House dust, sampling methods

LC-MS uses different types of soft chemical ionization that produces molecular ions and no fragmentation pattern. In MS/MS instruments the molecular ions can be fragmented by collision with a gas for example, He. This fragmentation can be used for identification of a compound. No mass spectral libraries exist for LC-MS hence identification of unknown compounds is more time-consuming than for GC-MS. For known compounds LC-MS is a very sensitive and specific method, using LC-MS/MS systems the analytical performance can be increased even more. LC-MS analysis is especially suitable for non-volatile POMs such as non-ionic surfactants in house dust samples (Clausen et al., 2003). 

Aside from instrumental methods, enzyme-hnked immunosorbent assay for PCP and 2,4-D is commercially available but positive biases for 2,4-D as well as for PCP were seen in most house dust samples [ 104]. Thus, the enzyme-hnked immunosorbent assay cannot be recommended as a quantitative analytical tool, but might be useful as a screening tool [105]. 

Eocant et al. (2003) have described a rapid method of analyzing selected PCBs in human serum by gas chromatography-isotope dilution time-of-flight mass spectrometry. Analysis of soil and house dust samples for PCBs by enzyme-linked immunosorbent assay (ELISA) has been described (Chuang et al. 

Analytical methods have been developed by the Southwest Research Institute, Battelle-Columbus, and others for analyzing pesticides, PAHs, and PCBs in many environmental matrices, including indoor air and house dust samples (Camann 1994 Chuang et al. 1994). Progress in sampling and analysis make possible improvements in exposure analysis and the epidemiological studies discussed in the following sections. 

Que Hee SS, Peace B, Clark CS, et al. 1985b. Evolution of efficient methods to sample lead sources, such as house dust and hand dust, in the homes of children. Environ Res 38 77-95. 

Lanphear, B.P., M. Emond, D.E. Jacobs, M. Weitzman, M. Tanner, N.L. Winter, B. Yaki and S. Eberly (1995). A side-by-side comparison of dust collection methods for sampling lead-contaminated house dust. Environ. Res., 68, 114-123. 

Method performance in air analysis involves terms such as accuracy, storage stability, capacity, sampling rate, recovery, and sensitivity. To evaluate the performance of a developed method, certified reference materials for particulate matter, such as urban dust SRM 1649a particulate matter from NIST (Gaithersburg, MD, USA) can be purchased. In addition, a standard reference material has been recently developed for the determination of organic compounds in house dust the SRM 2585 is intended for using in method validation for the analysis of PAHs, PCBs, chlorinated pesticides, and PBDEs (Poster et al. 2007). 

Accurate analysis was achieved using optimum LC-MS/MS conditions LOD was 0.58 ng/ml or higher and LOQ was 2.5 ng/ml in all the analytes. The spike recovery test was conducted with internal standards and the average recovery was 97.9% or higher [relative standard deviation (RSD) 5.8%, n = 6], thereby suggesting that this method is useful to quantitatively determine PFCs in house and carpet dust. This method revealed that PFC concentration in house dust was extremely high compared to that in environmental samples, including environmental water and air. 

This review summarizes occurrence and exposure studies for pollutants in house dust and related indoor air exposures. A standard sampling method and control methods to reduce these exposures are discussed, including recommendations for future research. 

Studies of the source of exposure to PFCs have rarely been conducted. Thus, studies of the source of contamination with PFC, the source of exposure, the difihision path, the accumulated form, and toxicity are necessary. Currently, environmental contaminant of PFCs were mainly reported in polluted mud, ° environmental water, ° and atmosphere. However, the concentrations of detected PFCs are extremely low, and it is not sufficient to evaluate them as an exposure source. Therefore, we focused on house and carpet dust, ° which exists in our daily lives and contains many chemicals, to clarify the source of e xisure to PFCs, and discussed a highly sensitive and accurate method for the analysis of PFCs in house and carpet dust. The analytes were PFOS, PFOA, PFNA, and PFHxS, which are frequently detected in human blood, and surrogate standards were C4-PFOS and Cx-PFOA. The supercritical fluid extraction (SFE) method was used for house and carpet dust. Effective extraction is expected when supercritical liquid is used as the extraction solvent, as the elution ability of supercritical liquid is similar to that of conventional liquid and supercritical fluid can permeate every comer of the sample, as air does. 

The NHANES 2004 PbB survey was accompanied by household dust Pb sampling and the relationships between blood lead and household dust Pb analyzed through various statistical methods (Dixon et al., 2009 Gaitens et al., 2009). There was a statistical association of PbB to floor dust Pb. Child age and other child/family variables as well as year of house construction and window sill and floor Pb were significant predictors of PbB. These workers also calculated via logistic regression analyses that up to 5% of children in homes with floor dust Pb at 12 pg/ft would have a PbB >10 pg/dl. 

To further understand the behaviour of these radionuclides and to support the ciurent EPR2011 permits, Tata Steel UK has developed in-house radioanalytical methods for the measurement of °Po and °Pb in a wide range of iron and steel-making materials including raw materials, waste dusts and emission samples. The methods have been validated and accredited by the United Kingdom Accreditation Service (UKAS) according to the International Standard Organisation (ISO) 17025. 

As part of the quality control programme and to support accreditation according to the EN lEC/ISO 17025 2005 [6], each batch of samples should contain a reference material to validate the results. As there are currently no suitable and traceable certified reference materials available, several in-house reference materials (RMs) were developed. One iron ore and one sinter dust were selected to be developed as RMs for the alpha spectrometry method and the same sinter dust along with a blast furnace dust were selected for the gamma spectrometry method. When analysing stack emission samples, one blank filter was spiked with a known amount of a certified Pb standard solution (R22-02, National Physical Laboratory, UK) and used as a reference for result validation. 

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