Development and Characterization of an Automated Direct Sample Insertion/Inductively Coupled Plasma/Atomic Emission Spectrometry System

Abstract

A new direct sample insertion (DSI) device that can be used vertically with inductively coupled plasma atomic emission spectrometry (ICP-AES) or horizontally with ICP mass spectrometry (ICP-MS) has been designed, and an automated ICP-AES system has been developed around this DSI device. The automated DSI-ICP-AES system was characterized by using microliter volumes of liquids and milligram amounts of powders. Analysis of solids with minimum pretreatment was a key goal in developing this system, and several calibration methods for powders were investigated. Examples of these are liquid standards, a few milligrams of different reference material or a different weight of the same material and standard additions of liquids onto a powder in the cup. Sample handling, weighing, sampling, and homogeneity concerns were partially addressed by using slurries. In addition, slurry DSI-ICP-AES for botanical, geological, and biological powdered reference materials is briefly described. Carbide formation is a key chemical limitation of graphite-cup DSIs, and it was addressed by using in situ chemical modification by mixing SF6 with the plasma gases.

Novel setup for investigation of the plasma conditions in direct sample insertion inductively coupled plasma atomic emission spectrometry (DSI-ICP-AES)

“…In DSI-ICP-AES, analyte appearance time, shape (width and height) of the analyte peak, SBR, and background intensity depend on the position of the sample probe in the ICP discharge. [1][2][3][4][5][6][7][8][9][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Generally, increasing the cup position from a lower position of the ICP (e.g., below the top of the load coil) to a higher position (e.g., above the top of the load coil) gives sharper and more symmetrical analyte emission peaks and, therefore, enhanced SBR. The effects of probe position on plasma excitation conditions, however, are rarely discussed in the literatures.…”

Rhenium-cup, in-torch vaporization (ITV) sample introduction for axially viewed ICP-AES and its application to the analysis of a microscopic, ng-weight solid sample

“…The polychromator was a Model 750 AtomComp 2 (Thermo Jarrell Ash Corporation, Franklin, MA, USA). 8 A schematic illustration of the imaging optics is shown in Fig. 1.…”

Calcium content of individual, microscopic, (sub) nanoliter volume Paramecium sp. cells using rhenium-cup in-torch vaporization (ITV) sample introduction and axially viewed ICP-AES

“…The spectrometer was a Model 750 AtomComp 2 (Thermo Jarrell Ash Corporation, Franklin, MA, USA) direct-reading polychromator equipped with 20 photomultiplier tube (PMT) channels. 16 In this case, only the Ca line (at 393.366 nm) was monitored. The current output of the Ca-channel PMT was converted to voltage using a The sample holder of the ITV device consists of a strip of Rhenium (Re) foil shaped into a cup and a metal support (Fig.…”

“…The cellular Ca content in single cells may be determined using a sample introduction system capable of introducing into an ICP discrete nL volume samples with minimum or no sample pre-treatment (i.e., directly). Sample introduction systems that may be used for this purpose include electrothermal vaporization (ETV), [13][14][15] direct sample insertion (DSI) 15,16 and in-torch vaporization (ITV). [1][2][3][4] In the typical ETV-ICP and DSI-ICP systems, a sample is vaporized from a graphite surface.…”