Gniazdowska Elżbieta, Korytowska Natalia, Kłudka Grzegorz, Giebułtowicz Joanna
Łukasiewicz Research Network, Industrial Chemistry Institute, 8 Rydygiera, 01-793 Warsaw, Poland.
Department of Bioanalysis and Drugs Analysis, Doctoral School, Medical University of Warsaw, 61 Żwirki i Wigury, 02-091 Warsaw, Poland.
Pharmaceuticals (Basel). 2020 Dec 12;13(12):458. doi: 10.3390/ph13120458.
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%, ), concentration of AA (0, 10, 20 and 30%, ), and pH (3.5, 6.8 and 10.2). The addition of 10% of AA increased recovery twice. For 20 and 30% () 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 (r > 0.990).
由于基质效应（ME），浊点萃取（CPE）在药物测定中很少与液相色谱-质谱联用（LC-MS）。然而，我们最近发现基质效应并非浊点萃取的限制因素。通过添加盐可以提高低萃取效率，但浊点萃取中使用的盐均不适用于LC-MS。首次研究了挥发性盐乙酸铵（AA）对浊点萃取效率和基质效应的影响。我们对浊点萃取的改进还包括使用乙醇代替乙腈，以降低样品粘度并使该方法更环保。我们开发并验证了用于同时测定血浆中21种抗抑郁药的CPE-LC-MS方法，该方法可用于临床和法医毒理学。所选参数包括Triton X-114浓度（1.5%和6%）、乙酸铵浓度（0%、10%、20%和30%）以及pH值（3.5、6.8和10.2）。添加10%的乙酸铵可使回收率提高两倍。对于20%和30%的乙酸铵，会形成三相，从而延长萃取过程。通过LC-MS/MS同时测定人血浆中的21种抗抑郁药，成功验证了所开发的浊点萃取方法（6% Triton X-114、10%乙酸铵、pH 10.2）。线性范围为10-750 ng/mL（r > 0.990）。
