Screening for Water Pollutants

With the Agilent SureTarget

GC/MSD Water Pollutants
Screener, SureTarget Workflow, and
Customized Reporting

Application Note

Authors Introduction
Angela Smith Henry and Bruce Quimby Laboratories conducting water analysis increasingly need to screen samples for
a large number of compounds prior to performing a full quantitative analysis. The
Agilent Technologies, Inc. qualitative analysis of extracted water samples with GC/MSD provides the ability to
Wilmington, DE understand what is in the sample at approximate levels.

Existing qualitative screening workflows depend on manual screening, which is

extremely time-consuming and highly dependent on the analyst’s skill. Manual
screening processes can also lead to overlooked or misassigned compounds,
potentially due to complex matrices. Additionally, the discrepancy between
analysts’ results and any bias associated with compound identification can lead to a
significant amount of time exhausted on data analysis. Typically, a compound list for
manual review is approximately 50 compounds. Since each compound is reviewed
and identified by its retention time (RT), mass spectrum, and target and qualifier
ion ratios, greatly increasing the number of compounds to review per single sample
would multiply the complexities already faced. For example, if an analyst were
to screen a sample for 1,000 possible compounds, it could take up to 18 hours to
review that single sample.

The Agilent SureTarget GC/MSD Water Pollutants Screener provides a

straight‑forward and easy analysis workflow for the qualitative screening of water
samples. Not only will the Agilent SureTarget analysis workflow allow for the fast
screening of a large, wide-reaching compound list, but it will also remove bias
and inconsistencies in compound identification. The SureTarget GC/MSD Water
Pollutants Screener is preconfigured with the optimal hardware, consumables,
software, and analytical methods to allow for the fast implementation of screening
methods for pollutants in water.
Experimental Table 1. GC and MSD Parameters for Data Acquisition

GC Conditions
Water samples were collected from two sources: unfiltered
Column Agilent HP-5MS UI, 30 m × 0.25 mm, 0.25 µm
tap water in Lehigh County, Pennsylvania, USA, and effluents
Injection 1.0 µL cold splitless with CO2 cooled MMI
from the Wilmington, DE, USA wastewater treatment plant.
From the Wilmington wastewater plant, three samples were Solvent Dichloromethane
drawn: Inlet temperature program Rate (°C/min) Temp (°C) Hold time (min)
Initial 20 0.05
• Primary effluent – Sedimentation stage
Rate 720 300 0
• Secondary effluent – Biological content degradation
Carrier gas and mode Helium in constant pressure mode*
• Final effluent – Final filtration and disinfection RTL Compound and time Fluorene at 15.577 minutes
Oven temperature program Rate (°C/min) Temp (°C) Hold time (min)
Sample preparation
Initial 40 2
Each water sample, including the blanks, were extracted
Rate 10 300 8
through liquid-liquid extraction (LLE). Three milliliters of
dichloromethane (DCM) were added to a 30 mL water sample, MS transfer line temperature 280 °C
shaken for 5 minutes, and the DCM layer was extracted and MS Conditions
deposited into 2-mL autosampler vials for analysis. Solvent delay 1.82 minutes
Scan acquisition range 35–550 amu
Reference standards Tune Etune.u
Method 8270 Semi-Volatile by Capillary GC/MS mixtures Source temperature 250 °C
(Mixes 1, 2, 3, 4A, 4B, 5, and 6) were purchased from
Quad temperatures 150 °C
AccuStandard and diluted to concentrations ranging between
100 ppb and 10 ppm in DCM (86 compounds in total). * Final pressure dependent on RT-Locking procedure
One microliter of the Reference Gas Oil mix (RGO) was spiked
into each of the diluted AccuStandard samples to provide a
complex matrix. The SureTarget workflow is enabled in MassHunter
Quantitative Analysis upon installation of the water screener
Instrumentation feature disc. When the SureTarget analysis method is used,
the deconvolution algorithm will remove the background
All analyses were run on an Agilent 7890B Gas
and interfering mass fragments in the raw mass spectra
Chromatograph (GC) coupled with an Agilent 5977B InertPlus
from an identified compound’s mass fragments (Figures 1
Mass Spectrometer Detector (MSD). A CO2-cooled multimode
and 2). Figure 1A displays a total ion chromatogram (TIC)
inlet (MMI) was used to temperature program the inlet,
with an overlaid extracted ion chromatogram (EIC) for
which provided additional separation between the DCM
1-naphthylamine in a time window of 14.5 to 15.5 minutes
solvent peak and some early-eluting semivolatile compounds.
with the 1-naphthylamine peak located at 14.92 minutes.
Table 1 provides the GC and MSD method parameters for data
Figure 1B shows the complex raw mass spectrum under the
acquisition.
peak selected at 14.92 minutes; the deconvolution algorithm
cleans this complex mass spectrum of interferences.
Data analysis
All samples were analyzed using the SureTarget workflow Figure 2 illustrates the result of the deconvolution
with deconvolution in Agilent MassHunter WorkStation process, which is a clean, deconvoluted mass spectrum
Software Quantitative Analysis Version B.08.00 for GC/MS. for 1-naphthylamine at 14.92 minutes. The deconvoluted
The results of the SureTarget workflow were then compared spectrum was compared, in a head-to-tail fashion, with
to the results of the (same) samples analyzed in MSD the reference library spectrum of that compound. Next, the
ChemStation Data Analysis program with Deconvolution software automatically compared the deconvoluted mass
Reporting Software (DRS), which uses AMDIS (deconvolution spectra to the reference library, and generated a library match
software developed by NIST) as the deconvolution tool. score (LMS). This LMS is based on the similarity between
the deconvoluted mass spectrum and the library mass

