Understanding the residue behavior of spirodiclofen (SPI) and chlorfenapyr (CHL) is crucial for ensuring food safety and safeguarding human health. This study systematically investigated the degradation patterns, residue accumulation, and dietary risk assessment in the pear orchard environment. The experimental results indicate that the average recovery rate of SPI and CHL in pear ranged from 80.9% to 110.6%, with a RSD of 0.2% to 5.3%. The degradation half-lives of SPI and CHL in pears were 6.3 days and 10.3 days, respectively. Following repeated pesticide applications, both compounds exhibited a certain degree of residue accumulation in pears. The results of the dietary risk assessment indicate that the intake of CHL in pears does not pose significant health risks and remains within acceptable limits. However, the dietary exposure levels of SPI suggest a potential chronic dietary intake risk for children. For SPI, it is recommended to apply a single spray at the maximum recommended dose. The interval to harvest is 28 days. For CHL, it is recommended to use it at the maximum recommended dose, spraying twice with an interval of 7 days. The interval to harvest is 7 days. This study offers a critical foundation for the development of pesticide application guidelines and Maximum Residue Limit (MRL) values for SPI and CHL on pears.

Nucleic acid aptamers are short oligonucleotide sequences selected in vitro by Systematic Evolution of Ligands by EXponential enrichment (SELEX). Often described as “chemical antibodies”, they can recognize diverse targets with high affinity and specificity through structure-dependent interactions and offer multiple attractive features. Although riboswitches contain natural aptamer domains, SELEX has remained the dominant strategy for aptamer generation for over 35 years, with ongoing methodological development. These advances have expanded the application potential of aptamers in food safety, disease diagnosis, and drug delivery. Nevertheless, their reliable translation into practical applications remains challenging, largely due to complex matrix effects in real samples, which may interfere with aptamer folding, stability, and target recognition. In response to this challenge, increasing efforts have focused on matrix-integrated SELEX strategies that incorporate representative sample environments into the selection process. This review systematically summarizes recent progress in this developing field and discusses its potential as an upstream strategy for improving aptamer robustness and applicability. We first outline the biological basis of aptamers and the evolution of SELEX, followed by a brief overview of post-SELEX optimization approaches. We then provide an integrated analysis of matrix-integrated SELEX strategies, with emphasis on matrix-spiked selection, matrix-based negative selection, and holistic matrix selection, together with their underlying mechanisms, performance outcomes, and representative applications in environmental adaptation, interference suppression, and biomarker discovery. Finally, we discuss the remaining technical and conceptual challenges and highlight future directions for developing more robust, efficient, and application-oriented aptamer screening platforms.

Through field trials, this study comprehensively investigated the dissipation, metabolism, processing factors (PFs), and risk assessment of dinotefuran, imidacloprid, pyraclostrobin, thiamethoxam, and their metabolites in shiitake mushrooms from cultivation to postharvest processing. In the laboratory, common postharvest industrial and household processing methods were simulated, including washing, boiling, pickling, stir-frying, sauce processing, hot-air processing, and crisp processing. Understanding the fate of residues is crucial for ensuring food safety and safeguarding human health. The limit of quantification (LOQ) for 6-chloronicotinic acid, thiamethoxam and clothianidin was 10 μg/kg, while the LOQs for other analytes were 2 μg/kg. Field trials showed that the degradation of the four pesticides followed first-order kinetics, with half-lives ranging from 1.1 to 1.8 days. After washing, boiling, pickling, stir-frying, and sauce processing, the concentrations of all pesticides-except for a metabolite of pyraclostrobin (BF-500-3)-were reduced to varying degrees (PF < 1). Hot air processing led to 4.3- and 4.6-fold increases in the concentrations of dinotefuran and 6-chloronicotinic acid, respectively, while the concentrations of all other pesticides decreased (PF < 1). Crisp processing increased the concentration of all pesticide residues by a factor of 2.0 to 4.0. Additionally, the content of BF-500-3 increased significantly by 2.9-4.9 times after washing, boiling, pickling, and stir-frying. However, it decreased after hot air processing and sauce processing. The risk quotient values of all pesticides were below 1, indicating that both chronic and acute dietary risks were acceptable. This study provides valuable data for the control of pesticide residues in processed products, which has both theoretical and practical significance in ensuring the quality and safety of shiitake mushrooms and protecting human health.

