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Chinese Journal of Chromatography
2019, Vol. 37, No. 4
Online: 08 April 2019

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Volume 37, Number 4 Content 2019, 37 (4):  0-0.  Abstract ( 155 )   PDF (7424KB) ( 40 )

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Advances in microfluidic chip-based extracellular vesicle separation LIAO Zerong, LI Yongrui, GU Le, LEI Runhong, MIAO Yunfei, LAN Hongying, DENG Yulin, GENG Lina 2019, 37 (4):  343-347.  DOI: 10.3724/SP.J.1123.2018.11045 Abstract ( 386 )   [Full Text(HTML)] () PDF (875KB) ( 511 )   Extracellular vesicles (EVs) are hemispherical vesicles that have a lipid bilayer. Studies have shown that EVs have important biological functions. The amount, types, and compositional changes of proteins, lipids and ribonucleic acids are closely related to diseases. The separation and capture of EVs from the complicated body fluid samples is a prerequisite for medical research and liquid biopsy based on EVs. However, presently the majority of EVs separation and capture still use the traditional separation methods with low purity and low efficiency. Therefore, efficient and highly selective EVs separation method is in urgent need. To meet this challenge, advanced microfluidic chip technology, which has the advantages of miniaturization, integration, and automation, can be utilized. The development of EV separation technology combined with microfluidic chips has become the focus of research. This paper summarizes the latest research progress in this area.

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A brief history of the development of chromatography and its enlightenment to us LIU Huwei, FU Ruonong 2019, 37 (4):  348-357.  DOI: 10.3724/SP.J.1123.2018.11003 Abstract ( 797 )   [Full Text(HTML)] () PDF (4892KB) ( 429 )   This article describes the brief history of chromatography and clarifies a few confusions in some Chinese publications on the history of chromatography. Based on the analysis of several milestones in the development of chromatographic techniques, we summarized the enlightenment that the history tell us:(1) fundamental research has always been the source of advancements in science and technology, including chromatography; (2) the needs of social development have been the main driving force for the innovations in chromatographic methods; (3) interdisciplinary study has been an important approach to technological innovation; and (4) an unremitting persistence and courage to explore are the necessary conditions for technical innovation. Finally, the future development prospects of chromatography are also briefly discussed.

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Advances in capture methods of circulating tumor cells LIU Lukuan, YANG Kaiguang, LIANG Zhen, ZHANG Lihua, ZHANG Yukui 2019, 37 (4):  358-366.  DOI: 10.3724/SP.J.1123.2018.12016 Abstract ( 330 )   [Full Text(HTML)] () PDF (4550KB) ( 225 )   Since circulating tumor cells (CTCs) in the blood carry the genetic and phenotypic information of tumor tissues, they are regarded as important markers for liquid biopsy, especially for the early diagnosis of cancer, determination of treatment options and evaluation of prognosis. However, the capture and detection of CTCs is challenging because of their extremely low concentration in blood. In this review, recent advances in capture methods of CTCs based on their biophysical properties, affinity, and artificial antibodies are summarized. The advantages and drawbacks of these methods are discussed from the aspects of capture efficiency, capture purity and maintenance of activity after release. Future trends in CTCs capture are also discussed.

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Common mathematical-physical essence involved from chromatographic separation to intelligent medicine: irreversibility LIANG Heng, LUO Yuanyuan 2019, 37 (4):  367-375.  DOI: 10.3724/SP.J.1123.2018.12008 Abstract ( 222 )   [Full Text(HTML)] () PDF (1719KB) ( 103 )   The chromatographic separation processes for many molecules in solute bands by stationary phase-mobile phase separation can be compared to ordering disease severity. The common features of chromatographic processes and machine-disease diagnosis-doctor's advice is the separation (classification) of components (individual disease states), both of which show irreversibility of time evolution; however, the former is caused by linear non-equilibrium thermodynamics and latter by nonlinear non-equilibrium thermodynamics (dissipative structure). When the scientific view is extended from drug detection and preparation to evidence-based medicine (EBM), discrete mathematics (axiomatic set theory and probability measure), and artificial intelligence (AI) cloud computing, the convection-diffusion equation and irreversibility in non-equilibrium thermodynamics form a common and core essence of mathematical physics that crosses fields of chromatographic separation and intelligent medicine. It is of profound scientific and practical significance to construct and develop a unified and all-encompassing mathematical framework by incorporating the generality and characteristics of the two subjects.

