Perfluorooctanoic acid (PFOA) is a synthetic carboxylic acid of particular importance in the semiconductor industry, with the most common use being in photolithography and anti-reflective coatings. In addition to having direct applications to the semiconductor industry, it is also used widely to construct parts which make up a large portion of the manufacturing materials and equipment, such as Teflon. However, up until the last few years the effect of PFOA emissions on human health had not been widely considered or regulated.
In December 2016, a proposal restricting emissions of PFOA from all semiconductor manufacturing equipment and individual parts to 25 ppb (by volume) was passed, coming into effect over the next five years. In 2022, it will be a requirement that all semiconductor equipment, whether new or used, is PFOA-free.
SIFT-MS has recently been applied to the real-time measurement of PFOA in air samples. A mass spectrum obtained for PFOA with the O2+ reagent ion can be seen below in figure 1., with the peaks of interest summarized in the following table.
Figure 1. Full scan analysis of PFOA headspace with the SIFT-MS O2+ reagent ion
|Product m/z||Molecular formula||Branching ratio (%)|
|Minor ions||(CF2)2+ (m/z 100), CF2CFCO+ (m/z 109), C3F5(CF2)2+ (m/z 181), (CF2)3CFCO+ (m/z 209)||12 (total)|
Qualitative measurements on multiple compounds of particular interest to the semiconductor industry, including PFOA, can be carried out simultaneously in less than a minute, with no pre-concentration, sample preparation or chromatographic separation required.