To investigate the impact of brassinolide (BR) and sodium nitrophenolate (CNS) applied during the growth period on the aroma profile of stored Huangguan pear, this study utilized headspace solid-phase microextraction (HS-SPME) in combination with two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC-TOFMS) technology to obtain the aroma fingerprint of Huangguan pear. The results revealed that both BR and CNS inhibited the formation of volatile substances; the inhibition produced by CNS was weaker than that by BR prior to the mid-storage period; the accumulation brought by BR was stronger than that by CNS in the later storage stage. BR and CNS significantly modified the aroma characteristics, and were not beneficial for enhancing the flavor quality of Huangguan pear. This research elaborated in detail on the effects of BR and CNS on the flavor characteristics of pear fruits during storage, providing significant theoretical support for the applicability of plant growth regulators in production.

Lateral flow immunochromatography (LFIA) combined with surface enhanced Raman scattering (SERS) offers significant potential for highly sensitive point-of-care (POC) diagnostics. Using probes with strong SERS signals in the silent region (1800-2800 cm(-1)) avoids interference from complex fingerprint region spectra (<1800 cm(-1)), thus improving the accuracy of surface-enhanced Raman scattering-based lateral flow immunoassay (SERS-LFIA) strips. However, the scarcity of strong, non-overlapping silent region spectra and the signal reproducibility restricted by stringent preparation conditions limit practical application of SERS-LFIA based on silent region probes. To address these challenges, we combined two enhancement substrates (gold and silver) with three Prussian blue-like signal substances (Fe-4[Fe(CN)(6)](3), Cu-2[Fe(CN)(6)], and Pb-2[Fe(CN)(6)]) in a one-pot process, creating six SERS probes with highly reproducible and non-overlapping signals in the silent region. Notably, the use of different enhancement substrates enabled more non-overlapping spectra, improving the applicability of silent region probes in multiplex analysis. Additionally, the one-pot preparation and antibody coupling process improved signal reproducibility across different batches, crucial for quantitative analysis. In a proof-of-concept demonstration for detecting five aminoglycoside antibiotics, six SERS probes were combined with competitive immune reactions to develop a SERS-LFIA strip with robust analytical performance. This study advances the rational design of instant multiplex analysis system and can be applied to a wide range of POC analyses, including food safety and environmental monitoring.

To achieve rapid screening and semi-quantitative analysis of pesticide residues in mobile laboratories and on-site tea testing, a novel method based on thermal-assisted plasma ionization–time-of-flight mass spectrometry (TAPI-TOF/MS) has been developed for the detection of 20 pesticide residues, including insecticides and fungicides, in tea. This method eliminates the need for liquid chromatography, or column connections. Instead, it utilizes the high temperature of the sample inlet and stage to fully volatilize and inject the sample. By integrating TAPI-TOF/MS with an automated pesticide residue pretreatment instrument, the entire sample extraction process can be performed automatically. The analysis time for each sample has been reduced to 1.5 min, allowing for the processing of 60 samples per batch. An accurate mass spectrometry database has been established for screening and confirmation purposes. The software automatically matches the mass spectrometry database by analyzing the measured ion mass deviation, ion abundance ratio, and the relative contribution weight of each ion, generating a qualitative score ranging from 0 to 100. The lowest concentration yielding a qualitative score of ≥75 was defined as the screening limit, which ranged from 0.10 to 5.00 mg/kg for the 20 pesticides. Within their respective linear ranges, the method demonstrated good linearity with correlation coefficients (R2) ranging from 0.983 to 0.999. The average recovery rates (n = 5) of the target pesticides ranged from 70.6% to 117.0% at the set standard concentrations, with relative standard deviations (RSD) ranging from 1.7% to 13.1%. Using this method, 15 tea samples purchased from the Rizhao market in China were analyzed. Ten samples were found to contain residues of metalaxyl or pyraclostrobin, yielding a detection rate of 66.7%. This technology provides technical support for the rapid detection and quality control of multiple pesticide residues in tea, meeting the requirements for high-throughput and on-site analysis.

Through field trials, this study investigated the dissipation, metabolism, processing factors (PFs), and risk assessment of 26 pesticides and their metabolites from field to table. The half-lives of 25 pesticides detected in strawberries ranged from 1.3 to 4.8 days, following first-order dissipation kinetics. During cooking, the concentrations of most pesticide residues increased (PF = 1.13-2.44). Freeze-drying significantly increased residue levels for nearly all pesticides (PF = 4.01-30.02), except for pymetrozine. In contrast, soaking was found to effectively reduce the concentrations of most pesticide residues (PF = 0.04-0.84). Chronic and acute dietary risk assessments conducted across various countries and populations indicate that the health risks associated with the consumption of fresh strawberries, strawberry crisps, and strawberry jam are within acceptable limits. This study provides valuable data for controlling pesticide residues in processed products, offering significant theoretical and practical implications for ensuring the quality and safety of strawberries.

