Analytical techniques for boron quantification supporting desalination processes: A review

Several studies have been reported over the last two decades to improve the analysis of boron and to determine its isotopic composition. The isotopic composition of boron is of significance to SWRO because second pass processes result in a boron isotopic shift in the permeate, thereby creating a unique process signature. This paper reviews the different boron detection and quantification techniques ranging from plasma-based techniques, to thermal ionization mass spectrometry (TIMS), and other MS-based and non-MS based techniques. The most recent precision and detection levels are reported, and the complexity of analysis and sample preparation, as well as the major disadvantages and limitations associated with the measurements of boron and its isotopic composition (e.g., spectral and isobaric interferences, mass fractionation, and memory effect) are compared among analysis techniques. While positive-TIMS (PTIMS) has been reported as the most precise, and the negative-TIMS (NTIMS) as the most sensitive, plasma-based techniques such as multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) are characterized by their fast speed of analysis and high sample throughput. Several recent improvements have increased precision and lowered the detection level of the MC-ICP-MS, making it capable of competing with PTIMS and NTIMS.