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Accurate and Reliable Analysis of Low-Level Volatile Organic Compounds by GC-Single Quadrupole MS Jessie Butler, David Steiniger, Eric Phillips, Trisa Robarge, Thermo Fisher Scientific, Austin, Texas USA Abstract Volatile organic compounds (VOCs) are released as gases naturally from plants or man-made solids and liquids and can have hazardous effects on human health and the environment. As a result, the anthropogenic VOCs are strictly regulated, especially indoors where concentrations can be up to ten times higher than outdoors. Legislation has triggered the need for a precise and dependable method; however, traditional analytical techniques are not able to detect the low levels of VOCs that are usually present in the atmosphere. This article describes how gas chromatography (GC)-single quadrupole mass spectrometry (MS) is a viable method for analyzing VOCs in line with current regulations. Experimental results demonstrate that the method decreases analyst review time by 50%, significantly increases sample throughput and allows the detection of lower method detection limits (MDLs) of VOCs compared with conventional techniques. Introduction VOCs are emitted in the form of gases from plants and a wide range of solid and liquid products, including building materials, furnishings, office equipment, household products, fossil fuels, paints and coatings. All of these products can release VOCs while they are being used and to some degree while they are kept in storage. Studies indicate that elevated concentrations of VOCs can also persist in the air long after the product has been used1. Some VOCs have been associated with short-term and long-term adverse health effects such as headaches, loss of coordination, nausea and damage to liver, kidneys and the central nervous system. In addition, some of these compounds are suspected or known to cause cancer. Certain VOCs are also hazardous to the environment, as they act as major contributing factors to the formation of ground level ozone, which is a common air pollutant that has been shown by the United States Environmental Protection Agency (EPA) to affect the normal function of lungs. In response, strict regulations are enforced to minimize the human health and environmental hazards posed by increased concentrations of VOCs. In India, minimization of VOCs is a major concern and legislation exists to regulate all steps of chemical management from inception to completion. The Environment Protection Act of 1986 serves as an umbrella act for all regulations concerned with the protection of the environment and the subsequent protection of human health. HCFCs (hydrochlorofluorocarbons), a dangerous VOC, is regulated in India through the Ozone Depleting Substances (Regulation and Control) Rules 2000, which provides a comprehensive set of regulations to control and monitor the production and use of ozone depleting substances2. To facilitate compliance with stringent legislation and protect human health and the environment, the industry requires a method capable of monitoring VOCs in an accurate and reliable manner. However, VOCs usually exist in low concentrations, making their detection and analysis a challenging task. Technological advancements have led to the introduction of a method that couples GC with single quadrupole MS to deliver lower detection limits and increased throughput,

enabling regulatory compliance. The technique is specified by the EPA Method 524.3 for the measurement of purgeable organic compounds in water. EPA Method 524.3 requires integration of a range of instrumentation, including the sample introduction system, gas chromatograph, mass spectrometer and software for data interpretation, analysis and reporting3. An experiment was performed to demonstrate the capabilities of GC-single quadrupole MS for analyzing VOCs in an array of solid and liquid products in line with current legislation. Experimental For this experiment, a standard GC-MS method for VOC analyses was developed according to published quality control guidelines and EPA Method 524.3. After establishing a baseline of performance according to these guidelines, improvements to the method were tested by combining changes to the GC-MS, applying a software package developed around routine environmental GC-MS workflows. By using this method, laboratories can reduce analyst review time by 50%, as well as increasing the number of samples that can be analyzed during a 12 hour shift. . GC/MS parameters The Thermo Scientific ISQ gas chromatograph/single quadrupole mass spectrometer (GC-MS) was evaluated at a scanning speed of 2,650 amu/sec (0.1 sec) over a mass range of m/z 35 to 300. An OI EclipseTM 4660 Purge and-Trap Sample Concentrator equipped with a sample heater and 4551A autosampler were used to deliver 5 mL of sample for the analysis and was operated at a sample purge temperature of 40° The internal standard and surrogates were added by the C. Standard Addition Module (SAM) unit. The gas chromatograph was operated in the split mode. For this experiment, the water management temperature was set at 110° (purge), 0° (desorb) and C C 240°C (bake). Purge took place at 40mL/minute for 11 minutes, the desorb temperature was 190°C for 0.5 minutes and bake rinse cycles took place twice at 210° for 10 minutes. C In addition, the GC-MS was coupled to a TR 524 20 meter x 0.18mm, 1.0µm column and split ratio inlet conditions were 40 / 1 at constant pressure of 25 psi at 175° GC temperature was set at C. 40° for four minutes, 18°C per minute to 100° and 40° per minute to 230° for five minutes. C C C C The solvent delay was 0.5 minutes before activating filament and the MS source temperature was 250°C. Results and Discussion Peak Shape The EPA Method 524.3 recommended range of values for the purge and trap parameters reduced the cycle time of the purge and trap and minimized the amount of water injected. The shorter desorb time and a rapid oven temperature program on a narrow-bore 0.18 mm id capillary column gave a shorter analysis time of 15 minutes (Figure one). Improvement in the carrier gas control reduced band broadening of the first six gases, resulting in more Gaussian peak shapes (Figure one). Better precision with high scan speeds of 2,650 u/sec resulted in achievement of excellent detection limits and was compatible with faster chromatography. A combination of shortened analytical time and reduction in data review time lead to an overall improvement in productivity (Figure two).

