Table 1. Details of Generation, Sampling, Redeposition, and Analysis Methods for Engineered Stone Aerosol from Grinding and Calibration Samples.
| material | generation method | sampling methoda | redepositionb | replicates | analysis method |
|---|---|---|---|---|---|
| engineered stone | grinding | MOUDI with PVC filterc | 4 | FT-IRg | |
| MOUDI with aluminum foild | silver filtere | 1 | XRD,g O-PTIRj | ||
| MOUDI | SEM stubs,h TEM gridsi | 1 | SEM, TEM | ||
| SRM 1878 | nebulization (aqueous) | QCM | silver filtere | 1 | XRD |
| SRM 1878b | vortex shaking (dry)46 | MOUDI | PVC filterf | 2 | FT-IR |
| Min-U-Sil 5 | MOUDI | silver filtere | 1 | XRD | |
| MOUDI with PVC filterc | 1 | FT-IR | |||
| AAC | PVC filterf | 1 | |||
| SRM 1879b | MOUDI | silver filtere | 3 | XRD | |
| MOUDI with PVC filterc | 1 | FT-IR | |||
| MOUDI | PVC filterf | 2 | FT-IR |
If specified, filter/foil was mounted on the impactor substrates, else aerosol was sampled directly on the impactor substrates.
Substrates with sampled aerosol were rinsed in 2-propanol (A461–212, Optima LC/MS grade, Fisher Scientific). The resuspensions were vacuum filtered on the filtration media.
47 mm, 5 μm pore size, SKC, Inc.
47 mm, TSI Inc.
25 mm, 0.45 μm pore, SKC, Inc.
25 mm, pore size 5 μm, SKC Inc. The deposition area on these filters was smaller than the 47 mm PVC filters used for collecting the aerosol from grinding. For calibration, this difference was accounted for by normalizing the mass with the ratio of the deposition areas.
Mass of the sub-100 nm and submicron sized samples was much lower than the micron-sized samples. To minimize the potential particle loss during ashing when sampled on PVC filters as recommended in the NIOSH 750047 and NIOSH 760348 methods, we opted to resuspend the sampled aerosol on aluminum foil in 2-propanol and redeposit on silver filters for XRD. Additionally, we opted to measure the aerosol sampled on PVC filters directly for FT-IR.
Transferred to adhesive carbon conductive tabs (PELCO Image Tabs, Ted Pella, Inc.) mounted on SEM pin stubs (Aluminum, grooved edge, Ted Pella, Inc.) before rinsing the substrate in 2-propanol.
Sub-100 nm and submicron sized samples suspended in 2-propanol were pipetted onto TEM grids (400 mesh carbon coated Ni or Cu, SPI) and dried under ambient conditions. Micron-sized samples (dry collection) were transferred to the TEM grids using a needle-tip.
Measurements were performed on the same silver filters used for XRD.