The new prototype device is applied to the Solvent Front Position Extraction (SFPE) sample preparation procedure. The mobile phase is deposited onto the chromatographic plate adsorbent layer by the pipette, which is moved, according to programmed movement path, by a 3D printer mechanism. The application of the prototype device to SFPE procedure leads to the increased repeatability of the results and significant reduction of the analysis time in comparison to the classical procedure of chromatogram development. Additionally, the new equipment allows use procedures that are not possible to run using the classic chromatogram development. In this paper, the results of manual and semi-automatic sample preparation with SFPE are compared and the possible application of this prototype device is discussed.

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Solvent front position extraction procedure was used to prepare biological samples containing selected antihypertensive drugs (ramipril, lercanidipine, indapamide, valsartan, hydrochlorothiazide, perindopril, and nebivolol). Substances separated from the biological matrix components (bovine serum albumin) were quantified by means of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Sample preparation process was performed with the use of a prototype horizontal chamber with a moving pipette driven by a 3D printer mechanism enabling a controlled eluent flow velocity. Application of this device was advantageous for simultaneous preparation of several samples for further quantitative analysis, with a synchronized reduction of manual operations and solvent consumption. Quantitative results obtained for the majority of the investigated antihypertensive drugs in a complex biological matrix were satisfactory. The values of the %RSD were around 5% for six of the seven substances (with the exception of indapamide). The method exhibits a suitable accuracy (the relative error percentage was below 10% for most drugs). The values of LOD and LOQ were in the range of 1.19 µg/L–8.53 µg/L and 3.61 µg/L–25.8 µg/L, respectively.

The determination of the selected antihypertensive drugs in human plasma samples with the novel solvent front position extraction (SFPE) technique is presented. The SFPE procedure combined with LC-MS/MS analysis was used for the first time to prepare a clinical sample containing the drugs mentioned above from different therapeutic groups. The effectiveness of our approach was compared with the precipitation method. The latter technique is usually used to prepare biological samples in routine laboratories. During the experiments, the substances of interest and the internal standard were separated from other matrix components using a prototype horizontal chamber for thin-layer chromatography/high-performance thin-layer chromatography (TLC/HPTLC) with a moving pipette powered by a 3D mechanism, which distributed the solvent on the adsorbent layer. Detection of the six antihypertensive drugs was performed by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) in multiple reaction monitoring (MRM) mode. Results obtained by SFPE were very satisfactory (linearity R2 ≥ 0.981; %RSD ≤ 6%; LOD and LOQ were in the range of 0.06–9.78 ng/mL and 0.17–29.64 ng/mL, respectively). The recovery was in the range of 79.88–120.36%. Intra-day and inter-day precision had a percentage coefficient of variation (CV) in the range of 1.10–9.74%. The procedure is simple and highly effective. It includes the automation of TLC chromatogram development, which significantly reduced the number of manual operations performed, the time of sample preparation and solvent consumption.

In this work, analysis of some drugs used in the treatment of neurodegenerative disorders (sulpiride, olanzapine, carbamazepine, trazodone, clomipramine, and pridinol) was achieved through micellar electrokinetic chromatography (MEKC). The effect of surfactant (sodium dodecylsulphate), acetonitrile, and buffer pH and concentration on the solute retention was also investigated. Successful separation of all compound mixtures was obtained. The method was applied for the quantitative analysis of investigated compounds, and the LOD and LOQ were determined. The LOD values were in the range from 0.0127 mg/mL for clomipramine, to 0.1398 mg/mL for pridinol, while LOQ were in the range 0.0384 mg/mL for clomipramine, to 0.4237 for pridinol. The mode was also applied for the determination of investigated solutes in pharmaceutical prescriptions.