Optimization ofultrasoundassisted-emulsification-dispersiveliquid–liquid

VIVIANA P.JOFRÉ A.; MARIELAV.ASSOF.; MARTÍNL.FANZONEA,; HÉCTORC.GOICOECHEAB. MARÍA F.SILVA B,C; LUIS D. MARTINEZ

ANALYTICA CHIMICA ACTA

ELSEVIER SCIENCE BV

Año: 2010 p. 100 - 105

0003-2670

A newmethodwasdevelopedforanalyzingsulfurcompoundsinthearomaofwhitewines using ultrasoundassisted-emulsification-dispersiveliquid–liquidmicroextractioncoupledwithgas chromatography–mass spectrometrydetection.Inthepresentwork,theanalyticalmethodforsimultane- ous determinationofsevensulfurcompounds(methylmercaptoacetate,methyl(methylthio)acetate,2- methylthioethanol, 3-methylthiopropanol,3-methylthiohexanol,4-methylthio-4-methyl-2-pentanone and hexanethiol)isreported.Parametersthataffecttheefficiencyofthemethodologysuchasextract- ing anddispersingsolvents,samplevolume,ionstrength,cavitationtimeandcentrifugationtimewere investigated usingafractionatedfactorial26–1 (R =V)screeningdesign.Then,thefactorspresentingsig- nificant positiveeffectsontheanalyticalresponse(extractingvolume,ionstrength,cavitationtimeand centrifugation time)wereconsideredinafurthercentralcompositedesigntooptimizetheoperational conditions fortheultrasoundassisted-emulsification-dispersiveliquid–liquidmicroextractionproce- dure. Additionally,multipleresponsesimultaneousoptimizationbyusingthedesirabilityfunctionwas used tofindtheoptimumexperimentalconditions.ThebestresultswereobtainedusingpHsample 4.25, extractantvolume150 L, ionicstrength8.75%NaCl,cavitationtime20sandcentrifugationtime 50 s.Theuseoftheoptimizedultrasoundassisted-emulsification-dispersiveliquid–liquidmicroextrac- tion techniqueallowedtoobtainthebestextractionresultswiththeminimuminterferencefromother substances fromthematrix,anditallowedtoquantifytheanalytesinwhitewinesamplesbycalibration graphs. Recoveriesrangingfrom91.99%to125.87%forallsulfurcompoundsprovedtheaccuracyofthe proposed methodinwhitewinesamples.Methoddetectionlimitswereintherangeof0.36–1.67ngmL−1 and limitsofquantitationwerebetween0.63and3.02ngmL−1 for sulfurcompoundsinwhitewinesam- ples. Theproposedmethodologywassuccessfullyappliedforthedeterminationconcentrationsofsulfur compounds indifferentcommercialChardonnaywinesamplesfromMendoza,Argentine. © 2010 Elsevier B.V. All rights reserved 6–1 (R =V)screeningdesign.Then,thefactorspresentingsig- nificant positiveeffectsontheanalyticalresponse(extractingvolume,ionstrength,cavitationtimeand centrifugation time)wereconsideredinafurthercentralcompositedesigntooptimizetheoperational conditions fortheultrasoundassisted-emulsification-dispersiveliquid–liquidmicroextractionproce- dure. Additionally,multipleresponsesimultaneousoptimizationbyusingthedesirabilityfunctionwas used tofindtheoptimumexperimentalconditions.ThebestresultswereobtainedusingpHsample 4.25, extractantvolume150 L, ionicstrength8.75%NaCl,cavitationtime20sandcentrifugationtime 50 s.Theuseoftheoptimizedultrasoundassisted-emulsification-dispersiveliquid–liquidmicroextrac- tion techniqueallowedtoobtainthebestextractionresultswiththeminimuminterferencefromother substances fromthematrix,anditallowedtoquantifytheanalytesinwhitewinesamplesbycalibration graphs. Recoveriesrangingfrom91.99%to125.87%forallsulfurcompoundsprovedtheaccuracyofthe proposed methodinwhitewinesamples.Methoddetectionlimitswereintherangeof0.36–1.67ngmL−1 and limitsofquantitationwerebetween0.63and3.02ngmL−1 for sulfurcompoundsinwhitewinesam- ples. Theproposedmethodologywassuccessfullyappliedforthedeterminationconcentrationsofsulfur compounds indifferentcommercialChardonnaywinesamplesfromMendoza,Argentine. © 2010 Elsevier B.V. All rights reserved