Journal of Chromatography A最新文献

{"title":"A modeling method based on incomplete mixed cells in counter-current chromatography: Interphase mass transfer ratio","authors":"Haijun Chen ,&nbsp;Shunjie Zhang ,&nbsp;Jiayi Chen ,&nbsp;Xiaobing Hu ,&nbsp;Aihua Peng","doi":"10.1016/j.chroma.2024.465486","DOIUrl":"10.1016/j.chroma.2024.465486","url":null,"abstract":"<div><div>Complex mass transfer processes are highly involved in the performance of counter-current chromatography (CCC), so profound exploration should be conducted to improve the overall performance. To more accurately estimate the interphase mass transfer efficiency in the elution process, this study proposes an incomplete mixed cell model by linking layering-mixing-layering behavior and wave-like mixing. With the model, we proposed a fast estimation algorithm for interphase mass transfer ratio (IMTR), which can independently reflect the magnitude of the interphase mass transfer efficiency. The experimental results show that the IMTR of all samples was relatively small, with an average value of not &gt;10 % under different operating conditions. This indicates that the low column efficiency of CCC may be mainly due to the low efficiency of interphase mass transfer. In addition, by analyzing the influencing factors of IMTR, it is found that IMTR is positively correlated with the number of theoretical plates and the retention of stationary phase (<em>S_f</em>), but negatively correlated with the number of incomplete mixing cells (<em>n</em>). Therefore, in the study of column efficiency optimization, we recommend that the distribution ratio, <em>S_f</em>, and <em>n</em> should remain unchanged in control experiments to ensure that IMTR directly reflects the effect on interphase mass transfer efficiency. This study further completes the evaluation index of the CCC column efficiency, revealing the underlying mechanisms of IMTR on column efficiency and providing a theoretical foundation for future research on high-efficiency CCC.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465486"},"PeriodicalIF":3.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142602217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Custom GC×GC configuration for the selective isolation or removal of compounds from complex samples","authors":"Matyas Ripszam,&nbsp;Tobias Bruderer,&nbsp;Federico Maria Vivaldi,&nbsp;Serena Reale,&nbsp;Fabio Di Francesco","doi":"10.1016/j.chroma.2024.465484","DOIUrl":"10.1016/j.chroma.2024.465484","url":null,"abstract":"<div><div>We developed a novel approach to selectively isolate or remove nearly any compound from complex mixtures of volatile organic compounds. This was achieved by customizing a GC×GC system with a Deans switch, a passive splitter, and a custom-made adapter for sample recollection. The new setup was evaluated with 106 standard chemicals covering a wide range of volatility (boiling points: 56 – 343 ⁰C) and polarity (log P: 0.2 – 9.4). The method was used to remove two notorious malodorous compounds from spoiled wine samples. We found that the recovery can be maximized if a custom-made adapter is attached directly on the flame ionization detector port (average recovery rate of 76 ± 7 % for the standards). Eventually, we could selectively isolate or remove chemicals with peaks separated by a minimum distance of 50 ms for the second column throughout the whole chromatographic run. The developed system is expected to mainly be used in the field of flavor and fragrance analysis (i.e., selection of flavors and odorants of interest or removal of off-flavor or malodorous compounds). At present, we can reasonably collect about 100 ng of each single compound and are currently working on sample enrichment to improve our method to isolate sufficient amounts for further chemical analysis (e.g. high sensitivity nuclear magnetic resonance or chemical ionization tandem mass spectrometry).</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465484"},"PeriodicalIF":3.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142567173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fingerprinting analyses of low molecular weight heparin with an orthogonal MHC 2D LC-MS system","authors":"Wenjing Zhang,&nbsp;Lei Chen,&nbsp;Wen Zhu,&nbsp;Luyun Qiu,&nbsp;Chang Liu,&nbsp;Lin Yi,&nbsp;Duxin Li,&nbsp;Yilan Ouyang,&nbsp;Zhenqing Zhang","doi":"10.1016/j.chroma.2024.465482","DOIUrl":"10.1016/j.chroma.2024.465482","url":null,"abstract":"<div><div>In this work, a synthetical glycan fingerprinting strategy using a multiple heart-cut two-dimensional liquid chromatography system linked to mass spectrometry (MHC 2D LC-MS) was developed to analyze enoxaparin, a widely used low molecular weight heparin (LMWH). Glycans from an enoxaparin standard were prepared offline based on size, and the derived tetra-, hexa-, octa- and decasaccharides were profiled using a qualitative analytical platform. Strong anion exchange chromatography (SAX) was employed as the