二苯并噻吩及其氧化物与离子液体相互作用的理论研究

采用密度泛函理论方法比较了DBT/DBTO₂和[BMIM]⁺[PF₆]^-/[BMIM]⁺[BF₄]^-的相互作用。对最稳定的[BMIM]⁺[PF₆]^-、[BMIM]⁺[PF₆]^--DBT、[BMIM]⁺[PF₆]^--DBTO₂、[BMIM]⁺[BF₄]^-、[BMIM]⁺[BF₄]^--DBT、[BMIM]⁺[BF₄]^--DBTO₂进行了NBO和AIM分析。结果表明,DBT和[BMIM]⁺[PF₆]^-/[BMIM]⁺[BF₄]^-中的咪唑环彼此相互平行,NBO和AIM分析表明它们之间发生了π-π相互作用。H1'和H9'形成的F…H氢键有利于π-π堆积作用的形成。DBTO₂倾向于趋近C2-H2和甲基基团形成O…H相互作用;DBTO₂优先吸附在[BMIM]⁺[PF₆]^-/[BMIM]⁺[BF₄]^-。在模拟油中,[BMIM]⁺[PF₆]^-和[BMIM]⁺[BF₄]^-离子液体对DBTO₂的萃取能力大于DBT,其原因是可能是DBTO₂具有较大的极性和O…H与F…H的氢键作用。     

新型己二胺四甲叉膦酸钠配位化合物的合成及其晶体结构

氢氧化钠与己二胺四甲叉膦酸（H₈L）在水溶液中反应合成了一个新型的配合物[Na₃(H₆L)₂(H₂O)₈][Na(H₂O)₆]·8H₂O（1）,其结构经IR和X-射线单晶衍射表征。结果表明1属P-1空间群,晶胞参数a=7.705 9(1) , b=11.655 6(2) , c=18.119 7(3) ,α=97.247(1)°,β=94.797(1)°, γ=101.827(1)°。 1中部分钠离子通过与四膦酸配体中的氧原子配位,形成一维链状结构{[Na₃(H₆L)₂(H₂O)₈]^-}_∞,该阴离子链的电荷被孤立离子团[Na(H2O)⁶]⁺平衡。在未配位的膦酸基团、氨基、配位水分子、结晶水分子之间的氢键相互作用下,化合物堆积形成一个结构致密的三维超分子结构。     

溶液中杯[4]芳烃双冠-6与Cs~+配位化学研究

研究了溶液中杯[4]芳烃双冠-6(BisC₆)与Cs⁺配位行为.常温下,BisC₆/NPME(邻硝基苯甲醚)体系单级萃铯百分率达99.36%,模拟料液中,Cs⁺/Na⁺和Cs⁺/K²⁺分离系数分别为3.92×10⁴和2.21×10⁴.局域结构模型实验表明,配合物分子中可能存在水或(和)硝酸(根).ESI-MS谱表明,NPME体系中,铯离子与BisC₆同时形成1:1(单核)和2:1(双核)的配合物,并且存在[BisC₆·H₂O],[BisC₆·Cs⁺]⁺,[BisC₆·2Cs⁺·H₂O]₂+和[BisC₆·2Cs₁₀⁺·No₁₀^-3]10⁺等多种配合物分子.EXAFS实验表明,溶液中铯离子的配位数为7,形成7个氧配位的稳定结构,ADF计算验证了EXAFS实验结果.     

水合铵硼氧酸盐及其饱和溶液的FTIR和Raman光谱研究

研究了NH₄B₅O₈·4H₂O和(NH₄)₂B₈O₁₃·6H₂O及其饱和溶液于20℃的FTIR和Raman光谱,对振动频率进行了归属.根据振动光谱特征,预测(NH₄)₂B₈O₁₃·6H₂O中所含基本结构单元为[B₇O ₁₁(OH)·B(OH)₃]^2-.首次将Raman光谱中516cm^-1处的强散射峰归属为这一多聚硼氧配阴离子的对称脉冲振动峰,并对以上2种铵硼氧酸盐饱和溶液中硼氧配阴离子的存在形式{B(OH)₃,[B₃O₃(OH)₄]^-和[B₅O₆(OH)₄]^-}和相互作用机理进行了探讨.     

