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.

Volatile Organic Compounds in Human Breath

A comprehensive analysis of volatile organic compounds (VOCs) from the exhaled breath sample is termed as breathomics. Breath samples are a complex mixture composed of a multitude of VOCs and other molecules. The analysis of total VOCs in exhaled breath provides a promising tool for the diagnosis of many diseases because it enables the observation of biochemical processes in the body in a non?invasive way. VOCs are produced in various physiological and pathophysiological conditions thus making it a potential biomarker for several diseases.

Breath acetone: trends in techniques and its potential clinical applications in diabetes management / 国际生物医学工程杂志

Human exhaled gases contain thousands of trace amounts of trace volatile organic compounds (VOCs), some of which are endogenous substance and can be detected as potential biomarkers for disease. Acetone, the second highest VOCs in human exhaled gases, has been widely used in non-invasive diagnosis and monitoring of diabetes. At present, more than 30 independent studies have been undertaken on the range of breath acetone concentration and its influencing factors, and the quantitative relationship between blood glucose and glycosylated hemoglobin in diabetic patients. However, there are still many challenges in the application of breath acetone as a clinical regulatory parameter for diabetes. In this paper, the research status and progress in the breath acetone and analysis method were reviewed, and the existing problems in diabetes diagnosis and monitoring were discussed. Besides, the future development prospects were analyzed with the present technical level.

Proton Transfer Reaction Time-of-Flight Mass Spectrometry for Detection of Trace Volatile Organic Compounds in Breath / 分析化学

Based on the modification of inlet of a proton transfer reaction time of flight mass spectrometry ( PTR-TOF-MS) instrument developed in our laboratory, a new method for real-time and on-line quantitation of volatile organic compounds ( VOCs) from human exhalation was established. A 28-day real-time and on-line monitoring of exhaled breath from 23 volunteers (11 male healthy subjects, 11 female healthy subjects and 1 stomach-sick patient) was carried out and the experimental results showed that the major potential VOCs markers were identified as formaldehyde, propylene, acetone, acetaldehyde, isopropanol and isoprene, and their concentrations obeyed the Normal Distribution. The concentrations of formaldehyde, propylene and isopropanol were mainly in the range of 40 to 100 ppb, acetaldehyde in the range of 80 to 180 ppb, acetone in the range of 500 to 1500 ppb, and isoprene in the range of 8 to 20 ppb. Meanwhile, the concentrations for some compounds were different for men and women. Men have higher level of acetone, and women have higher levels of acetaldehyde and isopropanol. In addition, the concentrations of formaldehyde and acetone in the exhaled breath of stomach sicknesses were significantly higher than that in healthy people. Ethanol and acetaldehyde were the main potential markers of exhale breath after drinking alcohol. The acetaldehyde was the major metabolite of ethanol, and the concentration of acetaldehyde changed with the concentration variation of ethanol in degradation process.

Within-breath respiratory impedance and airway obstruction in patients with chronic obstructive pulmonary disease

OBJECTIVE: Recent work has suggested that within-breath respiratory impedance measurements performed using the forced oscillation technique may help to noninvasively evaluate respiratory mechanics. We investigated the influence of airway obstruction on the within-breath forced oscillation technique in smokers and chronic obstructive pulmonary disease patients and evaluated the contribution of this analysis to the diagnosis of chronic obstructive pulmonary disease. METHODS: Twenty healthy individuals and 20 smokers were assessed. The study also included 74 patients with stable chronic obstructive pulmonary disease. We evaluated the mean respiratory impedance (Zm) as well as values for the inspiration (Zi) and expiration cycles (Ze) at the beginning of inspiration (Zbi) and expiration (Zbe), respectively. The peak-to-peak impedance (Zpp=Zbe-Zbi) and the respiratory cycle dependence (ΔZrs=Ze-Zi) were also analyzed. The diagnostic utility was evaluated by investigating the sensitivity, the specificity and the area under the receiver operating characteristic curve. ClinicalTrials.gov: NCT01888705. RESULTS: Airway obstruction increased the within-breath respiratory impedance parameters that were significantly correlated with the spirometric indices of airway obstruction (R=−0.65, p<0.0001). In contrast to the control subjects and the smokers, the chronic obstructive pulmonary disease patients presented significant expiratory-inspiratory differences (p<0.002). The adverse effects of moderate airway obstruction were detected based on the Zpp with an accuracy of 83%. Additionally, abnormal effects in severe and very severe patients were detected based on the Zm, Zi, Ze, Zbe, Zpp and ΔZrs with a high degree of accuracy (>90%). CONCLUSIONS: We conclude the following: (1) chronic obstructive pulmonary disease introduces higher respiratory cycle dependence, (2) this increase is proportional to airway obstruction, and (3) ...

Exhaled volatile organic compounds detection in cancer diagnosis / 国际肿瘤学杂志

Volatile organic compounds (VOCs) are organic chemicals which can exist in the form of vapor at room temperature.Endogenous VOCs can be produced by different biochemical processes in the human body.They can be transfered to lung through bloodstream and released through breath.Many researches show that exhaled VOCs can be significantly changed when people suffering cancers or inflammation. Detecting exhaled VOCs through instrument with high sensitivity make it possible to detect cancers in early phase in a noninvasive and rapid way,which reduce the suffering of patients.In conclusion,exhaled VOCs detection is a promising method for early diagnosis of cancers.

Spectral analysis of respiratory flow and gas concentrations / Análise espectral de fluxo e concentrações de gases respiratórios

In this research we obtained samples of human respiratory flow, oxygen concentration and carbon dioxide concentration signals from 20 healthy subjects and evaluated the average power spectral density (PSD) of these signals. For each subject,the respiratory samples were acquired in four progressive levels of exercise in a cycle ergometer. Auto regressive moving average models were designed to represent the PSD found in each phase. An average PSD of the four levels was also calculated. Results have shown that the bandwidth of O2 concentration, CO2 concentration and flow signals was 8  Hz, 7 Hz, and 15  Hz, respectively, within the dynamic range of 50  dB. The PSD curves found can be used for optimal filter design for signal enhancing in fast on-line measurement of these signals.

Nesta pesquisa foram registradas amostras dos sinais respiratórios de fluxo, concentração de oxigênio e concentração de gás carbônico em 20 voluntários saudáveis. A densidade espectral de potência (DEP) média foi então calculada. Para cada voluntário, as amostras dos sinais foram registradas em quatro intensidades progressivas de esforço físico em uma bicicleta ergométrica. Para representar a DEP encontrada em cada fase foram ajustados modelos auto-regressivos de média móvel. Uma DEP média entre as quatro intensidades também é fornecida. Os resultados mostraram que as larguras de banda dos sinais de concentração de O2, concentração de CO2 e fluxo foram 8  Hz, 7  Hz e 15  Hz, respectivamente, dentro de uma faixa dinâmica de 50  dB. As curvas de DEP encontradas podem ser usadas em projetos de filtros ótimos para equalização destes sinais em medições em tempo real.