Method for the Determination of Beta Blockers from Urine Using SOLA CX

Thermo Scientific SOLA CX cartridges and plates are suitable for the extraction of four beta blockers from urine. High precision and excellent recoveries were observed while using low loading volumes.

Introduction

SOLA products are a revolutionary new solid phase extraction (SPE) product range. This first-in-class SPE product introduces next generation, innovative technological advancements and gives unparalleled performance characteristics compared to conventional sample preparation techniques.

SOLA products have significant advantages for the analyst when processing compounds in complex matrices, particularly in high throughput bioanalytical and clinical laboratories where reduced failure rate, higher levels of reproducibility, speed of analysis and lower sample/solvent requirements are critical. The increased performance from SOLA products provides higher confidence in analytical results and lowers cost without compromising ease of use or requiring complex method development.

Experimental details

Sample pretreatment

Prepare a mixed standard spiking solution in methanol at a concentration of 0.5mg/mL (atenolol, metoprolol, propranolol and alprenolol). Prepare a working internal standard solution in methanol at a concentration of 0.5 mg/mL (pindolol). Take 800 µL of blank human urine or sample. Add to this 100 µL of mixed primary standard and 100 µL of internal standard. Mix well.

Sample preparation

Compound(s): atenolol, metoprolol, propranolol, alprenolol, pindolol (IS)

Matrix: Human urine

Cartridge type: Thermo Scientific SOLA CX 10 mg/1 mL p/n 60109-002

Conditioning stage: 500 µL methanol, 500 µL water

Application stage: Load 200 µL of spiked human urine and allow to flow under gravity

Washing stage: 250 µL 0.1% formic acid in water then 250 µL 0.1% formic acid in methanol

Elution stage: 250 µL 5% ammonia solution in 80:20 Dichloromethane (DCM)/ Isopropyl alcohol (IPA)

Additional stage: Dry and reconstitute in 200 µL 90:10 (v/v) water/acetonitrile. Sonicate for 5 min.

Separation conditions

Instrumentation: Thermo Scientific Accela 1250

Column: Accucore C18, 2.6µm, 50 × 2.1 mm p/n 17126-052130

Mobile phase A: water + 0.1% formic acid

Mobile phase B: methanol + 0.1% formic acid

Gradient: 10–40%B in 2.5 minutes

Flow rate: 0.7 mL/min

Column temp: 45 °C

Injection volume: 1 µL

UV detection wavelength: 220 nm

Results

Four beta blockers were extracted from human plasma with recoveries >88%. Quality control (QC) samples were run in replicates of six at a concentration of 0.05 mg/mL. The precision for each of the compounds were < 5% coefficient of variation (CV). Recovery and precision data is shown in Table 1.

Table 1: Precision and recovery data.

Conclusions

SOLA CX SPE cartridges and Accucore C18 HPLC allows robust and efficient analysis of four beta blockers from human urine to be carried out simply and quickly. The advantages of SOLA ensure excellent recoveries and precision with a reduction in elution solvent volume, hence solvent costs and drying times are reduced

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