ANALYSIS OF CHLORINATED BY-PRODUCTS IN SWIMMING POOL WATER BY MEMBRANE INTRODUCTION MASS SPECTROMETRY- INFLUENCE OF WATER PHYSICOCHEMICAL PARAMETERS

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1 ANALYSIS OF CHLORINATED BY-PRODUCTS IN SWIMMING POOL WATER BY MEMBRANE INTRODUCTION MASS SPECTROMETRY- INFLUENCE OF WATER PHYSICOCHEMICAL PARAMETERS N. CIMETIERE. N. GARANDEL, P. HUMEAU

2 INTRODUCTION Chlorine in swimming pool Microbiological qualities DBPs formation Reaction from bathers loads Irritant compounds : NCl 3 Carcinogenic compounds: CHCl 3 Exposition : air / water THMs in swimming pools Water : µg/l (90% CHCl 3 ) Air : µg/m 3 NCl 3 in swimming pools Water : µg /L Air : µg /m 3 2

3 RESEARCH PROJECT Flow modelling Coupling approaches Simulation and prediction MO + HOCl CHCl 3, NCl 3 Model calibration and validation Treatment efficiency evaluation Exposure assessment Aqueous chemical kinetics Analytical development Real time monitoring of DBPS in water and air Membrane inlet Mass Spectrometry 3

4 ANALYTICAL CONTEXT NCl 3 determination by DPD DPD method suffer form interferences by the other (in)organic chloramines. No on-line (realtime) methods available Heavy sample preparation for NCl 3 determination in air THMs determination Water sample preparation: LLE or HS GC-MS or ECD Cost expensive, time-consuming methods MIMS Promising method (Blatchley, Andersen, Soltermann ) Not used in France Simultaneous determination of various DBPs in water and air samples Sensitivity and selectivity of the mass spectrometry techniques Real time quantification in swimming pool facilities 4

PRINCIPLE OF MIMS Pervaporation of analytes through a thin membrane Steady-state analysis Flow-injection analysis Flow of analyte transferred to the MS governed by diffusion according to the Fick law.

5 PRINCIPLE OF MIMS Pervaporation of analytes through a thin membrane Steady-state analysis Flow-injection analysis Flow of analyte transferred to the MS governed by diffusion according to the Fick law. Sensitivity / selectivity may affected by: Nature of the membrane (material, surface exposed, thickness ) Flow conditions (solvent viscosity, fluid phase velocity gradient ) Physicochemical parameters (Temperature, ph, ionic strength ) Mass spectrometry : Electron impact simple quad separation Electron multiplier Detector 5

6 OBJECTIVES Selection of specific ions for the quantification of DBPs Effect of various parameters on the determination by MIMS Temperature, ph, Ionic strength, rate of agitation In the range of values traditionally observed in swimming pool Determination of Limit of detection / quantification DBPs : THM4 : CHCl 3 (TCM), CHBrCl 2 (BDCM), CHBr 2 Cl (DBCM), CHBr 3 (TBM) Chloramines : NH 2 Cl, NHCl 2, NCl 3 Test of application Real-time monitoring of TCM in a pilot swimming-pool 6

ph MATERIAL AND METHODS MIMS : HPR40 (Hiden Analytical) Dual membranes inlet: Reference vs Measure Aqueous vs gazeous Chloramine solutions: Daily prepared From reaction between HOCl and NH

7 ph MATERIAL AND METHODS MIMS : HPR40 (Hiden Analytical) Dual membranes inlet: Reference vs Measure Aqueous vs gazeous Chloramine solutions: Daily prepared From reaction between HOCl and NH 4 Cl THM solutions: Daily prepared Dilution from pure analytical standards Chemically stable Cl/N = 0,8 ph = 8,5 200 mg.l -1 Cl/N = 0,8 ph = mg.l -1 Cl/N Cl/N = 11 ph = 4 50 mg.l -1 7

8 RESULTS ION SELECTION Selection of specific ions for the quantification of DBPs Acquisition of mass spectrum of THMs and chloramines TCM BDCM DBCM TBM Not Specific Specific 4 mains ions selected for simultaneous monitoring of THMs Specific ions: m/z = 173 (TBM only) ; 208 (DBCM only) Common ions: m/z=83 (TCM and BDCM) ; m/z=129 (BDCM and DBCM) 8

