Chinese Journal of Chromatography

2025, Vol. 43, No. 3
Online: 08 March 2025

CN 21-1185/O6
ISSN 1000-8713
Editors-in-Chief: Prof. Yukui Zhang
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Contents
CONTENTS
2025, 43 (3):  0-0. 
Abstract ( 4 )   PDF (3693KB) ( 11 )  
Articles
Integrative transcriptomics-metabolomics approach to identify metabolic pathways regulated by glutamine synthetase activity
LING Ting, SHI Jing, FENG Tingze, PEI Shaojun, LI Siyi, PIAO Hailong
2025, 43 (3):  207-219.  DOI: 10.3724/SP.J.1123.2024.04003
Abstract ( 160 )   HTML ( 7 )   PDF (3025KB) ( 70 )  
Supporting Information

Glutamine synthetase (GS), the only enzyme responsible for de novo glutamine synthesis, plays a significant role in cancer progression. As an example of the consequences of GS mutations, the R324C variant causes congenital glutamine deficiency, which results in brain abnormalities and neonatal death. However, the influence of GS-deficient mutations on cancer cells remains relatively unexplored. In this study, we investigated the effects of GS and GS-deficient mutations, including R324C and previously unreported K241R, which serve as models for GS inactivation. This study provided intriguing insights into the intricate relationship between GS mutations and cancer cell metabolism.

Our findings strongly support recent studies that suggest GS deletion leads to the suppression of diverse signaling cascades associated with glutamine metabolism under glutamine-stripping conditions. The affected processes include DNA synthesis, the citric acid cycle, and reactive oxygen species (ROS) detoxification. This suppression originates from the inherent inability of cells to autonomously synthesize glutamine under glutamine-depleted conditions. As a key source of reduced nitrogen, glutamine is crucial for the formation of purine and pyrimidine bases, which are essential building blocks for DNA synthesis. Furthermore, the citric acid cycle is inhibited by the absence of negatively charged glutamate within the mitochondrial matrix, particularly when glutamine is scarce. This deficiency decreases the flux of α-ketoglutarate (α-KG), a principal driver of the citric acid cycle. Intermediate metabolites of the citric acid cycle directly or indirectly contribute to the generation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a core component of redox homeostasis.

Using the GS_R324C and GS_K241R mutants, we conducted an integrative transcriptomics and metabolomics analysis. The GS mutants with reduced activity activated multiple amino acid biosynthesis pathways, including arginine-proline, glycine-serine-threonine, and alanine-aspartate-glutamate metabolism. This intriguing behavior led us to hypothesize that despite hindrance of the citric acid cycle, abundant intracellular glutamate is redirected through alternative processes, including transamination. Simultaneously, key metabolic enzymes in the amino acid synthesis pathways, such as glutamic-oxaloacetic transaminase 1 (GOT1), glutamic-pyruvic transaminase 2 (GPT2), pyrroline-5-carboxylate reductase 1 (PYCR1), and phosphoserine aminotransferase 1 (PSAT1), exhibited increased mRNA levels. Additionally, GS deficiency appeared to upregulate the expression of glutamine transporters SLC38A2 and SLC1A5. Thus, restricting extracellular amino acids, such as glutamine, induces a stress response while promoting transcription or translation by a select group of genes, thereby facilitating cellular adaptation. However, similar to GS_WT, both GS_R324C and GS_K241R were modulated by glutamine treatment.

Among GS-activity-dependent behaviors, the increased expression of numerous aminoacyl-tRNA synthetases (ARSs), which are critical for aminoacyl-tRNA biosynthesis, remains poorly understood. Most ARS-encoding genes are transcriptionally induced by activating transcription factor 4 (ATF4), the expression of which increases under oxidative stress, endoplasmic reticulum stress, hypoxia, and amino acid limitation. In GS-deficient cells, the increased expression of ATF4 was accompanied by pronounced stress caused by glutamine starvation. Thus, ARS upregulation may predominantly arise from increased ATF4 expression in GS-deficient cells. Additionally, transcriptomic analysis revealed the differential expression of specific genes, regardless of GS activity, suggesting that GS is involved in various processes other than glutamine synthesis, including angiogenesis. Although our omics study was limited to H1299 cells, in subsequent experiments, we validated our findings using additional cell lines, including Hepa1-6 and LN-229. To attain a more comprehensive understanding of the impact of the newly identified GS_K241R mutant, our investigation should be extended to various cell types and mouse models.

