on-column chiral derivatization designed to separate and analyze the enantiomers of stimulants with a primary or secondary amine using a normal gas chromatography column.
In the past, separation and analysis of enantiomers required either the use of a chiral stationary phase column for analysis without pretreatment, or a pretreatment consisting of a reaction with a chiral derivatization reagent to form a diastereomer for analyses using a normal column.
MTPA-Pyrazole allows for derivatization reactions with stimulants with a primary or secondary amine by on-column injection, enantiomers can be quickly separated and analyzed without any pretreatment.


Preparation of MTPA-Pyrazole Solution: Dissolve MTPA-Pyrazole Reagent in ethyl acetate (Special Grade) to obtain a concentration of about 10 % (w/v).
Device (Example):
Gas Chromatography (GC) equipped with a DB1 or DB5 capillary column (30m x 0.25mm, 0.25 µm film thickness)
Oven Temperature: 70°C (1 min.) to 280°C at 20°C per min.,
Injection Port Temperature: 200 ~ 250 °C
Injection Technique: split/splitless
(1)Draw 1.0 µL of MTPA-Pyrazole Solution into the microsyringe for GC injection, then draw 2.0~4.0 µL of air, and fi nally 0.2~1.0 µL of the stimulant extract *1.
(2)By Injection this into GC, the stimulant is derivatized with MTPA within the injection port or column, allowing for the enantiomers to be separated and detected.
*1 : Free base form of a stimulant by dissolved in hexane.

Mass spectra of MTPA derivative of d,l-amphetamine

Total Ion Chromatogram of d,l-amphetamine and d,l-methamphetamine,
on- column chiral derivatized with MTPA-Pyrazole

Mass spectra of MTPA derivative of d,l-methamphetamine
Description Wako Cat. No. (Pkg. Size) Storage Shelf Life
MTPA-Pyrazole Reagent, 98.0+%(HPLC)
for Medicolegal Investigation
134-15221 (100 mg)
130-15223 (1 g)
Keep at -20°C in a dark place.
Filled with an inert gas.
5 years after production
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Wako Product Update No.20 [ page. 19 ]