Bodiniosides S–Y, Seven New Triterpenoid Saponins from Elsholtzia bodinieri and Their Anti-Influenza Activities

Investigation of the n-BuOH extract of the aerial parts of Elsholtzia bodinieri led to the isolation of seven new triterpenoid saponins, Bodiniosides S–Y (1–7, resp.). Their strictures were elucidated on the basis of spectroscopic techniques, including HSQC, HSBC, and HSQC–TOCSY experiments, together with acid hydrolysis and GC analysis. The anti-influenza activities of compounds 1–7 were evaluated against A/WSN/33/2009 (H1N1) virus in MDCK cells. The results showed that compounds 2 and 5 exhibited moderate anti-influenza activities against A/WSN/33/2009 (H1N1), with inhibition rates of 35.33% and 24.08%, respectively.

Artifact Peaks Due to Minor Decomposition of Sample Diluent DMSO in Head Space-GC Analysis: Mass Spectrometric Investigation Using Deuterated DMSO and Quadrupole Time-of-Flight Mass Detection

<p><b>Rationale: </b>Head space gas chromatography (HS-GC) has become a widely used analytical technique for residual solvents determination in drug substances and drug products. During our method development of residual solvents by HS-GC for certain drug substances, four unknown peaks were observed when dimethyl sulfoxide (DMSO) was employed as sample diluent.</p><p><b>Methods:</b> Use of other sample diluents replacing DMSO did not show these unknown peaks in the HS-GC analysis. HS-GC-MS was then utilized to investigate these peaks. As part of the investigation, DMSO-<i>d₆</i> was used to trace the origins of these unknown peaks to DMSO. A stress study of methanethiol and formic acid was carried out to provide further evidence that <i>S</i>-methyl methanethioate was one of the unknown peaks observed during the original HS-GC analysis.<b></b></p><p><b>Results:</b> The four unknown peaks have been identified as methanethiol, dimethylsulfide, <i>S</i>-methyl methanethioate, and dimethyldisulfide, respectively, and it has been demonstrated that the four peaks are clearly related to DMSO through the use of its deuterated counterpart. Plausible formation mechanisms of these species are proposed.</p><p><b>Conclusions:</b> The occurrence of the peaks is due to minor degradation of DMSO, facilitated by certain drug substances as analytes of the analysis. These peaks are artifacts, rather than genuine impurities of the drug substances. These artifact peaks could widely occur in HS-GC analysis, when DMSO is used as sample diluent.</p>

Artifact Peaks Due to Minor Decomposition of Sample Diluent DMSO in Head Space-GC Analysis: Mass Spectrometric Investigation Using Deuterated DMSO and Quadrupole Time-of-Flight Mass Detection

<p><b>Rationale: </b>Head space gas chromatography (HS-GC) has become a widely used analytical technique for residual solvents determination in drug substances and drug products. During our method development of residual solvents by HS-GC for certain drug substances, four unknown peaks were observed when dimethyl sulfoxide (DMSO) was employed as sample diluent.</p><p><b>Methods:</b> Use of other sample diluents replacing DMSO did not show these unknown peaks in the HS-GC analysis. HS-GC-MS was then utilized to investigate these peaks. As part of the investigation, DMSO-<i>d₆</i> was used to trace the origins of these unknown peaks to DMSO. A stress study of methanethiol and formic acid was carried out to provide further evidence that <i>S</i>-methyl methanethioate was one of the unknown peaks observed during the original HS-GC analysis.<b></b></p><p><b>Results:</b> The four unknown peaks have been identified as methanethiol, dimethylsulfide, <i>S</i>-methyl methanethioate, and dimethyldisulfide, respectively, and it has been demonstrated that the four peaks are clearly related to DMSO through the use of its deuterated counterpart. Plausible formation mechanisms of these species are proposed.</p><p><b>Conclusions:</b> The occurrence of the peaks is due to minor degradation of DMSO, facilitated by certain drug substances as analytes of the analysis. These peaks are artifacts, rather than genuine impurities of the drug substances. These artifact peaks could widely occur in HS-GC analysis, when DMSO is used as sample diluent.</p>

Thermogravimetric Analysis of Marine Gas Oil in Lubricating Oil

Marine lubricating oil (LO) is deteriorated by contaminants—especially marine gas oil (MGO), which is invariably mixed during its usage—that can damage engine performance. This study investigates a method for determining the content of MGO in lubricating oil. Weight loss from MGO-containing lubricant was evaluated through thermogravimetric analysis (TGA), and a standard calibration curve was plotted to establish a correlation with MGO content. A comparison of the commonly used ASTM–based gas chromatography (GC) analysis, and this TGA approach revealed that the former was more accurate when the lubricant contained ≤1% MGO; however, TGA afforded higher accuracy when the MGO content was between 0.5% and 15%. Hence, TGA can be used as a simple, reliable, and rapid method to analyze the contents of a lubricant contaminant such as MGO.

Pretreatment Method for Peroxides Decon Water Before GC Analysis of HD, VX, and GD

Peroxides like sodium percarbonate (SPC) and sodium percarbonate-acetylsalicylic acid (SPC-Aspirin) can be used to destroy chemical warfare agents (CWAs) such as HD, VX and GD due to the former's oxidation capacity and nucleophilicity. In this paper, experiments were performed to study factors affecting CWAs recovery from peroxides decontaminant water (decon water) and develop the method to recover residual CWAs from peroxides decon water before GC analysis. Results showed that extraction solvent and neutralization were important for high CWA recovery. DCM was more suitable than PE as extractant for most samples except SPC decon water containing HD. Sodium sulfite could well neutralized decontaminant reactivity in decon water. When suitable conditions of simultaneous neutralization and extraction were carried, CWAs recovery from SPC decon water were greater than 90% at a concentration range of 10 mg l-1 to 10000 mg l-1, the recovery of HD, VX and GD from SPC-Aspirin decon water was more than 90%, 80% and 95% respectively at a concentration range of 100 mg l-1 to 10000 mg l-1, while CWAs recovery were relatively lower from SPC-Aspirin decon water with CWAs concentration of 10 mg l-1 due to the degradation of CWAs during pretreatment processes.