In summary, we identified and investigated GS-deficient mutations in cancer cells and conducted an integrative transcriptomics-metabolomics analysis with comparisons to wild-type GS. This comprehensive approach provided crucial insights into the intricate pathways modulated by GS activity. Our findings advance the understanding of how GS functions in the context of reprogrammed cellular metabolism, particularly during glutamine deprivation. The altered metabolism triggered by elevated glutamate levels arising from GS mutations highlights the remarkable plasticity of cancer cell metabolism. Notably, considering the increasing research focus on GS as a potential therapeutic target in various cancer types, the findings of this study could provide innovative perspectives for drug development and the formulation of clinical treatment strategies.

Determination of 30 bile acids in the bile of Micropterus salmoides and Ctenopharyngodon idella using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry
MAO Lingwen, SUN Hao, CHEN Haijie, YANG Qianzhan, XU Lan
2025, 43 (3):  220-227.  DOI: 10.3724/SP.J.1123.2024.03004
Abstract ( 62 )   HTML ( 5 )   PDF (877KB) ( 34 )  

Bile acids (BAs), the primary components of bile, play significant roles in sugar, lipid, and cholesterol metabolism. Normal BA metabolism maintains a dynamic equilibrium by regulating gut microbiota to effectively protect the liver and intestines, thereby sustaining overall health. Conversely, abnormal BA metabolism can cause intestinal tissue and liver damage, disruption of enterohepatic circulation homeostasis, dysbiosis of gut microbiota, and gastrointestinal and hepatic diseases. Although largemouth bass (Micropterus salmoides) and grass carp (Ctenopharyngodon idella) are important freshwater fish species in China, their BA profiles have not been fully characterized. Elucidating these profiles could provide valuable data to support the aquaculture industry.

In this study, a qualitative and quantitative method for the simultaneous determination of 30 BAs in the gallbladders of M. salmoides and C. idella was developed using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry. The samples were centrifuged and then the supernatant was extracted, vortex-mixed with methanol, and filtered through a 0.22 μm membrane. Various mobile phase systems commonly used in liquid chromatography-mass spectrometry were investigated, including formic acid, acetic acid, ammonium formate, acetic acid-ammonium, and methanol-acetonitrile. Based on the response intensity, chromatographic separation, and peak shape of each substance, the optimal mobile phase was acetic acid and acetonitrile, and the concentration of acetic acid in water was optimized. To improve the ionization efficiency, the most effective ion scanning mode was selected by comparing the response intensities and peak conditions of each BA during mass spectrometry in positive and negative ion modes. Furthermore, the interface voltage for each BA and the ion source interface temperature were investigated to determine the optimal mass spectrometry conditions. Ultimately, separation was performed using a Shim-pack Velox SP-C18 column (100 mm×2.1 mm, 1.8 μm) with gradient elution of 0.01% acetic acid aqueous solution and acetonitrile, and the total analysis time was 14 min. The column temperature was 50 ℃ and the injection volume was 2 μL. Multiple reaction monitoring of 8 positive ions and 22 negative ions was carried out using electrospray ionization. Different series of mixed standard working solutions, prepared based on the response intensity of each BA, were used to construct standard curves. All 30 BAs exhibited good linearities within the investigated concentration ranges, with correlation coefficients (R2) of 0.9975-0.9997, indicating high accuracy. Spiked recoveries were 72.3%-117.2%, and the inter-day precisions were in the range of 0.46%-13.23%. The limits of detection and quantification were 0.01-0.75 ng/mL and 0.02-2.28 ng/mL, respectively, enabling the precise detection of low-concentration BAs. Using the established method, 19 BAs were successfully detected in the bile of M. salmoides, and 16 BAs were detected in the bile of C. idella, enriching the BA profiles of both species. Notably, five BAs present in the gallbladder of M. salmoides were undetected in the gallbladder of C. idella, whereas two BAs found in the gallbladder of C. idella were absent from the gallbladder of M. salmoides, demonstrating differences between the BA compositions of these species. The developed method is characterized by simplicity, speed, high sensitivity, and accuracy, harnessing the high-throughput advantages of ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS), and is suitable for the simultaneous detection of the 30 BAs in the gallbladders of M. salmoides and C. idella.

