Chemistry Reference
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completely removed by subsequent granular activated carbon (GAC) ilters. Acesulfame readily
reactswithozone.However,theappliedozoneconcentrationsandcontacttimesundertypicalwater-
worksconditionsonlyledtoanincompleteremoval(18%-60%)intheozonationstep.Acesulfame
waseficientlyremovedbysubsequentGACilterswithalowthroughputoflessthan30m
3
kg
−1
,
butremovalstronglydependedontheGACpreload.
Zygler,Wasik,andJacekNamiesnik(2010)providedinformationabouttheapplicationofSPE
fortheisolationofninehigh-intensitysweeteners(acesulfameK,alitame,aspartame,cyclamate,
dulcin,neotame,saccharin,sucralose,andNHDC)fromaqueoussolutions.Theinluenceofsev-
eral types of LC-MS compatible buffers (different pH values and compositions) on their recov-
ery has been studied and discussed. A number of commercially available SPE cartridges, such
as Chromabond C18 ec, Strata-X RP, Bakerbond Octadecyl, Bakerbond SDB-1, Bakerbond SPE
Phenyl,OasisHLB,LiChrolutRP-18,SupelcleanLC-18,DiscoveryDSC-18,andZorbaxC18,were
tested in order to evaluate their applicability for the isolation of analytes. Very high recoveries
(better than 92%) of all studied compounds were obtained using formic acid-N,N-diisopropyle-
thylamine buffer adjusted to pH 4.5 and C18-bonded silica sorbents. The behavior of polymeric
sorbentsstronglydependsontheirstructure.Strata-XRPbehavesmuchlikeaC18-bondedsilica
sorbent. Recoveries obtained using Oasis HLB were comparable with those observed for silica-
basedsorbents.Theonlycompoundlesseficiently(83%)retainedbythissorbentwascyclamate.
Bakerbond SDB-1 shows unusual selectivity toward aspartame and alitame. Recoveries of these
twosweetenerswereverylow(26%and42%,respectively).Itwasalsofoundthataspartameand
alitamecanbeselectivelyseparatedfromthemixtureofsweetenersusingaformicacid-triethyl-
aminebufferatpH3.5.
Stevia rebaudiana Bertoni
containsglycosides,whichareinsolubleincarbondioxideandsol-
ubleinmixturesofcarbondioxideandapolarsolvent.Yodaetal.(2003)studiedthesupercritical
luidextractionoftheseglycosidesfromstevialeavesusingatwo-stepprocess:(1)CO
2
extraction
at 200 bar and 30°C and (2) CO
2
+ water extraction. The chemical compositions of the extracts
wereanalyzed by GC-FID, GC-MS, TLC,and HPLC.The overallextraction curves for thesys-
tem stevia + CO
2
had the typical shape and were successfully described by the Sovova model.
Approximately72%oftheCO
2
-solublecompoundswererecovered,andthemajorcompoundwas
austroinulin.Thestevia+CO
2
+watersystembehavedasexpectedat10°Cand16°Cand120bar
and250bar,butitsbehaviorwasunusualat30°Cand250bar.Theprocessremovedapproximately
50%oftheoriginalsteviosideandabout72%oftherebaudiosideA.
Herrmann,Damawandi,andWagmann(1983)reportedonamethodforthedetectionofaspar-
tame,cyclamate,dulcin,andsaccharinusinganion-pairHPLCseparationwithindirectphotometric
detection.However,suchvariedmethodswiththeirdifferingderivatizationprotocolsmaketheanaly-
sisofartiicialsweetenerstimeconsumingandlaborintensive.Recently,somemethodsemploying
liquidchromatographymassspectrometryhavebeenpublishedfortheanalysisofsucralose(Looset
al.2009)andotherartiicialsweetenersinwatersamples(Scheurer,Brauch,andLange2009).
A methodology for the chromatographic separation and analysis of three of the most popu-
larartiicialsweeteners(aspartame,saccharin,andsucralose)inwaterandbeveragesampleswas
developedusingliquidchromatography/time-of-lightmassspectrometry(LC/TOF-MS)byFerrer
and Thurman (2010). The sweeteners were extracted from water samples using SPE cartridges.
Furthermore, several beverages were analyzed by a rapid and simple method without SPE, and
thepresenceofthesweetenerswasconirmedbyaccuratemassmeasurementsbelow2-ppmerror.
The unambiguousconirmationofthecompoundswasbasedonaccuratemassmeasurementsofthe
protonatedmolecules[M+H]+,theirsodiumadducts,andtheirmainfragmentions.Quantitation
wascarriedoutusingmatrix-matchedstandardcalibration,andthelinearityofresponseovertwo
ordersofmagnitudewasdemonstrated(
r
>0.99).Adetailedfragmentationstudyforsucralosewas
carriedoutbyTOF,andacharacteristicspectrumingerprintpatternwasobtainedforthepresence
ofthiscompoundinwatersamples.Finally,theanalysisofseveralwastewater,surfacewater,and
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