Determination of Caffeine in Urea by Bubble-in-drop Single Drop Microextraction and Gas Chromatography-Mass Spectrometry
	    		
		   		
		   			
		   		
	    	
    	 
    	10.11895/j.issn.0253-3820.160862
   		
        
        	
        		- VernacularTitle:气泡微萃取-气相色谱-质谱法测定尿中咖啡因
 
        	
        	
        	
        		- Author:
	        		
		        		
		        		
			        		Aiying SONG
			        		
			        		;
		        		
		        		
		        		
			        		Lihong WANG
			        		
			        		;
		        		
		        		
		        		
			        		Yanxia ZHANG
			        		
			        		;
		        		
		        		
		        		
			        		Enlin SHI
			        		
			        		;
		        		
		        		
		        		
			        		Junling ZENG
			        		
			        		
		        		
		        		
		        		
		        		
		        		
			        		
			        		
		        		
	        		
        		 
        	
        	
        	
        	
        		- Keywords:
        			
	        			
	        				
	        				
			        		
				        		Bubble-in-drop single drop microextraction;
			        		
			        		
			        		
				        		Caffeine;
			        		
			        		
			        		
				        		Gas chromatography-mass spectrometry;
			        		
			        		
			        		
				        		Urea
			        		
			        		
	        			
        			
        		
 
        	
            
            
            	- From:
	            		
	            			Chinese Journal of Analytical Chemistry
	            		
	            		 2017;45(5):707-712
	            	
            	
 
            
            
            	- CountryChina
 
            
            
            	- Language:Chinese
 
            
            
            	- 
		        	Abstract:
			       	
			       		
				        
				        	A method for the determination of caffeine in urea was developed based on bubble-in-drop single drop microextraction (BID-SDME) followed by gas chromatography/mass spectrometry (GC-MS).Under the optimum conditions including chloroform as extraction solvent, an exposure volume of 1 μL, a bubble volume of 1.6 μL, stirring for 5 min at 300 r/min, 15% (m/V) NaCl, and a distance of 1 cm between bubble and stirring bar, the detection limit of this method was as low as 0.003 mg/L and the linear range was from 0.005 mg/L to 10 mg/L with correlation coefficient of 0.982.The recoveries of caffeine were from 89.2% to 107.5% at different spiked levels in human urine and the relative standard deviation (RSD, n=6) was less than 8%.