high performance liquid chromatography

摘要： The health-promoting properties and chemical profiles of 30 Jew’s ear mushroom varieties were investigated. The antioxidant properties were determined by ferric reducing antioxidant power(FRAP), 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical scavenging, 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) free radical scavenging, and metal chelating ability(MCA) assays, while phenolic profiles were determined by total phenol content(TPC) and total flavonoid content(TFC) colorimetric assays. Total carbohydrate, β-glucan, and melanin contents were determined by colorimetric methods. 5’-Nucleotides, vitamin D_(2), ergosterol, and ergothioneine contents were determined by high performance liquid chromatography(HPLC). Anti-inflammation activities of Jew’s ear were evaluated by the colorimetric protease inhibitory method. The results showed that Jew’s ear mushrooms possessed substantial phenolics and antioxidant properties. All the Jew’s ear varieties contain high amount of total carbohydrate, β-glucan, reducing sugar, melanin, pectin, vitamin D2, ergosterol, and ergothioneine. The current findings could provide scientific information for breeders to nurture desired varieties and for food industry to develop new health promoting products.

摘要： The modification of high-performance liquid chromatography parameters leads to a more effective oligonucleotide-A purification process. Using various experimental parameters such as buffer, concentration, and pH, a method for optimizing the purification of an oligonucleotide-A on a reverse-phase C18 column was created. To purify oligonucleotide-A, High-Performance Liquid Chromatography (HPLC), Ultraviolet-Visible Spectrophotometry (UV-Vis), Liquid Chromatography-Mass Spectrometry (LC-MS), and lyophilization were used. Chromatographic data were collected with a semi-prep HPLC system, quantified with the UV-Vis technique, and validated with the LC-MS method. The most optimized parameters found to obtain the purity of 93.0% are 40 mM triethylammonium bicarbonate (TEAB) buffer with pH 7, which is approximately 6.0% higher than the reported method of which the purity is 87.0%. However, the yield under these conditions was reduced by about 5%. The worst possible optimized settings that resulted in the lowest purity (84.0%) and yield (69.0%) are 10 mM ammonium acetate (NH4CH3CO2) with pH 7.

摘要： Resistant cultivar deployment is an effective method for cereal aphid management.Under greenhouse conditions,preliminary antibiosis resistance screening was conducted on 114 Ethiopian and 22 Chinese spring wheat accessions.After performing a bioassay to determine antibiosis resistance,aphid feeding behaviour and phenolic acid content analyses were performed on the aphid resistant wheat accessions by electrical penetration graph(EPG)and high performance liquid chromatography(HPLC),respectively.Among the wheat accessions,two high resistances,27moderate-resistances,and 35 low-resistances to Sitobion miscanthi were identified.The antibiosis resistance test showed prolonged pre-adult and pre-reproductive periods,shorter reproductive periods,lower fecundity,an intrinsic rate(rm)of increase,and a finite rate(λ)of increase of S.miscanthi on Lunxuan 145,Wane,Lunxuan 6,204511,Lunxuan 103and 5215 than those on the aphid-susceptible accession Beijing 837.The changes for the parameters of aphid feeding behaviour,including spending a longer time in the penetration and phloem salivation phases and less time in the phloem sap-feeding phase on the resistant wheat accessions,indicated that the aphid resistance may occur during the phloem phase and may be due to difficulties in the mechanical probing of the mesophyll cells.Additionally,the HPLC analysis showed higher contents of:1)ferulic acid in Lunxuan 145,Lunxuan 103 and Lunxuan 6;2)p-coumaric acid in Lunxuan145;3)vanillic acid in Lunxuan 145,Wane and Lunxuan 6;4)syringic acid in Lunxuan 103;and 5)caffeic acid in 5215.The contents of some phenolic acids within wheat leaves,such as p-courmaric acid and vanillic acid showed significant positive correlation with the duration of aphid development,but negative correlation with the aphid fecundity.The concentrations of these acids may be the causes of antibiosis resistance to S.miscanthi.The identification of grain aphid-resistant wheat accessions in our study will be helpful in future breeding program for pest control.

