Low resolution mass spectrometry LRMS

Finally, low resolution mass spectrometry (LRMS) is applied to each separation fraction which exceeds a specified concentration when referred to the sample sources. The present levels are 0.5 fig/rn for gas streams, 1 mg/kg for solids, and 0.1 mg/1 for liquids. The selection of this particular technique, firmly in the middle of a transition between Levels 1 and 2, caused many philosophical problems concerning its proper use. The original Level 1 scheme did not contain LRMS. It has been included in the modified strategy to prevent potential triggering of Level 2 efforts based on large amounts of suspicious, but innocuous, oiganics. However, LRMS can be costly if constraints are not placed on how frequently it is applied. 

PCDE analyses can be performed by high resolution gas chromatography (HRGC) combined with low resolution mass spectrometry (LRMS) or using HRGC combined with high resolution mass spectrometry (HRMS). For example, a Hewlett Packard 5970 mass selective detector system, which is a qua-drupole mass analyzer, has been used as an LRMS instrument in Finnish studies [33, 57, 113, 114, 122-125, 139]. Compared to LRMS, HRMS is more sensitive, allows less sample cleanup, and eliminates interference more effec-... 

The external standard was PCA-60, except as noted. LRMS = low resolution mass spectrometry HRMS = high resolution mass spectrometry ECD = electron capture detector SIM = selected ion monitoring TIC = total ion current CV = coefficient of variation ADM = average deviation from mean nd = not determined. b True concentration (by weight) = 74 ng/pl. c True concentration (by weight) =118 ng/pl. 

HIGH-RESOLUTION GAS CHROMATOGRAPHY-LOW-RESOLUTION MASS SPECTROMETRY (HRGC-LRMS)... 

US EPA (1998a) Polychlorinated Dibenzo-p-dioxins and Polychlorinated Dibenzofurans by High Resolution Gas Chromatography-Low Resolution Mass Spectrometry (HRGC-LRMS), US EPA Method 8280B, Rev. 2, January 1998. 

GC coupled with low-resolution MS (LRMS) provides the required sensitivity and selectivity for the determination of PCBs. Nevertheless, the use of high-resolution mass spectrometry (HRMS) at a resolution between 6000 and 10 000 in El mode allows complete removal of the contribution of matrix interfering compounds, achieving low limits of detection (20-100 fg). Therefore, this is the technique of... 

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