Breath-by-breath measurement of exhaled ammonia by acetone-modifier positive photoionization ion mobility spectrometry via online dilution and purging sampling / 药物分析学报

Exhaled ammonia(NH3)is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH3 with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH3 product ion peak of(C3H6O)4NH4+(K0=1.45 cm2/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C3H6O)2H+(K0=1.87 cm2/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH3 qualitative identification.Moreover,the interference of high humidity and the memory effect of NH3 molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92 μmol/L with a response time of 40 ms was achieved,and the exhaled NH3 profile could be synchronized with the concentration curve of exhaled CO2.Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH3 of healthy subjects,demon-strating its great potential for clinical disease diagnosis.

Effect of Different Drying Methods on Volatile Components in Pseudostellariae Radix Based on GC-IMS / 中国实验方剂学杂志

ObjectiveTo compare the effects of different drying methods on volatile components of Pseudostellariae Radix. MethodThe samples were dried by different methods， including air drying， sun drying， hot air drying （40， 60， 80 ℃） and vacuum freeze drying. Gas chromatography-ion mobility spectrometry （GC-IMS） was used to compare the changes of volatile components in the samples after different treatments. The samples were incubated at 80 ℃ and 500 r·min-1 for 15 min， the injection temperature was 85 ℃， the injection volume was 200 μL， the flow rate of carrier gas was from 2 mL to 150 mL during 20 min， and the temperature of IMS detector was 60 ℃. SE-54 capillary column （0.32 mm×30 m， 0.25 μm） was used， the column temperature was 60 ℃， and the analysis time was 35 min. The differential spectra of volatile components were constructed and analyzed by principal component analysis （PCA）. ResultA total of 37 volatile components were identified from dried Pseudostellariae Radix. The number of compounds in descending order was ketones， aldehydes and alcohols. There were some differences in the volatile components in samples dried by different methods. And the volatile components in samples with sun drying， air drying and hot air drying at 40 ℃ were similar， compared with other drying methods， vacuum freeze drying and hot air drying at 80 ℃ had great effects on the volatile components of Pseudostellariae Radix， and the compounds in the samples with vacuum freeze drying were the least. ConclusionIn this study， GC-IMS for the detection and analysis of volatile components in Pseudostellariae Radix is established， which has the characteristics of high efficiency， nondestructive inspection and simple sample processing. This method can be used for the distinction of Pseudostellariae Radix dried by different methods. And hot air drying at 40 ℃ can effectively retain the volatile components of Pseudostellariae Radix， and achieve similar flavor to samples with sun drying and air drying.

GC-IMS Analysis of Volatile Components in Rhododendri Mollis Flos at Different Flowering Stages / 中国实验方剂学杂志

Objective:The volatile components of Rhododendri Mollis Flos were determined and the differences of volatile components at different flowering stages were compared and analyzed. Method:Gas chromatography-ion mobility spectrometry （GC-IMS） was used to detect the volatile components in Rhododendri Mollis Flos at different flowering stages （bud stage， initial flowering stage， half-flowering stage， blooming stage and late blooming stage）. GC-IMS spectra combined with cluster analysis， principal component analysis （PCA） and orthogonal partial least squares-discriminant analysis （OPLS-DA） were used to compare the differences and similarities of volatile components in different flowering stages. Result:A total of 70 volatile components in Rhododendri Mollis Flos at different flowering stages were detected， among which 67 were common components， and 47 were identified qualitatively， mainly alcohols， esters and aldehydes. Carveol was a special component at the late blooming stage. The content of alpha-terpineol is the highest at the initial flowering stage， but not at the blooming stage and late blooming stage. The relative contents of the active ingredients ［6-methyl-5-hepten-2-one， nonanal， alpha-terpineol， 1，8-cineole， linalool oxide， 1-octen-3-ol， （<italic>E</italic>）-3-hexenol］ showed a decreasing trend during flowering stages. GC-IMS spectra showed that the samples at different flowering stages had their own characteristic peak regions， and also had common regions. The results of cluster analysis， PCA and OPLS-DA all showed that the samples at different flowering stages were distinguishable. OPLS-DA was used to screen 19 different components to distinguish different flowering stages， including <italic>γ</italic>-butyrolactone， 1，8-cineole， ethyl hexanoate， etc. Conclusion:Rhododendri Mollis Flos samples at different flowering stages can be distinguished obviously， and the active substances in the volatile components are gradually dissipated with the degree of flower opening， which can provide reference for the improvement of material basis and the study of different flowering stages of Rhododendri Mollis Flos.

