碎片离子

苯环上的取代基团X对分子离子和一些碎片离子的强度有明显的影响：随X电负性的增强，相应离子的强度下降。

The intensity of molecular ions and some fragment ions of all compounds ( 1 ~ 25 ) was closely related to the electronic nature of substituted group X.

结果表明，分子离子的稳定性、基峰的生成方式以及碎片离子的多少主要取决于取代基R的性质。

The stability of molecular ion , the mode of formation of the base peak and the number of fragment ions depend mainly upon the property of substituent group .

用同步辐射研究苯基氰分子的单光子电离与碎解，精确地测量它的电离势、在不同的飞行时间产生的自发的和亚稳态碎片离子的出峰电势（appearancepotential）。

Single photon ionization and fragmentation of benzonitrile is studied using synchrotron radiation . The ionization potential of benzonitrile , and the appearance potentials of spontaneous or prompt and metastable fragment ions for different flight time are measured precisely .

采用数据库搜索方法或者denovo从头解序方法，可从这些碎片离子的m／z值中鉴定出多肽的序列来。

Consequently , the peptides can be identified by these m / z values of ions in tandem spectrum with a sequence database searching or De novo sequencing or the combining of the two above methods .

根据CID技术得到的RDX和HMX的分子离子，加合离子和特征碎片离子，易确定RDX和HMX的结构。

According to the molecular ions , the adduct ions and characteristic fragmentation ions of RDX and HMX obtained by CID technique , the structures of RDX and HMX are easily confirmed .

实验中，从色谱中分离出来的多肽经过CID过程被裂解成碎片离子，这些离子的质量／电荷比值（m／z）被质谱仪器检测到，形成串联质谱。

During experiments , the peptides separated from liquid chromatographers are fragmented and ionized by collision-induced dissociation ( CID ) and the ions are measured by mass spectrometer in mass / charge ratios ( m / z ) .

扫描方式为选择反应监测（SRM），用于定量分析的二级碎片离子m/z分别为327.4（醋酸甲羟孕酮）和325.4（醋酸甲地孕酮，内标）。

The scanner mode was selection response monitor ( SRM ) . The second order fragment ion of monitor was at 327.4 ( medroxyprogesterone acetate ) and m / z 325.4 ( megestrol acetate , internal standard ) .

对经过液相色谱分离后的化合物进行源内碰撞诱导裂解（CID），并对化合物及其碎片离子进行精确质量测定，测定质量与理论质量之间误差不超过2.5mDa。

With in-source collision induced dissociation ( CID ) and exact mass measurement , the differences between the calculated mass and the theoretical mass of all compounds and fragments were less than 2.5 mDa .

一些丹参醌类二萜醌在电子轰击下的裂解反应&关于一种不常见的（M-O）碎片离子的观察

Studies on the fragmentation of diterpene quinones related to tanshinone under electron impact & the observation of an unusual ( m-o ) fragment ion

由于共振增强多光子电离（REMPI）母体离子谱与碎片离子谱的相似性，可用探测总离子信号的方法来替代单独的母离子探测，有效地提高痕量探测的灵敏度。

Similarities in the REMPI spectra of all the ions could lead to greater trace detection sensitivity if the total ion yield is concerned instead of only the parent ions .

7种大环酮的EI电离质谱图有相似的谱态和一些相同的碎片离子，烯丙基离子（m／z41）和烯羰基离子（m／z55）是基峰。

Electron impact mass-spectra of 7 macrocyclic ketones have similar appearance and several same fragment ions , allylic ion ( m / z 41 ) and allylic carbonyl ion ( m / z 55 ) are base peaks .

特丁磷选择监测离子为（m/z231、233、288），其丰度比约为100：14：11。采用选择离子监测（SIM）方式，以峰值最高的碎片离子作为监视离子进行定量分析。

The determination and confirmation were made by means of selected monitoring ions ( SM ) mode , SIM ( m / z ) were 231,233,288 amu ( abundance ratio was 100:14:11 ), using external standard method . The intense fragment ions were chosen as monitoring ions for quantitative analysis .

IBA和JA的标准试剂显示了相同的质谱图形变化，在60V时能得到最强分子离子峰，当电压继续升高时分子离子峰的强度逐渐减弱，并出现一些m/z更小的碎片离子峰。

Both IBA and JA standard chemicals showed almost same changes of mass spectrum pattern . Optimum drift voltage for most intensity was 60 V , as drift voltage increased , the intensity of molecular ion peak decreased and the fragment ion peaks shifted to smaller m / z one .

