noora perkola finnish environment institute · 11/9/2011 · noora perkola finnish environment...

Noora Perkola

Finnish Environment InstituteNordic MS Symposium

November 9, 2011, Båstad, Sweden

Noora Perkola - 2nd Nordic MS Symposium 9.11.2011

Artificial Sweeteners Used as additives in various food products to replace

sugar

4 non-caloric sweeteners

Acesulfame Potassium (ACS-K)

Saccharin (SAC)

Cyclamate (cyclamic acid) (CYC)

Sucralose (SCL)


Table 1. Analytes; Properties and origin of the standards

1 TRC = Toronto Research Chemicals Inc. (North York, Ontario, Canada)2 Ehrenstorfer = Dr. Ehrenstorfer-Schäfers (Augsburg, Germany)3 ADI = Acceptable Daily Intake


Artificial Sweeteners in Environment ACS-K, SAC, CYC and SCL detected in environmental

water samples

Levels up to over 2 µg/L of ACS-K

SAC and CYC 10-150 ng/L

SCL 10-1000 ng/L

Loos et al, Journal of Chromatography A (2009) 1216: 1126-1131

Scheurer et al, Anal Bioanal Chem (2009) 394: 1585-1594


Artificial Sweeteners in Environment Pass through human body and WWTPs

SAC and CYC eliminated over 90 %

ACS-K up to 41 %, SCL 20 %

ACS-K and SCL – tracers of domestic waste water

Effects to aquatic ecosystems unknown

Scheurer et al, Anal Bioanal Chem (2009) 394: 1585-1594


Sample pretreatment Reversed phase SPE (Waters Oasis HLB and J.T. Baker

Bakerbond SDB 1) and ion exchange SPE (Waters Oasis WAX and Oasis MAX) were tested

Oasis WAX chosen – possibility to have SCL in different extract (different concentration factor)


Sample pretreatment SPE procedure (Oasis WAX cartridges):

Conditioning 10 ml MeOH + 5 ml H2O

Load sample (pH 3.0)

Wash with 2 ml 2 % HCOOH (aq)

1st elution 6 ml MeOH

2nd elution 6 ml 1 % NH3 in MeOH

Recoveries between 70 and 120 % with extractionvolumes 50 – 200 ml



Sample

• 50-200 mL

• pH 3.0

• Add ISTD (d-ACS-K, d-SCL, d-CYC, 13C-SAC)

SPE (WAX)

• Condition: 10 mL MeOH + 5 mL H2O

• Load Sample: 1 drop sec-1

• Elute: 6 mLMeOH + 6 mL 1 % NH3 (MeOH)

Evaporation

• To dryness

• Redissolve to H2O

LC-MS/MS analysis

Figure 1. Sample pretreatment procedure

LC separation Acquity UPLC

Flow rate 0.400 mL/min, Column T 40 °C

• LC eluents A: 2 mM NH4OAc (aq); B: 2 mM NH4OAc (MeOH)

Gradient:

Initial: 99.9 % A

0.10 min: 99.9 % A

2.00-2.30 min: 0.1 % A

2.40-3.00 min: 99.9 % A


LC separation• Comparison of HSS T3 1.8 µm 2.1 x 50 mm

and BEH C18 1.7 µm 2.1 x 50 mm columns

• HSS: better retention for polar analytes –longer retention times but less matrixinteractions?


Figure 2. Chromatogram of standard solution of ACS-K (1), SAC (2), CYC (3) and SCL (4) with BEH C18 column (1a-4a) and HSS column (1b-4b).

14-Oct-2011 2 WAX, HSS

Time0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20

%

0

100

chromtest_111014_21 Sm (Mn, 2x1) 1: MRM of 6 Channels ES- 162 > 82 (acesulfame)

2.47e50.96

14-Oct-2011 2 WAX, HSS

Time1.12 1.14 1.16 1.18 1.20 1.22 1.24 1.26 1.28 1.30 1.32 1.34 1.36 1.38 1.40 1.42 1.44 1.46 1.48 1.50 1.52 1.54 1.56 1.58

%

0

100

chromtest_111014_21 Sm (Mn, 2x1) 2: MRM of 3 Channels ES- 178 > 80 (cyclamate)

7.70e31.29

1.10

1.15 1.39

Figure 3. Example: Chromatogram of river water sample

ACS-K

CYC

MS/MS analysis Xevo TQ MS

ESI-

MRM

Table 2. Optimization of MS parameters


ESI- MS/MS LOQs for ACS-K, SAC, CYC and SCL 25 ng/L, 25 ng/L,

6.5 ng/L and 210 ng/L, respectively

Sample volume 100 mL

Extract volume 1.0 mL

Matrix suppression

70-80 % for ACS-K and SAC

60-90 % for SCL

Less than 20 % for CYC


Enhancing ionization MS optimization with matrix?

Lower matrix effects in MeOH than in 1 % NH3

(MeOH)

More efficient wash step in SPE or clean-up for extract?

Modificator to enhance ionization in ES?


IDMS Isotope Dilution Mass Spectrometry

Mass labelled standards for all analytes

d4-ACS-K

d11-CYC

d6-SCL

13C6-SAC

Quantification using labelled standards

Reliable results despite low recoveries


AcknowledgementsI wish to thank

Waters

Association of Maa- ja Vesitekniikan Tuki ry for financial support


Thank You!


noora perkola finnish environment institute · 11/9/2011 · noora perkola finnish environment...

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