两个基于八钼酸盐的无机-有机杂化材料的合成、结构和光催化性能

通过水热法成功合成了两个新的基于(β-Mo₈O₂₆)^4-构型的无机-有机杂化材料,分子式分别为{[Ni(β-Mo₈O₂₆)(H₂O)₄](H₂Fbix) 2H₂O}_n(1)和{[Co(β-Mo₈O₂₆)(H₂O)₄](H₂Fbix) 2H₂O}_n(2)(Fbix=2,3,5,6-四氟-二(1,4-咪唑-1-甲基)苯)。利用X-射线单晶衍射、X-射线粉末衍射、红外光谱、热重分析和元素分析等对该化合物的结构和性能进行了表征。晶体结构分析表明：化合物1和2为同构化合物。在化合物1中,扭曲八面体构型的Ni^II与两个β-[Mo₈O₂₆]^4-单...     

两例新的镧系金属-有机框架化合物高效去除Cs+离子研究※

¹³⁷Cs具有强放射性和较长半衰期, 一旦从核废液中泄露将对人类健康和环境造成很大危害. 由于¹³⁷Cs⁺的高溶解性、易迁移性和废液中干扰离子的影响, 从复杂的放射性废液中有效去除¹³⁷Cs⁺仍然是一个挑战. 本研究通过溶剂热法合成了两例新的三维微孔镧系金属-有机框架化合物(Me₂NH₂)_0.5(H₃O)_0.25Na_0.25Ln(OH)(stp)•0.25H₂O (FJSM-LnMOF; Ln=Eu, Tb; H₃stp=2-磺酸基对苯二甲酸), 它们具有良好的水稳定性和一定的耐酸碱性. FJSM-EuMOF和FJSM-TbMOF对Cs⁺离子吸附具有快速的动力学和高的吸附量(q_m^Cs分别为229.25和211.28 mg/g). 它们对Cs⁺离子具有良好的选择性(K_d^Cs值高达2.18×10³ mL/g). 即使在Na⁺, K⁺, Mg²⁺, Ca²⁺离子干扰的情况下, 它们仍然表现出对Cs⁺离子的选择性吸附性能. 我们成功获得了Cs⁺吸附产物的单晶结构, 通过单晶结构分析结合X射线光电子能谱(XPS), 红外(IR), 扫描电镜能量色散谱(EDS)和元素分析(EA)等多种表征方法, 证实了FJSM-EuMOF对Cs⁺离子的吸附为离子交换的机理. 结果表明, FJSM-EuMOF对Cs⁺离子的高效吸附主要源于镧系金属-有机阴离子框架中有机配体上的 COO^–和 $\text{SO}_{3}^{}$官能团对Cs⁺离子强的作用力以及通道内存在易交换的[Me₂NH₂]⁺阳离子和[H₃O]⁺离子. 这项工作表明, 镧系金属-有机框架化合物在放射性铯的修复中具有潜在的应用价值.     

一个半水合和五水合醋酸镧的脱水过程及脱水焓测定

醋酸镧已报道三种水合物:LaAc₃·1.5H₂O(Ⅰ)^[1,2]、LaAc₃·5H₂O(Ⅱ)^[3]和LaAc₃·H₂O(Ⅲ)^[4],迄今尚未见(Ⅰ)和(Ⅱ)的脱水焓数据发表,我们继(Ⅲ)的研究工作后,采用新的合成方法制得了(Ⅰ)和(Ⅱ),并采用DTA-TG-DTG联用技术和DSC技术分别对这两种水合物进行了脱水过程及脱水焓的测定。测得(Ⅰ)和(Ⅱ)的脱水过程分别为:     

二维钨-钒簇聚物[Cu(en)2]2·[VⅤO44{Cu(en)2(H2O)}2]·3H2O的合成与表征

采用水热法合成了一个钨-钒簇聚物[Cu(en)₂]₂[V^Ⅴ{Cu(en)₂(H₂O)}₂]·3H₂O(1, en=乙二胺), 并通过X射线单晶衍射、 元素分析、 傅里叶变换红外光谱、 X射线粉末衍射、 热重分析、 价键计算、 X射线光电子能谱、 电子顺磁共振和磁性分析对其结构和性能进行了表征. 结果表明, 化合物1是以双支撑的四帽Keggin结构 [(V^ⅤO₄){Cu(en)₂(H₂O)}₂]^4- 钨-钒簇合物阴离子为基本结构单元, 与4个[Cu(en)₂]²⁺配合物阳离子以共价键和弱键相连接形成二维层状结构, 相邻层又通过氢键连接成三维超分子网络. 研究了化合物1的磁性及光催化降解罗丹明B的活性.     

