Patent ID: 9217733
Filing Date: 2015-12-22
Classification: G01N,H01J,Y10T

Abstract:
1. A method for detecting drug residues as low as pico-gram level in human body by incorporating high performance liquid chromatography with chip and mass spectrometry (HPLC-Chip-MS/MS) for detecting drug residues in human hair, the method comprises: (1) Sample preparation; (2) Liquid chromatography; and (3) Mass spectrometry, wherein the (1) sample preparation further comprises: (i) collecting the human hair at different lengths from a human subject; (ii) washing the collected human hair in 0.2% SDS, deionized water and acetone by ultrasonication; (iii) drying the washed human hair by nitrogen gas followed by digesting the dried hair sample with 0.5 mL hydrochloric acid at a concentration of 0.15 mol/L for 4 hours at 60° C.; (iv) cooling the digested human hair to room temperature followed by neutralizing with 0.03 mL sodium hydroxide at a concentration of 2 mol/L and 2 mL sodium phosphate buffer at a concentration of 0.1 mol/L in pH 6.8; (v) adding 2 mL extraction mixture comprising 90:10 v/v, dichloromethane:hexane for phase extraction by vortexing for 5 minutes followed by centrifugation; (vii) collecting lower organic phase and drying the lower organic phase by nitrogen gas; (viii) resuspending the dried lower organic phase with 50 μL acetonitrile and the resuspension is ready for liquid chromatography, and wherein the (2) liquid chromatography further comprises: (i) A single chip being directly installed on an ion source with a micro-camera for monitoring of ionization spray from said ion source; and (ii) A capillary pump having the following conditions: Mobile phase A is 0.1-0.2% of formic acid in water; Mobile phase B is 0.1-0.2% formic acid in acetonitrile; a flow rate of 1-6 μL/min; Mobile phase A gradient is 10-97%; and Mobile phase B gradient is 90-3%; or (iii) A nano pump having the following conditions: Mobile phase A and B are the same to that of said capillary pump; Flow rate used is 0.1-0.6 μL/min; Mobile phase A gradient is 5-97%; Mobile phase B gradient is 95-3%; and (iv) A chip injection volume which is 2-4 μL, and wherein the (3) mass spectrometry further comprises: (i) a drying gas temperature of 325° C.; (ii) a drying gas flow of 4 L/min; (iii) a capillary voltage of 1950V; (iv) a polarity in positive ion mode; (v) a scan mode in Multiple Reaction Monitoring (MRM); and (vi) an ion pair for detection of product ions, and wherein the drug residues comprises one or more of ketamine, methadone, morphine, 6-acetylmorphine, cocaine, benzoylecgonine, amphetamine, methamphetamine, MDMA and MDA.