The Column - August 2007 - (Page 10)

Q&A The Column www.thecolumn.eu.com August 2007 The Unsweet Smell of Success Professor Ling from the National Tsing Hua University in Taiwan spoke to The Column about the use of chromatography to identify the source of unwanted odours in the environment. Why are you developing techniques to analyse odours? Taiwan is experiencing rapid economic activity, which is obviously good for the country, but in some areas there has been a decrease in the quality of life because of increased levels of offensive odours being introduced to the environment. The Government has strived hard to balance growing the economy with maintaining a sustainable environment in the surrounding communities. The lack of regulatory laws relating to odour and the limitations of the official methods used for this type of analysis make effective regulatory control — and ways of determining the composition and sources of these odours — more difficult. Analysing odorous compounds is a challenging task because of their unique properties. They are fugitive, transient and some have a low odour threshold for instrumental detection. They are often present in complicated matrices and vary spatially and temporally. Most of all, odour is easily affected by the state and variations of the planetary boundary layer (PBL). Poor vertical mixing of ground air and atmospheric air during the night when the PBL becomes smaller causes offensive odours to linger in the environment. Analytical methods capable of rapid, on-site, real-time detection of trace amounts of targeted odorous compounds in complex matrices need to be developed. These methods need to detect analytes over a large area of the atmosphere under different weather conditions. No single analytical method could simultaneously overcome all the difficulties mentioned so we use a range of analytical techniques and the human sense of smell (olfaction). For example, for sulfur-containing species, human sensitivity is at the sub-ppb level whereas GC–MS sensitivity is at ppb level at best or higher. Contact: Professor Ling E-mail: ycling@mx.nthu.edu.tw When did you start working in this area? We started to develop analytical methods for measuring odorous compounds in 2001 when the local community around the HsinChu Science Park, which is heavily populated with high-tech industries, complained about the smell coming from this area. We collected odour information using olfaction from volunteers in the local community monitoring network. This community-based monitoring approach encourages concerned citizens, community groups, government agencies, industry and academia to work together to monitor, track and respond to environmental issues of concern in their community. The network encourages communities to perform environmental monitoring using sight and smell to track down polluters. We then started work on identifying and, if possible, quantifying the odours. We used sampling bags, sorbent sample tubes and air canisters to sample the volatile organic compounds (VOCs). We targeted compounds listed in Japan’s national offensive odour control law, which includes ammonia, hydrogen sulphide, methyl mercaptan, methyl thioether, trimethylamine, aldehyde, toluene, xylene, styrene, organic ketones and acids and so on. A range of maximum permissible concentrations at ground-level on the boundary line of a place of business are provided by this law. What techniques did you use to analyse these compounds? These odorous compounds were then identified and quantified using thermal desorption/gas chromatography–mass spectrometry (TD/GC–MS). Thermal desorption was achieved using a CDS 8000 sample 10 http://www.thecolumn.eu.com

Table of Contents for the Digital Edition of The Column - August 2007

Contents
News
The Unsweet Smell of Success
Time to Rethink Outsourcing?
Market Trends and Analysis
Hyphenated Techniques in Ion Chromatography
Tips & Tricks: GPC/SEC

The Column - August 2007