两个新颖的铜-二氮杂菲和钼(磷,硒)杂多酸组成的有机-无机杂合化合物:合成和晶体结构

水热法合成了两个新颖的有机-无机杂合化合物{[Cu(o-phen)(H₂O)]₃[Mo₅P₂O₂₃]}•4.5H₂O (1) 和{[Cu(o-phen)- (H₂O)]₂[Mo₅Se₂O₂₁]} (2) (o-phen＝1,10-phenanthroline). 通过红外光谱和单晶X射线衍射分析确定了它们的结构. 结构分析表明两个分子结构中的相邻[Mo₅P₂O₂₃]^6－或[Mo₅Se₂O₂₁]^4－阴离子均由两个桥式的[Cu(o-phen)(H₂O)]单元连接成分别为风车状和双侧桥联状一维聚合链, 化合物1的双金属链又通过若干链间氢键形成层状堆积结构. 讨论了钼杂多酸阴离子和第二种金属-配体亚单元阳离子之间的相互匹配关系.     

吡啶二羧酸修饰的稀土嵌入碲钨酸盐的合成及电化学生物识别性质

在乙酸钠水溶液中, 采用微波加热一步自组装策略合成了一系列罕见的2,6-吡啶二羧酸修饰的稀土嵌入Keggin型碲钨酸盐(PTEA)₇H₃K[RE₂(B-α-TeW₉O₃₃)₃W₃O₅(H₂O)₃(HDPA)]·22H₂O[RE=Ce³⁺(1), Pr³⁺(2), Nd³⁺(3), Sm³⁺(4); H₂DPA=2,6-吡啶二羧酸; PTEA=质子化的三乙醇胺]. 化合物1~4的聚阴离子由3个三缺位Keggin型 [B-α-TeW₉O₃₃]^8-构筑块通过1个{RE₂W₃O₅(H₂O)₃(HDPA)}¹³⁺异金属簇连接而成. 该异金属簇中, 2,6-吡啶二羧酸作为四齿配体与2个稀土离子(RE1和RE2)配位形成平面三杂环结构, 且RE1和RE2所在平面与W2, W2A, W16形成的平面互相垂直. 此外, 化合物1可与羧基化多壁碳纳米管(CMWCNT)复合形成1-CMWCNT复合材料. 该复合材料可以作为电极材料构建电化学生物传感器, 用于检测特定的DNA序列.     

Electrospray ionization mass spectrometry of ginsenosides

Ginsenosides R(b1), R(b2), R(c), R(d), R(e), R(f), R(g1), R(g2) and F(11) were studied systematically by electrospray ionization mass spectrometry in positive- and negative-ion modes with a mobile-phase additive, ammonium acetate. In general, ion sensitivities for the ginsenosides were greater in the negative-ion mode, but more structural information on the ginsenosides was obtained in the positive-ion mode. [M + H](+), [M + NH(4)](+), [M + Na](+) and [M + K](+) ions were observed for all of the ginsenosides studied, with the exception of R(f) and F(11), for which [M + NH(4)](+) ions were not observed. The signal intensities of [M + H](+), [M + NH(4)](+), [M + Na](+) and [M + K](+) ions varied with the cone voltage. The highest signal intensities for [M + H](+) and [M + NH(4)](+) ions were obtained at low cone voltage (15-30 V), whereas those for [M + Na](+) and [M + K](+) ions were obtained at relatively high cone voltage (70-90 V). Collision-induced dissociation yielded characteristic positively charged fragment ions at m/z 407, 425 and 443 for (20S)-protopanaxadiol, m/z 405, 423 and 441 for (20S)-protopanaxatriol and m/z 421, 439, 457 and 475 for (24R)-pseudoginsenoside F(11). Ginsenoside types were identified by these characteristic ions and the charged saccharide groups. Glycosidic bond cleavage and elimination of H(2)O were the two major fragmentation pathways observed in the product ion mass spectra of [M + H](+) and [M + NH(4)](+). In the product ion mass spectra of [M - H](-), the major fragmentation route observed was glycosidic bond cleavage. Adduct ions [M + 2AcO + Na](-), [M + AcO](-), [M - CH(2)O + AcO](-), [M + 2AcO](2-), [M - H + AcO](2-) and [M - 2H](2-) were observed at low cone voltage (15-30 V) only.     