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Preparation and application of temperature-sensitive affinity chromatographic materials for enrichment of phosphoric acid compounds DAI Guoxin, WANG Di, WANG Yan, CAO Zhihan, DAI Rongji 2019, 37 (4):  376-382.  DOI: 10.3724/SP.J.1123.2018.08041 Abstract ( 200 )   [Full Text(HTML)] () PDF (970KB) ( 155 )   Supporting Information Based on the surface initiated-reversible addition fragmentation chain transfer (SI-RAFT) method, an immobilized metal ion affinity chromatographic material, silica@ploy(N-isopropylacrylamide-co-(aminomethyl)phosphonic acid)-titanium(Ⅳ) (silica@p(NIPAAm-co-AMPA)-Ti4+), was synthesized by the method of rapid introduction of functional groups. The synthesis of the material was confirmed by FT-IR and X-ray photoelectron spectroscopy. The grafting ratio and lower critical solution temperature (LCST) of the material were measured by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the material had excellent temperature-sensitive properties and could successfully capture and release adenosine triphosphate successfully. The service life of the material could be extended by online supplementation of Ti4+.

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Preparation of macrocycle antibiotic chiral stationary phases by wrapping with a net in high performance liquid chromatography HE Yijuan, LI Keli, LI Qian, ZHANG Peng, AI Ping, YUAN Liming 2019, 37 (4):  383-391.  DOI: 10.3724/SP.J.1123.2018.08035 Abstract ( 287 )   [Full Text(HTML)] () PDF (6448KB) ( 132 )   Vancomycin and teicoplanin are glycopeptide macrocyclic antibiotics with three-dimensional ring structures and multiple chiral centers. They are commonly used chiral recognition materials in enantioseparation by high-performance liquid chromatography. In this study, six chiral stationary phases wrapped with a net on silica gels were prepared by interfacial polymerization using vancomycin and teicoplanin as chiral selectors, piperazine as a monomer, 4,4'-diphenylmethane diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI), and 2,4-toluene diisocyanate (TDI) as crosslinker. The fabricated chiral columns were used for enantioseparations. Compared to the crosslinked and commercial columns composed of vancomycin and teicoplanin, the columns wrapped with a net exhibited complementarity for the optical resolutions.

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Preparation and adsorption characteristics of lysozyme-imprinted polymer membrane LI Yuanyuan, ZHANG Xin, CHEN Weijie, LIU Hongyang, SUN Liquan, LUO Aiqin 2019, 37 (4):  392-397.  DOI: 10.3724/SP.J.1123.2018.10022 Abstract ( 226 )   [Full Text(HTML)] () PDF (1356KB) ( 124 )   In this work, a novel polymer membrane molecularly imprinted on a silanized glass substrate was prepared. Lysozyme was chosen as the template protein, and acrylamide and N,N'-methylenebisacrylamide were used as the functional monomer and crosslinking agent, respectively. The adsorption equilibrium time, maximum adsorption capacity, specific recognition ability, reusability, and application of the prepared lysozyme-imprinted polymer membrane were investigated experimentally. The prepared polymer membrane exhibited special recognition ability and could quickly adsorb lysozyme. Under optimal conditions, the adsorption equilibrium time of the prepared polymer membrane for lysozyme was 5 min, and the adsorption behavior conformed to the Langmuir adsorption model; the theoretical maximum adsorption capacity was 42.5 mg/g, and the adsorption capacity for an egg sample was 30 mg/g. Additionally, the polymer membrane showed a high selectivity toward the template protein, lysozyme, and exhibited no obvious adsorption of several interfering proteins; the imprinting factor was 3.0. The maximum adsorption capacity of the polymer membrane decreased by 5% after being reused five times. The polymer membrane was used for the adsorption of lysozyme in samples, and good results were obtained. This strategy has potential for the separation and enrichment of target proteins in complex biological samples.