Determination of vitamin D and 25-hydroxyvitamin D in animal-derived foods by derivatization-ultra performance liquid chromatography-tandem mass spectrometry
LIU Yu, XIE Jihui, ZHANG Pingping, ZHOU Di, ZHAO Weike, ZHANG Juzhou
2025, 43 (3):  228-236.  DOI: 10.3724/SP.J.1123.2024.02003
Abstract ( 78 )   HTML ( 2 )   PDF (1874KB) ( 41 )  

Animal-derived foods are essential sources of vitamin D and 25-hydroxyvitamin D in the human diet. Currently, the relevant regulatory methods in China are limited to using non-derivatization methods to determine vitamin D content. In this study, 4-phenyl-1,2,4-triazoline-3-5-dione (PTAD) was used as a derivative reagent, and the ionization efficiencies of vitamin D and 25-hydroxyvitamin D were improved by introducing readily ionizable groups via the Diels-Alder reaction. This method allowed for the simultaneous determination of vitamin D and 25-hydroxyvitamin D in animal-derived foods using derivatization and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The conditions for derivatization, sample pretreatment, chromatographic separation, and MS detection were optimized. The results showed that the derivatization reaction was effective in acetonitrile solvent at a target compound to PTAD mass ratio of 1∶10000 and stabilized after 1 h. Compared with Silica and C18 solid-phase extraction (SPE) columns, hydrophilic lipophilic balanced (HLB) SPE columns yielded higher recoveries of the target compounds, while simultaneously reducing the matrix effect. The detection sensitivity was significantly improved by adding 5 mmol/L methylamine to the water-methanol mobile phase system. An isotopic internal standard was added to the homogenized samples, which were saponified with alkali solution, extracted and concentrated, purified using a SPE column, derivatized, and separated on a Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) with a gradient elution using 0.1% formic acid-5 mmol/L methylamine aqueous solution and 0.1% formic acid-5 mmol/L methylamine of methanol as the mobile phases. The analytes were determined by multiple reaction monitoring (MRM) in positive electrospray ionization mode (ESI+) and quantified using the internal standard method. The results for both vitamin D and 25-hydroxyvitamin D showed good linearity in the range of 0.2-50 μg/L, with correlation coefficients of 0.9995-0.9999. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.018-0.066 and 0.06-0.22 μg/kg, respectively. Recoveries were 92.6%-99.4% at three spiked levels (0.20, 1.0, and 5.0 μg/kg), and the relative standard deviations (RSDs) were 3.6%-6.2%. This highly sensitive method yields reproducible and accurate results for the quantitative determination of vitamin D and 25-hydroxyvitamin D in animal-derived foods.