9 RESULTS ION SELECTION Simple relations for TBM and DBCM [TBM] = 1 I 173 mes (I 173 mes : signal intensity of the m/z 173 ion) [DBCM] = 2 I 208 mes ion ratio R 129/208 DBCM = 100 / 7 Use of ion ratio to quantify BDCM and TCM Total I mes 129 BDCM : I BDCM 129 DBCM : I DBCM 129 Used to determine [BDCM] calculated from [DBCM] and ion ratio [BDCM] = 3 I BDCM 129 with I BDCM 129 = I mes 129 -(I mes 208 x(r DBCM 129/208 ) [TCM] = 4 I TCM 83 with I TCM 83 = I mes 83 -(I mes 129 x(r BDCM 83/129 ) 9

I 83 TCM = I 83 mes - (I 129 mes xrbdcm 83/129 ) I 83 TCM = I 83 mes - (I 129 mes xrbdcm 83/129 ) RESULTS LIMIT OF QUANTIFICATION According to the AFNOR NF-T-90-210 method Y = ax + b : LOQ = (b+10 b

8 µg/l THM : LOQ close to values observed in swimming pool. r 2 = 0.997 Analytical performances can be improved 2E-12 by increasing calibration 1E-10 points 95% confidence interval r 2 = 0.

10 I 83 TCM = I 83 mes - (I 129 mes xrbdcm 83/129 ) I 83 TCM = I 83 mes - (I 129 mes xrbdcm 83/129 ) RESULTS LIMIT OF QUANTIFICATION According to the AFNOR NF-T method Y = ax + b : LOQ = (b+10 b )/a I 208 4E-10 3E-10 2E E-12 2E-12 1E-12 TCM LOQ = 3.3 µg/l r 2 = % confidence interval concentration (µg L -1 ) 8E-12 6E-12 4E-12 0 BDCM LOQ = 3.8 µg/l THM : LOQ close to values observed in swimming pool. r 2 = Analytical performances can be improved 2E-12 by increasing calibration 1E-10 points 95% confidence interval r 2 = DBCM LOQ = 5.8 µg/l NCl 3 : LOQ 500 µg NCl 3 /L 1,4E-11 Need to be improved 1,2E-11 I 173 1E-11 8E-12 6E-12 4E concentration (µg L -1 ) r 2 = TBM LOQ = 5.1 µg/l 95% confidence interval 2E-12 95% confidence interval concentration (µg L -1 ) concentration (µg L-1) 10

Signal (m/z 83) Signal (m/z 129) RESULTS EFFECT OF AGITATION BDCM 10µg/L Signal increases with velocity gradient in

MIMS 1,5E-10 fast enough to enable real-time monitoring in swimming pool water 1,0E-10 Control 5,0E-11 of the fluidic

phase) 0,0E+00 0,E+00 0 20 40 60 80 100 120 0 20 40 60 80 100 120 Time (minutes) Time (minutes) 2,E-11 1,E-11 Cs (MS

11 Signal (m/z 83) Signal (m/z 129) RESULTS EFFECT OF AGITATION BDCM 10µg/L Signal increases with velocity gradient in the solution Similar results obtained with other THMs and chloramines Modification of rotation rate 2,0E-10 3,E-11 MIMS 1,5E-10 fast enough to enable real-time monitoring in swimming pool water 1,0E-10 Control 5,0E-11 of the fluidic needed to perform Rate 2 Rate Rate 6 accurate quantification Liquid boundary layer Membrane Cs (bulk liquid phase) 0,0E+00 0,E Time (minutes) Time (minutes) 2,E-11 1,E-11 Cs (MS vac.) Liquid boundary layer limits the mass transfer of analytes Phenomenons becomes negligible with under sufficient mixing 11

12 I 83 (mes)/i 83 (ref) Raw signal RESULTS EFFECT OF PHYSICOCHEMICAL PARAMETERS Influence of ph 120% 110% Inlet 1 (mes) : DBCM 10 µg/l ph ranging from 6.2 to 9.5 Inlet 2 (ref) : DBCM 10 µg/l constant ph = 6.2 ph does not influence MIMS signal 2,E-10 ref mes 1,E % 0,E+00 0:00 2:24 4:48 90% 80% 70% 60% ,1 8,2 8,7 9,0 9,2 9,4 9,5 ph Important deviation of raw signal: loss by evaporation Working in relative mode increase the signal noise but allows interpretation in the case of signal deviation 12

Signal (m/z 83) RESULTS EFFECT OF PHYSICOCHEMICAL PARAMETERS Influence of ionic

$NaCl 4-6 g/l Liquid/membrane partition based on molar fraction (not concentration)$ I, T Cs (bulk liquid phase) Membrane Cs (MS vac.