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Asymmetrical flow field flow fractionation combined with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry used to screen allergen protein epitopes LI Yang, YANG Yi, SHAO Bing, ZOU Yue, SONG Yu, SHU Lin, LIANG Qihui, HAN Nanyin 2019, 37 (4):  398-403.  DOI: 10.3724/SP.J.1123.2018.11047 Abstract ( 211 )   [Full Text(HTML)] () PDF (1771KB) ( 86 )   Asymmetrical flow field flow fractionation (AF4) combined with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was used to screen allergen protein epitopes. The selected allergen protein (tropomyosin, TM) was enzymatically digested into peptide segments and analyzed via UPLC-QTOF-MS to establish a protein-specific peptide database. The peptide segments were incubated with immunoglobulin E (IgE) for 30 min. During the incubation procedure, the specific peptide segments (with the antigen epitope) combine with IgE while the other peptide segments remain in solution. After incubation, the solution was injected into the AF4 device. The combined peptide segments flowed out of the outlet along with IgE, and the other peptide segments flowed into the waste liquid. The components of outlet were then collected, analyzed by UPLC-QTOF-MS, and the results matched with the spectra of the protein peptides. Eventually the specific peptide segments were identified to detect the antigen epitopes. This study extends the application of AF4 with a preliminary exploration of the detection of an allergen protein epitope, providing a novel research strategy for the screening of allergen epitopes.

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Simultaneous determination of five neurotransmitters in neonatal rat hippocampus by adding vitamin C coupled with isotope dilution-ultra-high performance liquid chromatography-tandem mass spectrometry KUANG Hongxuan, ZHANG Haibin, TAN Jianhua, LUO Yifan, LIU Shuhua, PANG Qihua, LI Chuhua, FAN Ruifang 2019, 37 (4):  404-411.  DOI: 10.3724/SP.J.1123.2018.11012 Abstract ( 262 )   [Full Text(HTML)] () PDF (2390KB) ( 139 )   Analysis of neurotransmitters in brain tissue is useful for mechanistic studies of the central nervous system. Isotope dilution coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of glutamic acid, γ-amino butyric acid, acetylcholine, dopamine, and serotonin in the hippocampus tissue. A 2% (v/v) acetic acid in water-methanol (9:1, v/v) solution was used to prepare the standards and re-dissolute samples after nitrogen drying. An Ultimate AQ-C18 column (150 mm×4.6 mm, 3 μm) was used as the analytical column and 0.1% (v/v) formic acid in water and methanol were used as the mobile phase. Gradient elution was performed and all target compounds were eluted over 3 min at 28℃. Vitamin C spiked during the sample pretreatment and storage periods significantly retarded the oxidation of dopamine and serotonin and improved the neurotransmitter stability. The developed method showed good linearities (correlation coefficient (R2)>0.998), low detection limits (0.15-1.0 μg/L), good inter-and intra-day precisions (relative standard deviations:0.39%-13.6%), good accuracy (92.9%-119%), low carry-over, and excellent stability. Moreover, the method was successfully applied and validated in the determination of rat hippocampus exposed to bisphenol A.

