###### Abstract  
A portable mass spectrometer (PMS) was combined with a mesoporous silica material (SBA-15) coated solid-phase microextraction (SPME) Arrow to develop a rapid, easy-to-operate and sensitive method for detecting five veterinary drugs--amantadine, thiabendazole, sulfamethazine, clenbuterol, and ractopamine--in milk and chicken samples. Equipped with a pulsed direct current electrospray ionization source and a hyperboloid linear ion trap, the PMS can simultaneously detect all five analytes in approximately 30 s using a one-microliter sample. Unlike traditional large-scale instruments, this method shows great potential for on-site detection with no need for chromatographic pre-separation and minimal sample preparation. The SBA-15-SPME Arrow, fabricated via electrospinning, demonstrated superior extraction efficiency compared to commercially available SPME Arrows. Optimization of the coating preparation conditions and SPME procedures was conducted to enhance the extraction efficiency of the SBA-15-SPME Arrow. The extraction and desorption processes were optimized to require only 15 and 30 min, respectively. The SBA-15-SPME Arrow-PMS method showed high precision and sensitivity, with detection limits and quantitation limits of 2.8-9.3 \(\upmu\)g kg\({}^{-1}\) and 10-28 \(\upmu\)kg kg\({}^{-1}\), respectively, in milk. The LOD and LOQ ranged from 3.5 to 11.7 \(\upmu\)g kg\({}^{-1}\) and 12 to 35 \(\upmu\)g kg\({}^{-1}\), respectively, in chicken. The method sensitivity meets the requirements of domestic and international regulations. This method was successfully applied to detect the five analytes in milk and chicken samples, with recoveries ranging from 85% to 116%. This approach represents a significant advancement in food safety by facilitating rapid, in-field monitoring of veterinary drug residues. portable mass spectrometer; solid-phase microextraction arrow; on-site detection; mesoporous silica SBA-15; veterinary drug residues 2020 September 202411 October 202411 October 2024 severe toxicity in humans, affecting vital organs such as the liver, kidneys, nervous system, and bone marrow [5]. Additionally, synthetic beta-2 adrenergic stimulants, like clenbuterol and ractopamine, used to promote animal growth, can accumulate in tissues, leading to adverse effects in humans, ranging from muscle pain to life-threatening heart conditions [6]. To mitigate these risks, several regions and countries, including the European Union, the United States, and China, have implemented strict regulations to limit the use of these substances in livestock and poultry production [7; 8; 9]. Thus, developing rapid, accurate methods for detecting veterinary drug residues in food is critical for ensuring food safety, with increasing emphasis on on-site analytical techniques. Traditional large-scale instrumental methods, such as thin-layer chromatography, high-performance liquid chromatography (HPLC), HPLC-mass spectrometry (HPLC-MS), gas chromatography (GC), and GC-MS, are accurate but suffer from high costs, energy consumption, and time limitations [10; 11]. In contrast, a portable mass spectrometer (PMS) is a compact, field-deployable device that enables rapid, on-site detection without the need for chromatographic separation [12]. A typical PMS consists of three core subsystems: an ionization source, a mass analyzer, and a detector. The ionization source converts sample molecules into ions, which are then separated based on their mass-to-charge ratios by the mass analyzer [13; 14; 15]. The detector then captures and quantifies the ions, enabling the identification and quantification of multiple analytes simultaneously [16]. Commonly used ionization sources for PMS include paper spray ionization [17], ambient ionization [18], dielectric barrier discharge ionization [19], and pulsed direct current electrospray ionization (PDESI) [20].