Chemistry Reference
In-Depth Information
Thedeterminationofsaccharinindividuallyorsimultaneouslywithothersweetenersinmix-
turesisveryimportantforconsumersafety.Researchersfocustheireffortsondevelopinganalytical
methods for simple, rapid, and low-cost sensitive determination. Sensitive and robust analytical
methodsareessentialtomeettheneedsofgrowingmarketsinqualitycontrolandconsumersafety.
Scientistshaveappliedawidevarietyofinstrumentaltechniques.Today,themethodofchoicefor
thedeterminationofartiicialsweetenersindifferentcomplexfoodmatricesisHPLCbecauseofits
multianalytecapability,compatibilitywiththephysicochemicalpropertiesofsweeteners,highsen-
sitivity,androbustness.However,biosensortechnologyhasofferedsomemethodsofdirectdetec-
tioninsimplerandcheapermatrices,withoutsamplepreparation.Duetoaconstantrisingdemand
foralternativemethodsfordeterminationofsaccharin,andduetotheincreasingdevelopmentof
MSortandemmassspectrometricmethods,anumberofproceduresbasedonMScoupledwithLC
forthedeterminationofsaccharinareexpectedtoappear.
4.15.7 Determination of Sucralose
SincesucralosedoesnotabsorbintheusableUV/Visrange,makingsensitiveandspeciicdetec-
tionbydirectUVabsorptiondificult,aderivatizationprocedureisnecessary.Thistaskcanbeaccom-
plished using p-nitrobenzoyl chloride (PNBCl). Sucralose treated with PNBCl is converted into a
stronglyUV-absorbingderivative,havingstrongabsorptionat260nm,whichallowsforitssensitive,
directUVdetection.AnothersolutionistouseanRIorMSdetector(Kobayashietal.2001).
A simple, fast TLC method was proposed for the quantiication of sucralose in various food
matrices.Themethodrequireslittleornosamplepreparationtoisolateortoconcentratetheana-
lyte.Theseparationofsucralosewasperformedonamino-bondedsilica-gelhighperformancethin
layerchromatography(HPTLC)plate.TheuseoftheDADresultedinexcellentlimitofdetection
(Spangenbergetal.2003).
Afewproceduresfordeterminationofsucraloseinvariousfoodandbeverageproductswere
reported. In all cases, high performance anion exchange chromatography (HPAEC) with pulsed
amperometricdetection(PAD)wasapplied.ThehighresolvingpowerofHPAECandthespeci-
icityofPADallowthedeterminationofsucralosewithlittleinterferencefromotheringredients.
Highprecision,methodruggedness,andhighspikerecoveryarepossibleforthesecomplexsample
matrices(HankoandRohrer2004).
CEwithindirectabsorptionmeasurementisalsoasuitabletoolformonitoringthecontentof
sucraloseinvariousfoodstuffs.Sucralosedeterminationinlow-caloriesoftdrinkscanbeachieved
without any sample cleanup using 3,5-dinitrobenzoate buffer at pH 12.1 and indirect UV detec-
tionat238nm.Thescopeofthemethodhasbeenextendedtoincludethepossibilityofanalysis
ofyogurtsandcandiesbyintroducingasamplecleanupstep(centrifugation,iltration,andSPEon
AluminaAcartridges;McCourtetal.2005).
4.16 MULtIaNaLYte aNaLYSIS
However,thesemethodsaretimeconsumingordonothavetheselectivityrequiredforASPdeter-
minationinsomecommercialsamples.SpectrophotometryisusuallycoupledwithanFIAsystem.
TheanalysisofanalytemixturesbymeansofFIAsystemshasbeenaccomplishedindifferentways:
1. Useofamicrocolumnafterlowcelltoretainoneanalytepreferentially,theotherbeingtransiently
retainedinthesolidsupportplacedinthelow-throughcell(Ruiz-Medinaetal.2001).
2. Useofdifferencesintransientretentionforbothanalytesatthelowcell.Thetransientretentionof
oneanalyteintheupperpartofthelowcell,awayfromthemeasuringarea,makesitpossibleto
measurewhatislessretained(Capitán-Vallveyetal.2004a).
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