Determination of trace anions in G2-grade phosphoric acid using two-dimensional ion-exclusion-ion-exchange chromatography with valve-switching technology
WANG Jiading, TANG Gao, LU Yan, LU Hengjun, YE Tao
2025, 43 (3):  237-244.  DOI: 10.3724/SP.J.1123.2024.04010
Abstract ( 59 )   HTML ( 2 )   PDF (1284KB) ( 15 )  

This study established a method for determining trace anions in G2-grade phosphoric acid under ultra-clean conditions that used two-dimensional ion-exclusion-ion-exchange chromatography coupled with valve-switching technology. The optimal flow rate of ultrapure water through the ion-exclusion column in the first dimension was determined to be 0.5 mL/min through comparative experiments. The valve-switching window was optimized to minimize enriching PO43- on the anion-enrichment column and reduce interference from the phosphoric-acid matrix. The use of external water mode for the suppressor led to lower baseline noise, and optimizing the elution program of the second dimension enabled target trace anions to be well separated, thereby avoiding the risk of a false positive for NO3-. The anions of Cl-, Br-, NO3-, and SO42- exhibited good linearities within the 0.5-20 μg/kg, with correlation coefficients ≥0.999. The limits of detection (LODs) and quantification (LOQs) were 0.09-0.29 μg/kg and 0.29-0.97 μg/kg, respectively. The spiked recoveries of each anion at four spiked levels ranged from 91.7% to 103.6%, with RSDs of 0.1%-4.9%. The developed method demonstrated excellent stability through repeated injections, and low detection limits; it is highly precise and accurate, and meets the detection requirements for trace anions in G2-grade phosphoric acid. Additionally, retention-time comparisons with single standard substances led to the discovery of other phosphorus-related anions and anion clusters, such as hypophosphite (HPO3-) and hexametaphosphate (PO3-)6, in G2-grade phosphoric acid, in addition to conventional anions. This finding is theoretically and practically significant for the future development of purification processes for higher-purity phosphoric acid.

Determination of glucose in exhaled breath and saliva by ion chromatography
XU Jianjun, LOU Chaoyan, ZHUO Yanhong, ZHU Yan
2025, 43 (3):  245-251.  DOI: 10.3724/SP.J.1123.2024.06011
Abstract ( 20 )   HTML ( 4 )   PDF (1420KB) ( 4 )  

A novel noninasive method was developed for determining glucose levels in human exhaled breath and saliva using ion chromatography. This innovative approach involves collecting exhaled breath and saliva samples using a self-designed condensation device and non-stimulative method to ensure minimal participant discomfort. The glucose contents in both exhaled breath condensate (EBC) and saliva were analyzed using ion chromatography, which is highly sensitive and specific. The experimental conditions were optimized, including a condensation temperature of -14 ℃ and an expiratory flow of 15 L/min. A Dionex CarboPac MA1 ion chromatography column (250 mm×4 mm) was used to separate glucose, with the column temperature maintained at 30 ℃. Sodium hydroxide solution (0.8 mol/L) with a pump flow rate of 0.4 mL/min was used as the mobile phase for ion chromatography. Under these conditions, glucose exhibited a good linear relationship in the range of 0.01-20 mg/L, with a correlation coefficient of 0.9999, along with limits of detection (LOD) and quantification (LOQ) of 2.1 and 7.0 μg/L, respectively. The intra- and inter-day precisions of glucose content in exhaled breath and saliva samples of ≤7.5% (n=5) and ≤8.4% (n=5), respectively. The results reveal that the glucose levels in exhaled breath and saliva are strongly correlated with blood glucose levels. The method was validated by measuring the glucose contents of exhaled breath and saliva from six diabetic patients and six healthy subjects. Little variation in the glucose contents of the exhaled breath of the two groups was observed under fasting states. However, the exhaled breath of the diabetic patients exhibited significantly higher (by factors of 6-80) glucose contents (48.4-140.0 ng/L) than those of healthy subjects (1.7-7.9 ng/L) 1 h after glucose ingestion. Saliva samples from fasting diabetic patients contained 1.2-5.0-times more glucose contents (87.6-158 mg/L) than those of healthy subjects (31.6-70.9 mg/L). In addition, the saliva of the diabetic patients exhibited glucose contents (136-257 mg/L) that were 1.8-7.7-times higher than those of the healthy subjects (33.1-75.2 mg/L) 2 h after glucose ingestion. The developed method provides a simple, precise, and non-invasive means of detecting glucose contents in a manner that does not harm the human body; hence, it is a promising non-invasive metabolic-monitoring tool. This study opens new avenues for the development of innovative technologies for monitoring glucose and other biomarkers, which is expected to greatly enhance metabolic-study accuracy and ease, particularly in the context of managing diabetes and other metabolic disorders.

