Croton fruit poisoning was successfully identified through a series of chromatographic technologies. A suspected compound named 2-methyl-butenoic acid was screened out using gas chromatography-mass spectrometry, and the hydrolysate of isoguanosine in soup sample was further detected by high performance liquid chromatography-tandem mass spectrometry. The identification of croton fruit poisoning was confirmed basing on these laboratory tests together with the clinical symptoms of the patients. Especially, the false-negative result and the interferences were successfully excluded through simulation test, spectral analysis and chromatographic separation technique. Such study is significant for croton poisoning identification and provides beneficial references for disposing untargeted food poisoning incident.

Triazine-based covalent organic frameworks functionalized by thiol and thioether (COFS-CH3/COFS-SH) were designed and served as a platform that could bind with mercury ions specifically based on Hard-Soft-Acid-Base theory. As such, when employing COFs as a modifier in a carbon paste electrode (CPE), the COFS-CH3-modified CPE revealed an extraordinary performance (detection limit of 0.01 ppb; linear range of 0.1 to 1.0 ppb) and repeatability for electrochemical detection of trace mercury, even in real samples collected from tap or lake water. This innovative approach leverages the inherent properties of covalent organic frameworks (COFs) to enable highly sensitive and selective detection of target analytes.

Halobenzoquinones (HBQs), which are emerging chlorinated disinfection byproducts (DBPs), have attracted increasing attention because they are frequently detected in treated tap water, entrainment water, etc. These compounds are mainly generated during the water treatment process using chlorine, chloramine, and chlorine dioxide as disinfectants, and display more toxic effects than regulated DBPs, such as trihalomethane and haloacetic acid. HBQs have been recognized as potential bladder carcinogens and are harmful to the nervous system. Additionally, they can exert genotoxic effects and cause oxidative damage to DNA and proteins. The risk of HBQs in aquatic products is expected to rise because the disinfection of public facilities has significantly increased in recent years. Therefore, developing a sensitive and accurate analytical method to detect HBQs in aquatic products is of great importance. Several analytical methods, including gas chromatography, gas chromatography-mass spectrometry, electrochemical methods, liquid chromatography, and liquid chromatography-tandem mass spectrometry, can be used to identify and quantify HBQs in water. However, to the best of our knowledge, no reports on the determination of HBQ levels in aquatic products are yet available. Further, pretreatment is essential for HBQ determination because of the complex matrix effects of aquatic products. Herein, a sensitive and accurate method based on the QuEChERS technique coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of five HBQs in aquatic products. For the QuEChERS procedure, the pretreatment conditions, such as the extraction solvent and adsorbent species, were systematically optimized. The sample was extracted with 10 mL of 10% methanol acetonitrile solution (containing 0.1% formic acid), dehydrated, and centrifuged with sodium chloride and anhydrous magnesium sulfate. The supernatant was purified using a QuEChERS packing material consisting of 50 mg N-propylethylenediamine (PSA), 30 mg of graphitized carbon black (GCB), and 30 mg of neutral alumina (Al2O3), dried with nitrogen, and concentrated. The five HBQs were separated on a Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) using 0.25% acetonitrile formate solution and 0.25% formic acid aqueous solution as the mobile phase under a gradient elution program and then detected using UPLC-MS/MS with negative electrospray ionization (ESI-) under multiple reaction monitoring (MRM) mode. Quantitative analysis was performed using a matrix-matched external standard method. The five HBQs achieved rapid separation within 6 min, indicating that the proposed method has a much shorter separation time compared with previous studies. The matrix effect was evaluated by establishing a matrix-matched calibration curve. The results showed that 2,5-dichloro-1,4-benzoquinone (2,5-DCBQ) presented a matrix-enhancing effect, whereas the other HBQs displayed matrix-inhibiting effects. In particular, tetrachlorobenzoquinone (TCBQ) exhibited strong inhibitory effects. Under the optimized experimental conditions, the five HBQs demonstrated good linear relationships in the range of 1.0-50.0 μg/L, with correlation coefficients (r)≥0.9992. The detection limits of the method were 0.15-0.8 μg/kg, and the recoveries of the target compounds were 85.9%-116.5%. The relative standard deviations were 1.4%-8.2%, which indicates good reproducibility. The proposed method was successfully applied to actual sample detection, and 2,6-dichloro-3-methyl-1,4-benzoquinone (2,6-DCMBQ) was detected in grass carp. The proposed method is convenient, sensitive, accurate, and suitable for the simultaneous determination of five HBQs in aquatic products. Moreover, the developed method provides a reliable reference for the routine monitoring of trace HBQs in food samples.

