determination of 17 organotin compounds by gcqqq
DESCRIPTION
Determination of 17 Organotin Compounds by GCQQQTRANSCRIPT
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Sensitive Determination of 17 Organotin
Compounds in Beverages
Using Agilent 7890A / 7000B GC-MS/MS System
Agilent Technologies
Wang Wenwen Cao Zhe
• Organotin compounds (OTCs) have been widely used as polymerized
preservatives, insecticides and pesticides. The highest amount of
OTCs found among coating materials in boats to prevent biological
attachment in the ocean can reach to over 20% of the total which
addressed great concerns. OTCs are identified as endocrine
disruptive chemicals (EDCs) which may cause negative impact on
human health via food chain.
• OTCs were found in ocean water, sediments, textiles and human
urines however studies on OTCs in food were relatively less. There
were studies on analysis of OTCs by GCMS (single Quadrupole) and
ICPMS or LC-ICPMS, yet conventional GCMS method is with limited
separation and sensitivity capacity, which can normally detect less
than 10 OTCs in one run. So far, speciation studies of OTCs by GC
triple Quadrupole mass spectrometer (GCMS/MS) technique are
seldom seen.
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Background
• Agilent 7000B GCMS/MS was applied in this research
work to establish a precise, rapid and reliable method
to study 17 OTCs in beverages. 11 kinds of beverages
samples were tested to check preliminary
contamination status of OTCs in the market which
could be polluted by Tin containers.
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Background
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Experiment
• Samples, Reagents
• Standards, Derivatization method
• Sample Preparation
• Chromatographic Parameters
• Mass Spec Parameters
• The beverages were obtained from local grocery stores
• Acetate buffer: 82g/L sodium acetate in water, adjusted to pH4.5
with acetic acid
• Derivatization reagent :Dissolve 2g NaBEt4(Sigma-Aldrich ) in
10mL ethanol. This solution should be freshly prepared
• Ethanol, Hexane, Methanol： chromatography grade purity
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Samples, Reagents
Standards , Derivatization method
• Standards: The standards were dissolved in methanol at 1000
ppm (1mg/mL) concentration and were further diluted, depending
on the derivatization method used.
• Derivatization method: To 1 mL standard solution , 1 mL acetate
buffer and 50 µL derivatization reagent are added. The solution is
shaken and allowed to react for 30min. After addition of 5mL
water, the derivated compounds are extracted in 1 mL hexane. The
mixture is vortexed for 10 s and the two phases are allowed to
separate. The clear upper layer (apolar hexane phase) is
transferred to an autosampler vial for analysis.
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Sample Preparation
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The derivated compounds are extracted in 1 mL hexane. The mixture is vortexed for
30 s and the two phases are allowed to separate. The clear upper layer (apolar
hexane phase) is transferred and filtered to an autosampler vial for analysis.
To this solution, 2 mL acetate buffer and 200 µL
derivatization reagent are added. The sample is shaken and
allowed to react for 30 min.
Weigh 10 mL beverage sample into 22mL bottle
(P.N 5183-4323), add 5.0 mL Methanol，
ultrasonic extraction 10 min.
Chromatographic Parameters
• GC system: Agilent 7890A
• Column: Agilent HP-5 MS UI capillary column (30 m×0.25 mm×0.25
μm)（P.N 19091S-433UI）;
• Column temperature: 50 ℃ hold 1.5 min , at 10 ℃ /min to 300 ℃, hold 1
min;
• Carrier gas: Helium;
• Flow rate: 1.1mL/min;
• Injection port temperature: 280 ℃;
• Injection volume: 2 μL;
• Injection mode: Splitless, purge on after 1 min
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Mass Spec Parameters
• Mass system : 7000 MS/MS;
• Ion source: EI;
• Ion source polarity: Positive ion;
• Ionization voltage: 70 eV;
• Ion source temperature: 230℃;
• Interface temperature: 280℃;
• Collision Gas：Nitrogen 1.5 mL/min;
• Quenching Gas ：Helium 2.25 mL/min;
• Solvent delay: 2.0 min;
• Optimized MRM Parameters:(See Table1)
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Table 1. Optimized MRM Parameters
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No. Compound RT
Quantifier MRM
transition (m/z) Qualifier MRM
transition(m/z) Collision/eV
1 Trimethyltin 2.72 165-135 163-133 15;15
2 Dimethyltin 3.86 179-151 151-135 5; 10
3 Monomethyltin 5.34 165-137 193-165 5; 5
4 Monobutyltin 9.45 179-151 179-123 5; 10
5 Tripropyltin 10.38 193-151 193-123 5; 10
6 Tetrapropyltin 11.35 207-165 207-123 5; 10
7 Dibutyltin 11.66 179-151 263-207 5; 5
8 Monophenyltin 12.92 255-199 255-277 15; 5
9 Monoheptyltin 13.29 179-151 179-123 5; 10
10 Tributyltin 13.54 207-151 207-123 5; 15
11 Monooctyltin 14.49 179-151 179-123 5; 10
12 Tetrabutyltin 15.16 235-179 291-179 5; 10
13 Diphenyltin 17.78 303-275 303-197 5; 15
14 Diheptyltin 18.00 249-151 249-123 5; 15
15 Dioctyltin 19.83 263-151 263-123 5; 15
16 Tricyclhexyltin 21.78 351-197 349-195 20; 20
17 Triphenyltin 21.80 233-151 233-123 5; 15
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Results and Discussion
• Chromatographic separation results
• Calibration Curve, Linear Fit
• Recovery Results
• Analysis results of 11 Kinds of Beverages
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GC separation was finished in 22 min with 15 of 17 compounds ideally
separated. Although the last two OTCs could not be separated as expected,
extraction of transition ions and precise quantitation were accomplished by
unique feature of GC-MS/MS given that appropriate ions were selected,
extracted and monitored, at meantime, optimized GC and MS parameters
were applied.