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Reversed-phase liquid chromatography separation and mass spectrometry fragmentation analysis of mitiglinide and three isomers LI Min, LIU Haitao, HOU Jinfeng, WANG Chenggang, LI Wendong, CHE Baoquan 2019, 37 (4):  412-417.  DOI: 10.3724/SP.J.1123.2018.11046 Abstract ( 187 )   [Full Text(HTML)] () PDF (964KB) ( 82 )   The separation of mitiglinide and its three isomer impurities was achieved by reversed-phase ultra-performance liquid chromatography-high resolution mass spectrometry. An ACQUITY UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm) was used as the stationary phase and water-acetonitrile-n-pentanol (75:25:1, v/v/v; formic acid was added to adjust pH to 1.8) was used as the mobile phase with a flow rate of 0.4 mL/min. According to the exact mass and high resolution mass spectrometry fragmentation (Q Exactive), significant differences were observed in the fragment ion abundance in the secondary mass spectra of mitiglinide and its three isomer impurities. Two of these isomer impurities were newly discovered. The possible fragmentation mechanisms of mitiglinide and its three isomer impurities were also deduced. The limit of detection of the developed method was 1 μg/L. The linearity of the developed method was good from the limit of quantitation (2 μg/L) to 10000 μg/L with a correlation coefficient of 0.9999. The relative standard deviation of the peak area was 2.0%. On the basis of these results, the sources of the mitiglinide isomer impurities were discussed. Isomer impurity 1 was degraded at high temperature, while isomer impurities 2 and 3 were determined to be synthetic impurities. In addition, samples of mitiglinide calcium raw materials were analyzed.

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Determination of 104 volatile organic compounds in air by double column gas chromatography-mass spectrometry/flame ionization detector coupled with electronically controlled cryo-focusing unit ZHANG Ting, ZHANG Yixiang, DU Zhenyu, DAO Xu, ZHANG Xiulan, CAO Guan, JIA Yueqing, DU Shijuan, TANG Ka, SHAN Danying, ZHOU Hao, ZHOU Rui 2019, 37 (4):  418-425.  DOI: 10.3724/SP.J.1123.2018.12022 Abstract ( 241 )   [Full Text(HTML)] () PDF (1611KB) ( 211 )   A method for the determination of 104 volatile organic compounds (VOCs) in ambient air based on double column multi dean switching gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) coupled with sorbent assisted electronically controlled cryo-focusing unit was developed and evaluated. The sorbent assisted electronically controlled cryo-focusing unit was used for trapping, dehydration and focusing of VOCs sampled in summa canisters. The VOCs were split into two parts by the multi dean switching unit in GC-MS/FID. The C2-C3 components were determined in a PLOT capillary column with an FID detector, while the C4-C12 components were determined in an Intercap-624 capillary column with a MS detector. The C2-C3 components were qualitatively confirmed from the retention time and quantified by the calibration curves, while the C4-C12 components were qualitatively confirmed from the retention time and the relative abundance ratio of characteristic ions, and quantified by the internal standard calibration curves. The major factors influencing the cryo-focusing performance including the type of sorbent tube, the pressure employed in assisted pressure control unit (APC), and the split point in multi dean switching unit were investigated. The chromatographic and MS parameters were optimized. Under optimum conditions, a linear relationship was observed with the content of VOCs ranging from 0.0446 to 0.892 μmol/m3, and correlation coefficients (r) no less than 0.9984. The average spiked recoveries of the six VOCs at two levels of 0.0446 μmol/m3 and 0.223 μmol/m3 were 86.4%-116.1%, with relative standard deviations in the range of 0.9%-11.3% The method detection limits (MDLs) and the limits of quantification (LOQs) were 0.145-1.90 μg/m3 and 0.435-5.70 μg/m3, respectively. The method is accurate, sensitive and simple, and is suitable for the determination of the 104 VOCs in ambient air.

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Analysis of accelerant in fire debris by pyrolysis gas chromatography-mass spectrometry ZHANG Jian, LIU Jida 2019, 37 (4):  426-431.  DOI: 10.3724/SP.J.1123.2018.11039 Abstract ( 219 )   [Full Text(HTML)] () PDF (1103KB) ( 109 )   A strategy for the analysis of the accelerant and combustion residues in fires was developed by pyrolysis gas chromatography-mass spectrometry (PyGC-MS). Two kinds of accelerants (gasoline and diesel) and two kinds of carriers (cotton cloth and polyethylene terephthalate (PET) plastic) were selected for this research. Combustion residues of the accelerant and carrier were prepared. The characteristic temperatures of the samples were determined by thermal analysis technology. Then the analysis conditions were optimized and selected. The samples were subjected to PyGC-MS by a stepwise method consisting of flash analysis and pyrolysis analysis. The experimental results showed that the pyrolysates of the original combustion residues of the PET carrier consisted of 35 components, while the pyrolysates of the combustion residues of the PET carrier with gasoline, and ones of the combustion residues of the PET carrier with diesel oil consisted of only 25 components. The types and contents of the pyrolysates were different. The established method could distinguish the self-combustion residue of the carrier from the combustion residue of the accelerant and the same carrier. It was suitable for the analysis of the accelerant from the fire debris, and could determine the presence of the accelerant in the fire field. The method can provide a scientific basis for the judgement of the fire property and fire investigation work.