摘要： For identifying and quantifying prohibited substances,solid-phase microextraction(SPME)continues to arouse interest as a sample preparation method.However,the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography(HPLC)systems.Only octadecyl(C18)and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this purpose.To address this situation,the present study evaluated 12 HPLC-compatible coatings,including several chemistries not currently used in this application.The stationary phases of SPME devices in the geometry of thin filmcoated blades were prepared by applying silica particles bonded with various functional ligands(C18,octyl,phenyl-hexyl,3-cyanopropyl,benzenesulfonic acid,and selected combinations of these),as well as unbonded silica,to a metal support.Most of these chemistries have not been previously used as microextraction coatings.The 48 most commonly misused substances were selected to assess the extraction efficacy of each coating,and eight desorption solvent compositions were used to optimize the desorption conditions.All samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass spectrometry.This evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the analytes.Ultimately,using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.

摘要： Objective: To analyze the effect of spectrofluorimetry and highperformance liquid chromatography in the detection of aflatoxin in Chinese medicinal materials. Methods: The content of aflatoxin in Chinese medicinal materials was determined by spectrofluorimetry and high-performance liquid chromatography respectively, and the effects of the two detection methods were compared. Results: The results of sample detection by spectrofluorimetry showed that except for Angelica and Sophora flavescens with "detection dada error", the other 25 kinds of Chinese medicinal materials were positive for aflatoxin, but the types of aflatoxin derivatives could not be distinguished, and the tested content was generally high. The recovery experiment of mixed reference substance based on the concentration levels showed that the recovery rate of aflatoxin was 93.60%-99.70% in the case of high-performance liquid chromatography,and the RSD was 1.83%-6.70%. The sample detection results by high-performance liquid chromatography showed that among the 18 kinds of Chinese medicinal materials,only Radix Peucedani, almond, barley, raw Jianqu and aflatoxin were positive, and the types of aflatoxin derivatives could be accurately differentiated. Conclusion: Compared with spectrofluorimetry, high-performance liquid chromatography is more accurate in the determination of aflatoxin content in Chinese medicinal materials, which can distinguish the types of aflatoxin derivatives.

摘要： [Objectives]This study was conducted to compare the accuracy and detection speed of high performance liquid chromatography for determining the content of doxycycline hydrochloride in doxycycline hydrochloride soluble powder under different chromatographic conditions, in order to improve the level of laboratory testing. [Methods] Four sets of experiments were designed through a cross-test method. The contents of doxycycline hydrochloride in the raw materials of doxycycline hydrochloride and doxycycline hydrochloride soluble powder were determined by changing the chromatographic column and mobile phase conditions, and the feasibility and practicability of the four methods were judged by comparing the detection results through data and chromatographic signal processing. [Results] The content of doxycycline hydrochloride in finished doxycycline hydrochloride soluble powder and the raw materials of doxycycline hydrochloride could be accurately determined under the four chromatographic conditions, of which the experimental group using Agilent C18 column and the mobile chromatography conditions of finished doxycycline hydrochloride soluble powder had the shortest retention time. [Conclusions] The high performance liquid chromatography method using Agilent C18 chromatographic column and mobile phase chromatographic conditions of finished doxycycline hydrochloride soluble powder products can quickly and accurately determine the content of doxycycline hydrochloride in doxycycline hydrochloride soluble powder.

摘要： Aflatoxin B1 is a mycotoxin that can contaminate a wide feedstuffs variety. Ingestion of contaminated feed by poultry can lead to impaired health and zootechnical performances but also a human diet safety problem related to residues presence in animal origin products. Aflatoxin B1 contamination of poultry feed samples marketed in Dakar city and in peri-urban areas (Gorom, Sangalkam) was studied. A total of 15 samples were collected from Dakar city markets as well as from poultry farms in Gorom and Sangalkam areas. Aflatoxin B1 quantification was performed by high performance liquid chromatography and thin-layer chromatography. HPLC results showed that all samples were contaminated with levels ranging from 0.15 to 22 ppb, 0.099 to 2.05 ppb and 0.099 to 4.95 ppb respectively for Gorom, Sangalkam and Dakar. Only the finishing feed from Gorom had an aflatoxin B1 level above the maximum limit set by regulations. TLC is a suitable method for aflatoxins detection. However, it was associated with overestimation for aflatoxin B1 quantification. Results suggest that poultry feed represents a real source of human diet contamination. In addition, HPLC remains the most reliable quantification technique for quality control.

