For purposes of implementing and enforcing Section 43020, the State Air Resources Board shall purchase and install a wavelength dispersive XRF spectrometer with the capability to analyze gasoline and diesel fuels and other petroleum products for sulfur content according to ASTM procedures specified by regulation.
Source:
Section 43013.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=HSC§ionNum=43013.5..