Liquid Nebulization Research Articles

Optimization and Calibration of Laser Ablation–Inductively Coupled Plasma Atomic Emission Spectrometry by Measuring Vertical Spatial Intensity Profiles

X. MAO and RICHARD E. RUSSO, J. Anal. At. Spectrom., 1997, 12, 177 DOI: 10.1039/A606059E

Determination of Platinum, Palladium, Rhodium and Titanium in Automotive Catalytic Converters Using Inductively Coupled Plasma Mass Spectrometry With Liquid Nebulization

O. V. BORISOV, DAVID M. COLEMAN, KRISTINE A. OUDSEMA and R. O. CARTER III, J. Anal. At. Spectrom., 1997, 12, 239 DOI: 10.1039/A605159F

Determination of Vanadium, Rhodium and Platinum in Automotive Catalytic Converters Using Inductively Coupled Plasma Mass Spectrometry With Spark Ablation

A high voltage unidirectional spark source was used as a sampling tool for ICP-MS analysis of automotive catalytic converters. Electrical conductivity of the samples, required for spark experiments, was provided by mixing samples with powdered graphite. Spark discharge parameters, such as peak current and repetition rate, which influence spark sampling efficiency, were studied and optimized. Prior work involving liquid nebulization ICP-MS analysis of series of lladium-only wavelength dispersive X-ray fluorescence secondary standards’ was compromised owing to spectral interferences arising primarily from polyatomic oxide species. Additional separation techniques were required in order to separate analyte from matrix elements in cases where interferences could not be resolved. Spark ablation, with its dry plasma, was shown to result in a significant reduction in the formation of polyatomic species and simplification of the analytical procedure. Analytical results achieved by ICP-MS with liquid nebulization and with solid sampling are compared. Limitations of the spark ablation technique owing to high voltage rf interference on the ICP-MS instrument and spark discharge wander around the sample surface are discussed.

Ultrasonic transducer with silicon: A well known material with new applications

Abstract The vibrations of piezoelectric driven (ZnO) thin Si membranes up to 200 kHz are studied. Non-linear vibrations with amplitudes of a couple of micrometers for subharmonic frequency produce considerable ultrasonic radiation. The application of the discussed structure as a liquid nebulizer is investigated. A high mode vibration with a large amplitude is a necessary condition for the generation of surface acoustic waves (SAW) in the liquid film and drop formation.

A fluidized-bed sampler for direct powder introduction inductively coupled plasma atomic emission spectrometry: particle size segregation

The determination of trace elements in powdered solids with direct powder introduction ICP-AES and ICP-MS is subject to errors associated with particle-size if (a) the powder sampler hardware introduces bias in the particle size distribution during the sample transport, or (b) if the efficiency of the processes leading to emission of analytes in the plasma is a function of particle size. The magnitude of particle size-segregation which is caused by a fluidized-bed powder sampler was estimated with two simple fluid dynamic models of powder collection: the first based upon the relative forces of gravity and the viscous drag on particles moving through a gas, and the second based upon the relative effects of particle inertia and the force of viscous drag on the particles. Experimental measurement of size-segregation was based on a series of 13 synthetic binary mixtures of 21 ± 6 (±1 SD) and 34 ± 10 μm silica particles ranging in composition from 1 to 99% by weight of the smaller particle, the balance made up of the larger particle. The smaller particle was labelled with Mn and Co via complexation with immobilized 8-hydroxyquinoline, and the larger was labelled with Cu and Cd. Mixtures of the particles were analyzed by add extraction of these labels, followed by conventional liquid nebulization ICP-AES. The composition of the particle mixture after passage through the sampler was related to the original mixture by ( y a / y b ) = 1.96 ( x a / x b ) where y a , and y b are the fractions by weight of 21 and 34 μm particles after, and x a and x b are the fractions before, transport through the sampler. A mixture which was 1:1 by weight of these particles prior to transport, contained about 65% small and 35% large particles (by weight) after passage through the fluidized-bed sampler. Hardware designs which minimize the particle size-segregation should include mechanical provision for continuous formation of an aerosol of sample in the vicinity of the uptake capillary.

