Lowering reporting limit values for respirable crystalline silica analysis by X-ray diffraction in preparation of the 0.025 mg/m3 occupational exposure limit.

Internationally, respirable crystalline silica (RCS) occupational exposure limits (OELs) are being reassessed and, in some jurisdictions, lowered, putting pressure on the capabilities of the analytical techniques used to achieve robust analyses and reliable detection limits. In preparation of a lower OEL, options for lowering the limit of detection (LoD) for RCS analysis have been assessed. Using a Direct-on-Filter X-Ray Diffraction (XRD) analysis under reduced scan speeds in combination with low-noise RCS sampling filters, an LoD of 0.