Flavor profiles of various Pyrus spp. cultivars exhibit significant variations, yet the underlying flavor-contributing factors remain elusive. In this investigation, a comprehensive approach encompassing metabolomics analysis, volatile fingerprint analysis, and descriptive sensory analysis was employed to elucidate the flavor disparities among Nanguoli, Korla fragrant pear, and Qiuyueli cultivars and uncover potential flavor contributor. The study comprehensively characterized the categories and concentrations of nonvolatile and volatile metabolites, and 925 metabolites were identified. Flavonoids and esters dominated the highest cumulative response, respectively. Utilizing weighted correlation network analysis (WGCNA), seven highly correlated modules were identified, yielding 407 pivotal metabolites. Further correlation analysis of the differential substances provided potential flavor constituents strongly associated with various sensory attributes; taste factors had a certain association with olfactory characteristics. Our findings demonstrated the manifestation of flavor was a result of the synergistic effect of various compounds; evaluation olfactory flavor necessitated a comprehensive consideration of taste substances.

The flavor profiles of cherries cultivated in greenhouse and those grown in open fields show significant variations, however, the underlying flavor-contributing factors remain unidentified. Hence, a joint investigation with widely targeted metabolomics analysis, volatile fingerprint analysis, and descriptive sensory analysis for the Russia 8 and Tieton cherry cultivars was conducted using UPLC-MS/MS and GC × GC-TOFMS to clarify the flavor differences of open-air and greenhouse-grown cherries. The study found that open-air cultivation could lead to the accumulation of non-volatile flavor substances and prompted appearance of higher acidity, astringency, plum-like flavor, and fresh herb notes; most of differential metabolites were significantly positively correlated with astringency, plum-like flavor and bitterness. Through correlation analysis and path analysis, potential flavor components and key important pathways contributing to flavor disparities were provided, and light intensity, soil moisture content, temperature and humidity were inferred as the main factors affecting the flavor profiles of open-air and greenhouse-grown cherries.

Nucleic acid aptamers have attracted considerable attention in recent years, particularly in the fields of disease diagnosis and treatment and biosensing. However, complex matrix effects have severely hindered their progress towards practical application. In this study, the novel strategy of a pattern recognition-based aptasensor array was introduced for target recognition based on the predictable selectivity capability of aptamers by circumventing the challenge of the interference of the matrix effect. As one proof of concept, we chose lactoferrin as the target protein, three selected aptamers with differential affinity as its recognition probes, eleven matrix samples of milk powder as the pattern discrimination model, and AuNPs color as the response signals. In the AuNPs colorimetric arrays, the lactoferrin-added milk powder matrix induced different degrees of protection on the surface of AuNPs particles due to different degrees of binding of lactoferrin to the three aptamer sequences and therefore exhibited differentiated red-to-blue color change along with salt-induced aggregation behaviors. The difference in color responses exhibited with and without lactoferrin addition was considered as the fingerprint pattern of the lactoferrin in each milk powder matrix, followed by the supervised machine learning analysis of linear discriminant analysis (LDA) for better orthogonality to complete the identification and prediction of the unknown samples. By this strategy, eleven kinds of milk powder at the added concentration of lactoferrin (50 nmol/L) presented a distinct response pattern and have been identified and classified with accuracies of 100 % via LDA patterns (three aptamers x eleven milk powder matrices x five replicates) with three canonical factors (91.2 %, 8.58 %, and 0.22 %). Furthermore, the accuracy of 22 unknown samples was 100 %, indicating the achievement in differentiating between different milk powder matrices and the identification of each matrix. The proposed aptasensor array complements the traditional "lock-and-key" single aptasensor and opens a new direction for developing sensitive sensing array systems circumventing complex matrix effects.