Technical Notes
Determination of 17 perfluorinated/polyfluoroalkyl compounds in serum by high-throughput solid-phase extraction-ultra-high performance liquid chromatography-tandem mass spectrometry
LIN Qiang, WANG Jian, LI Jingjing, SU Dongxia, LI Meili, WANG Jia, NIU Yumin, SHAO Bing
2025, 43 (3):  252-260.  DOI: 10.3724/SP.J.1123.2024.03007
Abstract ( 127 )   HTML ( 6 )   PDF (1558KB) ( 47 )  

Perfluorinated/polyfluoroalkyl compounds (PFASs) are a group of synthetic chemicals. Since the 1940s, PFASs have been widely used in industrial and daily consumer fields. PFASs can enter the human body through various pathways, such as drinking water, food, and air. Toxicological studies have shown that PFASs feature developmental and reproductive toxicity. Thus, the accurate assessment of PFAS exposure levels plays an important role in determining the health risks of these compounds. Biological monitoring is considered the most ideal means of monitoring and evaluating PFAS levels in the human body. The concentration of PFASs in serum can directly reflect their level of absorption in the human body after exposure; therefore, serum is widely used as a biological matrix for evaluating PFASs.

In this study, a high-throughput solid-phase extraction (SPE)-ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the determination of 17 PFASs in serum. A laboratory-made straight-through SPE column was used to purify serum samples. The SPE column used a new inorganic material with a low perfluorinated compound background. Unlike traditional SPE columns, the extraction column does not require activation before use, and the sample can be directly loaded into it for purification. The straight-through SPE column adopts a stepped design, which does not require a large sample volume and is suitable for the pretreatment of precious biological samples such as serum. The serum sample size adopted in this study was only 50 μL, which is much lower than that required by other extraction methods. The straight-through SPE column can be used in conjunction with a 96-well plate, and the purification treatment of 96 serum samples can be completed within 30 min with high efficiency.

The mass spectrometry parameters were optimized, and the results indicated that the electrospray ionization source temperature had a significant impact on the PFASs with later elution peaks. The effects of ion-source temperatures of 400 and 500 ℃ on the peak shapes and response values of the target compounds were compared, and 400 ℃ was selected. The sample pretreatment and ultra-high performance liquid chromatographic conditions were optimized. Briefly, 50 μL of the sample was loaded into the SPE column and extracted twice using 200 μL of acetonitrile each time. The purified solution was collected, blown with nitrogen at 40 ℃ to near dryness, dissolved in a 50% methanol aqueous solution, and then separated on a Poroshell 120 EC-C18 chromatographic column (100 mm×3 mm, 2.7 μm) with 5 mmol/L ammonium acetate aqueous solution and methanol as mobile phases. Detection was conducted in multiple-reaction monitoring mode, and quantification was performed using an isotope internal standard method. The 17 detected PFASs had good linear relationships within the corresponding mass concentration ranges (r2>0.995), with limits of detection ranging from 3.6 ng/L to 14 ng/L and limits of quantification ranging from 11 ng/L to 42 ng/L. The recoveries in spiked serum samples were 89.3%-110.2%, the intra-day RSDs were 2.5%-9.8%, and the inter-day RSDs were 3.6%-10.2%. The method was applied to the detection of 20 human serum samples, and all 17 compounds were successfully detected. The proposed method is easy to operate, highly sensitive, has a small sample size and high detection efficiency, and is suitable for the large-scale monitoring and exposure assessment of PFASs in human serum samples.