Kojic acid naturally appears in fermented foods and can be formed during the aerobic fermentation process induced by Aspergillus and Penicillium fungi. It is widely used in the food industry because it exhibits antibacterial and antifungal properties and does not affect food taste. However, recent studies indicate that kojic acid may be a potential carcinogen. Therefore, assessing the health risks of kojic acid in fermented foods are of great importance, and developing a sensitive and accurate analytical method for this compound is a significant endeavor. Much efforts have been devoted to the detection of kojic acid using electrochemistry, high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). HPLC and HPLC-MS/MS are the analytical techniques most often employed for this purpose. Of these two methods, HPLC-MS/MS displays excellent sensitivity and is the optimal selective technique. Pretreatment is usually necessary for kojic acid determination because of the complex matrix effects of fermented foods. However, few researches on the determination of kojic acid in food are available, and, to the best of our knowledge, the determination of kojic acid using solid-phase extraction (SPE) pretreatment has not been reported yet. Herein, a convenient, sensitive, and accurate method was developed to determine kojic acid in fermented foods using solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS). The pretreatment conditions, such as the extraction solvent, cartridge, rinse solvent, and eluent, were systematically optimized. The samples, including soy sauce, vinegar, liquor, sauce, fermented soya bean, and fermented bean curd, were extracted with 0.1% formic acid-absolute ethyl alcohol and purified using a PRiME HLB cartridge. Kojic acid was separated using an ACQUITY UPLC® BEH C18 column (100 mm×2.1 mm, 1.7 μm) with formic acid-acetonitrile (1∶999, v/v) and formic acid-5 mmol/L ammonium acetate (1∶999, v/v) solutions as the mobile phases under gradient elution mode. MS was performed in electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM) modes. An internal standard method was used for quantification. Under optimized conditions, good linearity was achieved at mass concentrations of 5.0-100.0 μg/L, with a correlation coefficient (r) of 0.9994. The limits of detection and quantification of the method for kojic acid were 2-5 μg/kg and 6-15 μg/kg, respectively. Good recoveries of 86.8%-111.7%, intra-day precisions of 1.0%-7.9% (n=6), and inter-day precisions of 2.7%-10.2% (n=5) were also obtained. The matrix effect was evaluated by establishing a matrix-matching calibration curve, and weak inhibitory effects were found in vinegar and liquor; moderate inhibitory effects in fermented bean curd, fermented soya bean, and soy sauce; and a strong inhibitory effect in sauce. The developed method was used to detect kojic acid in 240 fermented foods, and the results showed that the detection rate of vinegar was the highest, followed by liquor, sauce, soy sauce, fermented soya bean, and fermented bean curd, the contents were 5.69-2272 μg/kg. Matrix interferences can be significantly reduced by optimizing the pretreatment and detection procedures. The proposed method is sensitive, accurate, and can be used to analyze kojic acid in fermented foods.

A sensitive, selective and convenient method for the simultaneous determination of 9 nitrosamines (NAs) in biological samples was developed using isotope dilution ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UPLC-QTRAP-MS). Multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) scan mode was performed to eliminate false positive results, and the whole detection procedure was characterized by less time consuming and simple sample preparation. 9 NAs were separated through a T3 column with the gradient elution of acetonitrile and water, and detected by UPLC-QTRAP-MS with an atmospheric pressure chemical ionization (APCI) source in the positive mode. The quantitative analysis was carried out via the isotope internal standard method with a matrix calibration curve. Under the optimized conditions, good linearity for the 9 NAs was achieved in the range of 0.2-20 μg L-1 with correlation coefficients (r) higher than ≥0.9991, and the limits of detection and limits of quantitation were 0.02-0.1 μg L-1 (S/N = 3) and 0.06-0.3 μg L-1 (S/N = 10), respectively. Satisfactory recoveries ranging from 79.4% to 108.0% were obtained, and the precision of the proposed method, indicated by the relative standard deviations (RSDs), was 2.3-12.9%. The matrix effect study showed that NDMA, NMOR and NMEA presented a matrix suppression effect, NDPHA displayed a matrix enhancement effect, and the matrix effects of the other 5 analytes could be ignored. Real application of the developed method in 13 urine and 24 plasma samples demonstrated that NDBA, NPIP and NPYR occurred in both urine and plasma samples with the concentration of 0.038-0.60 μg L-1, while other NAs were not detected. Such a method was sensitive and selective, and could be applied to the rapid qualitative and quantitative analysis of the 9 NAs in biological samples.

