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建立了一种新的基于过程分析技术(PAT)和质量源于设计(QbD)设计空间的中药制药过程终点分析与控制方法.以近红外(NIR)光谱技术为PAT工具, 采集正常操作条件下制药过程的多批次NIR光谱; 采用主成分分析结合移动块相对标准偏差(PCA-MBRSD)法, 确定每一批次过程的理想终点样本(DEPs), 由多批DEPs的光谱信息构成过程终点设计空间; 在过程终点设计空间确定的范围内, 建立多变量统计过程控制(MSPC)模型, 利用多变量Hotelling T2和SPE控制图对过程终点进行判断.应用上述方法, 进行了金银花醇沉加醇过程终点检测研究, 结果表明该方法灵敏、准确, 适宜于中药制药过程终点检测. 相似文献
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基于交互式自模型混合物分析的近红外光谱波长变量优选方法 总被引:2,自引:1,他引:1
为了提高近红外光谱定量分析的预测精度和建模效率,提出了一种基于交互式自模型的混合物分析的波长优选方法,根据光谱各波长变量的纯度值和标准差值,选择含有用信息的波长变量,并引入相关权函数解决变量间共线性问题.通过依次迭代选择的变量建立定量校正模型,由交互验证均方根预测误差(RMSECV)确定最佳波长变量个数.应用该波长变量优选方法对具有不同葡萄糖含量的两组(四成分葡萄糖水溶液实验和人体血浆实验)近红外光谱数据进行分析,两组数据中分别只选择了全部变量的0.3%建立定量校正模型,其验证集葡萄糖浓度的均方根预测误差(RMSEP)分别减少为669和15 mg/L.与全谱范围及优选波段建立的定量校正模型比较,本方法能够通过波长变量优选最小化冗余信息、提高预测精度及建模效率. 相似文献
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结合采样误差分布分析(SEPA)框架和最小角回归(LAR)算法,提出了一种SEPA-LAR变量逐步筛选方法用于波长选择,并建立了稳健的近红外光谱分析模型。利用蒙特卡洛采样(MCS)获得多个数据集划分建立多个模型,对光谱各变量(波长)在所有模型的LAR系数进行统计分析,按其回归系数绝对值总和由大到小排序,选择排序靠前的波长建立偏最小二乘(PLS)模型,以未参与SEPA-LAR和建模的独立验证集对该模型进行评价。将玉米湿度、柴油密度以及奶酪脂肪的近红外光谱数据用于SEPA-LAR的性能检验,独立验证集的预测均方根误差(RMSEP)分别为0.001 44%(湿度指标)、0.001 58 g/mL(密度指标)以及1.13 g/100 g(脂肪含量指标)。结果表明,相较于竞争自适应重加权采样法(CARS),该方法具有更优异的稳定性;相较于移动窗口偏最小二乘(MWPLS)以及蒙特卡洛无信息变量消除(MCUVE)方法,该方法选择的变量更少,预测误差更低,预测性、可解释性和稳定性更优异。 相似文献
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电喷雾萃取电离质谱直接检测人体呼出气体中的乙腈 总被引:1,自引:0,他引:1
人体呼出气体携带大量的生理病理信息,在临床诊断和代谢组学研究中发挥着日益重要的作用。本研究在未对样品进行预处理条件下,采用电喷雾萃取电离质谱(EESI-MS)技术直接测定呼出气体中乙腈分子。在优化的实验条件下,结合多级串联质谱,有效地获得了人体呼出气体中乙腈含量的信息。对气相乙腈的检出限为5.71 pL/L,线性范围为76.4~1910 pL/L。以两名健康志愿者呼出气体为实例,实际检测了其中乙腈的含量分别为134.49和104.40 pL/L,相对标准偏差(RSD)分别为6.3%和7.2%。结果表明,本方法灵敏度高、精密度好、分析速度快、特异性强,能够承受呼出气体中复杂基体的影响,适合于呼出气体中痕量乙腈的直接半定量检测,也可为呼出气体中其它小分子物质的检测提供新思路。 相似文献
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将稳定度自适应重加权采样特征变量选择算法用于支持向量机定性分析(Support vector machine-stability competitive adaptive reweighted sampling,SVM-SCARS)。该算法通过对数据多次采样建模计算各变量的稳定度值,稳定度值能更加客观准确地评估变量在建模中的作用,因此可作为变量重要性的评价依据。通过循环迭代方式,采用自适应重加权采样技术逐步筛选变量,然后以每次循环所得变量子集建立SVM模型,并以模型交叉验证分类正确率(Correct classification rate of cross validation,CCRCV)评估子集优劣,确定最优特征变量子集。将该算法结合漫反射近红外光谱技术建立了制浆造纸常用木材的树种识别模型,实现了对4种桉木和2种相思木的快速识别分类。最终共筛选出15个特征变量建立分类模型,模型对各树种分类的正确率达97.9%,具有较好的分类效果。与全光谱模型和递归特征消除支持向量机模型相比,SVM-SCARS能够筛选出更少的特征变量,且模型具有更好的预测性能和稳定性。研究结果表明,SVM-SCARS算法能够有效优化光谱特征变量,提高近红外在线分析模型在木材材性分析中的稳健性和适用性。 相似文献
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《分析试验室》2017,(7)
采用可见-近红外透射光谱结合CARS变量优选方法优化模型,对棕榈油碘值进行近红外定量分析。通过将使用不同预处理方法产生的建模效果进行比较,找到了理想的预处理方法,通过CARS变量选择方法优选出与棕榈油碘值相关的有效波点共60个,利用60个有效波点建立棕榈油碘值优化模型。根据优化模型的建模集相关系数(R_c=0.9814)和预测集相关系数(R_p=0.9806),得到的建模均方根误差(RM SEC=0.0398)和预测均方根误差(RM SEP=0.0406)优于采用全波段建立的模型得到的系数误差。利用可见近红外透射光谱结合CARS变量优选方法,简化了棕榈油碘值模型,并能够保证碘值预测的准确度。 相似文献
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《Analytical letters》2012,45(12):1910-1921
Multiblock partial least squares (MB-PLS) are applied for determination of corn and tobacco samples by using near-infrared diffuse reflection spectroscopy. In the model, the spectra are separated into several sub-blocks along the wavenumber, and different latent variable number was used for each sub-block. Compared with ordinary PLS, the importance and the contribution of each sub-block can be balanced by super-weights and the usage of different latent variable numbers. Therefore, the prediction obtained by the MB-PLS model is superior to that of the ordinary PLS, especially for the large data sets of tobacco samples with a large number of variables. 相似文献
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Kaisa Raninen Ringa Nenonen Elina Jrvel-Reijonen Kaisa Poutanen Hannu Mykknen Olavi Raatikainen 《Molecules (Basel, Switzerland)》2021,26(9)