2
 ×104
5
A Results and Discussion
Counts

4
3
2 Each prepared AccuStandard mixture included 86 compounds
1
for identification, which are also found in the water screener
13.8 14.0 14.2 14.4 14.6 14.8 15.0 15.2 15.4 15.6 15.8 16.0 16.2 16.4 16.6
×104 Acquisition time (min) library. These samples were run at 1 ppm, 200 ppb, and
B
1.6 55.1
69.1
83.1 97.1 119.1
148.1
100 ppb in RGO (complex matrix). After data acquisition,
105.1 the SureTarget deconvolution workflow was completed on
Counts

1.2 41.1
0.8 133.1
159.1173.1 187.1
204.2
10 samples per concentration level, and the results (number
0.4
0 of identified compounds and LMSs) were averaged. The
0 20 40 60 80 100 120 140 160 180 200 220 240
Acquisition time (min)
unfiltered tap water sample (Lehigh County, Pennsylvania),
primary effluent, and final effluent of wastewater treatment
Figure 1. TIC (A) and raw spectrum (B) of 1-naphthylamine (from (Wilmington, Delaware) were each averaged over five
AccuStandard mixtures) in reference gas oil matrix.
replicate runs to provide more analytical data for the
deconvolution comparison.
×103
143
1.0 Deconvoluted compound mass spectrum The number of identified compounds and their LMS values
0.8
0.6 at each concentration were observed and documented for
0.4 115 all AccuStandard mixtures and real-world water samples.
0.2
Once the SureTarget workflow on the extracted water
Counts

58
0
39 51 63 72 89 126
-0.2 samples was complete, the data analysis was repeated with
-0.4 Reference library spectrum
-0.6 115 the DRS, which uses AMDIS (NIST software). Both sets
-0.8 of data analysis results were then compared (Table 2 for
-1 143 AccuStandard results, and Table 3 for tap water results).
30 40 50 60 70 80 90 100 110 120 130 140 150
Mass-to-charge (m/z)
The data files were analyzed with DRS (AMDIS) and
Figure 2. Head-to-tail comparison of the deconvoluted mass spectrum (top) SureTarget to evaluate the ability of SureTarget. At each
and reference library spectrum (bottom) for 1-naphthylamine. The
concentration level for AccuStandard samples (Table 2), both
deconvoluted spectrum is very different from the raw spectrum
in Figure 1B, as the software was able to separate out all of the DRS and SureTarget reported a similar number of compounds,
interfering ions. within a margin of error (fewer than four compounds
difference on average), and similar LMS values (within
spectrum of the identified compound. The analysis method ~1 point per concentration level). These results indicate that
also looks for alternative peaks in the retention time window SureTarget performs very well and similarly to DRS (AMDIS),
that produce high library match scores. This additional with respect to identified compounds and corresponding
peak search aids in the review of the data, especially when LMSs.
analyzing complex matrices. The software then compares
and matches each SureTarget deconvoluted mass spectrum Table 2. Number of Identified Compounds and Average Library Match
to mass spectra in the NIST library and ranks each of the Scores (LMSs) of the AccuStandard 8270 Semivolatiles Mixture
matches in the NIST hit list; a hit list is generated for each with a 0.1 % Reference Gas Oil (RGO) Spike per Software Package
SureTarget identified compound. Figure 3 displays a graphical Approximate No. of
representation of the SureTarget workflow steps. AccuStandard Deconvolution tool compounds Average
concentration (software package) found (of 86) LMS
1 ppm AMDIS (DRS) 82 90.6
Alternative peaks
Deconvolution Library search in RT window NIST search SureTarget (in Quant B.08) 84 89.4
200 ppb AMDIS (DRS) 69 80.2
SureTarget (in Quant B.08) 72 79.3
Removes ions Matches against Looks for Looks for 100 ppb AMDIS (DRS) 59 76.0
from background a SureTarget alternate peaks alternate hits SureTarget (in Quant B.08) 62 75.6
and coeluting reference library that are a better that are a better
interferences match match

Figure 3. The four major Agilent SureTarget workflow steps include mass
spectral deconvolution in the RT window, library search of
deconvoluted mass spectrum, identification of alternative peaks
(in the RT window), and search of the NIST library.

