连续样条小波变换用于分解重叠峰的研究

以B-样条小波为分析小波，提出了用于分析化学重叠信号解析的新方法——连续样条小波变换，结果表明：连续样条小波变换应用于分析化学信号的处理，能使峰变窄同时还能提高信号的信噪比，是一种新型有效的重叠信号解析方法，能从含噪声重叠信号中直接得到重叠峰的峰数目及其相应的峰位置。     

直观推导式演进特征投影法解析多环芳烃的重叠色谱峰

用高效液相色谱法(HPLC)测定多环芳烃时,因芴、苊和菲,茚(1,2,3-cd)芘和苯并(g,h,i)苝的色谱峰严重重叠而影响测定结果。本研究用高效液相色谱-二极管阵列检测器(DAD)和荧光检测器(FLD)测定多环芳烃,在激发波长λex=230nm,发射波长λem=300～500nm范围内采集重叠峰的HPLC-FLD二维色谱数据,再用直观推导式演进特征投影法(HELP)解析它们的重叠色谱峰,分辨结果令人满意。该方法对重叠组分的分辨下限为0.02mg/L。结果表明,用二维色谱荧光数据解析色谱重叠峰,灵敏度更高,可用于环境样品中多环芳烃的测定。     

Study on spline wavelet self‐convolution in filtering and resolving overlapped voltammetric signals simultaneously

The normal distribution function is used as resolving factor and spline wavelet self‐convolution is used to resolve the overlapped peaks containing noise. The resolution of several kinds of overlapped peaks (SNR from 5 to 50) simulated by computer has been discussed in details. It is known that the overlapped peaks with noise can be separated (SNR > 50) directly and the noise is removed at the same time in time domain. Base‐line separation can be achieved. The relative errors of peak area and position are less than 5.0%. The satisfactory results are also obtained in resolving voltammetric overlapped signals by this method.     

Resolving overlapped spectra with curve fitting

A novel method of curve fitting based on Gaussian function, which is used to resolve the overlapped peaks, is presented in this paper. The resolution of several kinds of overlapped peaks with noise simulated by computer has been performed and discussed in details. This method has been used for resolving of the UV-vis overlapped spectrum. The results indicate that the proposed algorithm can been used to resolve overlapped spectra effectively and satisfactorily.     

一种基于光谱分析的二元不完全重叠色谱峰的分离解析方法

基于二极管阵列检测器获得的色谱-光谱数据,建立了一种二元不完全重叠液相色谱峰的解析方法: 色谱数据经过去噪、归一化处理后,计算各时间点的光谱差异并进行系统聚类分析,提取特征光谱后,利用非负最小二乘法对色谱-光谱矩阵进行解析,得到基于特征光谱的流出曲线,进而得到分离后的色谱峰。将解析结果和纯标样的色谱峰进行比较,解析后的光谱图和纯标样的光谱图无显著差异,保留时间相差小于0.01 min。实验结果表明,该方法在二元不完全重叠液相色谱峰的解析方面能取得良好的效果。     

Computerized separation of chromatographically unresolved peaks

A computerized peak deconvolution software and mass spectra were successfully applied for the deconvolution of overlapped peak cluster in the chromatogram obtained separating the complex mixture of pesticides by retention time locking gas chromatography-mass spectroscopy. The method based on the unique fragment ions in the spectra can be used for deconvolution of peak clusters if mass spectra of overlapped peaks differ. This method allows determining actual retention times of overlapped peaks. Peak areas found by this method however, cannot be used naturally for the quantitative purposes as the abundance of fragment ions used for this deconvolution procedure can dramatically differ. Computer assisted deconvolution of peaks in the peak clusters gives more realistic peak area ratios as at this method it is supposed equal response for all peaks overlapped in a cluster.     

GC-MS Assisted with Chemometric Methods Applied for Investigation of Migration Behavior of Phthalate Plasticizers in Fatty Foods Simulant

PVC films with different thickness and different contents of 9 phthalate plasticizers (PAEs) were manufactured according to a uniform design method. The migration contents of PAEs in isooctane, which was set as a fatty foods simulant, were first determined using GC-MS analysis. It was found that the chromatographic peaks of diisononyl ortho-phthalate (DINP) and diisodecyl ortho-phthalate (DIDP) very considerably overlapped, with a lower signal to noise ratio (SNR). For resolution of the noisy overlapped peaks, twice continuous wavelet transform (CWT) was adopted. Then, the migration models of PAEs were obtained by the non-negative least squares method (NNLS). The results show that the noisy overlapped peaks were successfully resolved with increasing the SNR 10 times; the migration ratio of the 9 PAEs at 70 °C are located with the range 0.0556–0.3383 %; the migration amount of a specific plasticizer is proportional to its content and some coexisting plasticizers; temperature is a significant impact factor for the migration process. The proposed chemometric-assisted GC-MS analysis provides a new approach for investigation of this complex process.     