first-dimensional chromatography (¹D) to separate glycans of the same size but with different charges or sequences, while size exclusion chromatography (SEC) was used in the second dimension (²D) for desalting before MS analysis. The retention times (RTs), accurate masses and structural compositions of the glycans were fully characterized. Real samples were analyzed using the same platform but with ¹D and ²D exchanged: SEC was used to separate enoxaparin glycans by size, followed by SAX using the same parameters as in the qualitative platform to separate glycans by charge or sequence. Glycans in real samples were identified by matching their RTs to those assigned in the qualitative analysis and semi-quantitated after normalization of peaks in each SAX chromatogram of glycans of different sizes. The analyses were performed automatically and robustly using this synthetical platform, enabling the fingerprinting and differentiation of enoxaparins from various sources. This platform could serve as a powerful tool for structural analysis, quality control, and heparin-related drug development.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465482"},"PeriodicalIF":3.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142563889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting biophysical properties of small molecules from chromatographic measurements and the solvation parameter model","authors":"Colin F. Poole ,&nbsp;Sanka N. Atapattu","doi":"10.1016/j.chroma.2024.465461","DOIUrl":"10.1016/j.chroma.2024.465461","url":null,"abstract":"<div><div>Biopartitioning processes are challenging to study and often require the sacrifice of multiple animals. Therefore, it is more practical and cost-effective to correlate these processes with easily determined properties, such as chromatographic retention data, or to make predictions based on structural descriptors such as quantitative structure-property relationships or linear free energy relationships. Abraham's solvation parameter model uses six solute properties to characterize the interactions responsible for the transfer of neutral compounds between immiscible phases in chromatographic or biological systems. This review discusses the prediction of biological properties of small molecules from chromatographic measurements and the solvation parameter model. It covers the characteristics of solute descriptors in the solvation parameter model, as well as experimental approaches for their determination. Additionally, it explores recent applications of the solvation parameter model in characterizing biological systems and its use in identifying surrogate chromatographic models for predicting biological properties.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465461"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142611202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of volatile compound metabolic profiles during the fermentation of filler tobacco leaves through integrated E-nose, GC–MS, GC-IMS, and sensory evaluation","authors":"Mingzhu Zhang ,&nbsp;Dongfeng Guo ,&nbsp;Guanglong Wu ,&nbsp;Ping Han ,&nbsp;Yaqi Shi ,&nbsp;Tianfei Zheng ,&nbsp;Xiaohui He ,&nbsp;Eryong Zhao ,&nbsp;Hui Zhang ,&nbsp;Xingjiang Li","doi":"10.1016/j.chroma.2024.465472","DOIUrl":"10.1016/j.chroma.2024.465472","url":null,"abstract":"<div><div>Tobacco is an agricultural commodity with great economic significance. Producers recognize that the flavor characteristics of filler tobacco clear-out (FTLs) affect the quality of cigar tobacco items. To identify the major volatile organic compounds (VOCs) responsible for differences in FTLs, E-nose, HS-SPME-GC–MS, and HS-GC-IMS were employed for multi-dimensional analysis of nine groups of FTLs at various fermentation stages. The E-nose results indicated a progressive increase in nitrogen-oxygen compounds during fermentation. Coupled with these findings, HS-SPME-GC–MS identified 56 VOCs, and HS-GC-IMS revealed 55 VOCs in the FTLs. Principal component analysis (PCA) suggested that FTLs from various fermentation stages of the Yunxue No 39 tobacco plant exhibit significant differences. Partial least squares discriminant analysis (PLS-DA), along with the variable importance in projection (VIP) method for feature selection, pinpointed 12 VOCs as the essential unmistakable metabolites embroiled within the agrarian fermenting prepare of matured FTLs. During the fermentation process, these crucial metabolites are predominantly enriched in pathways including pyruvate metabolism, phenylalanine metabolism, as well as nicotinate and nicotinamide metabolism. The study provides insights into the differences and diversity of FTLs at agricultural fermentation stages. It offers valuable information for optimizing the quality of agricultural fermentation and guiding the directional fermentation of tobacco leaves.