7000 Scan TIC
Chromatographic separation results
Calibration Curve, Linear Fit
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No. Compound Linear range (µg/L) R2
1 Trimethyltin 1-200 0.999
2 Dimethyltin 1-200 0.995
3 Monomethyltin 1-100 0.999
4 Monobutyltin 1-200 0.999
5 Tripropyltin 1-200 0.996
6 Tetrapropyltin 1-200 0.996
7 Dibutyltin 1-200 0.999
8 Monophenyltin 1-200 0.998
9 Monoheptyltin 1-200 0.999
10 Tributyltin 1-200 0.999
11 Monooctyltin 1-200 0.997
12 Tetrabutyltin 1-200 0.998
13 Diphenyltin 1-200 0.998
14 Diheptyltin 1-200 0.999
15 Dioctyltin 1-200 0.999
16 Tricyclhexyltin 1-200 0.998
17 Triphenyltin 1-200 0.999
Calibration curves were prepared at 1.0-200 µg/L(1.0、5.0、10.0、20.0、50.0、100.0、200.0 µg/L 7 points)
17 Organotin Compounds 1.0ppb MRM
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17 Organotin Compounds 5.0ppb MRM
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Monobutyltin
0.999 Dibutyltin
0.999
Tributyltin
0.999 Tetrabutyltin 0.998
Organotin compounds Standard Calibration Curve Results (1)
(µg/ml) (µg/ml)
(µg/ml) (µg/ml)
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Monomethyltin 0.999
Trimethyltin
0.999 Tetrapropyltin
0.996
Organotin Compounds Standard Calibration Curve Results (2)
(µg/ml)
(µg/ml)
(µg/ml)
Monophenyltin
0.998
(µg/ml)
Recovery Results
Beverage samples were spiked with 10 µg/L and 50 µg/L mixed
standard thus precision and recovery study of the method were
conducted, majority of RSDs were within 10% and recoveries
within 70-120%.
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NO. Compound
Name 10µg/L(n=3) 50µg/L(n=3)
AVE RSD AVE RSD 1 Dibutyltin 108.9 3.2 114.9 2.4 2 Diheptyltin 76.0 6.5 83.7 1.8 3 Dimethyltin 136.3 5.1 136.8 2.4 4 Dioctyltin 67.5 6.3 75.5 0.8 5 Diphenyltin 102.1 5.6 96.7 2.3 6 Monobutyltin 156.2 5.8 135.7 2.8 7 Monoheptyltin 116.2 9.4 114.4 9.0 8 Monomethyltin 113.0 7.0 163.4 9.2 9 Monooctyltin 129.4 3.8 112.8 8.1
10 Monophenyltin 115.4 4.6 118.0 1.7 11 Tetrabutyltin 63.4 8.2 77.9 11.3 12 Tetrapropyltin 71.0 3.5 87.7 6.1 13 Tributyltin 117.9 7.8 112.1 8.9 14 Tricyclhexyltin 107.4 6.1 99.8 2.2 15 Trimethyltin 87.3 6.7 119.5 10.6 16 Triphenyltin 82.2 7.5 82.4 3.4 17 Tripropyltin 104.9 4.7 114.3 2.4
Analysis results of 11 Kinds of Beverages
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11 kinds of Beverages were then
tested with above established
method for the 17 OTCs among
which both Dimethyltin and
Monobutyltin were detected in 2
brands at sub ppb level.
Analysis results of Sample 1
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Dimethyltin Monobutyltin
OT RT（min） Concentration（µg/L）
Dimethyltin 3.86 0.27
Monobutyltin 9.46 0.37
Analysis results of Sample 2
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OT RT（min） Concentration（µg/L）
Dimethyltin 3.86 0.27
Monobutyltin 9.46 0.39
Dimethyltin Monobutyltin
Summary
Agilent 7000 GCMS/MS technique with MRM
mode has the advantage of eliminating
background interferences, highly sensitive and
selective, so that it turned out to be suitable and
effective in analyzing 17 OTCs in beverages.
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Reference
Agilent application note :
Improving the Analysis of Organotin Compounds Using
Retention Time Locked Methods and Retention Time
Databases
5988-9256EN
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Thank you !!!
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