Determination of cycloxaprid and paichongding residues in foods of plant origin by ultra performance liquid chromatography-tandem mass spectrometry
LIU Junjun, LI Ju, YU Wanwan, HAN Ying, MA Xinxin, ZHAN Chunrui, LI Shixiang, WU Huawen, HU Kui, WAN Jianchun
2025, 43 (3):  261-268.  DOI: 10.3724/SP.J.1123.2024.04016
Abstract ( 66 )   HTML ( 3 )   PDF (935KB) ( 30 )  

Neonicotinoid insecticides play an important role in the prevention and control of pests in crops, such as rice, wheat, corn, and vegetables, because of their broad spectrum, high efficiency, low toxicity, and low residue formation. However, their widespread use poses potential threats to the environment and human health. Cycloxaprid and paichongding are two new classes of neonicotinoid insecticides. The National Food Safety Standard Maximum Residue Limits for Pesticides in Foods (GB 2763) specifies the maximum residue limits for paichongding and cycloxaprid in rice, brown rice, wheat, and cabbage. However, the established limits are only temporary. In addition, no detection standards have yet been specified, and no relevant standards have been established in China. Therefore, establishing a method for analyzing cycloxaprid and paichongding residues in food is of particular importance. In this study, an optimized method was established to determine the residues of cycloxaprid and two noncorresponding isomers of paichongding in plant foods using ultra performance liquid chromatography-tandem mass spectrometry. The chromatographic conditions, matrix extraction methods for dried fruits and tea, and amounts of the purification materials C18, PSA, GCB, and anhydrous magnesium sulfate were optimized. The pesticides were extracted using an acetonitrile solution and separated from water with the addition of sodium chloride. The samples were centrifuged at 5000 r/min for 5 min, after which 1.00 mL of the supernatant was purified using 150 mg of anhydrous magnesium sulfate, 25 mg of C18, 25 mg of PSA, and 10 mg of GCB. Cycloxaprid and paichongding were separated on a ACQUITY UPLC BEH C18 chromatographic column (100 mm×2.1 mm, 1.7 μm) via gradient elution with 0.1% formic acid aqueous solution containing 5 mmol/L ammonium formate-acetonitrile as the mobile phase, and detected in electrospray positive ionization mode coupled with multiple-reaction monitoring (MRM) mode. Quantitative analysis was performed using an external standard method. Cycloxaprid and paichongding demonstrated good linear relationships within their respective concentration ranges, and the corresponding correlation coefficients were all above 0.99. The limits of detection (S/N=3) and quantification were 0.05 μg/kg and 0.01 mg/kg, respectively, which meet the requirements specified in GB 2763-2021 and GB 2763.1-2022. The established method was used to validate the recoveries of cycloxaprid and paichongding spiked in foods of plant origin, such as paddy, brown rice, wheat, rice, peanut, raisin, cabbage, lettuce, green bean, tomato, potato, shiitake mushroom, apple, citrus, and tea substrates, at three levels. The spiked levels covered the limit levels specified in GB 2763-2021 and GB 2763.1-2022. The mean recoveries of the target substances added to the 15 substrates at concentrations of 1, 2, and 10 times the LOQ or the limit values specified in GB 2763-2021 and GB 2763.1-2022 were distributed between 78% and 110%, and the RSDs were within the range of 0-12.8%. One hundred batches of fruit and vegetable samples were analyzed using the developed method, and the results showed that the selected samples were not contaminated with either cycloxaprid or paichongding. The proposed method is simple, sensitive, and universal, and has wide coverage. Thus, it can be used as a confirmatory and quantitative detection method for epoxidine and piperidine in foods of plant origin.