Effect of Different Hot Air Drying Methods on Chemical Constituents of Trichosanthis Fructus / 中国实验方剂学杂志

Objective:To compare the effects of different drying methods on the chemical constituents of Trichosanthis Fructus. Method:Trichosanthis Fructus was dried by means of air drying， sun drying， hot air drying （40， 60， 80 ℃） and variable temperature drying （50-80， 80-50 ℃）. The contents of nucleosides and flavonoids in Trichosanthis Fructus peels and seeds treated by different methods were compared by high performance liquid chromatography （HPLC）， mobile phase was acetonitrile-0.2% acetic acid aqueous solution （3∶7） （A）-acetonitrile （B） for gradient elution （0-15 min， 97-95%B； 15-30 min， 95%-90%B； 30-35 min， 90%-87%B； 35-40 min， 87%-86.5%B； 40-48 min， 86.5%-97%B； 48-50 min， 97%B）， the detection wavelength was 260 nm， and the flow rate was 0.4 mL·min^-1. Gas chromatography-ion mobility spectrometry （GC-IMS） was used to compare the changes of volatile components in the samples treated by different treatments. The volatile components were incubated on a SE-54 capillary column （0.32 mm×30 m， 0.25 μm） at 80 ℃ and 500 r·min^-1 for 15 min， the injection temperature was 85 ℃， the injection volume was 400 μL， the analysis time was 35 min， carrier gas was high purity nitrogen， the flow rate of carrier gas was 2.0 mL·min^-1， the flow rate of drift gas was 150 mL·min^-1， and the temperature of IMS detector was 45 ℃. Result:The contents of uridine， adenosine and adenine were higher after hot air drying at >50 ℃. Low temperature drying was conducive to maintaining the stability of cytidine， cytosine， rutin， luteolin and 2ʹ-deoxyadenosine. GC-IMS technology could realize the analysis and identification of Trichosanthis Fructus samples after different treatments. There were more volatile components after hot air drying at 80 ℃ and variable temperature drying. Conclusion:Hot air drying at 40 ℃ and 60 ℃ can retain nucleosides and flavonoids， and the volatile components are similar to those in traditional drying methods， which has the advantages of high efficient， controllable and suitable for industrial production.

Analysis of volatile organic compounds (VOCs) fingerprint of raw and honey-fried licorice based on headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS) / 中国中药杂志

Licorice is one of the most commonly used traditional Chinese medicine. In clinic, raw licorice and honey-fried licorice are used in medicines, with the main effects in clearing away heat and detoxifying, moistening lungs and removing phlegm. Honey-fried licorice has effects in nourishing the spleen and stomach and replenishing Qi and pulse. Because traditional Chinese medicine exerts the effects through multiple components and multiple targets, the index components used in the quality evaluation of licorice are often difficult to reflect their real quality. In addition, most of studies for the quality standards have shown that honey-fried licorice are the same as licorice, with a lack of quality evaluation standards that can demonstrate their processing characteristics. The quality of medicine is directly related to its clinical efficacy, so it is necessary to establish a more effective quality control method. Licorice has a beany smell, which is one of the main quality identification characteristics. In this study, by taking advantage of the odor characteristics, a headspace-gas chromatography-ion migration mass spectrometry technology was used to establish a quality evaluation method. A total of 76 volatile components were identified. Through the dynamic principal component analysis, 7 kinds of volatile substances in raw licorice and 13 kinds of volatile substances in honey-fried licorice were statistically obtained, and could be taken as index components for the quality evaluation of raw and honey-fried licorice, respectively. This study could help realize the combination and unification of modern detection and traditional quality evaluation methods, and make a more realistic evaluation for the quality of licorice.

Ion mobility spectrometry: the diagnostic tool of third millennium medicine

SUMMARY Ion mobility spectrometry (IMS) is a fast, low cost, portable, and sensitive technique that separates ions in a drift tube under the influence of an electric field according to their size and shape. IMS represents a non-invasive and reliable instrumental alternative for the diagnosis of different diseases through the analysis of volatile metabolites in biological samples. IMS has applications in medicine in the study of volatile compounds for the non-invasive diagnose of bronchial carcinoma, chronic obstructive pulmonary disease, and other diseases analysing breath, urine, blood, faeces, and other biological samples. This technique has been used to study complex mixtures such as proteomes, metabolomes, complete organisms like bacteria and viruses, monitor anaesthetic agents, determine drugs, pharmaceuticals, and volatile compounds in human body fluids, and others. Pharmaceutical applications include analysis of over-the-counter-drugs, quality assessment, and cleaning verification. Medical practice needs non-invasive, robust, secure, fast, real-time, and low-cost methods with high sensitivity and compact size instruments to diagnose different diseases and IMS is the diagnostic tool that meets all these requirements of the Medicine of the future.

