Characterization and Optimization of a Direct Injection Nebulizer for Introduction of Organic Solvents and Volatile Analyte Species into an Inductively Coupled Plasma

A direct injection nebulizer (DIN) is evaluated as a means of introducing organic solvents and volatile analyte species into an inductively coupled plasma atomic emission spectrometer (ICP-AES). The DIN used in this work differs in several important aspects from a commercially available DIN, after which it is patterned. When used for flow injection analysis, the DIN exhibits a long-term precision of about 4% RSD while nebulizing pure organic solvents. Under normal operating conditions, detection limits are generally an order of magnitude worse in organic solvents than in water, but they can usually be improved by using higher forward powers and viewing higher in the plasma. Measurements of the atom/ion line intensity ratios of copper under various conditions indicate that a large but nearly constant degree of plasma cooling exists when organic solvents are nebulized. When compared to a Meinhard nebulizer-ICP system, the DIN-ICP system gives more uniform response towards different chemical species of the same element, even when great differences in volatility exist between the species.