Spring is upon us and all over the world people are out in their gardens planting their seeds for harvesting in the summertime. In my garden, this is a small operation with just a few chili peppers, some other veggies and a number of hops for my homebrew (if they ever grow!). Food-producing farms work on a much larger scale and plant a vast number of crops at this time of year. But how do we know that our crops are safe from environmental contaminants? We must analyze for contaminants in the soil, water, air and sediments to ensure that consumers are not exposed to harmful contaminants that could have negative health effects. Some examples of these toxic environmental contaminants are polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) which are resistant to environmental degradation and can enter the food chain where they can bio-accumulate. Often, these compounds are non-polar and have numerous congeners, many of which have identical masses that require chromatographic separation prior to detection, meaning that GC-MS is the technique of choice for this type of analysis. PAHs and PCBs are often analyzed in separate GC-MS methods to negate the complexity of the analysis.
There are numerous challenges associated with analyzing these chemicals including higher mass PAHs being prone to poor peak shape and separation, low detection limits to meet regulatory requirements and complex matrices (such as soils, sediments) causing interferences with the target analytes. In order to overcome these challenges, Thermo Fisher Scientific scientist Aaron Lamb has developed a combined PAH and PCB method using the ISQ™ 7000 Single Quadrupole GC-MS. The soil samples were extracted with a modified QuEChERS procedure and the method has been proven to be sensitive, robust, and suitable for the long-term, routine analysis with no system maintenance. Using this analytical approach, we can guarantee the timely analysis of hundreds of samples and ultimately ensure that our crops are not exposed to environmental pollutants. For more information on the full analytical method read the full application note here.