摘要： Objective:To analyze the effect of high-performance liquid chromatography(HPLC)for the determination of azithromycin and to provide references for related research work.Methods:The mobile phase was ammonixim dihydrogen phosphate at 0.067 mol/L(mixed with triethylamine;pH value was adjusted to 6.5).The chromatographic column was Kromasil C18(250 mm × 4.6 mm;5.0μm)and the relative standard deviation(RSD)of the drug content level was 1.25%.The injection volume was set to 20μL,the detection wavelength was set to 210 nm,the external standard method was used to complete the quantitative work,and the theoretical plate number should be more than 1000 according to the drug peak calculation.The effect of HPLC on the determmation of azithromycin was analyzed.Results:The concentration of azithromycin was 1.40-3.40 mg/mL,and the linear relationship was good.RSD of the drug content level was 1.25%.The representative test product had strong stability within 8.0 hours and the method had good repeatability.According to the recovery experiment method,the recovery rates of three standard samples from low to high were 99.87%,100.15%,and 100.62%.The average recovery rate was 100.21%.RSD value was 0.39%.It means that the recovery rate of HPLC is good.Conclusion:In the determination of azithromycin,the use of HPLC to complete the work was of high sensitivity,simple,and fast.The method had good repeatability in the determination of drug components which is worthy of further promotion.

摘要： BACKGROUND Glycated hemoglobin(Hb)(HbA1c)is an indicator that is used to diagnose and monitor the treatment of diabetes.Many factors can affect the detection of HbA1c.One of the most important of these factors is the Hb variant.Here,we report a rare Hb variant and evaluate its effect on HbA1c.CASE SUMMARY A 35-year-old man was suspected of harboring an Hb variant following the measurement of HbA1c with the Variant II Turbo 2.0 Hb detection system during a routine examination.Subsequently,we used the Arkray HA-8160 and ARCHITECT c4000 system to reanalyze HbA1c.Finally,the Hb variant was detected with a Capillary2FP analyzer that operates on the principle of capillary electrophoresis.We also used gene sequencing to investigate the mutation site.The value of HbA1c detected with the Variant II Turbo 2.0 system was 52.7%.However,the Arkray HA-8160 system did not display a result while the ARCHITECT c16000 system showed a result of 5.4%.The Capillary2FP analyzer did not reveal any abnormal Hb zones.However,gene sequencing identified the presence of a mutation in the Hbβ2 chain[CD2(CAC>TAC),His>Tyr,HBB:c.7C>T];the genotype was Hb Fukuoka.CONCLUSION Hb variants could cause abnormal HbA1c results.For patients with Hb variants,different methods should be used to detect HbA1c.

摘要： An understanding of the thermodynamics of the complexation process utilized in sustaining drug release in clay matrices is of great importance.Several characterisation techniques as well as isothermal calorimetry were utilized in investigating the adsorption process of a model cationic drug(diltiazem hydrochloride,DIL)onto a pharmaceutical clay system(magnesium aluminium silicate,MAS).X-ray powder diffraction(XRPD),attenuated total reflectance Fourier transform infrared spectroscopy(ATRFTIR)and optical microscopy confirmed the successful formation of the DIL-MAS complexes.Drug quantification from the complexes demonstrated variable behaviour in the differing media used with DIL degrading to desacetyl diltiazem hydrochloride(DC-DIL)in the 2 M HCl media.Here also,the authors report for the first time two binding processes that occurred for DIL and MAS.A competitor binding model was thus proposed and the thermodynamics obtained suggested their binding processes to be enthalpy driven and entropically unfavourable.This information is of great importance for a formulator as care and consideration should be given with appropriate media selection as well as the nature of binding in complexes.