DEPENDENCE OF ION INTENSITY IN ELECTROSPRAY MASS-SPECTROMETRY ON THE CONCENTRATION OF THE ANALYTES IN THE ELECTROSPRAYED SOLUTION
DEPENDENCE OF ION INTENSITY IN ELECTROSPRAY MASS-SPECTROMETRY ON THE CONCENTRATION OF THE ANALYTES IN THE ELECTROSPRAYED SOLUTION
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DOI：
10.1021/ac00072a020
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发表时间：
1993-12-15
影响因子：
7.4
通讯作者：
KEBARLE, P
中科院分区：
文献类型：
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作者：
TANG, L;KEBARLE, P
通过一系列不同浓度的实验，测定了电喷雾甲醇溶液中浓度为[A+]和[B+]的分析物A+和B+的质量分析离子强度I(A)和I(B)的依赖性。提出了一个将I(A)和I(B)与[A+]和[B+]联系起来的方程式(见公式4)，提供了有用的预测。得到了Li+、Na+、K+、Cs+和NH4+离子以及几种质子化生物碱(乙基)4N+、正丙基4N+、正丁基4N+、n-C7H15NH3+和n-C11H23NH3+的系数k。这些系数的值与Iribarne离子蒸发理论的预测值进行了比较。分析还包括液滴的溶剂损失率和瑞利不稳定性导致的液滴裂变。结果表明，当[A+]和[B+]在10(-8)-5×10(-6)mol/L范围内时，观测系数k与被分析物的表面活度有关；在5×10(-5)-10(-2)mol/L范围内，[A+]和[B+]的离子蒸发速率常数和表面活性与[A+]和[B+]的离子蒸发速率常数和表面活度有关。此外，还考虑了气相离子产生的替代方法。
The dependence of the mass-analyzed ion intensity I(A) and I(B) of analytes A+ and B+, whose concentration in the electrosprayed methanol solution was [A+] and [B+], was determined in a series of experiments and for a variety of concentrations. A proposed equation relating I(A) and I(B) to [A+] and [B+] (see eq 4) was found to provide useful predictions. Coefficients k for the ions Li+, Na+, K+, Cs+, and NH4+ and several protonated alkaloids, (ethyl)4N+, (n-propyl)4N+, (n-butyl)4N+, n-C7H15NH3+, and n-C11H23NH3+, were obtained. The values of the coefficients are compared with predictions of the Iribarne ion evaporation theory. Rates of solvent loss from the droplets and the fission of the droplets due to Rayleigh instability are also included in the analysis. It is concluded that the observed coefficients k depend on the surface activities of the analytes when [A+] and [B+] are in the range 10(-8)-5 x 10(-6) mol/L and on the ion evaporation rate constants and surface activities for [A+] and [B+] in the range 5 x 10(-5)-10(-2) mol/L. The ion evaporation rates predicted by the Iribarne equation are found just barely consistent with the experimental coefficients. Alternate methods for gas-phase ion production are also considered.