Simultaneous determination of six polyhydroxyl compounds in cosmetics and toothpaste using high performance liquid chromatography with evaporative light-scattering detection
ZHAO Shu’e, YUAN Lu, LIAO Dandan, LUO Xiang, XIAO Gengpeng
2025, 43 (3):  269-274.  DOI: 10.3724/SP.J.1123.2024.02019
Abstract ( 104 )   HTML ( 3 )   PDF (810KB) ( 52 )  

With the full implementation of the cosmetic formula ingredient registration system and the standardized management of labels and identification, the ingredients registered and declared on the label must be consistent with the actual ingredients contained in the product. Further, cosmetic manufacturers require accurate determination of the ingredients in cosmetics for formula analysis. Therefore, a method for the simultaneous determination of six polyhydroxyl compounds, Pro-Xylane, xylitol, sorbitol, mannitol, sucrose, and inositol, in cosmetics and toothpaste was established. According to this method, approximately 0.5 g of the sample was weighed into a 25 mL centrifuge tube. Water-dispersed and oil-in-water cosmetic samples were extracted using 10 mL water, followed by washing with 5 mL n-hexane and 5 mL ethyl acetate. The water-in-oil cosmetic samples were predispersed in 5 mL ethyl acetate, extracted using 10 mL water, and washed with 5 mL n-hexane. After filtration through a 0.22 μm membrane, the extracted solution was subjected to separation using an Ultimate XB-NH2 column (250 mm×4.6 mm, 5 μm), employing gradient elution with acetonitrile and distilled water as the mobile phases. This was followed by detection using evaporative light-scattering detector (ELSD) and quantification using the external standard method. Optimization experiments were conducted to select chromatographic columns, extraction processes, and chromatographic conditions. Specifically, the Ultimate XB-NH2 column and Ultimate XB-C18 column were compared in terms of separation efficiency. Based on the separation efficiency and analysis time, the XB-NH2 column was found to be more suitable as the separation column for this method. The effects of trichloromethane (TCM), ethyl acetate (EA), and n-hexane as predispersants and washing solutions were compared. Among them, the combination of ethyl acetate and n-hexane was found to be more suitable owing to its effective pre-dispersion capability and ability to remove both polar and nonpolar compounds from the extraction solution. The instrumental conditions were optimized using the gradient elution mode with acetonitrile and water as the mobile phase. The column temperature was set at 20 ℃, while the drift tube temperature and atomized gas pressure were set to 60 ℃ and 0.17 MPa, respectively. Under the optimized conditions, the method was validated in terms of linearity, sensitivity, recovery, and repeatability. The results showed that the six polyhydroxyl compounds exhibited excellent linearities within the range of 0.2-5.0 g/L, with correlation coefficients in the range of 0.991-0.996. Sensitivity is expressed as the limits of detection (LODs, S/N=3) and quantification (LOQs, S/N=10). The LODs and LOQs were 0.10% and 0.35%, respectively. Recovery tests were conducted at three levels (low, medium, and high) for oil-in-water cosmetics, water-in-oil cosmetics, and toothpaste matrices. Samples were extracted and measured six times in parallel. The average recoveries of the analytes were 84.7%-94.1%, with relative standard deviations (RSDs, n=6) of 2.2%-6.9%. Finally, the proposed method was employed to analyze six polyhydroxyl compounds in cosmetics and toothpaste that were randomly purchased from a local market. Sorbitol and xylitol were found to be the most commonly used ingredients in toothpaste, while Pro-Xylane was more common in whitening cosmetics. This method has the advantages of simplicity, stability, reliability, and good reproducibility and is suitable for the detection of polyhydroxy compounds in cosmetics. This method effectively addresses the current issue of inadequate detection of polyhydroxyl compounds in cosmetics.

