RESUMO
A number of polymers were hydrolyzed in NH4OH and studied using gas chromatography/ mass spectrometry (GC/MS) and particle beam liquid chromatography/mass spectrometry (particle beam LC/MS) techniques. The polymers studied in this report were as follows: BPDA-PDA, BPDA-PDA-ODA, BPDA-PDA-GFDA, PMDA-ODA, and BTDA-APB. Some of the polymer samples were hydrolyzed in both their acid and imide forms to see if any mass spectrometric differences could be detected. ln all cases, the acid and imide spectra looked the same. GC/MS was unable to determine either the amine or acid portion of these polymers via a direct injection of the sample, but when the samples were first extracted with diethyl ether and this ether extract was injected into the chromatograph, the amine portion of the polymers was readily detected. The acid portion was, again, not detected in either the sample or the ether extract. The particle beam was able to detect both the amine and acid monomeric units in the nonextracted sample.
RESUMO
Thermospray has been widely accepted as a reliable technique for the analytical scientist. Many manufacturers provide thermospray as an option on their mass spectrometers. One difficulty experienced with thermospray is the clogging of the probe inserts. This report describes two new probe insert designs that minimize the problems associated with clogged probe inserts. Both of these new designs minimize the expense and downtime associated with clogged probe inserts. The capillary can be easily and quickly replaced to ensure optimum performance. The new fused-silica probe insert design that is described worked. adequately; there was, however, some beam instability caused by rapid oscillation of the fused-silica tubing near the tip. This oscillation also caused the tip to become brittle, necessitating frequent replacement. The stainless steel probe insert described did not exhibit these problems. Last, a comparison is made between the two new designs and the standard Kratos thermospray probe insert.
