The application of inductively coupled plasma mass spectrometry (ICP-MS) to the determination of eight trace metals in a coastal seawater reference material is described. Accurate calibration has been achieved for Mn, Co, Ni, Cu, Zn, Cd, and Pb by standard additions techniques, while stable isotopes dilution has been applied for Cr, Ni, Cu, Zn, Cd, and Pb. In both cases the race metals were separated from the seawater and concentrated 50-fold by adsorption on silica-immobilized 8-hydroxyquinoline prior to instrumental determination. Detection limits are in the range from 0.2 to 2 ng L/sup -1/, low enough to permit the analysis of even open ocean samples. 12 references, 4 figures, 3 tables.

Determination of trace metals in seawater by inductively coupled plasma mass spectrometry with preconcentration on silica-immobilized 8-hydroxyquinoline

Analysis of acid digests of foods for As, Se, Sb, and Te was semiautomated. Hydrides generated by controlled addition of base stabilized NaBH₄ solution to acid digests are transported directly into a shielded, hydrogen (nitrogen diluted), entrained-air flame for atomic absorption spectrophotometric determination of the individual elements. The detection limits, based on 1 g of digested sample, are approximately 10 to 20 ng/g for all four elements. Measurement precision is 1 to 2 percent relative standard deviation for each element measured at 0.10 $mu$g. A comparison is made of results of analysis of lyophilized fish tissues for As and Se by instrumental neutron activation (INAA), hydride generation with atomic absorption spectrometry, fluorometry, and spectrophotometry. NBS standard reference materials (orchard leaves and bovine liver) analyzed for As, Se, and Sb by this method show excellent agreement with certified values and with independent NAA values. (auth)

Sequential determination of arsenic, selenium, antimony, and tellurium in foods via rapid hydride evolution and atomic absorption spectrometry.

Quantitative depth profile analysis by glow discharge

Glow discharge sputtering

Glow‐discharge mass spectrometry, in which an rf glow discharge is used both to sputter etch the sample undergoing analysis and to ionize the neutral sputtered species, is shown to be a promising new technique for the elemental analysis of thin solid layers or bulk solids. A description of the method is given followed by some examples of its application to composition profiling. The influence of some parameters is shown and opinions as to the advantages and disadvantages of the method are given.

Glow‐discharge mass spectrometry—Technique for determining elemental composition profiles in solids

Sequential analysis of metal alloys in depths of 0.1 to 40 μm are made with a glow discharge source for optical emission spectrography. The alloys examined have compositional variations in depth due to mass transfer in liquid sodium tests for materials studied in the fast breeder reactor program. The ion-sputtering action of the source produces progressive and discrete sampling of a defined area with concurrent excitation of the analytes in the negative glow region of the discharge. Integrated exposures of successive layers of attack are spectrographically recorded. The total weight loss is measured gravimetrically. Weight loss is assigned per exposure layer, and the depth of each attack is calculated. With more than 98% of the elemental composition measured, the sum of all elements is used as the internal standard. The precision approaches that of the photographic measurement process and does not indicate the ultimate precision of the source.

J. D. Johnson

Papers

In-Depth Compositional Profile Analysis of Alloys Using Optical Emission Glow Discharge Spectrography: