AutoDilution

PSS Accusizer 780/SPOS Single particle optical sizer consists of a patented autodilution stage, single particle optical sensor, pulse height analyzer/counter (PHA), systems computer/processor and software control. The autodiluter performs a continuous dilution of the concentrated sample... 

Fig. 9.12 Schematic diagram of the Particle Sizing Systems Accusizer autodilution apparatus and optical particle counter.

Nicomp380/DLS Submicron particle sizer uses dynamic light scattering with a size range of 0.003 to 5 pm with unique modular options. An Autodilution unit that eliminates the need for manual dilution of concentrated samples [307] an Auto-sampler that permits automatic batch analysis of as many as 76 samples high-power laser diodes, multi-angle options and zeta-potential accessory. 

An autodilution unit has been described to analyze on-line particle growth during a polymerization process [309]. The results compared favorably with off-line dynamic light scattering and on-line turbidimetric data [310]. 

The first commercially available flame photometer was introduced in the 1940s by the Perkin-Elmer Corporation. In 1948, Beckmann Instruments, Inc., introduced a flame attachment that could be used with their popular model D.U. spectrophotometer. By the late 1950s, instruments had been developed that used lithium as an internal standard to maximize precision. Autodilution features and microprocessor-controlled operations became widely used options in the 1970s. The most recent significant development was the introduction of cesium as the internal standard, by Instrumentation Laboratory, Inc. (Figs. 1-3). This development makes concurrent lithium determinations more practical. 

The Shimadzu Scientific Instruments AA-7000 has a flame microsampling option that uses a sampling port, which allows 50-100 pL of sample solution to be injected into the flame for a measurement. This microsampling option can be used when sample is in limited supply. In addition, it minimizes salt buildup on the burner and minimizes waste. The use of such small volumes allows autocalibration using one standard and also permits autodilution of the sample, simply by injecting less volume into the flame. More details are available at www. shimadzu.com. 

As an alternative to AutoDilution with two injection loops, automated dilutions can also be carried out using the more sophisticated AS-AP Autosampler in combination with the Dionex Sample Conductivity and pH Accessory [702]. With this device, an in-line sample conductivity measurement is determined prior to injection and, if the measured conductivity exceeds a specified cutoff... 

Figure 10.407 AutoDilution of a wastewater sample with conditional large-loop/smalHoop injection. (a) Large loop injection and (b) small-loop injection. Separator column lonPac AS18 column dimensions 250 mm X 4 mm i.d. eluent 33 mmol/L KOH (EG) detection suppressed conductivity.

Dionex Technical Note No. 84 Automatic Dilutions Using Chromeleon AutoDilution and Two Injection Loops. Dionex Corporation (now part of Thermo Fisher Scientific), Sunnyvale,... 

F. (2011) Technical Note No. Ill Automated Resampling Using Chromeleon AutoDilution, Two Injection Loops, and the Dionex AS-DV Autosampler. Thermo Fisher Scientific, Sunnyvale, CA, USA. 

Chapter 3 examines one of the most critical areas of the instrument—the sample introduction system. It discusses the basic principles of converting a liquid into a fine-droplet aerosol suitable for ionization in the plasma, and presents an overview of the different types of commercially available nebulizers and spray chambers. Although this chapter briefly touches upon some of the newer sampling components introduced in the past few years, such as microflow nebulizers and aerosol dilution systems, the new breed of desolvating nebulizers, chilled spray chambers, autodilution, and online chemistry systems, are specifically described in Chapter 17. 

There are many other nonstandard sample introduction devices such as laser ablation, ultrasonic nebulizers, desolvation devices, direct injection nebulizers, flow injection systems, enhanced productivity systems, autodilution, and online chemistry techniques, which are not described in this chapter. However, because they are becoming more and more important, particularly as ICP-MS users are demanding higher performance and more flexibility, they are covered in greater detail in Chapter 17. 

E. Pruszkowski, L. Davidowski, D. Wiederin, and R. Thomas, Spectroscopy, Special ICP/ICP-MS Issue, November 2012. http //www.spectroscopyonline.com/spectros copy/ICP-MS-with-Autodilution-and-Autocalibration-for-l/ArticleStandard/Article/ detail/796474. 

May,T.W., andWiedmeyer,R. H. (1998).The CETAC ADX-500 autodiluter system A study of dilution performance with the ELAN 6000 ICP-MS and ELAN software. At. Spec-trosc. 19(5), 143. 

---