An efficient method based on high-performance liquid chromatography coupled with atomic fluorescence spectrometry (HPLC-AFS) was successfully developed for the simultaneous determination of four mercury species including Hg2+, methylmercury (MeHg), ethylmercury (EtHg), and phenylmercury (PhHg) in water. Samples were enriched and cleaned up with a solid-phase extraction (SPE) pretreatment using a thiol cartridge. Some key parameters including the selection of a SPE cartridge, eluent type, eluent volume, and interference factors were systematically investigated. Chromatographic separation was achieved on a C18 column using a mobile phase consisting of methanol and 60 mmol L−1 ammonium acetate with 10 mmol L−1l-cysteine by gradient elution. Under the optimized conditions, good linearity (r ≥ 0.9991) was observed between 0.20 to 10.0 μg L−1. The limits of detection were in the range of 0.001–0.002 μg L−1. High recoveries (87.2 to 111%) and good reproducibility (1.1–6.5%) were obtained. Such a method is sensitive, selective and accurate, which can be applied to the quantification of mercury species in water samples.

Health food with nutritional or physiological effects is suitable for certain people, and it can be used to regulate body functions but not for curing diseases. Therefore, substances with therapeutic functions cannot be included in health food, as they are classified as special food and are specifically regulated. The use of health food has increased worldwide in the last few decades. However, illegal activities such as the manufacture and marketing of fake commodities, false advertising, and fraudulent sales have restricted the sustainable development of the health food industry. In particular, there is much concern regarding health food illegally adulterated with pharmaceuticals and their analogs because of the notable risk to public health. Therefore, there is an urgent need to develop accurate and sensitive detection methods for the qualitative and quantitative analysis of such compounds. Many methods have been developed for the determination of adulterants in health food, such as high performance liquid chromatography (HPLC), high performance liquid chromatography-mass spectrometry (HPLC-MS), direct analysis real-time mass spectrometry (DART-MS), and gas chromatography-mass spectrometry (GC-MS). However, in recent years, new features of adulterants in health food have emerged. For example, the chemical compositions of drugs added to health food, including prescription drugs, delisted drugs, drug analogs, and new drugs, are becoming increasingly sophisticated. Furthermore, there has been a change in trend from the addition of large doses of a single component to the addition of small doses of a class of components or multiple components. These pose great challenges to the identification and measurement of such illegal additives. Detection technologies for new drugs and structurally modified analogs are still scarce; hence, newer methods for non-targeted screening are necessary. Fortunately, several structure elucidation techniques have been introduced, including high-resolution time-of-flight (TOF) MS, infrared spectroscopy, as well as 1H and 13C nuclear magnetic resonance spectrometry. This study summarizes the types of drugs that may be illegally added in health food according to their pharmacological activities related to the claimed efficacy of health food; advances in detection technologies for illegal drugs; and future development prospects. The overall aim is to provide beneficial reference for the development of standard methods and for the routine monitoring of health food.

An improved gas chromatography-mass spectrometry (GC-MS) method was developed for the simultaneous determination of 24 polycyclic aromatic hydrocarbons (PAHs) in edible oils. A novel purification procedure based on the coupling double cartridges (molecular imprinting polymer (MIP) cartridge and PAHs special cartridge) was applied. Under the optimized conditions, the method presented excellent linearity (r ≥ 0.9990) in the range of 1.0–250 μg L−1, the detection limits were 0.1–1 μg kg−1, and high recoveries (86.0–116%) and good reproducibility (relative standard deviations (RSDs) ≤ 10.8) were also obtained using the two solid-phased extraction cartridges in combination. This method is sensitivity, accuracy, which can be used to detect 24 PAHs in edible oil samples.

An efficient method was developed for the simultaneous determination of 10 industrial dyes (basic orange 2, basic orange 21, basic orange 22, acid orange II, auramine, basic rhodamine B and Sudan I-IV) in the foodstuffs using high-performance liquid chromatography coupled with diode array detector. Samples were extracted with acetonitrile and cleaned up on a solid phase extraction cartridge using HLB. The chromatographic separation was achieved on a C18 column using a mobile phase consisting of methanol and 10 mmol/L ammonium acetate with 0.1% formic acid by gradient elution. Good linearity (r ≥ 0.9993) was observed between 0.050 and 5.0 μg/mL. The limits of detection were in the range of 0.007-0.01 mg/kg, high recoveries (80.6-104%) and good reproducibility (1.1-5.7%) were obtained. Such method is simple, feasible and accurate, which can be applied to the quantification of 10 dyes in food samples.