13 Signal (m/z 83) RESULTS EFFECT OF PHYSICOCHEMICAL PARAMETERS Influence of ionic strength In-situ chlorine production by salt electrolysis Operating conditions : NaCl 4-6 g/l Liquid/membrane partition based on molar fraction (not concentration) Salinity does not influence MIMS signal 2,0E-10 NaCl addition C s, liq /C s, memb I, T Cs (bulk liquid phase) Membrane Cs (MS vac.) 1,5E-10 1,0E-10 5,0E-11 0,0E+00 Reference (inlet 1) Reference (inlet 2) NaCl 10 g/l (inlet 2) Time (min) 13

Signal Intensity Normalized signal Temperature ( C) Signal Intensity RESULTS EFFECT OF PHYSICOCHEMICAL PARAMETERS Influence of Temperature 1,0 0,8 0,6 0,4 0,2 0,0 TCM addition T = 35 C T = 15 C -5 5

14 Signal Intensity Normalized signal Temperature ( C) Signal Intensity RESULTS EFFECT OF PHYSICOCHEMICAL PARAMETERS Influence of Temperature 1,0 0,8 0,6 0,4 0,2 0,0 TCM addition T = 35 C T = 15 C Increasing Temperature: Decreases equilibrium time Interface temperature must be controlled Promotes analyte mass transfer ,E-10 2,E-10 1,E-10 0,E+00 1,5E-11 1,0E-11 TBM TCM 15 C 25 C 35 C 6,5 ppb 13 ppb Optimal temperature for MIMS analysis: Decreases viscosity T = 35 C Increases diffusion coefficient T > 35 C : Noisy signal 5,0E-12 0,0E+00 5,6 ppb 11,2 ppb 14

Signal Intensity Signal Intensity Intensité MIMS RESULTS AIR/WATER INLET CALIBRATION Inflow calibration Dual measurement MIMS/GC-MS Simultaneous air and water calibration [TCM] controlled by online

15 Signal Intensity Signal Intensity Intensité MIMS RESULTS AIR/WATER INLET CALIBRATION Inflow calibration Dual measurement MIMS/GC-MS Simultaneous air and water calibration [TCM] controlled by online spiking using automated syringes and flowmeters 8,E-08 6,E-08 4,E-08 2,E-08 0,E+00 y = 6E-10x + 2E-09 R² = 0, Concentration GC-MS (mg/m3) 2,0E-10 1,5E-10 2,E-10 0,E+00 0:00 1:00 2:00 3,0E-10 2,5E-10 2,0E-10 m/z 83 m/z 85 1,0E-10 1,5E-10 5,0E-11 m/z 83 m/z 85 1,0E-10 5,0E-11-5,2E [TCM]air (µg/m3) 0,0E [TCM] water (µg/l) 15

Water concentration (µg.l -1 ) Air Concentration (µg.

stock solution After-mixing theoretical concentration : 40 µg/l TCM in water: Inj.

TCM in air: Air flow Air Sampling 40 m 3 MIMS fast and sensitive enough to study

16 Water concentration (µg.l -1 ) Air Concentration (µg.m -3 ) RESULTS APPLICATION TO SWIMMING POOL ANALYSIS Chloroform Injection of TCM stock solution After-mixing theoretical concentration : 40 µg/l TCM in water: Inj. Eq. Time : According to the RTD [TCM] meas. [TCM] theo. TCM in air: Air flow Air Sampling 40 m 3 MIMS fast and sensitive enough to study water/air transfers Liq. Sampling 70 Water Air Time (minutes) 16

17 CONCLUSIONS - PERSEPECTIVES THM and chloramines monitoring: Simultaneous quantification using multiple ion monitoring and ion ratio correction THM : LOQ lower than values observed in swimming pool Parameters affecting MIMS signal: Velocity gradient in the solution maximize the rate of agitation Temperature : Optimal temperature = 35 C Parameters without effects: Salinity ph Analytical perspectives Increasing sensitivity of NCl 3 Influence of humidity during air monitoring 17

18 THANKS FOR YOUR ATTENTION

Paper 4.3. Introduction

Paper 4.3. Introduction Paper 4.3 Removal of free and combined chlorine at GAC surfaces and impact on pool water quality Bertram Skibinski, PhD student, Susanne Müller, PhD student and Wolfgang Uhl, Chairholder, Water Supply