scope:

This method is for determining total trace arsenic in liquid organics and heavy petroleum fractions by microwave digestion and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The lower limit of quantitation for arsenic is 5 ng/g (mass-ppb).

Sample preparation by conventional extraction and digestion, such as that used in UOP Method 946, Arsenic in Petroleum Naphthas by HG-AAS, is time consuming and is problematic for high-boiling samples as it is possible for arsenic to be volatilized at the extreme sample preparation conditions required. UOP Method 986, Arsenic in Heavy Petroleum Fractions using Microwave Digestion and Graphite Furnace-AAS, uses microwave digestion, however due to sensitivity limitations of the GF-AAS, multiple digestions must be combined for analysis. A comparison of the methods is shown in Table 1