Particulate analysis, filter

Filter Particulate Analysis. In the laboratory, the filters were immediately placed in a desiccator for 24 hrs and then weighed. The particulate concentration was calculated from this weight and the previously determined tare weight of the filter. The filters were analyzed for mercury by a procedure previously reported by the author (11) consisting of boiling the filters in concentrated nitric acid. After being cooled, aliquots of these solutions were pipetted into the interchangeable sample tubes and analyzed by the direct aeration technique. 

Stack Gas Analysis. The measured concentrations of mercury in the stack gas at the sampling point, including both the filter particulates and volatile mercury, are presented in Table I. Tests 15 and 18 were contaminated and should not be considered. Data from the fourth amalgamator and the potassium permanganate backup solution showed that the standard sampling train had a collection efficiency in excess of 98% of the mercury entering the probe. 

Figure 1. Vertical concentration profiles for DMS, chlorophyll a and DMSP in the western basin of the Cariaco Trench off Venezuela (10° 39 N, 65°30 W). DMS was determined by sparging and gas chromatography with a flame photometric detector. Particulate DMSP was determined bv base treatment of material collected on 0.22 pm filters and analysis of the DMS released free DMSP was determined as DMS released upon base treatment of sparged water samples obtained after initial DMS analysis. Chlorophyll a data from W. Cooper and R. Zika (personal communication).

Ambient air pollution is understood to consist in human activity, during which one or more pollutants are introduced into the air. The pollution limit value is the highest permissible level of pollution of the air expressed in mass units per unit volume at normal temperature and pressure. The ambient air is most frequently sampled using methods of automatic continuous sampling, carried out by drawing the air directly into the analyzer or through a filter for analysis of dust and particulate matter (EN 12341 2000 Air... 

Sample streams contaminated with particulate matter can be filtered before analysis, as shown in Fig. 58. Ehie to the self-cleaning effect of a horizontal flow, such filters can even be used with highly contaminated samples for over a month without changing the filter [437],... 

Particulate interferents can be separated from dissolved analytes by filtration, using a filter whose pore size retains the interferent. This separation technique is important in the analysis of many natural waters, for which the presence of suspended solids may interfere in the analysis. Filtration also can be used to isolate analytes present as solid particulates from dissolved ions in the sample matrix. For example, this is a necessary step in gravimetry, in which the analyte is isolated as a precipitate. A more detailed description of the types of available filters is found in the discussion of precipitation gravimetry and particulate gravimetry in Chapter 8. 

Extraction Eiltering limits particulate gravimetry to solid particulate analytes that are easily separated from their matrix. Particulate gravimetry can be extended to the analysis of gas-phase analytes, solutes, and poorly filterable solids if the analyte can be extracted from its matrix with a suitable solvent. After extraction, the solvent can be evaporated and the mass of the extracted analyte determined. Alternatively, the analyte can be determined indirectly by measuring the change in a sample s mass after extracting the analyte. Solid-phase extractions, such as those described in Ghapter 7, also may be used. 

Particulate gravimetry is commonly encountered in the environmental analysis of water, air, and soil samples. The analysis for suspended solids in water samples, for example, is accomplished by filtering an appropriate volume of a well-mixed sample through a glass fiber filter and drying the filter to constant weight at 103-105 °C. 

As the gas stream proceeds through the sampling apparatus, the particulate matter is trapped on a filter, the moisture is removed, and the volume of the sample is measured. Upon completion of samphng, the collec ted material is recovered and sent to a laboratory for a gravimetric determination or analysis. 

Method 25 applies to the measurement of volatile organic compounds (VOC) as nonmethane organics (TGNMO), reported as carbon. Organic particulate matter will interfere with the analysis, and, therefore, in some cases, an in-stack particulate filter will be required. The method requires an emission sample to be withdrawn at a con-... 

Coal tar pitch volatiles measurement of particulates and cyclohexane soluble material in air Lab method using filters and gravimetric analysis 68... 

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