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1737 ","pages":"Article 465472"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142520581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sampling efficiency of flow-through air sampler: Effect of sampling rate","authors":"Qiu-liang Cai ,&nbsp;Lei Tong ,&nbsp;Ning Zhong ,&nbsp;Jie Zheng ,&nbsp;Meng-meng He ,&nbsp;Hang Xiao","doi":"10.1016/j.chroma.2024.465474","DOIUrl":"10.1016/j.chroma.2024.465474","url":null,"abstract":"<div><div>The Flow Through Sampler (FTS) serves as an efficient wind-powered active sampling device, enabling the collection of a significant air volume within a short duration. Throughout the actual sampling process, the sampling rate of FTS experiences continuous fluctuations, highlighting the need for in-depth investigation into its impact on breakthrough. In this study, we interconnected the FTS sampling column with three distinct pumps, operating at five varied sampling rates under 293 K and 303 K; and breakthrough profiles of PCBs, PAHs and OCPs on the FTS sampling column were investigated to understand the impacts of sampling rate, expressed as linear wind velocity through the cross section of FTS tube (<em>u</em>) on the sampling efficiency of the sampling column. It revealed that the number of theoretical plates (<em>N</em>) and the logarithm of breakthrough volume (log<em>V</em>_B) of compounds on the FTS-PUF column exhibit linear relationships with the inverse of wind velocity (1/<em>u</em>). The slopes of the fitted lines (K<em>_Nu</em>) are closely associated with the volatility of the compounds. Compounds with volatility experience a greater impact from variations in wind velocity on their <em>N</em> value on the sampling column. The effect on the most volatile PCBs surpasses that of PAHs and OCPs. Moreover, the slopes of log<em>V</em>_B for different compounds affected by wind speed (K<em>_VB-u</em>), display a significant correlation with compound volatility (log<em>P</em>_L). Wind speed exerts a stronger influence on the breakthrough volume of low volatile compounds compared to volatile compounds. Multiple linear regression and LSER analysis further confirms a significant positive correlation between <em>N</em> and log<em>V</em>_B across different temperatures and wind velocities (log(<em>V</em>_B/m³)=2010/(<em>T</em>/K)-0.00066/(<em>u</em>/(m/s))+0.55<em>N</em>-5.41, R²=0.83, <em>n</em> = 423, <em>p</em> = 0). Therefore, the collection performance of the FTS-PUF sampling column for all types of compounds can be predicted under varying temperatures and wind velocitiess/sampling rates. Given the known sampled air volume, the breakthrough level for any chemicals can be estimated, which provids valuable data support for accurate monitoring of atmospheric organic pollutant concentrations.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465474"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of in-house-built pipette-tip micro-solid-phase extraction devices for sample preparation in the analysis of amino compounds by liquid chromatography-tandem mass spectrometry","authors":"Larissa Silva Maciel ,&nbsp;Michaela Hříbková ,&nbsp;Koit Herodes","doi":"10.1016/j.chroma.2024.465480","DOIUrl":"10.1016/j.chroma.2024.465480","url":null,"abstract":"<div><div>Amino compounds are of significant interest in dietary, clinical, and quality control fields. Efficient extraction is crucial for comprehensive metabolomics, especially for amino acids and biogenic amines, but traditional solid-phase extraction (SPE) methods are costly and require large solvent volumes. Miniaturized SPE techniques, like pipette-tip micro-solid-phase extraction (PT-µ-SPE), offer promising alternatives by improving throughput and reducing solvent and sorbent usage. This study presents PT-µ-SPE for the screening and quantification of amino compounds in bee products, particularly honey. The method involves derivatization with diethyl ethoxymethylenemalonate (DEEMM) and analysis using liquid chromatography-triple quadrupole mass spectrometry. Silica-based SCX sorbents were effective for a broad range of amino compounds, while WCX sorbents were better for aliphatic amines. The method's extraction efficiency was assessed across sample loading, washing, and elution solution, with recovery rates of 70 - 120% in oat bran, sea buckthorn leaves, and honey extracts. Matrix effects were observed for four amino compounds in honey. Limits of detection (LoD) and quantification (LoQ) ranged from 0.37 to 57 µg L⁻¹ and 1.13 to 174 µg L⁻¹, respectively. Covering 48 amino compounds under different PT-µ-SPE conditions, this method has been applied to several samples, demonstrating accuracy, environmental sustainability, cost-effectiveness, portability, and versatility in amino compound analysis.