Monday, June 9, 2008
SIM / Sacn in 5975 MSD
That is to say: Signal for screening for unknowns or for structural information (CID).
SIM mode, on the other hand, offers significant improvement in sensitivity over full-scan.
SIM signal for quantification of target compounds.
How is Synchronous SIM/Scan performed? What are the benefits?
Synchronous SIM/Scan is an acquisition mode that enables collection of both SIM (Selected Ion Monitoring) data and full scan data in a single run.
The Agilent SIM/Scan mode combines the best of both SIM and full scan from a single sample injection to improve productivity.
Agilent MSD ChemStation's AutoSIM feature allows you to create a SIM method automatically from ANY existing full scan method. Once you create the SIM method you can run synchronous SIM/Scan.
The Agilent Synchronous SIM/Scan offers the following benefits:
• Confirmatory information – full scan data for library search capability.
•Maximun sensitivity - SIM data enables trace analysis.
•Automated setup conversion - The AutoSIM feature automatically processes full scan data of chemical standards into SIM acquisition parameters for use in the SIM/Scan method.
How to STORE the Brominated diphenyl ethers for GC/MS
(1) Standard solutions—Prepare from materials of known purity and composition or purchase as solutions or mixtures with certification to their purity, concentration, and authenticity.
If the chemical purity is 98 % or greater, the weight may be used without correction to calculate the concentration of the standard. Observe the safety precautions in Section 5 and the recommendation in Section 5.1.2.
(1.1) For preparation of stock solutions from neat materials, dissolve an appropriate amount of assayed reference material in solvent. For example, weigh 1 to 2 mg of BDE 99 to three significant figures in a 10-mL ground-glass-stoppered volumetric flask and fill to the mark with nonane. After the compound is completely dissolved, transfer the solution to a clean 15-mL vial with fluoropolymer-lined cap.
(1.2) When not being used, store standard solutions in the dark at room temperature in screwcapped vials with fluoropolymer-lined caps. Place a mark on the vial at the level of the solution so that solvent loss by evaporation can be detected. Replace the solution if solvent loss has occurred.See, VIP tip: Before store the standard solutions, replace a new fluropolymer-line cap, then will eliminate the introducing of caps-impurity for next analysis.
Sunday, June 8, 2008
Replacing the make-up gas adapter (GC-ECD)
The make-up gas adapter consists of a line from the detector pneumatics manifold that carries make-up gas to a weldment that screws into the bottom of the ECD detector.
When re-installing the make-up gas adapter, ensure the following:
• Approximately six inches of the make-up gas line should reside in the oven after installation.
• The make-up gas line should be bent into a coil that loops around the bottom of the detector weldment and make-up gas adapter.
Tip: There are two pneumatics blocks on the EPC version of the ECD pneumatics manifold. The outside block is the anode purge gas line and the inside block is the make-up gas line.
RoHS ( European Union - 2002/95/EC & 2005/618/EC)
The SIX most famous toxic components are: Pb、Hg、Cr6+、PBB、PBDE,Cd.
{ Note: Polybrominated biphenyls (PBB) and Polybrominated diphenyl ethers (PBDE)}
(1) Use the the X-ray Fluorescence (photoelectric effect) to measure the elemental composition of a sample. Also FT-IR can also be used for screening, specifically for PBB and PDBE.
(2) GC-MS for the PBB&PBDE assay:
Column: POMSi 15 -30 m, 0.25 mm, .1 um.
Temp Ramp: 110 C (hold for 5 min), increase to 200 C @ 40C/min, hold for 4.5 min, then to 325 C @ 10 C/min, hold for 15 min.
Inlet Temp: 250 C.
MS: EI full scan or selecting ion scan from 200.0amu to 960.amu @ 70 KV.
( Note from EPA8270c & ISO 17025)
(3) HPLC/Uv for the PBB&PBDE assay:
Mobile Phase : 97% MeOH and 3% Buffer(0.1509 g KH2PO4 and 0.2477 g NaHPO4 in 100ml D.I H2O) @ C18 Reverse phase column.
Run time 12 min, flow rate: 1ml/min。
Solvent: n-IPA.
Wavelength: 254 nm, 210 nm.
{From M. Riess and R. van Eldik, Journal of Chromatography A,827 (1998):65-71}
(3) Colorimeter for the Cr6+ assay. See more details from EPA 3060 A, 7196A, 7199A, 218.6, ISO 3613: 2000(E).
(4) AAS or ICP-MS for the Pb、Hg、Cd assay.
See EPA 7000.
(5) Final, use ISO 5725 for data analysis.