Determination of Antidepressants in Human Plasma by Modified Cloud-Point Extraction Coupled with Mass Spectrometry

Abstract

Cloud-point extraction (CPE) is rarely combined with liquid chromatography coupled to mass spectrometry (LC–MS) in drug determination due to the matrix effect (ME). However, we have recently shown that ME is not a limiting factor in CPE. Low extraction efficiency may be improved by salt addition, but none of the salts used in CPE are suitable for LC–MS. It is the first time that the influences of a volatile salt—ammonium acetate (AA)—on the CPE extraction efficiency and ME have been studied. Our modification of CPE included also the use of ethanol instead of acetonitrile to reduce the sample viscosity and make the method more environmentally friendly. We developed and validated CPE–LC–MS for the simultaneous determination of 21 antidepressants in plasma that can be useful for clinical and forensic toxicology. The selected parameters included Triton X-114 concentration (1.5 and 6%, w/v), concentration of AA (0, 10, 20 and 30%, w/v), and pH (3.5, 6.8 and 10.2). The addition of 10% of AA increased recovery twice. For 20 and 30% (w/v) of AA, three phases were formed that prolonged the extraction process. The developed CPE method (6% Triton X-114, 10% AA, pH 10.2) was successfully validated through LC–MS/MS simultaneous determination of 21 antidepressants in human plasma. The linearity was in the range of 10–750 ng/mL (r2 > 0.990).

The Chemometric Evaluation of the Factors Influencing Cloud Point Extraction for Fluoroquinolones

“…It results in the enhancement of the preconcentration of the sample. The most commonly used temperatures are in the range of 40-60 • C. At higher temperatures, there is a risk of the decomposition of both the micelle and the analyte [1,2,4,5,17]. The lowest temperature analyzed in this study was 45 • C. At lower temperatures, the separation of the micelle-rich layer was not observed.…”

“…The most commonly used temperatures are in the range of 40–60 °C. At higher temperatures, there is a risk of the decomposition of both the micelle and the analyte [ 1 , 2 , 4 , 5 , 17 ]. The lowest temperature analyzed in this study was 45 °C.…”

“…CPE is widely used in the pretreatment of aqueous samples. It was applied in the determination of the following drugs in human plasma: amitriptyline and fluoxetine [ 5 ], venlafaxine [ 6 ], meloxicam [ 7 ], and bisoprolol [ 8 ]. Vitamins A, E, and K were determined in aqueous solutions, plasma, and urine [ 4 ].…”

Polydopamine coated hypodermic needles as a microextraction device for the determination of tricyclic antidepressants in oral fluid by direct infusion MS/MS

“…Table 2 compares the sensitivity of the proposed method with other alternatives reported for the determination of tricyclic antidepressants in biouids, including saliva, urine, plasma and blood. 1,6,7,9,12,16,[49][50][51][52][53] Our method provides a wider linear range, allowing the determination of the target compounds at the therapeutic level. In the oral uid applications, the sensitivity of the new method is intermediate and only surpassed by the method based on high-resolution MS, although the latter provided a narrower linearity range.…”

“…In fact, they are considered driving-impairing medicines. 5 Although blood, plasma, or urine are the common bioanalytical specimens for determining antidepressants and other pharmaceuticals, [6][7][8][9][10][11] oral uid (OF) has demonstrated many advantages as an alternative matrix. OF is easy to be collected and presents high stability if properly stored.…”