Chemistry Reference
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mixtureisthoroughlystirredandtheniltered(Nietal.2009).Saccharinisdeterminedindietjams
bymixingthejamwithwaterandsonicatingthemixture.Themixtureisthenmadeuptoacertain
volumeandiltered(Boyce1999).Preservedfruitsaregroundedandhomogenized.Thenwateris
added,andtheformedmixtureisextractedultrasonicallyanddilutedtoacertainvolumewithwater
(ChenandWang2001).Fortheanalysisinjuicebeforeiltration,acentrifugestepmaybeneces-
sary.Inthecaseofstrawberrysweets,anadequateamountisweighedandthoroughlycrushedina
glassmortarandthendissolvedinwaterwiththeaidofanultrasonicbath.Afterthat,itiscentri-
fugedandiltered.Inthecaseoftomatosauce,theamountissuspendedinwater,andthenaportion
isdilutedandcentrifuged(Jiménezetal.2009).Whenthedeterminationofsaccharinintabletop
solidtabletsisneeded,tabletsareturnedintopowder.Aportionofthepowderisbeingweighed
anddirectlydissolvedinultrapurewater.Samplescharacterizedbyarelativelysimplematrixlike
liquidsweetenerscansimplybedilutedordissolvedindeionizedwaterorinanappropriatebuffer.
Theapproachesforthedeterminationofsaccharininsimplematricesaremucheasierandlesstime
consumingthanthedeterminationofsaccharininmorecomplicatedfoodsamplematrices.
4.15 aNaLYtICaL MethODOLOGY
ThenumberofmethodsforthedeterminationofASPandACS-Kinfoodsamplesislargeandis
classiiedaccordingtothedetectionmethod.Themethodisselectedasacompromisebetweenthe
followingfactors:(1)accuracy,(2)precision,(3)cost,(4)detectionlimits,(5)selectivity,(6)safety,
(7)samplethroughput,(8)consumptionofsampleandreagents,(9)simpleoperation(automatedor
not),and(10)contaminationrisks.
However, three main parameters are important in selecting the method of analysis: (1) The
reagents and the apparatus of the method must have a low cost. (2) We do not need a very sen-
sitive method with a low detection limit since the sweeteners luctuate in the micromolar range
andsensitivemethodsoftenarecostly.(3)Thesamplethroughputandtheconsumptionofsample
andreagentsmustberelativelylow.Thefollowinganalyticalanddetectiontechniquesmeetthese
criteria:
•
Biosensors
•
Spectrophotometry
•
Electroanalysis
•
Chromatography
These detection techniques have been applied to the simultaneous determination of several
kindsofsweetenersinfoods(Cantarellietal.2009).Themagnitudeofsensitivityandselectivityof
themethod(includingsamplepreparationpriortoanalysis)usedisdifferentwhenonlyoneofthese
twosweetenersinfoodstuffsisdeterminedanddifferentwhenthetwosweetenerssimultaneously
withotherfoodadditivesaredetermined.Whenanalystswanttodeterminesimultaneouslyanum-
berofcompounds,theymustcompromisethebestanalyticalparametersofeachcompound.Inthis
case,itiscommontolosemagnitudeofsensitivityandselectivityofthemajorityofthecompounds
analyzedsimultaneously.Ontheotherhand,thisdoesnotoccurwhenamethodforthedetermina-
tionofoneandonlycompoundisdeveloped.
For routine analysis of complex food matrix samples, MEKC, capillary zone electrophore-
sis, HPLC, and ion chromatography (IC) are preferred. Even thin-layer chromatography (TLC;
Baranowska et al. 2004) has been reported for the determination of the two sweeteners. These
instrumentalmethodsareimportantreferencemethodsforfoodsampleanalysisandarebasedon
expensiveanalyticalinstrumentsandreagents.Liquidchromatographicdeterminationinfoodsis
simplebecausebeveragesoraqueousextractsfromfoodscanoftenbeinjectedintothecolumns
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