Teaching Research
Open experiment: quantitative proteomics analysis of thyroid-cancer tissue slices using ultra-high performance liquid chromatography-tandem mass spectrometry
LI Yilan, YUAN Huiming, CAO Jingtian, ZHENG Yidi, LI Lan, GAO Peifeng
2025, 43 (3):  275-282.  DOI: 10.3724/SP.J.1123.2024.07009
Abstract ( 47 )   HTML ( 2 )   PDF (2694KB) ( 14 )  

Open experiments play crucial roles in developing undergraduate students’ practical abilities, innovative thinking, and teamwork. This open experiment is designed to use ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in proteomics, a frontier field, by quantitatively analyzing thyroid-cancer-tissue-slice samples. Various reagents are first screened for further study by evaluating their abilities to extract proteins. This approach aims to foster students’ hands-on abilities and their scientific-research thinking. The liquid-chromatography method is subsequently optimized to enable deep-coverage of the proteome, thereby enhancing students’ understanding of liquid chromatography and mass spectrometry. Paraffin-embedded thyroid-cancer-tissue slices are finally subjected to quantitative proteomic analysis, resulting in the identification of 33 differentially expressed proteins, thereby demonstrating their potential use in disease-typing applications. This open experiment integrates theoretical and experimental knowledge gained through instrumental analysis, analytical chemistry, and biochemistry, thereby imparting scientific research thinking and innovative spirit to undergraduates. It also provides students with opportunities to expand and solidify theoretical knowledge through hands-on instrumental operation and experiments, which helps to build a systematic knowledge framework and develop a comprehensive understanding of relevant fields. Moreover, it stimulates undergraduate interest in scientific research, cultivates innovative thinking, and fosters team cooperation.

Development of an ideological and political education design based on course characteristics: taking high performance liquid chromatography as an example
YANG Huili, TANG Gangfeng, LEI Jie
2025, 43 (3):  283-288.  DOI: 10.3724/SP.J.1123.2024.04008
Abstract ( 115 )   HTML ( 2 )   PDF (847KB) ( 63 )  

In response to the problems of the easy repetition of ideological and political education cases and the difficulty of evaluating ideological and political education, this study takes the classic experimental method of high performance liquid chromatography as an example to carry out the teaching practice of ideological and political education based on the characteristics of the course. First, the aim of the experiment, that is, the determination of preservatives and sweeteners in food, was introduced. Next, the specific practice processes, including case significance, case introduction, case implementation, case expansion, and effectiveness assessment, of two types of ideological and political programs, namely, universal and specialized cases, were introduced. Universal cases consider the importance of instrumental analytical experiments, while specialized cases consider the localization of high performance liquid chromatographs. We adjusted the ideological and political content of the instrumental analytical experimental course according to the course progress and actual experience of students, and integrated ideological and political education into the curriculum in stages. In addition to the functions of value guidance and ideological education, the role of ideological and political programs in promoting professional knowledge learning and innovation ability training was strengthened. We recommend that the effectiveness of ideological and political education be evaluated by mastering professional knowledge and improving innovative abilities.

Comprehensive instrumental analysis experiment: determination of gallium using inductively coupled plasma mass spectrometry
ZHENG Haijiao, ZHAO Yaming, WU Xiaofeng, XU Hai, JIA Qiong
2025, 43 (3):  289-294.  DOI: 10.3724/SP.J.1123.2024.04025
Abstract ( 53 )   HTML ( 2 )   PDF (1442KB) ( 17 )  

“Admiring the lofty mountains, one realizes their own lack of talent.” To further promote the implementation of new curriculum standards, a comprehensive instrumental analysis experiment was designed. Metabolomics, an emerging technology developed after genomics and proteomics, is an important part of systems biology. This study aims to explore the applications of metabolomics in the fields of environment and health. Sample pretreatment technology and detection methods for separating and enriching gallium were chosen through a literature review and group discussion. Students then experimentally analyzed the changes in metabolite content in cells cultured with metal-anticancer gallium drugs, which helped them understand the widespread application of metabolomics in the fields of environment and health. Additionally, material characterization was conducted using X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TG), and the gallium metal in metabolites was qualitatively and quantitatively analyzed using inductively coupled plasma mass spectrometry (ICP-MS). During discussions of this experiment, the teacher guided students in using large-scale instruments to solve problems comprehensively, fostering a research-based teaching approach to build a solid foundation for conducting efficient instrument analysis and comprehensive experiments within the classroom in future.