Exhaled breath is a potential noninvasive matrix to give new information about metabolic effects of diets. In this pilot study, non-targeted analysis of exhaled breath volatile organic compounds (VOCs) was made by comprehensive two-dimensional gas chromatography–mass spectrometry (GCxGC-MS) to explore compounds relating to whole grain (WG) diets. Nine healthy subjects participated in the dietary intervention with parallel crossover design, consisting of two high-fiber diets containing whole grain rye bread (WGR) or whole grain wheat bread (WGW) and 1-week control diets with refined wheat bread (WW) before both diet periods. Large interindividual differences were detected in the VOC composition. About 260 VOCs were detected from exhaled breath samples, in which 40 of the compounds were present in more than half of the samples. Various derivatives of benzoic acid and phenolic compounds, as well as some furanones existed in exhaled breath samples only after the WG diets, making them interesting compounds to study further. 相似文献
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Changsong Wang Enyou Li Guowang Xu Hui Wang Yulei Gong Peng Li Shujuan Liu Ying He 《Microchemical Journal》2009,91(2):149-152
Fentanyl, a kind of intravenous narcotic analgesic, is widely used in clinical anesthesia. As a potential pollution, it was detected in both the air of the cardiothoracic operating room and patients' expiratory circuit. However, whether the fentanyl in patients' expiratory circuit is exhaled by patients is unknown. In this study, breath samples were taken from the expiratory circuits of anesthetic machine linked to the patients who received intravenous fentanyl, a solid-phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) method was developed to detect and quantify fentanyl in breath samples. The parameters influencing adsorption (extraction time, temperature,) and desorption (desorption time) of the analyte on the fiber were investigated and validated for method development. The developed method was proved to be simple, easy, and inexpensive and offer high sensitivity and reproducibility. Linear range was obtained from 0.05 ng/mL to 0.8 ng/mL. The limit of detection was 0.01 ng/mL while an interday precision of less than 12.13% (n = 5) could be achieved. Six patients were involved in this study; results showed presence of fentanyl in the breath of patients who received intravenous fentanyl, and fentanyl concentrations in breath varied from 6.00 to 20.89 pg/mL. In conclusion, fentanyl can be exhaled by patients who received intravenous fentanyl. 相似文献
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Vasiliki Bessa Kaid Darwiche Helmut Teschler Urte Sommerwerck Thomas Rabis Joerg I. Baumbach Lutz Freitag 《International Journal for Ion Mobility Spectrometry》2011,14(1):7-13
COPD is a disease characterised by a chronic inflammation of the airways and a not fully reversible airway obstruction. The
spirometry is considered as gold-standard to diagnose the disease and to grade its severity. In this study we used the methodology
of Ion Mobility Spectometry in order to detect Volatile Organic Compounds (VOCs) in exhaled breath of patients with COPD.
The purpose of this study was to investigate if the VOCs detected in patients with COPD were different from the VOCs detected
in exhaled breath of healthy controls. 13 COPD patients and 33 healthy controls were included in the study. Breath samples
were collected via a side-steam Teflon tube and directly measured by an ion mobility spectrometer coupled to a multi capillary
column (MCC/IMS). One peak was identified only in the patients group compared to the healthy control group. Consequently,
the analysis of exhaled breath could be a useful tool to diagnose COPD. 相似文献
