Glow-Discharge Mass Spectrometry, GDMS

Because GDMS can provide ultratrace analysis with total elemental coverage, the technique fills a unique analytical niche, supplanting Spark-Source Mass Spectrometry (SSMS) by supplying the same analysis with an order-of-magnitude better accuracy and orders-of-magnitude improvement in detection limits. GDMS analy- 

Demonstration of GDMS feasibility and research into glow-discharge processes has been carried out almost exclusively using the combination of a glow-discharge ion source with a quadrupole mass spectrometer (GDQMS). The combination is inexpensive, readily available and suitable for such purposes. In addition, the quadru- 

The optimal analytical GDMS instrument for bulk trace element analysis is the one providing the largest analytical signal with the lowest background signal, the fewest problems with isobaric interferences in the mass spectrum (e.g., the interference of with Fe ), and the least contamination from instrument com- 

Accurate GDMS analysis has required the development of analytical procedures appropriate to the accuracy and detection limits required and specific to the mate- 

Pragmatically, the relative concentrations of elements are determined from the measured ion beam ratios by the application of relative sensitivity factors, which are determined experimentally from standard samples  

---

Table 9.4 Result of trace analysis of high purity indium and zinc measured by spark source mass spectrometry (SSMS) and glow discharge mass spectrometry (GDMS), respectively.

Table 3 Comparison of Glow Discharge Mass Spectrometry (GDMS) Results with Certified Values...

Inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS (LA ICP-MS), thermal ionization mass spectrometry (TIMS), secondary ion mass spectrometry (SIMS), glow discharge mass spectrometry (GDMS), resonance ionization mass spectrometry (RIMS), and accelerator mass spectrometry (AMS) have been used successfully to measure uranimn concentrations and isotope ratios in a wide range of sample matrices. The specific details of the methods are described fully in the relevant sections of this encyclopedia. There are specific advantages associated with each method, which depend on the sample of interest and the information required. 

Glow discharge mass spectrometry (GDMS) An analytical technique where atoms are sputtered from a surface, ionized in the plasma, then mass analyzed in a mass spectrometer. 

---