RESUMO A espectrometria de mobilidade iônica (IMS) é uma técnica rápida, de baixo custo, portátil e sensível que separa íons em um tubo de deriva sob a influência de um campo elétrico de acordo com seu tamanho e forma. A IMS representa uma alternativa instrumental não invasiva e confiável para o diagnóstico de diferentes doenças por meio da análise de metabólitos voláteis em amostras biológicas. A IMS possui aplicações em medicina no estudo de compostos voláteis para o diagnóstico não invasivo de carcinoma brônquico, doença pulmonar obstrutiva crônica e outras doenças que analisam respiração, urina, sangue, fezes e outras amostras biológicas. A IMS tem sido usada para estudar misturas complexas, como proteomas, metabólitos, organismos completos como bactérias e vírus, monitorar agentes anestésicos, determinar drogas, produtos farmacêuticos e compostos voláteis em fluidos corporais e outros fluidos. As aplicações farmacêuticas incluem análises de medicamentos sem receita, avaliação de qualidade e verificação de limpeza. A prática médica precisa de métodos não invasivos, robustos, seguros, rápidos, em tempo real e de baixo custo com instrumentos de alta sensibilidade e tamanho compacto para diagnosticar diferentes doenças e a IMS é a ferramenta de diagnóstico que atende a todos esses requisitos da medicina do futuro.

Detection of Amino Acids and Polypeptides by Electrospray Ionization-Ion Mobility Spectrometry / 分析化学

The electrospray ionization-ion mobility spectrometric (ESI-IMS) technique has the potential as an analytical separation tool in analyzing polypeptides and amino acids for fast screening unknown samples in anti-chemical and biological terror attacks. A method for detecting several polypeptides and amino acids was developed based on ESI-IMS using air as drift gas at room temperature. The ion mobility of four amino acids and two polypeptides dissolved in methanol was determined on the system at elution rate of 2 mL/ min. The spectra of these compounds had characteristics of finger-printing maps. The limit of detection of this instrument for Substance P could reach 855 ng / mL in 1 min. The results showed that a small, self-contained ESI-IMS instrument with reservoirs of air could be used to quickly detect and accurately identify polypeptides and amino acids.

Rapid Determination of Four Illegally Added Staining Substances in Safflower by Solid Phase Extraction-Electrospray Ionization-High Performance Ion Mobility Spectrometry / 中国药师

Objective: To establish a fast quantitative detection method for tartrazine, sunset yellow, orange Ⅱ sodium salt and allura red in safflower by solid phase extraction-electrospray ionization-high performance ion mobility spectrometry (SPE-ESI-HPIMS).Methods: The pigments were extracted by 70% ethanol with ultrasonic treatment, and then a polyamide SPE column was used to remove the complex matrix interference in safflower.The purified sample was then dissolved in 90% methanol and analyzed under the optimized IMS parameters.Results: The detection time of all the pigments was less than 20 ms.The limit of detection of tartrazine, sunset yellow, orange Ⅱ sodium salt and allura red was 0.17 , 0.15 , 0.30 and 0.25 μg·ml-1 , respectively.All the pigments showed excellent linearity within the range of 0.5-20 μg·ml-1 (r＞0.990 0), the method recovery was 88.0%-98.9% , and the RSD was 1.5%-5.2% (n =6).Conclusion: The method is rapid, simple, highly sensitive and reproducible, and suitable for the rapid quantitative detection of illegal added staining substances in safflower.

Combination of High Performance Liquid Chromatographywith Nano-electrospray ionization Chirp Z TransformIon Mobility Spectrometry / 分析化学

By combining frequency modulation Chirp Z transform ion mobility spectrometers (IMS) and multi nozzle electrospray array ionization source, a method of NanoESI-Chirp Z transform ion mobility spectrometry-high performance liquid chromatography was developed for the determination of n-alkyl ammonium bromide compounds.The parameters of NanoESI-Chirp Z transform IMS such as electric field intensity, solvent composition, and solution flow rate were investigated and optimized.Subsequently, four kinds of n-alkyl ammonium bromide compounds were respectively detected by this developed Chirp Z transform method and Fourier transform method, and the obtained results were compared.The result indicated that the optimum conditions were electric field intensity of 4.5 kV, and ESI solution flow rate of 8 μL/min.Then a test mixture containing tetrabutylammonium bromide, tetrapentylammoniumbromide, tetrahexylammonium bromide, tetraheptylammonium bromide, tetranoctylammoniumbromideandtetrakis(decyl) ammonium bromide was successfully separated and determined by the HPLC-nanoESI-Chirp Z IMS method.Chirp Z transform method provided higher signal to noise ratio compared to conventional signal averaging method, and was superior to FT method in the determination of drift time.