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Qualitative analysis of compositions of anthraquinone series working solution by gas chromatography-mass spectrometry ZHANG Yueqin, GAO Guohua, YANG Keyong, ZONG Baoning, XU Guangtong 2019, 37 (4):  432-437.  DOI: 10.3724/SP.J.1123.2018.11036 Abstract ( 306 )   [Full Text(HTML)] () PDF (942KB) ( 157 )   A method for the qualitative analysis of compositions of anthraquinone working solution (WS)/hydrogenated working solution (HWS) by gas chromatography-mass spectrometry (GC-MS) was developed. The composition of ethylanthraquinone (eAQ) WS/HWS was identified by GC-MS. Then the samples of amylanthraquinone (AAQ) WS/HWS were analyzed by GC-MS. Combined with the reaction mechanism, the composition of AAQ WS/HWS was inferred. The list of the degradation as well as the intermediate products in the industrial synthesis of H2O2 in anthraquinone WS was generated, and the information obtained regarding the composition of the anthraquinone WS/HWS was helpful in identifying and removing the unacceptable degradation products.

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Qualitative detection and source analysis of the organic chlorides in the byproducts of biodiesel prepared using swill-cooked dirty oil under sub-critical conditions HAN Jianghua 2019, 37 (4):  438-443.  DOI: 10.3724/SP.J.1123.2018.11033 Abstract ( 242 )   [Full Text(HTML)] () PDF (935KB) ( 162 )   This paper introduces a gas chromatography-mass spectrometry (GC-MS) qualitative detection method for organic chlorides in crude glycerol and distillated light components, which are the byproducts of biodiesel. Samples with a higher total chlorine content were obtained from the transesterification reaction between swill-cooked dirty oil and methanol under subcritical conditions. Before GC-MS analysis, n-hexane extraction was performed to remove the soluble lipid interfering components, such as methyl fatty acid ester and free fatty acids, from the samples. Moreover, the reference standards, 3-chlorinated glycerol and 2-chlorinated glycerol, and the degreased water phases of the samples were subjected to derivatization with phenylboronic acid (PBA), extraction with n-hexane, and concentration. After re-dissolution using n-hexane, GC-MS analysis was performed. The results showed that the organic chlorides in the biodiesel by-products mainly included 3-chlorinated glycerol and 2-chlorinated glycerol. The sources of the organic chlorides were discussed by considering previously reported results and the preparation process of the biodiesel. Therefore, we concluded that the presence of a large amount of inorganic chloride salts in the swill-cooked dirty oil is the main reason for the production of 3-chlorinated glycerol and 2-chlorinated glycerol.

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Determination of the key impurity in caprolactam produced from a combined process by gas chromatography-mass spectroscopy HAN Jianghua 2019, 37 (4):  444-448.  DOI: 10.3724/SP.J.1123.2018.11030 Abstract ( 319 )   [Full Text(HTML)] () PDF (908KB) ( 163 )   Caprolactam (CPL) is an important chemical raw material. Because even trace level contaminations in CPL can directly influence the polymerization and the resulting properties of fibers, the CPL monomer must be very pure. In this study, gas chromatography with a flame ionization detector (GC/FID) and gas chromatography mass spectroscopy (GC-MS) techniques were developed to determinate the key impurities in CPL using a novel process which characterized the ultraviolet (UV) absorption rates of the samples. The GC-MS results indicated that the major impurity had a relative molecular mass of 188 and was qualitatively characterized as 1,2,3,4,6,7,8,9-octahydrophenazine. Considering the reaction conditions and properties of the substances in the reactor, we speculated that the octahydrophenazine may have originated from a Neber rearrangement, which is a side-reaction of the Beckmann rearrangement. The impurity contains strong chromophores and severely impacted the UV absorption rate of the CPL product. Therefore, during CPL production, the concentration of octahydrophenazine must be strictly controlled.

