Flow Injection sample introduction for ICP-MS

In the past 5 years, great interest has been paid to the application and development of flow injection (FI) techniques using ICP-MS as the detection system. The majority of the studies devoted to this subject (i.e. about 70% of the published articles) have appeared since 1999 

Inductively Coupled Plasma Mass Spectrometry Handbook 

Some of the well known advantages of FI over continuous systems are (i) the sample and/or reagent consumed volumes are reduced by several orders of magnitude (ii) automation is easier (iii) the precision of the method is better (iv) the sample throughput is higher (v) matrix effects can be eliminated, although some studies have indicated that the interferences caused by nitric acid can be more severe in FI than in continuous mode and (vi) the sensitivity and limits of detection are in some cases better. FI-based methods are also interesting for the analysis of hazardous samples and the minimization of waste. 

Interestingly, in some instances it is better to monitor a part of the transient signal rather than the total signal. For example, it has been reported that when an ICP-TOFMS is used for isotope dilution (ID) procedures, with its detector operated in the analog mode, more precise results are obtained when calculating the ratio from at least five points at the peak apex than if the whole peak is considered. 

Additional factors to take into consideration such as the blank characteristics, working with either peak height or area and the working mode of the spectrometer are discussed in reference 2 of this section. 

---