Definitions and Concepts for Targeted and Non‐targeted Chemical Analysis

Targeted and non-targeted chemical analyses represent distinct but complementary strategies for investigating chemical systems. Targeted analysis relies on predefined analytes, analytical standards, and highly selective workflows to achieve precise quantification and regulatory compliance. Non-targeted analysis, in contrast, typically seeks to capture the broadest possible chemical profile without prior assumptions, thereby enabling the detection of unknown or unexpected compounds. While this conceptual difference is well established, it does not fully account for how methodological decisions shape the chemical information made available for interpretation. To address this, the concept of analytical information continuity (AIC) is introduced for evaluating the extent to which chemical complexity is retained or lost throughout the analytical workflow. Key dimensions influencing AIC include sample preparation, chromatographic separation, and mass spectrometric resolution. Each of these stages acts as a selective filter, and their combined effect determines the informational depth accessible from a given sample. Rather than viewing resolution as a stand-alone metric for chromatography and mass spectrometry, the discussion emphasizes its impact on the scope, structure, and interpretability of the resulting data, that is, how methodological and strategical choices define the limits of what can be observed, detected, and ultimately understood. Advances in multidimensional gas chromatography, mass spectrometry, and high-throughput data processing capabilities have stimulated a paradigm shift in molecular analysis over the past decades. Their combination, forming a final hyphenated high-resolution technique, enables the separation and monitoring of many more analytes and chemical domains within a given sample. In this chapter, we will discuss the concepts of targeted and non-targeted chemical analyses, focusing on their practical application through GC- or GC×GC-MS. Non-targeted analysis is the driving strategy of the modern omics sciences for the discovery and understanding of complex systems. At the same time, it sets the basis for the upcoming chapters, in which the non-targeted approach is discussed in various fields of application. From a future perspective, high-resolution techniques, which are well-suited for non-targeted analysis, can be further scaled-down to targeted and simpler techniques for routine analysis.