Mass Spectrometry in Food and Environmental Chemistry

Mass spectrometry (MS) has achieved great renown as a specific, selective, sensitive, and rapid technique for the analysis and evaluation of a wide range of food products and environmental matrices. The state of the art of MS in food and environmental safety and quality is presented to show the potential of this technique in the qualification and quantification of chemical characteristics of food and environmental samples, in the evaluation of the quality of meat, fish, fruits, vegetables, and other food products, as well as in the classification of environmental samples, and in the determination of contaminants in all their compartments. The features of each mass spectrometry advance for each category were summarized in the aspects of the investigated quality and safety attributes, and the used systems (low and high resolution mass spectrometry). With its success in different applications of food and environmental quality, and safety analysis and assessment, it is evident that MS can facilitate a variety of tasks. Continued development of methodology and instrumentation will enable more sensitive and timely detection in the coming years.

In current food safety and environmental monitoring, mass spectrometry methodologies are widely used for identification and quantification of various substances. However, studies have shown that various compounds in food and environment samples are found at ultra-trace concentration levels and the complexity of the sample matrix might limit the performance of selective and sensitive analytical method. Therefore, selection of a proper sampling strategy and sample preparation methods plays a critical role in achieving accurate and reliable results. Thus, this chapter is mainly focused on the recent trends in sample handling and preparation of food and environmental samples prior to MS analysis. Methodologies regarding mass spectrometry coupled with chromatographic separation have been reviewed to highlight the improvement in the analytical determinations of various compounds in food and environmental samples.

Analytical challenges of elemental mass spectrometry are discussed, introducing the fundamental principles of inductively coupled plasma mass spectrometry (ICP-MS) and its variants such as chromatographic techniques-ICP-MS, multiple-collector-ICP-MS, laser ablation-ICP-MS, and field flow fractionation-ICP-MS. Applications are discussed and commented. Some examples illustrate the analytical approaches, which are used to address specific issues in various areas of both food and nutrition and environmental research, such as food authentication, metallomics, speciation, toxic and nutritive elements, nanomaterials, and migration studies.

Isotope ratio mass spectrometry (IRMS) measures small differences in the abundances of light-stable isotopes of elements, mostly carbon, hydrogen, oxygen, sulfur, and nitrogen. The ratio of isotopes is dependent on the environment where the samples are located and therefore the measurement of the isotope signature in food and environmental samples can give information to help to distinguish samples that share the same chemical composition but can be under different conditions. This chapter provides an overview of isotope ratio mass spectrometry (IRMS) in the context of food and environmental sample analysis (e.g., food authenticity, food origin, or environmental contamination). The fundamentals and latest developments of the technique, most important aspects of the instrumentation, analysis of isotope ratio information as well as key applications are described to illustrate the impact of this rapidly growing field of research especially in terms of the number and type of applications. Finally, applications in nutrition and trophic, environment, soil science, and food authenticity are assessed by giving details on the progresses, advantages, and pitfalls.

This chapter describes recent advances in applications of gas chromatography (GC) and liquid chromatography (LC) coupled with mass spectrometry (MS) for analysis of contaminants in the field of environmental and food safety during the last decade (2011–2021). Most employed MS analyzers with unit-resolution, different ionization modes, and improvements in liquid and gas chromatography techniques are discussed. Regulatory compliance for GC-MS/(MS) and LC-MS/(MS) identification as outlined by regulatory agencies is presented. Examples of innovative uses of state-of-the-art methods for analysis of diverse contaminants in the last decade are provided, and an opinion on future trends in the field is offered.

In the past 20 years, the evolution of mass spectrometry has undergone tremendous technological advances to improve mass resolution, accuracy, and sensitivity, and brought commercially practical high-resolution mass spectrometers that can measure a mass-to-charge ratio (m/z) at the fourth or fifth decimal place (exact mass). Advanced high-resolution mass spectrometry (HRMS) instruments now feature fast scan speeds, sufficient dynamic range, and MS/MS capability in hybrid instruments, which facilitate the exploration of a large number of known and unknown chemicals in modern environmental analysis and food analysis. This chapter introduces the basic concepts of resolution, resolving power, exact mass, accurate mass, mass error, and mass measurement precision. In this chapter, two main modern high-resolution mass spectrometers, namely quadrupole time-of-flight mass spectrometer (Q-TOF) and quadrupole Orbitrap (Q-Orbitrap) mass spectrometer are introduced. The advantages of HRMS combined with gas chromatography and liquid chromatography in modern environmental and food analysis are discussed. This chapter also provides an overview of recent developments in extensive screening and non-targeted analysis (NTA) using state-of-the-art HRMS in food and environmental analysis. The NTA data acquisition modes and data analysis process and applications of HRMS-based non-targeted analysis approaches in the analysis of organic contaminants in foods for food quality and safety, are introduced, including lipidomics, proteomics, and metabolomics, as well as environmental samples for environmental safety.

Environmental-OMICS includes the applications of genomics, transcriptomics, proteomics, and metabolomics to understand better genetics, toxicity mechanisms, and modes of action in response to acute and chronic exposure to chemical pollution on aquatic and terrestrial organisms, and to understand which molecular events initiate these effects. These are essential goals in toxicology to predict adverse responses better or look for more efficient remediation approaches. In parallel and closely related, foodomics is a new discipline (Cifuentes, J Chromatogr A 1216:7109, 2009) applying the same omics technologies to study food and nutrition. It is a global discipline that integrates compound profiling assessment in food, food authenticity, and biomarker-detection related to food quality or safety, including contaminants in food, the development of transgenic foods, investigations on food bioactivity, and food effects on human health.