Deconvolution of overlapped peaks based on the exponentially modified Gaussian model in comprehensive two-dimensional gas chromatography

Comprehensive two-dimensional gas chromatography (GC x GC) has attracted much attention for the analysis of complex samples. Even with a large peak capacity in GC x GC, peak overlapping is often met. In this paper, a new method was developed to resolve overlapped peaks based on the mass conservation and the exponentially modified Gaussian (EMG) model. Linear relationships between the calculated sigma, tau of primary peaks with the corresponding retention time (tR) were obtained, and the correlation coefficients were over 0.99. Based on such relationships, the elution profile of each compound in overlapped peaks could be simulated, even for the peak never separated on the second-dimension. The proposed method has proven to offer more accurate peak area than the general data processing method.     

Application of wavelet transforms and an approximate deconvolution method for the resolution of noisy overlapped peaks in DNA capillary electrophoresis

A new procedure for resolving noisy overlapped peaks in DNA separations by capillary electrophoresis (CE) is developed. The procedure combines both a wavelet-based denoising method that effectively denoises the signal and a novel approximate deconvolution technique that resolves the fragment peaks and improves the ability to separate highly overlapped peaks early in the electrophoresis process. Different kinds of overlapped peaks with and without noise simulated by computer as well as some DNA experimental electropherograms were submitted to the new procedure. A second order differential operator with variable coefficients is applied to the entire electrophoresis signal at any given time and approximate deconvolutions of the individual Gaussian peaks are performed. The operator incorporates the effect of the superposition and gives exact annihilation in the neighborhood of each peak. Overlapped peaks with a resolution higher than 0.46 can be resolved directly. Also, the method can determine the peak components of signals with a signal to noise ratio higher than 1.4     

基于峭度的重叠峰解析新方法

峭度是表征曲线陡峭程度的物理量。本实验提出了基于峭度的组分分析(component analysis based on kurtosis,CABK)方法来解析重叠峰,从中分离出纯组分信息。这种新方法的优点在于半盲源分离。即只要判断出重叠峰所含组分的数目,就可从混合谱中分离出各组分的纯谱信息。将它用来解析模拟两组分重叠峰体系和酒样的GC-MS混合谱,得到了令人满意的结果。     

交互移动窗口因子分析法(AMWFA)用于二维数据重叠色谱峰的比较分析

采用交互移动窗口因子分析法(AMWFA), 通过挖掘两个体系中的选择性信息, 获得了不同样本间的共有组分数, 还同时得到了各物质对应的光谱或质谱信息. 详细阐述了本法的原理和计算方法, 并用一个模拟的GC-MS 数据对方法进行了验证.     

基于稀疏模型的气相色谱-质谱数据解析及其在严重重叠峰解析中的应用

提出一种气相色谱-质谱（GC-MS）数据解析算法。以色谱峰顶点处的质谱作为待测谱,在谱库中检索一定量相关参考谱,求解关于各纯组分色谱响应值的方程。质谱检索采取分步策略,先利用质谱碎片规律建立高速索引进行粗选,然后使用强峰高概率出峰准则和耐挤压性准则排除无关质谱。为求解色谱响应值方程,提出基于稀疏模型的回归算法,相比传统算法,稀疏算法利于提取待测谱的主要结构,避免"过拟合"。实验结果表明,该质谱检索算法具有较高的精度和规模较小的剩余参考谱集,而所提稀疏模型算法可有效解析严重重叠峰。该算法可作为GC-MS重叠峰解析,特别是严重重叠峰解析的一种有效解决方案。     

2nd-order spline wavelet convolution method in resolving chemical overlapped peaks

A 2nd-order spline wavelet convolution method in resolving overlapped peaks is developed. It determines the number of peaks, peak positions and width through wavelet's convolution, then uses spline function to construct the resoluter, which is used to resolve overlapped peaks. Theoretical proof is given, and the selections of wavelets and parameters are discussed. It is proven that baseline separation can be achieved after processed, the relative errors of peak position and area are less than 0.2% and 4.0% respectively. It can be directly applied to seriously overlapped signals, noisy signals and multi-component signals, and the results are satisfactory. It is a novel effective method for resolution.     