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Cáp P Dryahina K Pehal F Spanel P 《Rapid communications in mass spectrometry : RCM》2008,22(18):2844-2850
Collection of exhaled breath condensate (EBC) is a relatively simple noninvasive method of breath analysis; however, no data have been reported that would relate concentration of volatile compounds in EBC to their gaseous concentrations in exhaled air. The aim of the study was to investigate which volatile compounds are present in EBC and how their concentrations relate to results of direct breath analysis. Thus, samples of EBC were collected in a standard way from several subjects and absolute levels of several common volatile breath metabolites (ammonia, acetone, ethanol, methanol, propanol, isoprene, hydrogen cyanide, formaldehyde and acetaldehyde) were then determined in their headspace using selected ion flow tube mass spectrometry (SIFT-MS). Results are compared with those from on-line breath analyses carried out immediately before collecting the EBC samples. It has been demonstrated that SIFT-MS can be used to quantify the concentrations of volatiles in EBC samples and that, for methanol, ammonia, ethanol and acetone, the EBC concentrations correlate with the direct breath levels. However, the EBC concentrations of isoprene, formaldehyde, acetaldehyde, hydrogen cyanide and propanol do not correlate with direct breath measurements. Copyright (c) 2008 John Wiley & Sons, Ltd. 相似文献
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David Smith Andriy Pysanenko Patrik Španěl 《Rapid communications in mass spectrometry : RCM》2010,24(7):1066-1074
A study has been carried out of the decay of ethanol in mouth‐exhaled and nose‐exhaled breath of two healthy volunteers following the ingestion of various doses of alcohol at different dilutions in water. Concurrent analyses of sequential single breath exhalations from the two volunteers were carried out using selected ion flow tube mass spectrometry, SIFT‐MS, on‐line and in real time continuously over some 200 min following each alcohol dose by simply switching sampling between the two volunteers. Thus, the time interval between breath exhalations was only a few minutes, and this results in well‐defined decay curves. Inspection of the mouth‐exhaled and nose‐exhaled breath data shows that mouth contamination of ethanol diminished to insignificant levels after a few minutes. The detailed results of the analyses of nose‐exhaled breath show that the peak levels and the decay rates of breath ethanol are dependent on the ethanol dose and the volume of ethanol/water mixture ingested. From these data, both the efficiency of the first‐pass metabolism of ethanol and the indications of gastric emptying rates at the various doses and ingested volumes have been obtained for the two volunteers. Additionally and simultaneously, acetaldehyde, acetic acid and acetone were measured in each single breath exhalation. Acetaldehyde, the primary product of ethanol metabolism, is seen to track the breath ethanol. Acetic acid, a possible secondary product of this metabolism, was detected in the exhaled breath, but was shown to largely originate in the oral cavity. Breath acetone was seen to increase over the long period of measurement due to the depletion of nutrients. