Many in Germany argue that the minimum wage and other protective provisions for migrant workers will only be effective when workplace inspections by the enforcement body "Finanzkontrolle Schwarzarbeit" (FKS) are stepped up. For this reason, a novel cooperation agreement between the FKS and migrant workers' counseling offices has been signed, in June 2021. This step is informed by the FKS' public image of being a guardian of the minimum wage and of victims of labor exploitation. The hypothesis of this thesis is that the argument of more inspections lead to less exploitation is oversimplified. Therefore, it explores the role that the FKS has for migrant workers in more detail by using regime theory and a methodological approach informed by ethnographic border regime analysis. An analysis of the FKS' formal duties codified in the law reveals its ambivalent character. Especially the concept of unlawful employment serves as an umbrella term that conflates protective as well as punitive provisions for migrant workers. In eleven qualitative interviews, FKS officers and migrant workers' counselors mostly rejected the FKS' image as a "workers' protection squad". Instead, they think that the FKS only served the interests of the state. As a consequence, exploited workers have no immediate benefit from FKS inspections, and sometimes even experience heavy detriments like the loss of their job, housing, or unpaid wages. The most severe consequences, like expulsions or deportations, result from violations of the Residence Act. For these reasons, counselors reacted differently to the new cooperation agreement. While most counselors have strong reservations or even refuse to work with law enforcement bodies, others have found ways to cooperate without putting their clients at risk. For such successful cooperation it is crucial that FKS officers take workers' and counselors' needs seriously and adapt their routines and protocols in order to instill trust. Under the current legal and institutional configuration, increasing the number of FKS inspections is not pertinent to combat the exploitation of migrant workers. The argument that vulnerabilities of migrant workers emerge from a lack of enforcement is blinding out the fact that the enforcement of labor law itself produces vulnerabilities. Institutions tasked with the enforcement of protective provisions, must not be tasked with enforcing punitive provisions against migrant workers. Instead, workers need to be given an active role in the enforcement of their own rights.

Die Systematische Toxikologische Analyse (STA) stellt auf Grund der großen Vielfalt und der ständigen Zunahme an toxikologisch relevanten Substanzen eine der größten Herausforderungen in der chemischen Analyse dar. In der vorliegenden Arbeit wurde daher die Eignung der Flüssigchromatographie in Kombination mit der Hybrid-Quadrupol-Flugzeitmassenspektrometrie (LC-QTOF-MS) für diesen Zweck untersucht. Dazu wurden eine Datenbank mit über 7360 und eine CID-Spektrenbibliothek mit mehr als 2720 toxikologisch relevanten Substanzen erstellt und geeignete Probenvorbereitungsmethoden entwickelt. Die Erprobung der Methoden erfolgte an dotierten Blut- und Haarproben. Hierbei zeigte sich, dass die Analyse im Auto-MS/MS-Modus (Messzyklen von MS- und MS/MS-Spektren) eine Identifizierung basischer Substanzen mittels CID-Spektren zwischen 0,5 und 2 ng/ml im Blut ermöglichte. Die Nachweisgrenzen der für 24 Wirkstoffe validierten Methode in Haaren lagen bei 3 bis 15 pg/mg. Die Eignung der LC-QTOF-MS zur STA von Haarproben wurde an 30 Drogentodesfällen und 60 Todesfällen mit bekannter chronischer Medikamenteneinnahme zu Lebzeiten sowie an 77 Blutproben nachgewiesen. Für die Suche nach Metaboliten wurde ein Metaboliten-Tool entwickelt. In der praktischen Anwendung auf Datenfiles von Blut- und Haarproben erwies sich das Tool als wertvolles Hilfsmittel zur Identifizierung unbekannter Peaks und zur Bestätigung von Suchergebnissen in der Datenbank. Zur automatischen Konzentrationsabschätzung identifizierter Substanzen wurde ein Tool „Estimate Concentration“ geschaffen. Die Überprüfung des Verfahrens an realen Blut- und Haarproben durch Vergleich mit HPLC-DAD- und GC-MS-Ergebnissen wies eine gute Übereinstimmung der Konzentrationen auf. Insgesamt zeigten die Untersuchungen, dass die LC-QTOF-MS zurzeit die am besten geeignete Methode für die STA darstellt. Auch bei einem erst später aufkommenden Verdacht kann eine gezielte Suche in dem bereits gemessenen Datenfile durchgeführt werden. / Due to the large variety and the steady increase of toxicologically relevant substances, systematic toxicological analysis (STA) is one of the most difficult tasks in analytical chemistry and, therefore, a steady topic of research and methodical improvement. For this reason, the suitability of liquid chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for STA was investigated. For this purpose, a database of more than 7360 and a CID spectra library of more than 2720 toxicologically relevant substances and suitable methods for sample preparation were developed. The application was evaluated at spiked blood and hair samples. It was found that the analysis in Auto-MS/MS mode (alternating measurement cycles of MS and MS/MS spectra) allowed substance identification in blood using CID spectra between 0.5 and 2 ng/ml for basic substances. The detection limits of the validated method in hair ranged from 3 to 15 pg/mg for 24 drugs. The suitability of LC-QTOF-MS for STA was tested for hair samples from 30 drug-related death cases and from 60 death cases with known chronic medication as well as for 77 blood samples. For the search of metabolites, a metabolite tool was developed. In the practical application to data files from blood and hair samples, the tool proved to be very helpful for identification of unknown peaks and for confirmation of results obtained only from the database without CID spectra. A tool "Estimate Concentration" was created for automatic estimation of concentrations of identified substances. The application to real blood and hair samples and the comparison of the concentrations with results from HPLC-DAD and GC-MS showed good agreement. Overall, these investigations showed that LC-QTOF-MS is currently the most favorable method for STA. Because of the comprehensive registration of all substances in a sample, the data files can be checked for the presence of certain poisons even later without new measurements.