**7. Acknowledgment**

This work was conducted at the Pacific Northwest National Laboratory, which is operated for the U.S. Department of Energy by Battelle under Contract DE-AC05-76RL01830.

#### **8. References**

280 Environmental Monitoring

include particles sizes, filter types, filter loading and burial depths, and analysis of energy spectrums. More recently, others have evaluated sample filter deposition characteristics by conducting studies and using computer simulations (Luetzelschwab et al., 2000; Huang et al., 2002; Geryes et al., 2009; Barnett et al., 2009). From recent publications, additional information is now available on the self-absorption that occurs in filters, the measurement losses associated with the filter loading, and the use of Monte Carlo simulations (Fig. 9) to assess the energy spectra in different geometries. Ongoing research in this area is still warranted, given that standards call out a correction factor for self-absorption effects of

Fig. 9. Comparison of an experimental and simulated energy spectrum in a filter (Geryes et

Concepts for environmental radioactive air sampling and monitoring include establishing the basis for sampling/monitoring, criteria for sampling media and analytical requirements, and reporting and compliance. The processes utilized include a standards based and a DQO approach that should be integrated and applied to both direct effluent and environmental surveillance sampling and monitoring. In addition, program improvement can be enhanced through the sharing of knowledge derived from routine operations and the implementation of tested and reviewed ideas. The overall program is used to demonstrated to the stakeholders that the emissions of radioactive materials to the environment is below regulatory limits and that those doses reported from such emissions are reasonably and

more than 5% (ISO, 2010; ANSI, 2011).

al., 2009)

**6. Conclusion** 

conservatively accurate.


**17** 

*1Portugal 2Australia* 

**Multisyringe Flow Injection** 

*2School of Chemistry, University of Melbourne,* 

**Applications and Recent Trends** 

**Analysis for Environmental Monitoring:** 

Marcela A. Segundo1, M. Inês G. S. Almeida1,2 and Hugo M. Oliveira1 *1REQUIMTE, Department of Chemistry, Faculty of Pharmacy, University of Porto,* 

Multisyringe flow injection analysis (MSFIA) was introduced by Víctor Cerdà and coworkers in 1999 (Cerdà et al., 1999) as a robust alternative to its predecessor flow injection techniques, combining the multi-channel operation of flow injection analysis (Ruzicka & Hansen, 1975) with the possibility of flow reversal and selection of the exact volume of sample and reagent required for analysis as presented in sequential injection analysis (Ruzicka & Marshall, 1990). Generally, flow injection systems are automation tools where, in opposition to batch conventional assays, physico-chemical equilibrium is not attained prior to determination. Hence, flow injection analysis is based in three principles: (1) reproducible sample injection or insertion in a flowing carrier stream; (2) controlled dispersion of the sample zone; and (3) reproducible timing of its movement from the injector point to the

Since its inception, MSFIA has been the basis for automation of more than 120 different assays, reviewed in several publications (Almeida et al., 2011; Magalhães et al., 2009; Maya et al., 2009; Segundo & Magalhães, 2006). This type of automatic flow injection systems is based on the utilization of a multisyringe burette, depicted schematically in Fig. 1A and 1B. It is a multiple channel piston pump, containing up to four syringes, driven by a single motor of a usual automatic burette and controlled by computer software through a serial port. A two-way commutation valve is connected to the head of each syringe, allowing

Because the four syringes are driven by the same motor, all pistons move at once in the same direction either delivering (dispense operation) or loading the syringes (pickup operation) with liquids. Considering that the commutation valves can be placed in two positions, there are four possibilities for flow management as depicted in Fig. 1C. Hence, when the pistons are moving upwards, it is possible to dispense liquid into the flow system or send it back to its reservoir. This feature enables that only the necessary amount of reagent solution is introduced into the flow system. Furthermore, when the pistons are moving downwards, it is possible to refill the syringes with solutions present in the respective vessel or to aspirate

optional coupling to the manifold lines or to the solution reservoir.

solutions from the system in order to perform the sampling operation.

**1. Introduction** 

detection system.