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Selected-ion flow-tube mass spectrometry (SIFT-MS) has been used to monitor the volatile compounds in the exhaled breath of 30 volunteers (19 male, 11 female) over a 6-month period. Volunteers provided breath samples each week between 8:45 and 13:00 (before lunch), and the concentrations of several trace compounds were obtained. In this paper the focus is on ethanol and acetaldehyde, which were simultaneously quantified by SIFT-MS using H3O+ precursor ions. The mean ethanol level for all samples was 196 parts-per-billion (ppb) with a standard deviation of 244 ppb, and the range of values for breath samples analysed is 0 to 1663 ppb. The mean acetaldehyde level for all samples was 24 ppb with a standard deviation of 17 ppb, and the range of values for breath samples analysed is 0 to 104 ppb. Background (ambient air) levels of ethanol were around 50 ppb, whereas any background acetaldehyde was usually undetectable. Increased ethanol levels were observed if sweet drink/food had been consumed within the 2 h prior to providing the breath samples, but no increase was apparent when alcohol had been consumed the previous evening. The measured endogenous breath ethanol and acetaldehyde levels were not correlated. These data relating to healthy individuals are a prelude to using breath analysis for clinical diagnosis, for example, the recognition of bacterial overload in the gut (ethanol) or the possibly of detecting tumours in the body (acetaldehyde). 相似文献
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Carolina Lourencetti Pilar Fernández Celia Prado Joan O. Grimalt 《Analytica chimica acta》2010,662(1):23-30
A method for the estimation of the human intake of trihalomethanes (THMs), namely chloroform, bromodichloromethane, dibromochloromethane and bromoform, during showering and bathing is reported. The method is based on the determination of these compounds in exhaled breath that is collected by solid adsorption on Tenax using a device specifically designed for this purpose. Instrumental measurements were performed by automatic thermal desorption coupled to gas chromatography with electron capture detection. THMs in exhaled breath samples were determined during showering and swimming pool attendance. The levels of these compounds in indoor air and water were also determined as reference for interpretation of the exhaled breath results. The THM concentrations in exhaled breath of the volunteers measured before the exposure experiments showed a close correspondence with the THMs levels in indoor air where the sampler was located. Limits of detection in exhaled breath were dependent on THM analytes and experimental sites. They ranged between 170 and 710 ng m−3 in the swimming pool studies and between 97 and 460 ng m−3 in the showering studies. Application of this method to THMs determination during showering and swimming pool activities revealed statistically significant increases in THMs concentrations when comparing exhaled breath before and after exposure. 相似文献
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呼出气检测作为一种潜在的新型临床检测手段受到广泛关注。本文详细综述了人体呼出气中挥发性有机化合物(VOCs)的各类检测方法和技术,分别对色谱法、质谱法和光谱及传感器法的原理、特点和最新研究进展进行了介绍,对照总结了目前已确定的异戊二烯、丙酮等疾病生物标志物的各种分析方法和实测数据,并展望了未来的研究动向。 相似文献
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《Electroanalysis》2018,30(8):1610-1615
Nitric oxide (NO) levels in exhaled breath are a non‐invasive marker that can be used to diagnose various respiratory diseases and monitor a patient's response to given therapies. A portable and inexpensive device that can enable selective NO concentration measurements in exhaled breath samples is needed. Herein, the performance of an amperometric Pt‐Nafion‐based gas phase sensor for detection of NO in exhaled human nasal breath is examined. Enhanced selectivity over carbon monoxide and ammonia is achieved via an in‐line zinc oxide‐based filter. Exhaled nasal NO levels measured in 21 human samples with the sensor are shown to correlate well with those obtained using a chemiluminescence reference method (R2=0.9836). 相似文献