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Table 3. Extract of Lehigh County, PA, USA Unfiltered Tap Water Table 4. Compounds Identified in Primary Wastewater Effluent (After
Solid Separation Phase) and Final Effluent (After Sanitation of
SureTarget
Wastewater) with Agilent SureTarget Deconvolution
AMDIS (DRS) (Quant B.08)
RT Compound Avg. LMS Avg. LMS Average LMS
2.328 Trichloroethylene 82.2 85.3 Primary Final
RT Compound effluent effluent
2.388 Bromodichloromethane 90.2 93.5
3.419 Chlorodibromomethane 92.4 92.3 2.345 Bromodichloromethane 58.7
3.630 Tetrachloroethylene 87.3 79.9 2.366 1,4-Dioxane 68.5 80.4
4.817 Bromoform 83.0 84.2 3.606 Tetrachloroethylene 79.7 54
21.986 Bisphenol A 59.3 64.4 9.619 a,a-dimethylphenethylamine (Phentermine) 69.1 65.2
10.031 Tributylamine 94.6 92.6
12.383 Triacetin 60.2
In the unfiltered tap water sample (Lehigh County, 13.307 2,4,7,9-Tetramethyl-5-decyne-4,7-diol 75.3 55.6
Pennsylvania), six compounds were identified by both 15.500 N,N-Diethyl-m-toluamide (DEET) 83.8
analysis programs with similar match scores (within 15.776 4-tert-Octylphenol 84.8 60.1
five LMS points). Trihalomethanes (sanitation by-products), 16.223 N,N,N’,N’-tetraacetylethylenediamine (TAED) 59.1
trichloroethylene, and bisphenol A were identified with 18.610 Caffeine 91.1
high match scores in the tap water by both deconvolution 18.804 Diisobutyl phthalate 84.3 67.8
analyses. 24.278 Codeine 97.2 90.1
29.724 Cholesterol 79.1
With the confidence in the SureTarget deconvolution
workflow, the wastewater samples (Wilmington, Delaware;
wastewater plant) were examined with the SureTarget Obtaining the results may be the first part of any water
workflow in MassHunter Quantitative Analysis. Each screening analysis, but data reports are needed for
wastewater sample was averaged over five replicate runs communicating the results. The SureTarget GC/MSD Water
to achieve more confident results. Several compounds Pollutants Screener also supplies PDF reports to preview,
were identified in the primary and final wastewater effluent summarize, and graphically display the data (Figure 4).
samples, including a mixture of concerning compounds. The data preview report is designed to show the details
These compounds include 1,4-dioxane, tetrachloroethylene, (compound name, CAS number, RT, and LMS) associated with
codeine, and 4-tert-octylphenol. Other compounds identified a primary peak of an identified compound, and any alternative
in the primary effluent included caffeine, phentermine peak in the RT window with a high LMS (greater than
(weight loss drug), DEET (insect repellant), and cholesterol. minimum) for that compound. The preview report indicates
Table 4 displays the compounds identified in the primary which compounds have alternative peaks (with the alternative
and final effluent. Table 4 also provides a picture as to RT) for further user review in the Quantitative Analysis
what compounds were destroyed, or not destroyed, in the batch Table (Figure 4). The summary report is designed
wastewater treatment process. DEET, triacetin, caffeine, to summarize the identified compounds, all compound
TAED, and cholesterol were destroyed in wastewater related details (compound name and CAS number, RT, LMS,
treatment, while bromodichloromethane was introduced upon approximate concentration, and difference from reference RT
sanitation of the wastewater in the final stage. In contrast, in minutes), as well as the rank and score of the compound in
several compounds were retained through the wastewater the NIST hit list in a tabular view. If the SureTarget identified
treatment process, including codeine, 1,4-dioxane, compound is not found in the NIST list (user-defined list,
4-tert‑octylphenol, phentermine, and diisobutyl phthalate. sized between 1 and 100, and set in method parameters),
then the top hit will be recorded on a second line (Figure 4).
The detailed graphics report dedicates one page to each
identified compound in the sample (Figure 4). Each page
will display the overlaid target and qualifier EICs, raw mass
spectrum, deconvoluted spectrum, reference library spectrum,
and the NIST spectrum (if the NIST hit is different from the
identified compound).

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Figure 4. Examples of PDF reports showing the preview report (left), summary report (middle) and a detailed graphics report page for one compound (right).

Conclusions to support the complete optimal solution. These features

include alternative peak identification in the RT window, NIST
The Agilent SureTarget GC/MSD Water Pollutants Screener search, and customized report templates (preview, summary,
with the SureTarget deconvolution workflow offers and detailed graphics). The use of automated deconvolution
streamlined data analysis and reporting by enabling the data analysis considerably reduces the manual review time,
automated separation and identification of compounds in while increasing the number of reviewable compounds to
complex matrices, such as tap and wastewater samples. greater than 1,000. The library match score, generated from
The water screener includes the SureTarget deconvolution the deconvolution analysis, helps to communicate confidence
workflow, which is activated in Agilent MassHunter in compound identification along with the ability to visually
Quantitative Analysis (B.08.00), with additional features review a deconvoluted mass spectrum next to the reference
library spectrum.

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For More Information
These data represent typical results. For more information on
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Information, descriptions, and specifications in this publication are subject to change

without notice.

© Agilent Technologies, Inc., 2017

Printed in the USA
February 16, 2017
5991-7834EN