Application Note: Determination of N-nitrosodimethylamine using PCI and LVI

About this manual

The document presents a method to determine the carcinogenic compound N-nitrosodimethylamine (NDMA) in water samples at extremely low concentrations, addressing regulatory standards set by the EPA and California DHS. It highlights the limitations of existing methods, such as Electron Impact mass spectrometry, which suffer from poor selectivity due to non-unique fragmentation patterns.

To overcome these challenges, the authors propose a combined technique utilizing Positive Chemical Ionization (PCI) with ammonia reagent gas and Large-Volume Injection (LVI). This approach simplifies the mass spectrum by generating specific protonated and ammonium adduct ions, significantly enhancing sensitivity and signal-to-noise ratios compared to traditional Electron Impact ionization.

What's inside

• Introduction
• Experimental
• Instrumental Section
• Large-Volume Injections
• Results
• Mass Spectrum Analysis
• Linear Regression
• Reproducibility

Frequently asked questions

What detection limit does the EPA standard for NDMA in drinking water set?

The U.S. Environmental Protection Agency (EPA) has promulgated a regulatory standard of 0.7 ng/l (700 ppq).

What is the relative standard deviation of the response for replicate injections at a concentration of 20 fg/µL?

At a concentration of 20 fg/µL, the precision (RSD) of the response was less than 3%.