Section H – Sensors, automation and computing
H4 DATA ENHANCEMENT AND
DATABASES
Data processing Raw analytical data often contains electronic noise and other spurious signals
such as detector responses from sample components other than the analyte(s) of
interest. Digitizingand computer processingenable both the noise and inter-
fering signals to be reduced or eliminated using chemometric routines (Topic
B5). Additional software procedures can be used to process calibration and
sample data for quantitative analysis by establishing detector responses,
computing results and applying statistical tests. Quantitative data is conve-
niently handled by spreadsheets, such as Microsoft Excel and statistics
packages such as Minitab. Tabulated results can be incorporated into reports
generated in any required format by a word processor. Stored information can
be manipulated and presented in tabular or graphical forms to aid interpreta-
tion. The processing of spectrometric and chromatographic data provide good
examples of data enhancement and quantitative computations, for example:
● smoothing to reduce noise and co-adding spectra from multiple scans to
increase the signal-to-noise(S/N) ratio of weak spectra;
● spectral subtraction to remove background interference or contributions
from components of a sample that are not of interest to reveal the presence of
peaks that were previously obscured;
● scale expansion to show details in a particular region of a spectrum or to
increase sensitivity;
● flattening a sloping baseline that may be distorting spectral peaks;
● processing calibration and sample data for quantitative analysis;Key Notes
Digitized raw analytical data can be computer-processed to extract the
maximum amount of useful information. This includes noise reduction,
signal enhancement, calibration and quantitation, the identification of
unknown analytes, and the characterization of materials.Large amounts of analytical and other chemical data can be stored in
digital form for access when required. This can range from small locally
generated databases for use with a single instrument to large ones
compiled by national or international organizations for general
availability.Search software enables data libraries to be searched for specific
information, including physicochemical data on elements, compounds,
materials and products. The ability to identify or classify unknown
analytes or substances is an important facility of library search software.Related topic Computer control and data collection (H3)Data processingDatabasesLibrary searches