Matrix-assisted laser desorption/ionisation mass spectrometry of oligosaccharides and glycoconjugates

The technique of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) is described and examples are given of its use for the examination of glycoproteins, glycopeptides, glycolipids and oligosaccharides. Abundant [M + H]⁺ ions are produced by the glycoproteins and glycopeptides, whereas glycolipids and oligosaccharides give mainly [M + Na]⁺ ions. Resolution on time-of-flight (TOF) instruments is poor but improved resolution can be obtained by use of ion cyclotron resonance or magnetic sector instruments. Although the technique gives mainly [M + Na]⁺ ions from neutral, underivatised oligosaccharides, with little fragmentation when implemented on TOF systems, the use of a reflectron enables fragment ions produced by post-source decay to be obtained. Acidic sugars give less satisfactory positive ion spectra with TOF analysers. but generally produce abundant negative ions. Extensive fragmentation is observed with these compounds when the spectra are recorded with magnetic sector instruments. Neutral glycolipids produce strong spectra from several matrices but acidic glycolipids show extensive fragmentation as the result of sialic acid loss.     

Effective solvation of alkaline earth ions by proline-rich proteolytic peptides of galectin-3 upon electrospray ionisation

In an analysis of a combined chymotrypsin/AspN digest of galectin-3 by positive ion nano-electrospray ionisation mass spectrometry (nanoESI-MS) several peptides were observed which showed metal adduct ions as their most abundant ion signals. The most prominent adduct ions were observed at m/z values corresponding to [M+40]2+, [M+41]3+, and [M+42]4+ ions. Detailed investigation of the [M+40]2+ ion of the peptide GAPAGPLIVPY showed that it was not, as originally expected, a [M+H+39K]2+ adduct ion but had the composition [M+40Ca]2+. This was verified by several approaches: (i) nanoESI-MS/MS of the [M+Ca]2+ adduct ions resulted in the virtually exclusive formation of doubly charged fragment ions; (ii) mass determination by quadrupole time-of-flight (QTOF)-MS provided a preliminary identification; and (iii) accurate mass measurement using nanoESI Fourier transform ion cyclotron resonance (FTICR)-MS at a mass resolving power of 500 000 allowed the specific detection and identification of the isobaric ion pairs [M+40Ca]2+/[M+H+39K]2+ and [M+24Mg]2+/[M+H+23Na]2+. All peptides in the chymotryptic galectin-3 digest without a basic residue (K or R) showed addition of calcium as the most prominent ionisation principle. A further common feature of these nonbasic peptides was the presence of several proline residues, which is assumed to be a factor promoting the intense addition of calcium. It was observed that the common trace levels of sodium and calcium in analytical grade solvents (about 1-10 microM) are sufficient to generate the [M+H+23Na]2+ and [M+40Ca]2+ ions as the most prominent species of the peptide GAPAGPLIVPY. We conclude that the sequence motifs P-XX-P and P-XXX-P favour the solvation of alkaline earth ions in ESI-MS. In view of the successful detection of physiological Ca/protein interactions by ESI-MS, this finding may point to a solvation of Ca2+ by galectin in solution. The findings open new routes of research in the study of metal/protein and metal/peptide interactions     

Observation of Na(+)-bound oligomers of quercetin in the gas phase

While developing a liquid chromatography/tandem mass spectrometry method for the analysis of the flavonoid quercitin, it was observed that quercetin (3,3',4',5,7-pentahydroxyflavone) exhibited clustering in both the positive and negative ion mode. Two series of positive ion clusters were observed; the first series corresponds to singly charged [2M + Na](+) at m/z 627.2 to [13M + Na](+) at m/z 3947.5, while the second series corresponds to doubly charged [7M + 2Na](2+) at m/z 1080.4 to [25M + 2Na](2+) at m/z 3798.5. In the negative ion mode, the behavior of quercetin parallels that of apigenin (4',5,7-trihydroxyflavone) in that [M + NO(3)](-), [2M + NO(3)](-), and [3M + NO(3)](-) were observed at m/z 364.1, 666.0, and 968.9, respectively; in addition, quercitin clusters with chloride ions ([2M + Cl](-) at m/z 638.9 and [3M + Cl](-) at m/z 940. 9) were observed. The results of tandem mass spectrometric examination of several cluster ions are reported.     