Rapid detection of Chinese herbal medicine dyed by auramine O, amaranth and sunset yellow by ion mobility spectrometry / 中国药学杂志

OBJECTIVE: To develop a fast detecting method for three dyes (auramine O, amaranth and sunset yellow) illegally added into Chinese herbal medicine by ion mobility spectrometry (IMS). METHODS: The analysis was performed on ion mobility spectrometry, with source voltage 1 800 V for negative source and 2 300 V for positive source, drift tube voltage 7 500 V, gas inlet temperature 180℃, drift tube temperature 180℃, gate voltage 45 V, gate pulse width 120 μs, drift gas flow 1.2 L·min-1, exhaust pump 0.8 L·min-1, run time 30 s and spectrum length 25 ms. The samples were extracted by methanol, and then injected into the IMS system. The judgement of whether dye was added or not was made by comparing the migration time of the test samples with that of the reference substances. RESULTS: The auramine O, amaranth and sunset yellow could be rapidly identified. The minimum detection concentration of each compound was determined according to the signal to noise ratio (S/N) of 3. CONCLUSION: The IMS method for detecting auramine O, amaranth and sunset yellow illegally added into Chinese herbal medicine is simple, rapid and expected to be used as an initial screening method in drug rapid detecting system.

Development of Unidirectional Negative Corona Discharge Ion Mobility Spectrometer for Detection of Explosives / 分析化学

Abstract Ion mobility spectrometry ( IMS) based explosives detectors is wieldy deployed at the check points of airport, etc, so the development of new ionization method to replace the radioactive 63 Ni ion source in IMS is highly demanded. In this study, a novel negative corona discharge was developed for ion mobility spectrometer for rapid detection of trace explosives, which was running in the unidirectional mode to efficiently remove nitrogen oxides and ozone produced from the discharge process. The diameter of target electrode was 3 mm, the distance between the needle and the target electrode was 2 mm, the discharge voltage was 2400 V and the flow rate of drift gas was 1200 mL/min. Under the optimized conditions, the dominant reactant ions was O-2(H2O)n and could be used to directly detect the common explosives, such as trinitrotoluene (TNT), ammonium nitrate (AN), nitroglycerin (NG), pentaerythritol tetranitrate (PETN) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The limit of detection of TNT was 200 pg/μL. These results indicated that negative corona discharge ionization source, with the advantanges of the high sensibility, simple structure and no radioactivity, could be used as a potential and promising ionization source for ion mobility spectrometry to detect explosives.

Detection of Chemical Warfare Agents by Differential Mobility Spectrometry and Drift-time Ion Mobility Spectrometry Hybrid Technology / 分析化学

Using a novel hybrid technology combined differential ion mobility spectrometry ( DMS) with drift time ion mobility spectrometry DMS-IMS2 , we detected the typical chemical warfare agent simulants dimethyl methylphosphonate ( DMMP ) and methyl salicylate ( MS) . With carrier gas 800 mL/min and DMS RF voltage 1100 V, the chemical warfare agents DMMP and MS could be detected and characterized by DMS-IMS2 under DIMS mode. In addition, DMS-IMS2 is capable to monitor positive and negative ions of DMMP and MS simultaneously, and provides the two-dimensional separation parameters DMS compensation voltage ( CV) and IMS drift time ( Td ) , which provides more information for the identification of two chemical warfare agents. DMS-IMS2 has potential application in on-site detection and instrument miniaturization due to its advantages including small size, low power consumption and rapid response time.

Detection of Chemical Warfare Agent Simulants by UV Photoionization High-Field Asymmetric Ion Mobility Spectrometry / 分析化学

Accurate diffusion was used to get low concentrations samples, and then the samples were detected by UV photoionization high-field asymmetric ion Mobility spectrometry ( UV-FAIMS ) . The samples were chemical warfare agent simulants ( CWAS) vapor:dimethyl methylphosphonate ( DMMP ) , dimethyl sulfoxide ( DMSO) , tributyl phosphate ( TBP ) and dimethyl sulfoxide ( DMF) . The results of FAIMS spectra data were analyzed by separation of spectra at different dispersion voltage ( DV ) and compensation voltage ( CV ) . A two-dimensional spectrum of α2 and α4 of CWAS was established. It was shown that FAIMS could identify CWAS well and have a good sensitivity. Take DMMP as a example, the detection limit was better than 0. 55 μg/L.

Detection of Authenticity of Grape Seed Oil with Ion Mobility Spectrometry / 分析化学

A rapid method for authenticity detection of grapeseed oil was proposed based on Ion Mobility Spectrometry ( IMS) . After optimization, the inlet temperature was set at 170 ℃, drift tube temperature was set at 60 ℃. In this method, the oil sample was diluted in hexane (50-fold, V/V) and then directly analyzed in IMS. The detection time was 20 s. To establish an adulteration detection model, recursive Support Vector Machine ( R-SVM) was applied to classifying pure and adulterated grape seed oils. The result of 10-fold cross validation showed that the accuracy of discrimination was up to 91 . 2%. The results in study indicate that IMS method is a new, fast and convenient technique for the adulteration detection of edible oil.