使用激光多光子电离质谱技术，研究了甲胺分子在425nm～495nm波长范围内共振增强多光子电离碎裂（REMPIF）过程，记录了母体离子和与碎片离子产额与波长的依赖关系。

Laser ionization mass spectrometry is used to study the wavelength dependence of resonance-enhanced multiphoton ionization ( REMPI ) of methylamine , and both the parent and fragment ion yields are recorded in the wavelength range of 425 ￣ 495 nm .

小檗碱质谱碎片离子稳定性分析及碎裂机理的量子化学研究

Stability Analysis of Berberine Fragment Ions by Mass Spectrometry and Quantum Chemistry Studies on Fragmentation Mechanism

利用离子能量损失扫描谱，得到亚稳态碎片离子的衰变曲线。

Decay curves of metastable fragment ions is also obtained by means of ion energy loss scans spectroscopy .

根据HREI数据讨论了主要特征碎片离子的可能裂解途径。

Mass spectra fragmentation of characteristic fragment ions were discussed on the basis of High resolution mass spectra data .

碎片离子中除了芳香化合物通常具有的碎片外，还有反映树脂结构的碎片。

Fragment ions characteristic of resin structure were detected in addition to the aromatic ions generally formed from aromatic compounds .

通过分析碎片离子的m/z值，可以明确表达各肽段的氨基酸序列。

By analysing the m / z values of the fragment ions the sequences of amino acids can be expressed clearly .

同时获得了母体离子A-带的解离寿命，并探讨了碎片离子产牛机理。

The dissociation lifetime of the A-band for the parent molecule is obtained and the mechanisms to form the fragment ions are discussed .

采用高效液相质谱联用法（HPLE-MS）对其指纹图谱的主要特征峰对应的化学成分进行分析和鉴别，发现有相同的分子离子峰[M+H]+（m/z225），易形成碎片离子m/z207。

The fingerprint shows the similar molecule fragments [ M + H ] + ( m / z225 ) of mostly character peaks easily form m / z207 through HPLC - MS.

仪器采用了软电离方式，避免了碎片离子峰的形成，便于对污染环境中挥发性有机物的解析。

A VUV soft ionization source was adopted in the mass spectrometer , which can avoid the formation of fragment ions and analyze volatile organic compounds in ambient air without pre-separation .

采用正离子电离方式，每种化合物选择3个碎片离子为定性离子以获得高选择性，选取每个化合物丰度最高的碎片为定量离子以获得高灵敏度。

For each compound , three fragment ions were selected as qualitative ions to obtain high selectivity , and the most abundant fragment of each com-pound was selected for quantification to obtain high sensitivity .

高锥孔电压的采用能大大提高检测灵敏度，并且得到用于人参皂甙结构鉴定的加合离子和特征碎片离子。

At the high cone voltage , both the molecular weight and structural information ` were obtained from a single mass spectrum . It can also be used for isomer differentiation and structure determination of ginsenosides .

实验结果表明，在280~286.5nm区域内，二甲基硫分子以母体分子的电离通道为主，即首先电离生成母体离子然后母体离子再解离生成碎片离子。

It was shown that the main dissociation channel of dimethyl sulfide is the photoionization of parent molecule firstly in the range of 280 ~ 286.5 ? nm , then followed by photodissociation of parent ion .

根据质谱提供的分子离子和8个特征碎片离子的精确质量和相应的元素组成，提出了阿魏酸分子的裂解途径，结合谱图检索，从而确认该分子的结构。

According to the exact masses and corresponding elemental compositions of molecular ion and eight characteristic ions , a possible fragmentation pathway of the ferulic acid molecule was proposed , by which the molecular structure was confirmed .

此外，还给出了丰富的碎片峰；小分子药物的结构与CID电压对APCI/MS的分子离子峰及碎片离子丰度有明确的影响。

In APCI / MS the structures of small molecular drugs and CID voltage affected their molecular ion peaks and fragment ion peaks obviously .

试样在负离子电喷雾电离（ESI）过程中不产生碎片峰，但是在FAB过程中产生许多碎片，比较这些谱图，就可以区别碎片峰和分子离子峰。

No Sample fragments are found in negative ESI process , but a lot of fragments are almost presented in FAB process . Comparing these spectra , the fragments or molecular ion can be distinguished .