Influence of the labeling group on ionization and fragmentation of carbohydrates in mass spectrometry

The ionization and fragmentation behaviors of carbohydrate derivatives prepared by reaction with 2-aminobenzamide (AB), 1-phenyl-3-methyl-5-pyrazolone (PMP), and phenylhydrazine (PHN) were compared under identical mass spectrometric conditions. It has been shown that the intensities of signals in MS spectra depend on the kind of saccharides investigated and reducing end labels used. PMP sialyllactose, when ionized by ESI/MALDI, produced a mixture of [M + H]+, [M + Na]+, [M - H + 2Na]+ ions in the positive mode and [M - H]-, [M + Na - 2H]- ions in the negative mode. The AB and PHN derivatives formed abundant [M + H]+ and [M - H]- ions in ESI, and by matrix-assisted laser desorption/ionization (MALDI) produced abundant [M + Na]+ ions. PMP- and reduced AB-sialyllactose produced only Y-type fragment ions under both MS/MS sources. In the electrospray ionization (ESI)-MS/MS spectrum of PHN-sialyllactose, abundant ions corresponded to B, Z cleavages and in its MALDI-MS/MS spectrum, the abundant ions were consistent with Y glycosidic cleavages with the concurrence of B, C, and cross-ring fragment ions. In the MALDI-MS spectra of oligosaccharides acquired immediately after derivatization, it was possible to detect only PHN derivatives. After purification, spectra of all three types of derivatives showed high signal-to-noise ratios with the most abundant ions observed for AB reduced saccharides. [M + Na]+ ions were the dominant products and their fragmentation patterns were influenced by the type of the labeling and the kind of oligosaccharide considered. In the MALDI-PSD and -MS/MS spectra of AB-derivatized glycans, higher m/z fragment ions corresponded to B and Y cleavages and the loss of bisecting GlcNAc appeared as a weak signal or was not detected at all. Fragmentation patterns observed in the spectra of hybrid/complex PHN and PMP glycans were more comparable-higher m/z fragments corresponded to B and C glycosidic cleavages. For PHN glycans, the abundance of ions resulting from the loss of bisecting GlcNAc depended on the number of residues linked to the 6-positioned mannose. Also, PHN and PMP derivatives produced cross-ring cleavages with abundances higher than observed in the spectra of AB derivatized oligosaccharides. For high-mannose glycans, the most informative cleavages were provided by AB and PHN type of labeling. Here, PMP produced dominant Y-cleavages from the chitobiose while other ions produced weak signals.     

Electrospray and atmospheric pressure chemical ionization tandem mass spectrometric behavior of eight anabolic steroid glucuronides

Mass spectrometric and tandem mass spectrometric behavior of eight anabolic steroid glucuronides were examined using electrospray (ESI) and atmospheric pressure chemical ionization (APCI) in negative and positive ion mode. The objective was to elucidate the most suitable ionization method to produce intense structure specific product ions and to examine the possibilities of distinguishing between isomeric steroid glucuronides. The analytes were glucuronide conjugates of testosterone (TG), epitestosterone (ETG), nandrolone (NG), androsterone (AG), 5alpha-estran-3alpha-ol-17-one (5alpha-NG), 5beta-estran-3alpha-ol-17-one (5beta-NG), 17alpha-methyl-5alpha-androstane-3alpha,17beta-diol (5alpha-MTG), and 17alpha-methyl-5beta-androstane-3alpha,17beta-diol (5beta-MTG), the last four being new compounds synthesized with enzyme-assisted method in our laboratory. High proton affinity of the 4-ene-3-one system in the steroid structure favored the formation of protonated molecule [M + H]+ in positive ion mode mass spectrometry (MS), whereas the steroid glucuronides with lower proton affinities were detected mainly as ammonium adducts [M + NH4]+. The only ion produced in negative ion mode mass spectrometry was a very intense and stable deprotonated molecule [M - H]- . Positive ion ESI and APCI MS/MS spectra showed abundant and structure specific product ions [M + H - Glu]+, [M + H - Glu - H2O]+, and [M + H - Glu - 2H2O]+ of protonated molecules and corresponding ions of the ammonium adduct ions. The ratio of the relative abundances of these ions and the stability of the precursor ion provided distinction of 5alpha-NG and 5beta-NG isomers and TG and ETG isomers. Corresponding diagnostic ions were only minor peaks in negative ion MS/MS spectra. It was shown that positive ion ESI MS/MS is the most promising method for further development of LC-MS methods for anabolic steroid glucuronides.     

