CORRELATION-BASED DETECTION OF SPECTRAL INFORMATION USING MICROLITER VOLUMES, IN-TORCH VAPORIZATION (ITV) SAMPLE INTRODUCTION AND INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY WITH PHOTODIODE-ARRAY DETECTION

The application of Fourier transform-based cross-correlation technique s for automatic detection of spectral information using 10 mu l volume s is presented. The basic approach involves interrogation of a spectra l pattern from a multielement mixture for the presence of spectral fea tures obtained by running single element standard(s). In essence, the multielement mixture is ''interrogated'' for the presence of the sough t-for element and, thus, automatic interpretation of spectral informat ion is obtained. Spectral patterns from 10 mu l volumes of single elem ent standards and multielement mixtures were acquired using an electri cally heated wire-loop, in-torch vaporization (ITV) sample introductio n system and an inductively coupled plasma (ICP) spectrometer equipped with a photodiode array detector (Leco Plasmarray). The wavelength re gion from about 280 nm to about 410 nm was covered. Spectral patterns for 10 elements (Al, Be, Co, Ni, Sc, Sr, V, Y, Yb, and Zr) obtained us ing 10 mu l volumes of single element standards were converted to spec tral interference-free and noise-free binary software masks. Cross-cor relation of these binary software masks with spectral patterns obtaine d from 10 mu l volumes of multielement mixtures is discussed and a gra phical user interface that utilizes a color-coded periodic table to pr esent the likely composition (i.e. qualitative and semi-quantitative a nalysis) of a mixture on the computer screen is described.