Current Developments in Optical Emission Spectrometry with High‐Frequency and Microwave Induced Plasmas

AbstractThe state‐of‐the‐art and trends of development with the inductively coupled plasma (ICP) and microwave induced plasmas (MIP) as radiation sources for optical emission spectrometry arc presented. Especially techniques for sample introduction are discussed. Here special reference is given to the use of spark ablation as well as 10 direct sample insertion and slurry atomization for the direct analysis of powder samples. The development in MIP optical emission Spectrometry is shown to center on the improvement of the plasma sources, their characterization and their tailoring to various sampling techniques. Results of the use of pneumatic nebulization of liquids and electrothermal evaporation of dry solution residues will be presented.

Optimization of the instrumental parameters of a combined liquid chromatograph-mass spectrometer, coupled by an interface for direct liquid introduction : II. Nebulization of Liquids by Diaphragms

Direct liquid introduction interfaces for combined liquid chromatography-mass spectrometry (LC-MS) require a flow restriction to limit input liquid flow-rates to the small values tolerated by the mass spectrometer. In general, viscous type restrictions should be avoided. A non-viscous type restriction such as a 1-3-μm pinhole in a thin wall is acceptable for LC-MS as it produces a jet of small droplets of solution. However, jet instabilities affecting the mass spectral fragmentation pattern directly cannot be avoided in this simple nebulizer. Adding a hot gas to the ion source gives control of chemical ionization reactions and provides thermal energy for droplet vaporization, thus improving overall LC-MS performances. Application to analyses of monosaccharides and disaccharides illustrates the present state of the art of the technique.

Alterations in Airway Dynamics following Inhalation of Ultrasonic Mist

In three separately designed studies, ultrasonically nebulized mists of distilled water, normal saline and 5 percent saline were administered to normal healthy subjects and patients with chronic obstructive pulmonary disease (COPD). The normal subjects reacted to the inhalation of distilled water and 5 percent die with slight irritative cough but no change was observed in the values of WC, FEVl 0, airway resistance and pulmonary compliance following inhalation of any of the mists. The patients with COPD, however, complained of increased cough and wheezing with died water and 5 percent saline mist. In addition there was slight increase in airway resistance in tbose patients who tolerated the ultrasonic mist poorly, especially when 5 percent saline aerosol was used. These side effects of mist inhalation in the COPD patients were generally of short duration and could be reversed with inhalation of isoproterenol (Isuprel) combined with coughing and raising of sputum. Further, subjective tolerance of inhaled mist by the COPD patients was better and increase in airway obstruction less marked when the ultrasonic mist was inhaled at nebulizer outputs below 3.0 ml/min; at 6.0 ml/min output from the nebulizer, the ultrasonic mist was visually very dense and patients were unable to breathe the same comfortably. It is therefore suggested that patients with COPD receiving ultrasonic mists for any reason be closely monitored and the quantity of the inhaled mist adjusted to a suitable therapeutic level, preferably below 3.0 ml/min nebulizer output, which is comfortable for the patient. ltrasonic mist is commonly used in clinical U practice to increase the humidi6cation of the inspired air. The motive force for nebulization of liquids is the high frequency vibrational energy generated by a piezoelectric crystal, which in turn yields a mist, the volume output of which can be varied between 0.5 ml and 6.0 ml per minute.'s2 While the clinical applicatio~ of ultrasonic mist therapy and its beneficial effects are well recogni~ed,~ more recent studies reported by Cheney and Butlei' and Pflug and co-workers5 showed an increase in airways obstruction following inhalation of ultrasonic mist in patients with chronic obstruc

A new approach to the nebulization of liquids and its application to atomic absorption spectrophotometry

Summary A pneumatic nebulizer system is described for atomic absorption spectrophotometry. Originally developed for a low pressure burner, the system proved to be very effective for use at atmospheric pressure. Efficiencies of nebulization up to 90–93% have been achieved. Detection limits have been measured for cobalt, iron and copper with a conventional atomic absorption set-up. The high efficiency of the nebulizer, the stability of the flow, and the homogeneity of the spray, suggest applications of the system, not only for atomic spectroscopy, but also as an injection system for flames fed with liquids.