Lactopontin (LPN) is a highly phosphorylated O-glycosylated acidic protein closely associated with infant gut, brain, and immune development, and its recognition is urgent due to its rising application in fortified dairy products and infant formula. In this study, an ssDNA aptamer against LPN was obtained, among which two kinds of matrix-background-assisted systematic evolution of ligands via exponential enrichment (SELEX) approaches were performed and compared. The direct approach was to utilize the sample matrix as the mixing-incubation background between the ssDNA library and LPN that can theoretically increase screening pressure and simulate practical application scenarios. The indirect approach was to utilize a PBS buffer as a screening background and to include counter-screening steps that adopt the “sample matrix” as a whole as the counter-screening target. Their screening evolutions were monitored through qPCR assays from sequence diversity convergences of each sub-library based on the change in the proportion of hetero- and homo-duplexes from the dissociation curve and melting temperature, which were also verified from the sequence statistics of high-throughput sequencing. The common sequence of Seq.I1II3 from the two approaches was finally fished out as the aptamer through multiple analyses of combining the sequence frequency, secondary structures, homology, and binding assessments, which was demonstrated good specificity and low-nanomolar affinity by qPCR assay (KD, 5.9 nM). In addition, molecular docking and a dynamics simulation were performed for their binding site prediction and affinity confirmation. This study provides a potential identifying element and a basis for accelerating the development of methods for LPN detection in dairy products.

In this study, we propose an interference-free SERS-based aptasensor for trace detection of chlorpyrifos (CPF) in real samples. In the aptasensor, gold nanoparticles coated with Prussian blue (Au@PB NPs) were employed as SERS tags to provide a sole and intense Raman emission at 2160 cm- 1, which could avoid overlapping with the Raman spectrum of the real samples in 600-1800 cm- 1 to improve the anti-matrix effect ability of the aptasensor. Under the optimum conditions, this aptasensor displayed a linear response for CPF detection in the range of 0.1-316 ng mL-1 with a low detection limit of 0.066 ng mL-1. In addition, the prepared aptasensor shows excellent application to determine CPF in cucumber, pear and river water samples. The recovery rates were highly correlated with high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). This aptasensor shows interference-free, specific and sensitive detection for CPF and offers an effective strategy for other pesticide residue detection.

To comprehensively understand the volatile compounds and assess the aroma profiles of different types of Pyrus ussuriensis Maxim. Anli, Dongmili, Huagai, Jianbali, Jingbaili, Jinxiangshui, and Nanguoli were detected via headspace solid phase microextraction (HS-SPME) coupled with two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC-TOFMS). The aroma composition, total aroma content, proportion and number of different aroma types, and the relative quantities of each compound were analyzed and evaluated. The results showed that 174 volatile aroma compounds were detected in various cultivars, mainly including esters, alcohols, aldehydes, and alkenes: Jinxiangshui had the highest total aroma content at 2825.59 ng/g; and Nanguoli had the highest number of aroma species detected at 108. The aroma composition and content varied among pear varieties, and the pears could be divided into three groups based on principal component analysis. Twenty-four kinds of aroma scents were detected; among them, fruit and aliphatic were the main fragrance types. The proportions of aroma types also varied among different varieties, visually and quantitatively displaying changes of the whole aroma of the different varieties of pears brought by the changes in aroma composition. This study contributes to further research on volatile compound analysis, and provides useful data for the improvement of fruit sensory quality and breeding work.

为研究氟吗啉在辣椒中的残留消解情况及对居民的膳食摄入风险,本文采用高效液相色谱-串联质谱法测定氟吗啉在辣椒上的残留量,分析其消解动态规律.结果显示,氟吗啉在辣椒中的消解动态符合一级反应动力学方程,在浙江和湖南2个试验点的半衰期分别为3.4、4.1 d.氟吗啉在辣椒中的长期膳食摄入风险商为0.0138％;在所有登记作物中的总膳食摄入风险商为4.7219％.膳食风险评估结果表明,氟吗啉在辣椒中的残留对人群膳食风险在可接受范围内,按照推荐使用剂量、喷药次数及安全间隔期在辣椒上施用50％锰锌-氟吗啉可湿性粉剂,辣椒中的氟吗啉残留不会影响我国居民身体健康.

建立固相萃取-气相色谱-质谱(SPE-GC-MS)测定生姜中黄樟素及其衍生物的分析方法.样品经乙腈提取,氯化钠盐析后,采用PestiCarb/NH2柱净化,经DB-5MS毛细管色谱柱分离,选择离子监测模式(SIM)扫描测定,外标法定量.在0.01～1.0 μg/mL的线性范围内,黄樟素及其衍生物均成良好线性关系,相关系数(R2)均大于0.995,检出限为3.2～8.5 μg/kg;在50,100和500 μg/kg 3个添加水平下,回收率为89.8％～107.8％,相对标准偏差(SRSD,n=6)为1.8％～6.9％.该方法准确度高,回收率好,可用于生姜样品中黄樟素及其衍生物的定性及定量分析,为市场监管和实验室检测提供技术支持.