淫羊藿苷的电喷雾质谱研究

研究了淫羊藿苷的电喷雾质谱行为.结果表明,该化合物在正、负离子模式下均可得到较好的质谱信息,在负离子模式下,采用H/D交换方法,证明淫羊藿苷易形成加合2个水分子的准分子离子.利用电喷雾碰撞诱导解离方法,分别阐明了该化合物在正、负离子模式下的电喷雾质谱碎裂规律.     

Ion-molecule reactions observed for nitroaromatic compounds in negative ion fast atom bombardment mass spectrometry

Analyses of a series of nitroaromatic compounds using fast atom bombardment (FAB) mass spectrometry are discussed. An interesting ion-molecule reaction leading to [M + O ? H]^? ions is observed in the negative ion FAB spectra. Evidence from linked-scan and collision-induced dissociation spectra proved that [M + O ? H]^? ions are produced by the following reaction: M + NO₂^? → [M + NO₂]^? → [M + O ? H]^?. These experiments also showed that M^?˙ ions are produced in part by the exchange of an electron between M and NO₂^? species. All samples showed M^?˙, [M ? H]^? or both ions in their negative ion FAB spectra. Not all analytes studied showed either [M + H]⁺ and/or M⁺˙ in the positive ion FAB spectra. No M⁺˙ ions were observed for ions having ionization energies above ～9 eV.     

Mass spectral behavior of the hydrolysis products of sesqui- and oxy-mustard type chemical warfare agents in atmospheric pressure chemical ionization

Bis(2-hydroxyethylthio)alkanes and bis(2-hydroxyethylthioalkyl)ethers are important biological and environmental degradation products of sulfur mustard analogs known as sesqui- and oxy-mustards. We used atmospheric pressure chemical ionization mass spectrometry (APCI MS) to acquire characteristic spectra of these compounds in positive and negative ionization modes. Positive APCI mass spectra exhibited [M + H](+); negative APCI MS generated [M + O(2)](-), [M - H](-), and [M - 3H](-); and both positive and negative APCI mass spectra contained fragment ions due to in-source collision-induced dissociation. Product ion scans confirmed the origin of fragment ions observed in single-stage MS. Although the spectra of these compounds were very similar, positive and negative APCI mass spectra of the oxy-mustard hydrolysis product, bis(2-hydroxyethylthiomethyl)ether, differed from the spectra of the other compounds in a manner that suggested a rearrangement to the sesqui-mustard hydrolysis product, bis(2-hydroxyethylthio)methane. We evaluated the [M + O(2)](-) adduct ion for quantification via liquid chromatography-MS/MS in the multiple-reaction monitoring (MRM) mode by constructing calibration curves from three precursor/product ion transitions for all the analytes. Analytical figures of merit generated from the calibration curves indicated the stability and suitability of these transitions for quantification at concentrations in the low ng/mL range. Thus, we are the first to propose a quantitative method predicated on the measurement of product ions generated from the superoxide adduct anion of the sesqui-and oxy-mustard hydrolysis products.     

Sulfate migration in oligosaccharides induced by negative ion mode ion trap collision‐induced dissociation

Migration of sulfate groups between hydroxyl groups was identified after collision‐induced dissociation (CID) of sulfated oligosaccharides in an ion trap mass spectrometer in negative ion mode. Analysis of various sulfated oligosaccharides showed that this was a common phenomenon and was particularly prominent in sulfated oligosaccharides also containing sialic acid. It was also shown that the level of migration was increased when the sulfate was positioned on the flexible areas of the oligosaccharides not involved in the pyranose ring, such as the extra‐cyclic C‐6 carbon of hexoses or N‐acetylhexosamines, or on reduced oligosaccharide. This suggested that migration is dependent on the spatial availability of the sulfate in the ion trap during collision. It is proposed that the migration is initiated when the negatively charged ‐SO₃^– residue attached to the oligosaccharide precursor becomes protonated by a CID‐induced proton transfer. This is supported by the CID fragmentation of precursor ions depleted of acidic protons such as doubly charged [M – 2H]^2– ions or the sodiated [M + Na – 2H]^– ions of oligosaccharides containing one sulfate and one sialic acid in the same molecule. Compared to the CID fragmentation of their monocharged [M – H]^– ions, no migration was observed in CID of proton depleted precursors. Alternative fragmentation parameters to suppress migration of sulfated oligosaccharides also showed that it was not present when sulfated oligosaccharides were fragmented by HCD (High‐Energy C‐trap Dissociation) in an Orbitrap mass spectrometer. Copyright © 2011 John Wiley & Sons, Ltd.