In both cases, the state-of-the-art technologies to assess effects and new mass spectrometry (MS) approaches combined with bioinformatics are crucial to answer the main questions driving environmental-omics and foodomics, which are included in the One-Health concept. Human health is cross related to our environment, the organisms in this environment, and the food chain.

The primary aim of the present chapter is to provide an overview of the different strategies that have been used in recent years in the environmental-omics and foodomics with the common driver of the One-Health concept. The advantages and limitations will be discussed as well, and finally, new trends presented.

Pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) has confirmed to be a versatile technique that benefits food and environmental analyses. It has been used for the chemical characterization of materials and compounds that are not suitable for traditional gas chromatography (GC) because of their large size. The controlled thermal degradation carried out during pyrolysis is able to break down macromolecules into volatile fragments easier to identify because they become separable by GC and detectable by mass spectrometry (MS). A wide array of applications has been reported using Py–GC–MS, from characterization of macromolecules (polymers, paints, lacquers, adhesives, plastic, synthetic fibers, organic matter, etc.) in a variety of disciplines including forensics, history, engineering, and, of course, food and environmental sciences. In recent years, this technique has experienced an important increase due to its capability for the chemical fingerprinting of organic matter, and the identification and characterization of nano-, micro-plastics used for food package and present in environmental and food samples. In this chapter, we describe current Py–GC–MS instrumentation and working modes and summarize recent applications in food and environmental analysis with special emphasis on its strengths and limitations.

The challenge to develop enantioselective analytical methods to quantify chiral compounds in food and environmental matrices is an actual and imperative issue. It is well known that enantiomers may differ in their biological activities, but the stereochemistry and the discrimination of enantiomers are frequently ignored in analytical workflows. However, the knowledge about their proportion is crucial to guarantee food and environmental safety. In this sense, chiral analysis is a valuable tool to evaluate food quality and genuineness, to determine the geographical origin of a certain sample aiming to find out fraud or adulteration, to investigate toxicity and bioaccumulation of environmental contaminants (e.g., pharmaceuticals and pesticides). This chapter highlights the importance of chiral analysis in food matrices and its relationship with the environmental contamination. The last advances in chiral analysis by liquid chromatography (LC), gas chromatography (GC), and supercritical fluid chromatography (SFC) coupled to mass spectrometry (MS) are presented, with a special remark in the type of chiral column used for chromatography and the proposed workflow in the method development. Some of the most recent applications in chiral analysis of food and beverages, environmental monitoring of surface water, wastewater, soils, biodegradation studies, and contamination of foodstuff are presented and critically discussed.

The present chapter gives an overview on the use of ambient ionization techniques in mass spectrometry for analyzing environmental- and food-related samples. Ambient ionization techniques discussed include among others direct analysis in real time, desorption electrospray ionization, and rapid evaporative ionization. Developments within the field displayed in the literature published since 2015 are discussed. Strategies for improving sensitivity and selectivity by implementing sample pre-treatment devices into the ambient ionization source are presented, as are approaches to improve the ability for reliable quantitative analysis and further advancement in instrument design. Relevant applications published over the last 5 years are summarized and discussed.

Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful analytical technique currently used in numerous fields including food and environmental chemistry. IM-MS can be employed with several ionization methods and coupled with chromatographic separations to provide multidimensional identification of compounds based on the combination of retention time, collision cross section (CCS), and accurate mass. Experimentally obtained CCS values can be used to populate application-specific libraries that further allow identification and quantification in complex mixtures. This chapter will highlight recent advances in IM-MS methods and technology applied to the food chemistry and environmental chemistry fields. First, instances of IM-MS in nutritional analysis, food safety, food fingerprinting, and process control and quality assurance/quality control (QA/QC) will be discussed. Environmental applications including analysis of per- and polyfluoroalkyl substances (PFASs); polycyclic aromatic hydrocarbons (PAHs), benzene/toluene/xylene (BTX), and volatile organic compounds (VOCs); pesticides; and pharmaceutical and personal care products (PPCPs) will also be outlined. Overall, it is expected that IM-MS will continue to grow due to additional information offered in comparison with conventional methods and because of increased commercialization and improved resolution.

Mass spectrometry imaging (MSI) is a label-free, nonspecific tool that is effective in characterizing analytes from the surface of samples in situ by creating a two-dimensional image with high spatial resolution. Gaining molecular spatial information produces further insight into cellular processes, allowing for limitless possibilities when it comes to investigating food and environmental substances. MSI can be used exclusively to reveal the localization of material or in conjunction with other techniques to corroborate findings. In the field of food and environmental chemistry, MSI is slowly becoming a more popular technique owing to its countless applications and ease of use. MSI is governed by the ionization technique employed, and each ionization type has its own set of characteristics that control what classes of analytes can be studied. In this chapter, the applications of MSI within food and environmental chemical research are presented focusing on each of the ionization techniques and their specific characteristics that make them appropriate for the individual examples highlighted.

Nowadays, chip-based separation devices coupled to mass spectrometry are a leading analytical technique in many science areas of major interest. This interest is based on their economic, environmental, and analytical advantages, such as low volumes consumption of samples and reagent, gain on separation performance, and enhanced sensitivity with MS detectors. The application in food and environmental fields will keep in constant spreading, and new and miniaturized instrumental advances in chip technology will continue to be necessary for the coming years. This chapter summarizes the main features of chipLC–MS, chipGC–MS, and chipCE–MS, outlining their main parts. Finally, a description about some diverse applications of chip-based separations mass spectrometry devices is summarized. In this case, showing remarkable examples using chipLC–MS, chipGC–MS, and chipCE–MS to the analysis of food and environmental samples.