Roach John A G, Musser Steven M, Morehouse Kim, Woo Jason Y J
Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA.
J Agric Food Chem. 2006 Apr 5;54(7):2484-90. doi: 10.1021/jf052767m.
Usnic acid is unambiguously confirmed by tandem mass spectrometry (MS/MS) in tumbleweed shield lichen, Xanthoparmelia chlorochroa. The lichen contains 2% usnic acid by liquid chromatography with UV quantification at 282 nm. The UV linear range for usnic acid quantification is from its 4 ng limit of detection to 2 microg injected. UV signal saturation is recognized by distortion of the usnic acid UV spectrum. Positive ion electrospray-tandem mass spectrometry offers no similar means to recognize quantification data recorded above the linear range of electrospray. Electrospray ionization capacity and matrix effects limit the reliability of tandem mass spectrometry quantification. The combination of UV quantification and MS confirmation provides a reliable analytical method for measuring usnic acid levels in plant material.
通过串联质谱法（MS/MS）在松萝属地衣黄褐扁枝衣中明确证实了地衣酸的存在。通过液相色谱法结合在282nm处的紫外定量分析，该 lichen 含有2%的地衣酸。地衣酸定量分析的紫外线性范围是从其4ng的检测限到注入的2μg。地衣酸紫外光谱的畸变表明紫外信号饱和。正离子电喷雾串联质谱法没有类似的方法来识别在电喷雾线性范围之上记录的定量数据。电喷雾电离能力和基质效应限制了串联质谱法定量的可靠性。紫外定量和质谱确证的结合为测量植物材料中的地衣酸水平提供了一种可靠的分析方法。
