Danica Heller-Krippendorf develops concepts and approaches optimizing the applicability of MVA on data sets from an industrial context. They enable more time-efficient MVA of the respective ToF‐SIMS data. Priority is given to two main aspects by the author: First, the focus is on strategies for a more time-efficient collection of the input data. This includes the optimal selection of the number of replicate measurements, the selection of input data and guidelines for the selection appropriate data preprocessing methods. Second, strategies for more efficient analysis of MVA results are presented. ​About the Author: Danica Heller-Krippendorf did her research and dissertation at the University of Siegen, Germany, in collaboration with a German analytical service company. Now she is engineer in analytics at a DAX company.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful technique for the analysis of organic surfaces and interfaces for many innovative technologies. However, despite recent developments, there are still many issues and challenges hindering the robust, validated use of ToF-SIMS for quantitative measurement. These include: the lack of metrology and fundamental understanding for the use of novel cluster primary ion beams such as C60n+ and Ar2000 +; the need for validated and robust measurement protocols for difficult samples, such as those with significant micron scale surface topography; the lack of guidance on novel data analysis methods including multivariate analysis which have the potential to simplify many time-consuming and intensive analyses in industry; and the need to establish best practice to improve the accuracy of measurements. This thesis describes research undertaken to address the above challenges. Sample topography and field effects were evaluated experimentally using model conducting and insulating fibres and compared with computer simulations to provide recommendation to diagnose and reduce the effects. Two popular multivariate methods, principal component analysis (PCA) and multivariate curve resolution (MCR), were explored using mixed organic systems consisting of a simple polymer blend and complex hair fibres treated with a multi-component formulation to evaluate different multivariate and data preprocessing methods for the optimal identification, localisation and quantification of the chemical components. Finally, cluster ion beams C60 n+ and ArSOO-2S00 + were evaluated on an inorganic surface and an organic delta layer reference material respectively to elucidate the fundamental metrology of cluster ion sputtering and pave the way for their use in organic depth profiling. These studies provide the essential metrological foundation to address frontier issues in surface and nanoanalysis and extend the measurement capabilities ofToF-SIMS.

Time of Flight Secondary Ion Mass Spectrometry (ToF SIMS) is a powerful tool for advanced surface analysis. It produces large data sets, which consist of mass spectra at each pixel at an imaged area. Many ToF SIMS instruments use a type of detector that suffers from two problems that lead to non-linearity in the measured sample properties: detector saturation and dead time. Linearity in this type of system is defined as the proportionality of the measured and true ion counts. Non-linearity can influence the interpretation of the data with methods such as multivariate analysis. "Detector saturation" happens when more than one ion arrives at the detector in the time interval related to one specific channel but the detector records only a single count. "Dead time" is when one event happens at a certain channel and the detector become insensitive to subsequent ions arriving within the dead time window. These problems both lead to under-counting of ions. In this thesis, we mainly focus on correcting for the dead time effects. Using extensive simulations, we first characterize the adverse effects of dead time on the output and evaluate quality of existing ways to "correct" for dead time effects. Then, we propose a novel method using the Maximum Likelihood Estimation (MLE) to estimate the true spectrum for the measured data. Specifically, we incorporate the statistical distribution of the dead time affected data in MLE, which leads to a new method for dead time correction.

Designed to serve as the first point of reference on the subject, Comprehensive Chemometrics presents an integrated summary of the present state of chemical and biochemical data analysis and manipulation. The work covers all major areas ranging from statistics to data acquisition, analysis, and applications. This major reference work provides broad-ranging, validated summaries of the major topics in chemometrics—with chapter introductions and advanced reviews for each area. The level of material is appropriate for graduate students as well as active researchers seeking a ready reference on obtaining and analyzing scientific data. Features the contributions of leading experts from 21 countries, under the guidance of the Editors-in-Chief and a team of specialist Section Editors: L. Buydens; D. Coomans; P. Van Espen; A. De Juan; J.H. Kalivas; B.K. Lavine; R. Leardi; R. Phan-Tan-Luu; L.A. Sarabia; and J. Trygg Examines the merits and limitations of each technique through practical examples and extensive visuals: 368 tables and more than 1,300 illustrations (750 in full color) Integrates coverage of chemical and biological methods, allowing readers to consider and test a range of techniques Consists of 2,200 pages and more than 90 review articles, making it the most comprehensive work of its kind Offers print and online purchase options, the latter of which delivers flexibility, accessibility, and usability through the search tools and other productivity-enhancing features of ScienceDirect

Time of flight secondary ion mass spectrometry, TOF-SIMS, is a highly surface sensitive analytical technique that provides information about composition with submicron lateral resolution. For select materials, TOF-SIMS provides unparalleled sensitivity along with excellent reproducibility, and as a mass spectrometric technique, it also provides excellent specificity. Of the analytical methods available, it is among the most surface sensitive, but the physical principles that underlie it are also the least understood. This volume describes the instrumentation, the physical principles behind the technique to the extent they are understood, and provides a practical approach for the interpretation of TOF-SIMS data. The use of advanced data processing methods such as multivariate statistics are described in a readily approachable manner. Given a basic background in undergraduate chemistry and physics, the book will be of use to any student with an interest in the technique.