Optimizing mass spectrometric detection for ion chromatographic analysis. I. Common anions and selected organic acids

Abstract

We describe a systematic method of optimizing mass spectrometric (MS) detection for ion chromatographic (IC) analysis of common anions and three selected organic acids using response surface methodology (RSM). RSM was utilized in this study because it minimized the number of experiments required to achieve the optimum MS response and included the interactions between individual parameters for multivariable optimization. Five MS parameters, including probe temperature, nebulizer gas, assistant makeup flow, needle voltage and cone voltage, were screened and systematically optimized by two steps. Central composite design (CCD) was used to design the experiment points and a quadratic model was applied to fit the experimental data. Analysis of variance (ANOVA) was carried out to evaluate the validity of the statistical model and to determine the most significant parameters for MS response. The optimum MS conditions for each analyte were summarized and the method optimum condition was achieved by applying desirability function. Our observation showed good agreements between statistically predicted optimum response and the responses collected at the predicted optimum condition. Operable range of each parameter (with normalized MS response greater than 0.8 for each analyte) was provided for general anionic IC/MS applications.

Targeted Metabolomic Analysis of Head and Neck Cancer Cells Using High Performance Ion Chromatography Coupled with a Q Exactive HF Mass Spectrometer

“…In accordance with our nontargeted metabolomic analysis based on CapIC-MS, pyruvate, citrate, cis-aconitate, isocitrate, and 2-oxoglutarate were present with higher levels in CSCs, whereas succinate, fumarate, and malate showed progressively lower levels in CSCs when compared to noncancer stem cells (NCSCs). 12 Similar results were observed with the targeted metabolomic analysis in the current study, and this indicates that both nontargeted and targeted IC-MS methods are quantitative for metabolomic analysis of cancer cells. However, why these metabolites are differentially expressed between CSCs and NSCCs remains to be questioned and certainly warrants further investigation.…”

Direct analysis of volatile fatty acids in marine sediment porewater by two‐dimensional ion chromatography‐mass spectrometry

“…This was important to obtain a stable MS signal over several consecutive measurements. We also tested the addition of acetonitrile/water mixture to the eluent flow by a static mixing tee to use it as assistant makeup during the MS measurement (Wang and Schnute 2009). Although some VFA signals showed increased signal in the presence of the assistant makeup during MS measurement, such addition was of no benefit due to loss of the acetate signal.…”

“…Nebulizer gas pressure, needle voltage, and ESI probe temperature modifications can only be applied to the total analysis run, whereas cone voltage and dwell time can be set individually for each data acquisition channel in the SIM mode. These parameters need to be optimized for each application because the settings have a strong influence on the MS performance for individual compounds (Wang and Schnute 2009). To identify the optimum instrument conditions, we scanned each parameter at different settings by measuring a VFA standard mix in IAPSO standard seawater at a concentration of 200 ppb for each VFA.…”

New Determination Methods of Halides and Cyanide Ions by Electrospray Ionization Mass Spectrometry Based on Ternary Complex Formation

“…[1][2][3][4][5] In particular, perchlorate ion in environmental samples has been an important target for these methods. [2][3][4] Moreover, Minakata et al reported the determination methods of CN -and I -by ESIMS/MS, where Au(CN)2 -and AuI2 -were measured after their ion-pair extraction into 4-methyl-2-pentanone, respectively.…”