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465480"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of bisphenol analogues in bottled water using deep eutectic solvent and magnetic multi-walled carbon nanotubes followed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry","authors":"Yu Du ,&nbsp;Weiyi Jin ,&nbsp;Siyu Yang ,&nbsp;Yeqing Jia ,&nbsp;Xinghua Li ,&nbsp;Jianping Li ,&nbsp;Mingyue Zhang ,&nbsp;Yi Zhang","doi":"10.1016/j.chroma.2024.465479","DOIUrl":"10.1016/j.chroma.2024.465479","url":null,"abstract":"<div><div>Bisphenol analogues (BPs) are a class of typical environmental endocrine disruptors (EDCs) that have recently attracted increasing attention with regard to their potential effects on human health. The objective of this study was to develop a method using a magnetic soft material, which consisted of hydrophilic deep eutectic solvent (DES) and magnetic multi-walled carbon nanotubes (MMWCNTs), for the dispersive solid-phase extraction (d-SPE), coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), for the determination of the levels of nine BPs in bottled water. The hydrophilic DES enable the rapid dispersion of MMWCNTs when the material is injected rapidly into the sample solution using a pipette gun. This process can therefore be completed in a relatively short period of time, resulting in an efficient extraction. Under optimal conditions, the limit of detections (LODs) of the method were 0.0003–0.003 μg/L and the limit of quantifications (LOQs) were 0.001–0.01 μg/L. The relative standard deviations (RSDs) of the method were only 2.42–7.59 % for inter-day and 3.71–9.67 % for intra-day. The method demonstrated good reproducibilities and recoveries, rendering it suitable for the determination of BPs in large-volume water samples.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465479"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing ultrasonication-assisted comprehensive extraction of bioactive flavonoids from Pterocarpus santalinus leaves using response surface methodology","authors":"Yogita Dahat ,&nbsp;Soubhik Ganguly ,&nbsp;Arshad Khan ,&nbsp;Rahul L. Gajbhiye ,&nbsp;Deepak Kumar","doi":"10.1016/j.chroma.2024.465477","DOIUrl":"10.1016/j.chroma.2024.465477","url":null,"abstract":"<div><div>The leaves of <em>Pterocarpus santalinus</em> have been identified as a good source of health-beneficial flavonoids through the amalgamation of untargeted metabolomics using UHPLC-ESI-MS<em>ⁿ</em> leading to the identification of flavone-glycosides bearing isorhamnetin and quercetin skeletons. To unveil the optimum ultrasonication extraction conditions required for the comprehensive extraction of major flavone-glycosides, isorhamnetin-3-<em>O</em>-<em>β</em>-d-(2-<em>O</em>-<em>α</em>-L-rhamnopyranosyl)glucopyranoside and isorhamnetin-3-<em>O</em>-<em>β</em>-d-glucopyranoside, the response surface methodology based on Box-Behnken design was adopted. The influence of input extraction parameters extraction time (X₁): 15–45 min, temperature (X₂): 40–60 °C and biomass-solvent ratio (X₃): 60–100 on the extractive yield and comprehensive flavonoid content resulted in the optimal conditions as 19.09 min, 48.65 ^oC, and 72.15, respectively. The investigation provides a sustainable approach for recovering health-beneficial flavone-glycosides for utilization in various industries.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465477"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boronic acid functionalized of covalent organic framework for high performance capture of trace phthalates","authors":"Mengjie Qin,&nbsp;Mengmeng Zhou,&nbsp;Dongxue Li,&nbsp;Xuejing Lou,&nbsp;Jiawen Zhu,&nbsp;Xiao Tian,&nbsp;Ning Zhang,&nbsp;Wende Ma,&nbsp;Minghua Lu","doi":"10.1016/j.chroma.2024.465481","DOIUrl":"10.1016/j.chroma.2024.465481","url":null,"abstract":"<div><div>In order to improve the enrichment performance of parent covalent organic frameworks (COFs), boronic acid functionalized of COF (COF-B(OH)₂) was obtained by a simple standing method for the first time. The obtained COF-B(OH)₂ exhibited the new characteristics that were not possessed by pure COF and was employed as the solid phase microextraction (SPME) coating material for highly efficient enrichment of trace endocrine disruptors phthalates (PAEs). Compared to pure COF, the synergistic effect of the newly emerged unique pore structure and boric acid interaction sites, and the large specific surface area and the abundant benzene ring structure inherited by original COF framework endowed COF-B(OH)₂ with enhanced enrichment performance for PAEs. Combined with gas chromatography-mass spectrometry (GC–MS), COF-B(OH)₂ exhibited the good linearity over a wide concentration of 0.1–3000 ng l^-1 with good coefficients (R², 0.9916–0.9998) for PAEs. The developed method was successfully employed for detection of trace PAEs in milk and water samples, demonstrating high recoveries (90.6–111.3 %). This work provides a sustainable approach to developing high-performance materials for enriching environmental pollutants.</div></div>","PeriodicalId":347,"journal":{"name":"Journal of Chromatography A","volume":"1738 ","pages":"Article 465481"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142563845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}