New Features of Deconvolution Reporting Software Revision A.02 Technical Note

Transcription

1 New Features of Deconvolution Reporting Software Revision A.2 Technical Note Authors Mike Szelewski Chin-Kai Meng Agilent Technologies, Inc. 28 Centerville Road Wilmington, DE USA Abstract Deconvolution Reporting Software (DRS) was introduced in March 24 and revised in August 25. This new revision, A.2, has a feature set based on customer requests as a result of the widespread acceptance of the original release. The new features are discussed in detail in this technical note. Introduction DRS is a software application that combines results from the Agilent gas chromatography/mass selective detector (GC/MSD) ChemStation, automatic mass spectral deconvolution and identification software (AMDIS) and the National Institute of Standards and Technology (NIST) Search in an easy-to-read report. Details of this process can be found in previous publications [1, 2, 3]. Since introduction, there is widespread acceptance of DRS in many different applications areas, including pesticides, allergens, drugs and environmental analyses. Based on inputs from DRS customers, Agilent has revised the software to better meet the needs of a diverse set of application areas. This technical note describes in detail the new features of the current A.2 release, which are: 1) SIM analysis 2) Turn-off NIST Search 3) AutoGraphicsPrinting (AGP) 4) User selectable RI Calibration Data files, *.cal 5) User selectable AMDIS parameter files, *.ini The feature set of the original software is not described here but can be found in references 1, 2, 3. A recently revised technical note details the process of building DRS libraries for any application [4]. SIM Analysis The AMDIS software, shipped with the NIST5 Library CD-ROM, is capable of properly denconvolving selected ion monitoring (SIM) data, while previous AMDIS revisions were not. Testing has shown that proper compound identification requires four ions per compound. The Agilent 5973 MSD with Performance Electronics and the 5975 MSD can acquire a sufficient number of SIM data points with four ions/compound. The current DRS A.2 ships with both full scan and four ion SIM databases for pesticides. Figure 1 shows the DRS Method Configurator with SIM database specified, 1 and 2. Also shown is a usersim.ini file for AMDIS, 6. This file sets the proper parameters for AMDIS to run using SIM instead of scan data. Details of setting the.ini file are contained in the DRS User Information (HELP files).

2 Figure 1. DRS Method Configurator. Figure 2 shows the Information List from AMDIS, displaying corrections equal to zero, as most of these corrections are used for scan data. The user can quickly see that SIM analysis was done. The corresponding scan Information List is also shown for comparison. SIM results Scan results Figure 2. Using Correction values to confirm that SIM deconvolution was done. 2

3 Figure 3 is a ginseng extract spiked with 25 pesticides, with SIM data acquisition. The total ion chromatogram (TIC) for ginseng SIM data shows extremely large interferences. The pesticide amount on column was 2 pg each, post-column split 1:1 to a flame photometric detector (FPD), so the amount to the MSD was 1 pg each. The TIC for the pesticide spiking standard SIM data is also shown. DRS in SIM mode successfully identified 23 of 25 pesticides spiked in the ginseng extract, while the ChemStation alone only identified five SIM results of the ginseng extract (many peaks were beyond 1, counts) SIM results of the pesticide spiking standard Ginseng extract: courtesy of James Neal-Kababick, Flora Research Laboratories, Grand Pass, OR Figure 3. TIC from SIM data acquisition of spiked ginseng extract and the pesticide spiking standard. Turn-off NIST Search The NIST Search option in DRS defaults to on. It can be turned-off simply by deselecting the checkbox, see Figure 1, number 4. This is typically done for SIM analysis as the NIST library contains scan data. A time-savings is realized together with not showing poor library matches that are misleading. AutoGraphicsPrinting (AGP) AGP is allowed by AMDIS revisions 2.62 and later, and is programmatically called by DRS to produce a user-defined graphics output. AGP is selected in DRS, see Figure1, number 5, after setup in AMDIS. Details of the AMDIS setup are in the DRS User Information. Figure 4 shows an example of AGP. The top is the raw spectrum, the middle is the deconvolved clean spectrum and the bottom is the library spectrum. This example shows p,p'-dde found in spinach. One page in this user-defined format is printed for each target compound found by AMDIS, in addition to a full page TIC and the normal DRS report. 3

4 GC/MS Analysis - Data:C:\MSDCHEM\1\DATA\SPINACH Abundance [227] Scan 3926 (24.7 min) Raw spectrum m/z: Extracted spectrum (24.71 min) 246 Deconvolved spectrum m/z: Library Hit: p,p'-dde 246 Library spectrum m/z: Figure 4. Example of AutoGraphicsPrint (AGP). 4

5 User-selectable RI Calibration Data Files, *.cal RI Calibration Data files (*.cal) are used by AMDIS to establish the relationship between Retention Time (RT) and Retention Index (RI). DRS A.2 allows the user to specify a *.cal, Figure 1, number 3. This is typically used for precisely scaled RTL analysis. If the method is scaled to 3x speed, the same 1x speed databases can be used with a different *.cal file. The pesticide databases shipped with DRS are based on a 1x speed method, and *.cal files for both 1x and 3x speeds are included. User-Selectable AMDIS Parameter Files, *.ini AMDIS settings can be customized by the user for many parameters such as match factor, sensitivity, resolution and SIM versus scan analysis. These settings are saved in an *.ini file, such as the one described earlier, usersim.ini. The user specified *.ini file is called by DRS, Figure 1 number 6. This allows the user to select applications specific AMDIS settings if needed. The DRS User Information Tutorial section describes the process for creating *.ini files. Conclusion DRS was revised and improved, based on input from recent user experience. The ability to deconvolve SIM data opens DRS to those labs where SIM analysis is a requirement. NIST Search can be turned-off for time savings, such as when running SIM analyses or proprietary compounds. The AutoGraphicsPrinting gives detailed hard copy output, of interest to many forensic labs. The userselectable *.cal files save time by allowing data acquired with faster methods to be processed by DRS using existing databases. The user-selectable *.ini files make it easy for a lab to customize settings, depending on application and matrix. References 1. Philip L. Wylie, Michael J. Szelewski, Chin-Kai Meng, and Christopher P. Sandy, Comprehensive Pesticide Screening by GC/MSD using Deconvolution Reporting Software, Agilent Technologies, publication , 2. Mike Szelewski and Bruce Quimby, New Tools for Rapid Pesticide Analysis in High Matrix Samples, Agilent Technologies, publication , 3. Christopher P. Sandy, A Blind Study of Pesticide Residues in Spiked and Unspiked Fruit Extracts Using Deconvolution Reporting Software, Agilent Technologies, publication , 4. Xiaofei Ping, Chin-Kai meng and Michael Szelewski, Building Agilent GC/MSD Deconvolution Reporting Libraries for Any Application. Agilent Technologies, publication , For More Information For more information on our products and services, visit our Web site at The new DRS A.2 revision addresses customer needs for higher productivity with more reliable answers. 5

6 Agilent shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material. Information, descriptions, and specifications in this publication are subject to change without notice. Agilent Technologies, Inc. 25 Printed in the USA November 7, EN