分数导数结合傅里叶最小二乘拟合处理含噪音的重迭信号

提出了一种含噪音重迭信号的综合处理方法 :先用傅里叶最小二乘法拟合噪音数据 ,然后对拟合后的信号求 2 .5次导数 ,在对模拟数据研究的基础上 ,讨论了求导后峰位漂移及其影响因素 ,给出了一个用于矫正峰位值的经验公式。用该方法对模拟和实际的紫外含噪音重迭信号进行处理 ,结果良好     

Resolution of overlapped chromatograms by means of the kalmam filter : Data Processing of Liquid Chromatographic Signals without Solvent Peaks

If several samples are injected successively at short intervals into a liquid chromatograph, overlapped chromatograms of the samples will result. This paper describes an application of this successive-injection method to determination of samples without solvent peaks. Twenty peaks in the overlapped chromatograms resulting from five successive injections of samples with four components (phenetole, biphenyl, pyrene and perylene) were resolved and quantified by a reduced four-dimensional Kalman filter. The period of the single chromatogram of the four components is ca. 14 min, and the period of the five overlapped chromatograms ca. 26 min, for injection intervals of 3 min. The calibration lines for the four components are all straight and satisfactory; the slope, A, of every line was 1.005>A>0.9996 with correlation coefficients better than 0.999992. This successive-injection method with the reduced Kalman filter is time-saving for trivial routine work.     

二极管阵列检测高效液相色谱重叠峰的双波长分析方法

把光度分析的双波长法应用于二极管阵列检测高效液相色谱重叠峰的数据处理。对于色谱峰严重重叠的双组分,只要它们的紫外可见吸收光谱有差异,就可通过计算两个波长下的峰面积（其中一个组分在这两波长时的峰面积之比为常数ｋ,并通过计算另一个组分在ｋ比例系数下的两波长峰面积差）进行定量测定。检测了混合硝基苯类化合物,结果令人满意。     

Resolution of Overlapped Capillary Electrophoresis Peaks by Using Heuristic Evolving Latent Projections to Quantify Chloroquine Phosphate and Promethazine Hydrochloride

Chloroquine phosphate and promethazine hydrochloride are two main components in compound reserpine tablets. It is difficult to separate the two compounds with capillary electrophoresis (CE). Heuristic evolving latent projections (HELP) is a chemometric algorithm which is suitable for resolving overlapped peaks from CE and HPLC. In this paper, HELP was applied to resolving the completely overlapped peaks of chloroquine phosphate and promethazine hydrochloride from CE. Mathematical separation and satisfactory quantification results can be achieved easily without too much time involved in the procedure.     

高效毛细管电泳－电荷耦合器件检测器联用技术研究 Ⅴ．重叠电泳峰的多元线性回归多组分分析

使用多元线性回归方法，处理电荷耦合器件多波长荧光检测毛细管电泳装置得到的三维电泳图，将在电泳时未达到有效分离、重叠严重的混合物电泳峰，分解成单个组分的电泳峰，可进行有效的定性定量分析。该法用于电泳峰完全重叠的混合罗丹明荧光染料样品，结果令人满意。     

Continuous wavelet transform and its application to resolving and quantifying the overlapped voltammetric peaks

In order to resolve and quantify the overlapped peaks of voltammetry that can be described by sech²-function, continuous wavelet transform (CWT) is employed. Through CWT by using Marr wavelet, qualitative and quantitative analysis for the mixed solution of Cd(II) and In(III) can be performed from unresolved square wave voltammogram (SWV) and relevant theoretical basis is provided. A new method to construct the baseline for quantitative determination is also proposed. The results of analysis indicate that the overlapped voltammogram can be resolved and quantified effectively, conveniently and satisfactorily via CWT.     

Maximum spectrum of continuous wavelet transform and its application in resolving an overlapped signal

To estimate the number of peaks and to find the individual peak positions in an overlapped signal, a new method called maximum spectrum of continuous wavelet transform (MSCWT) was developed by extracting the maximum coefficients of continuous wavelet transform (CWT). The peak position in MSCWT was the same as that in its original signal. In this process, CWT was performed not on a single dilation but on an appreciation dilation range. To obtain such a range, a new criterion was introduced to choose a center dilation, which was used to form the dilation range. If Cdilation denoted the center dilation, the proper dilation range was [Cdilation -6 +/- 2, Cdilation +1 +/- 1]. The Mexican Hat function was an analytical wavelet. Utilizing the information of the peak number and the position detected by MSCWT, a fitting route was performed to recover the original signal. One simulated and four true overlapped signals, including high performance liquid chromatography (HPLC), ultraviolet-visible (UV) spectrum, and differential pulse voltammetric (DPV), were processed, and the results indicated that MSCWT could detect an overlapped peak number and position, and the curve fitting based on information of MSCWT had a higher accuracy. The proposed method was an efficient one in resolving different types of overlapped signals.