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Characterization of hydrolytic metabolism of malathion with Musca domestica by gas chromatography with nitrogen-phosphorus detector ZHANG Yi, SHI Xueyan, GAO Xiwu 2019, 37 (4):  449-453.  DOI: 10.3724/SP.J.1123.2018.10010 Abstract ( 188 )   [Full Text(HTML)] () PDF (896KB) ( 72 )   To examine the hydrolytic metabolism and related resistance of housefly Musca domestica (M. domestica) to malathion, differences in the hydrolytic metabolic abilities between malathion-susceptible and malathion-resistant M. domestica were examined using gas chromatography with nitrogen-phosphorus detector (GC-NPD). After incubation of M. domestica abdomen homogenates with malathion, the malathion residue was quantitatively determined by GC-NPD after extraction with a mixture of ethyl acetate and n-hexane at 2:1 (v/v). The hydrolytic metabolic abilities of M. domestica to malathion were then characterized. By comparing the differences in hydrolytic abilities between malathion-susceptible and malathion-resistant M. domestica, it was found that the hydrolytic abilities of malathion-resistant M. domestica were 6.68-fold than that of malathion-susceptible M. domestica, while the hydrolytic abilities toward α-naphthyl acetate were 1.39-fold. Resistance to malathion is related to the enhanced hydrolytic metabolism of malathion by M. domestica. Further understanding of the metabolic resistance mechanism will assist in developing a management strategy for malathion-resistant M. domestica. This method could be used for studying the metabolic ability and related resistance of M. domestica toward malathion.

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Effect of Cu-Ce/γ-Al2O3 catalyst on bio-oil production by hydrothermal deoxygenation of stearic acid YU Qi, ZHANG Zuhao, YIN Zhaosen, KONG Shengyan, YANG Ziheng, CHEN Jiayi, ZHANG Jinglai 2019, 37 (4):  454-461.  DOI: 10.3724/SP.J.1123.2018.10032 Abstract ( 192 )   [Full Text(HTML)] () PDF (1568KB) ( 100 )   In order to improve the hydrothermal deoxygenation of organic acids as well as to reduce the cost, we prepared a Cu-Ce/γ-Al2O3 catalyst to study the hydrothermal deoxygenation of stearic acid in the absence of H2. The Brunauer-Emmett-Teller surface area and X-ray diffraction pattern suggest that both CuO and CeO2 exist in the Cu-Ce/γ-Al2O3 catalyst. The crystals of Cu-Ce/γ-Al2O3 were more stable compared with those of the Cu/γ-Al2O3 catalyst after 12 h of hydrothermal liquefaction at 300℃, thereby indicating a better thermal stability of the former. The presence of Cu-Ce/γ-Al2O3 catalyst could greatly improve the conversion of stearic acid (94.71%) and the yield of hydrocarbon (81.41%). A preliminary analysis of the mechanism suggests that decarboxylation is the main step in the deoxygenation during the hydrothermal liquefaction of stearic acid. The addition of Cu/γ-Al2O3 and Cu-Ce/γ-Al2O3 decreased the yield of n-heptadecane and increased the yield of n-octadecane. Besides, the yields of n-paraffins increased drastically from 0.45% to 49.72% along the series from n-nonane to n-hexadecane. Thus, the cracking reactions could be improved in the presence of Cu-Ce/γ-Al2O3, suggesting that it is an efficient deoxygenation catalyst in the hydrothermal liquefaction of organic acid. In addition, the Cu-Ce/γ-Al2O3 catalyst could help in removing the carbonyl groups, and this effectively reduced the amounts of aldehydes and ketones in the bio-oil.