目的 建立气相色谱-串联质谱法(gas chromatography-mass spectrometry,GC-MS)测定韭菜中拟除虫菊酯类农药残留的分析方法.方法 样品采用QuEChERS处理,经乙腈提取,氯化钠盐析后,采用N-丙基乙二胺(primary secondary amine,PSA)净化,浓缩定容后用GC-MS在选择离子监测模式(select ion monitoring,SIM)下进行测定,外标法定量.结果 7种拟除虫菊酯农药在质量浓度0.01～1.0μg/mL范围内,线性关系良好,相关系数(r2)在0.9989～0.9995之间;检出限为0.6～3.0μg/kg.分别向韭菜样品中加入标准品0.01、0.1、0.5 mg/kg时,加标平均回收率为85.4％～102.4％,相对标准偏差(n=6)为1.8％～6.1％.结论 该方法简便快速、灵敏度好、准确度高,可用于韭菜样品中拟除虫菊酯类农药残留的测定.

[目的]建立测定甲氧虫酰肼在番茄上残留的高效液相色谱检测方法.[方法]样品经过酸化的甲醇高速匀浆提取,经过二氯甲烷萃取,采用甲醇:乙腈:水(30:55:15,V/V)为流动相,利用symmetry C18柱(4.0 mm×250 mm)进行检测.[结果]在0.01、0.50、2.00 mg/kg 3个添加浓度水平下,甲氧虫酰肼在番茄上的回收率为85％～105％,相对标准偏差(RSD)为0.6％～1.4％.相关系数(r)为0.9998.甲氧虫酰肼在番茄上的最低检出限为0.01 mg/kg,最小检出量为2 ng.在实际样品检测中检测出有甲氧虫酰肼的残留,但均未超过我国规定的最大残留限量值.[结论]在实际样品检测中,该方法能够快速、准确地对样品进行检测,为大量样品的检测提供了数据方法.

[目的]为确保4种农药在不同品种梨上的安全使用,评价其在梨上的消解趋势、残留水平,并且在2018年试验的基础上,验证毒死蜱、吡虫啉的安全使用评价标准及制定高效氯氟氰菊酯、多菌灵的安全使用评价标准.[方法]参考农药标签和梨果生产中调研的施药方法,选取全国6地的黄冠梨、莱阳梨、砂梨、早酥梨、砀山酥梨和鸭梨6个梨品种,开展田间试验.利用仪器分析方法,研究了毒死蜱、高效氯氟氰菊酯、吡虫啉、多菌灵在梨中的残留消解动态.[结果]4种农药在梨中的消解动态均满足一级反应动力学方程,半衰期分别为4.2、7.1、12.2、11.9 d.毒死蜱、吡虫啉的残留量及消解动态与2018年相比,较为吻合,年度差异不大,无超标现象.高效氯氟氰菊酯、多菌灵均有超标现象,多菌灵尤为突出.[结论]必须严格控制施药剂量及施药次数,并严格遵守安全间隔期.建议按照低剂量施药,每个作物周期最多施药3次,安全间隔期为21(高效氯氟氰菊酯)、28 d(多菌灵).按照推荐剂量及其操作规范在梨上施用是安全的.

应用气相色谱-离子迁移质谱对不同产地的翠冠梨果的香气指纹信息进行采集,通过主成分分析和相似度分析,判定香气之间的差异性,进而评价不同产地翠冠梨果的香气指纹信息、差异性及区分程度.经研究表明,6地翠冠梨中共鉴定香气物质43种,主要为酯类物质,也包括醇、醛、酮类物质;不同产地翠冠梨果中各类香气物质所占比例因梨果产地不同而不同;经统计分析确定受检梨果香气差异的主要贡献者,且以此可区分6地梨果.基于香气指纹差异性研究,可为梨果产地鉴别及溯源新方法开发提供理论依据和数据支持.

[目的]比较吡虫啉在大棚和露地蕹菜上的消解动态差异,为吡虫啉在蕹菜上的科学安全使用提供数据支持.[方法]采用QuEChERS-高效液相串联质谱法测定吡虫啉在大棚和露地上的残留量,分析其消解动态规律.在0.01～1 mg/kg添加水平下,吡虫啉的平均回收率为85％～103％,相对标准偏差(RSD)为3％～6％.[结果]吡虫啉在大棚和露地蕹菜中的消解动态均满足一级反应动力学方程,半衰期分别为3.50、2.29 d;在露地条件下吡虫啉药后10 d消解率达到95.11％,而大棚条件下药后21 d,消解率达到98.51％.[结论]露地条件下蕹菜中吡虫啉的原始沉积量及最终残留量均低于大棚,消解速率更快.