柑橘黄龙病时代的关键分析测试考量.pdf

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1、Critical Analytical Testing Considerations in the Era of Citrus GreeningSteve Allmon,Ph.DSenior Manager-Analytical SciencesThe Coca-Cola CompanyFLORIDAOrange groves in 2015Key Measurements for Liking Brix Acid Color Taste LimoninLimonin TestingESI APCIESI APCI2024 Limonin Ring Test 22.533.544.555.50

2、510152025303540ppm LimoninLab#Average:3.87 ppmMin:2.21 ppmMax:5.51 ppmStd Dev:0.58N=35 LabsMethodologyHPLC-UV:16LC-MS:8LC-MS/MS:4Not Reported:7 Well-characterized,“Mild”OJ usedMeasuring Limonin in the Era of GreeningThe Challenge:What is the“Consumer Relevant”Measurement?Prior Work(2005-USDA)Our App

3、roachHILIC-MS/MS MethodIsolation of LARL via C18 SPE,Buffer at pH=6.7In-House Trials Showed LARL survived pasteurization00.20.40.60.811.21.4-238131823ppm developable LimoninDaysPasteurization Conditions:200F,30s(red)194F,12s(others)100%Fresh,200F 30s past,30F storage100%Fresh,194F 12s past,45F stora

4、ge50%Fresh,194F 12s past,45F storage25%Fresh,194F 12s past,45F storageModels Aligned with Real WorldForced Degradation024681012010203040506070Conc.Of LARL(ppm)Time(min)75 C100%Fresh Juice50%Juice25%juice00.20.40.60.811.20102030405060Conc.(ppm)Time(min)Mass Balance-75 Limonin vs LARLtotallarllim Fres

5、h Juice needs thermal treatment to fully develop limoninRecommended protocol:75C for 1 hour.Required when juice less than 14 days old irrespective of pasteurization status(LARL survives pasteurization!)Consumer-relevant number IS the fully developed number.When it doubt,heat.Watchouts!Typical SPE-LC

6、-UV method,214nm(45%ACN)Lim Std40%ACN“Mild”vs“Wild”What can you do?Heat if appropriateSpectral Purity(if PDA)Monitor at 320nm(if VWD)LC-MS if higher volume?(consider sample prep cost)QC systemLimonin QC ProgramNew QC Rep#13.5623.4633.4543.4253.4263.4473.4983.5993.49103.56113.5012