Analysis of four antidepressants in plasma and urine by gas chromatography-mass spectrometry combined with sensitive and selective derivatization

A new approach with dried plasma spots: a rapid determination of antidepressants and antipsychotics by fast GC-MS

Background: The increasing prevalence of poisoning cases related to antidepressants and antipsychotics has raised concerns. Methods: To address this issue, a new adaptation of the dried plasma spot technique was developed using a 24-well plate and fast gas chromatography-mass spectrometry. The method involves the optimization of extraction variables and sample preparation, and was successfully validated. Results: The limits of quantitation ranged from 20 to 60 ng/ml, and accuracy ranged from 87.8% to 112.2%. The technique was applied to 102 human plasma samples from suspected poisoning cases, with positivity of 90.2%. Conclusion: This method provides a cheap, easy to implement and fast approach, making it ideal for toxicological emergency laboratories and promoting valuable support for healthcare professionals managing poisoning cases involving antidepressants and antipsychotics.

Combination of quadrupole isotope dilution mass spectrometry with simultaneous derivatization and spray assisted droplet formation-liquid phase microextraction for the determination of methamphetamine in human urine and serum samples by gas chromatography mass spectrometry

In this study, an analytical method with high accuracy and precision was developed for the determination of methamphetamine in human urine and serum samples by gas chromatography-mass spectrometry (GC-MS). A simultaneous derivatization and spray assisted droplet formation-liquid phase microextraction (SADF-LPME) method was proposed to derivatize and preconcentrate target analyte. Quadruple isotope dilution (ID⁴) was used to provide high accuracy and precision for methamphetamine determination in the samples. After the optimization studies for the derivatization and microextraction parameters, limit of detection (LOD) and limit of quantitation (LOQ) for the developed SADF-LPME method were found to be 48.0 and 159.9 μg/kg, respectively. Recovery studies were implemented to verify the applicability and accuracy of the developed method for human urine and serum samples. The SADF-LPME method gave low percent recovery results (30.5-61.0%) for the spiked urine and serum samples showing that it failed to minimize or eliminate matrix effects for the analyte. Hence, methamphetamine acetamide-d3 was synthesized and purified in our research laboratory to be used as methamphetamine isotopic analogue in the ID⁴ method. When the SADF-LPME method was combined with ID⁴, the percent recovery values for urine and serum samples were calculated as 99.7-100.0% and 99.4-100.2%, respectively. These results demonstrated the applicability and accuracy of the proposed method for urine and serum samples.

Influence of Chromatographic Conditions on LOD and LOQ of Fluoxetine and Sertraline Analyzed by TLC-Densitometric Method

This research introduces the analysis of fluoxetine and sertraline by means of the TLC-densitometric method. They provide information on LOD and LOQ under various chromatographic conditions. The study used adsorption (NPTLC) and partition (RPTLC) thin-layer chromatography in combination with a densitometric analysis. Four types of chromatographic plates precoated with: silica gel 60 F254, silica gel 60, silanized silica gel 60 F254 (RP-2), and a mixture of silica gel 60 and kieselguhr F254, as well as three mobile phases: chloroform + methanol + ammonia (9:1:0.4, v/v/v), chloroform + methanol + glacial acetic acid (5:4:1, v/v/v), and acetone + toluene + ammonia (10:9:1, v/v/v), were used in NPTLC. RP-18F254 and silanized silica gel 60 F254 (RP-2) plates and four mobile phases: methanol + water (10:0 and 9:1, v/v), acetone + water (10:0 and 9:1, v/v), were used in RPTLC. The lowest LOD and LOQ values for fluoxetine were obtained using a silanized silica gel 60 F254 (RP-2) with acetone + toluene + ammonia (10:9:1, v/v/v) in NPTLC, and with a silanized silica gel 60 F254 (RP-2) in combination with methanol + water (10:0, v/v) in RPTLC. The lowest LOD and LOQ values of sertraline were obtained using a silica gel 60 with acetone + toluene + ammonia (10:9:1; v/v/v) in NPTLC. The smallest amount of sertraline was detected on the silanized silica gel 60 F254 plate in combination with methanol + water (9:1, v/v) in RPTLC. The obtained results provide important information that can give a good basis and set the direction for further, more detailed research; the results can also benefit other researchers who analyze fluoxetine and sertraline with the TLC technique in model systems (testing standards) as well as in drug and biological samples.

A green and low-cost method employing switchable hydrophilicity solvent for the simultaneous determination of antidepressants in human urine by gas chromatography - mass spectrometry detection

In this study, the use of switchable hydrophilicity solvent with a simple and low-cost lab-made device for the extraction procedure in homogeneous liquid-liquid microextraction is proposed for the first time in the determination of antidepressants in human urine. The antidepressants studied consisted of fluoxetine, amitriptyline, nortriptyline, imipramine, desipramine and sertraline. The optimization of the main parameters that can influence on the extraction efficiency was performed through multivariate approaches. The analytes were separated and identified by gas chromatography coupled to mass spectrometry (GC-MS). The optimal extraction conditions consisted of using N,N-dimethylcyclohexylamine (DMCHA) as the switchable hydrophilicity solvent (SHS), 500 µL of urine sample previously diluted with ultrapure water at 1:1 ratio (v/v), 200 μL of a mixture of SHS:HCl 6 mol L^-1 (1:1 v/v), 600 μL of NaOH 10 mol L^-1 and 3 min of extraction time. A volume of 40 µL of diphenylamine at concentration of 500 µg L^-1 (20 ng) was used as internal standard. The method developed was in-house validated, providing coefficients of determination higher than 0.995 for all analytes, limits of detection (LOD) from 0.02 to 0.88 µg L^-1, limits of quantification (LOQ) from 0.05 to 2.92 µg L^-1, relative recoveries of 68 to 102%, intra-day precision from 0.5 to 15.9%, inter-day precision from 4.2 to 19.3%, selectivity and robustness. The method proposed was successfully applied in five human urine samples from a Toxicological Information Center located in Porto Alegre (Brazil). The results demonstrated that the µP-SHS-HLLME approach is highly cost-effective, rapid, simple and environmentally-friendly with satisfactory analytical performance.