Figure one: Total ion chromatogram of 20 µg/L standard with insert showing the extracted ion profile of first six gases at 0.4ppb.

Figure two: Reduction of analysis time through a combination of method and software workflow improvement. Data Review Thermo Scientific EnviroLab Forms 3.0 software ensured streamlined and rapid creation of reports with flags for data points that fail specific quality control criteria specified by the user. Data review is also simplified by the software by showing where peaks were manually integrated and whether the quality control (QC) criteria passed or failed. Available flags include manually integrated, ion ratio failure, below detection limit and carryover flags. Calibration Curve A calibration curve was made from 0.4 to 40 ppb. A 5 mL sample was purged onto a trap using the OI Eclipse 4660 and 4551 liquid autosampler. The internal standard (fluorobenzene) and surrogates (4-bromofluorobenzene and 1,2- dichlorobenzene-d4) were added automatically by the SAM unit at 1 µL of a solution at 25 µg/mL, resulting in a final concentration of 5 µg/L. The average percentage risk-specific dose (RSD) of all compounds was 8% RSD and the internal standard fluorobenzene was 6% RSD. The results in table one show the RSD of compounds investigated.

Table one: Calibration curve results, from 0.4 ­ 40 µg/mL and points at 0.4, 2, 4, 20 and 40 µg/L. Method Detection Limits MDLs were generated by analyzing seven replicates at 0.4 µg/L. The average MDL was 0.104 µg/L and the individual results are shown in table two.

Table two: Method detection limits (MDLs) based on replicate runs at 0.4 µg/L. Conclusion VOCs have proven to be harmful to both human health and the environment and as such they are strictly regulated substances requiring frequent monitoring. Experimental results demonstrate that when GC is coupled to single quadrupole MS, a powerful analytical platform capable of accurate detection and analysis of low-level VOCs is formed. Furthermore, the method reduces analyst review time by 50% and doubles sample throughput during a 12-hour shift from 24 to 48, while also enabling legislative compliance by achieving lower MDLs as set out by current regulations. Further benefits offered by the new method include good sensitivity, spectral purity and linear dynamic range. References 1. US Environmental Protection Agency, An Introduction to Indoor Air Quality, Volatile Organic Compounds (VOCs), 2. United Nations Environment Programme, Division of Technology, Industry and Economics, OzoneAction Branch, Legislation, regulations and policies to control HCFCs, 3. EPA Method 524.3 Measurement of Purgeable Organic Compounds in Water by Capillary Column gas Chromatography/Mass Spectrometry, U.S. Environmental Protection Agency, Cincinnati, OH, Version 1, June 2009.

Thermo Scientific is part of Thermo Fisher Scientific, the world leader in serving science. About Thermo Fisher Scientific Thermo Fisher Scientific Inc. (NYSE: TMO) is the world leader in serving science. Our mission is to enable our customers to make the world healthier, cleaner and safer. With revenues of more than $10 billion, we have approximately 35,000 employees and serve customers within pharmaceutical and biotech companies, hospitals and clinical diagnostic labs, universities, research institutions and government agencies, as well as in environmental and process control industries. We create value for our key stakeholders through two premier brands, Thermo Scientific and Fisher Scientific, which offer a unique combination of continuous technology development and the most convenient purchasing options. Our products and services help accelerate the pace of scientific discovery, and solve analytical challenges ranging from complex research to routine testing to field applications. Visit For further press information please contact: Celine Callender, The Scott Partnership, 1 Whiteside, Station Road, Holmes Chapel, Cheshire. CW4 8AA United Kingdom Tel: + 44 1477 539539 Fax: +44 1606 1477 539540 E-mail: [email protected]


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