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Significant advances in the measurement of atmospheric mercury species have been made in the past 10 years yet limited protocols on quality control (QC) and assurance on this data have been published in the literature. Recently, considerable work has been done to develop quality control and assurance programs within North America. Environment Canada and the National Atmospheric Deposition Network (NADP) independently developed programs, RDMQ™ and AMQC, respectively, to QC atmospheric mercury speciation data (including gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated to particles (PHg)). These 2 programs were assessed by the criteria on which the data is QCed and comparability of the final data products. Results show that the criteria used to flag data compare well within the 4 tested sites and that the number of flags for each criterion is generally comparable. The QC programs were applied to 2 distinct data sets and the final QCed data was compared. From a mid-latitude site, the final data sets compare very well and showed there to be a 0.3, 8.6 and 15% difference in the mean GEM, RGM and PHg concentrations post QC of each program. It is recommended that either the RDMQ or the AMQC programs be employed for a typical mid-latitude site. When the QC programs were applied to highly variable data, the data do not compare as well for RGM and PHg. Results showed a 2.7, 27 and 33% difference in the mean GEM, RGM and PHg concentrations, respectively, post QC of each program. It is recommended that RDMQ be used for data that is highly variable with high RGM/PHg concentrations as it allows for more manual correction over the QCed data. This investigation of 2 QC programs produced comparable data and that either of these programs can be used as standard methods for the quality control of atmospheric mercury speciation data.

A new method for the detection of selected flammable liquid accelerants from arson-suspected fire debris has been developed using headspace solid-phase microextraction (SPME). Two different techniques were used to validate the headspace SPME method. Preliminary headspace SPME was carried out by extracting small amounts of gasoline or barbecue lighter fluid spiked onto pre-burnt carpet or wood with subsequent analysis using GC–FID. Alternatively, small amounts of accelerant were burnt with wood or carpet and headspace SPME with GC–ion-trap mass spectrometry was performed on the residue. The FID and ion current chromatograms were used to determine a visual correlation so that the presence of the components that are commonly found in petroleum-based accelerants could be confirmed. Headspace SPME was capable of detecting trace amounts of gasoline from a sample obtained from a real arson-suspected fire, while conventional extraction methods, such as static headspace, lacked adequate sensitivity for the analysis so that accelerants were not detected.