Quantitative Analysis of Pseudoephedrine Tablets by UHPLC–MS

Guifeng Jiang, Ray Chen and Chris Loran, Thermo Fisher Scientific Inc., San Jose, California, USA.

An effective UHPLC–MS method for high throughput separation, identification and quantification of pseudoephedrine was developed on a Hypersil GOLD PFP 1.9 µm, 2.1 × 100 mm column.

Pseudoephedrine and ephedrine are highly coveted by drug traffickers who use them to manufacture methamphetamine, for the illicit market.¹ The separation and identification of pseudoephedrine from illicit drug mixtures, especially the methamphetamine group compounds, will help to identify the sources and the manufacture pathway of the methamphetamine seized in the illicit market.

We report separation, identification and quantification of pseudoephedrine in a mixture of five illicit drugs/metabolites by ultra high performance liquid chromatography–mass spectrometry (UHPLC–MS).

Experimental Conditions

Instrument: Thermo Scientific Accela UHPLC system Thermo Scientific MSQ Plus

Column: Hypersil GOLD PFP 1.9 µm, 100 × 2.1 mm

Flow-rate: 1 mL/min

Mobile phase: A: Water with 0.06 % acetic acid B: Acetonitrile (ACN) with 0.06% acetic acid

Gradient:

Injection volume: 1 mL partial loop injection, 25 mL loop size

Column temperature: 45 °C

Ionization: Electrospray (ESI)

Probe temperature: 450 °C

Cone voltage: 55.0 V

Scan mode: Full scan with mass range of 100–200 m/z

ESI voltage: 4.5 kV

Results and Discussion

Pseudoephedrine was identified as the major active ingredient for all the three brand name drugs by UHPLC–MS method (Figure 1). The peak retention time of 2.62 min for all three samples matched very well with the retention time of the pseudoephedrine standard at 2.60 min. The confirmation of pseudoephedrine at 2.6 min was further assured by the match of the MS spectra of the three samples with the pseudoephedrine standard.

An internal standard method was used for the quantitative determination of pseudoephedrine in its tablet form. The concentration of the assay samples determined (120.09 ppb) were in good agreement with the reported values (120 ppb).

Figure 1

Conclusions

A simple, fast and reliable separation and identification method for five drugs (pseudoephedrine, ephedrine, amphetamine, methamphetamine and 3,4-MDMA) using UHPLC–MS is developed. The ppb (ng/mL) level sensitivity and accuracy by this method are more than sufficient to identify and quantify pseudoephedrine and/or other components in the seized illicit drug samples.

References

1. Pseudoephedrine Notice, Office of Division Control, US Department of Justice, Drug Enforcement Administration.

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