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Speed Accuracy Productivity Solutions that meet your demands for: speed accuracy productivity Excellent choices for environmental applications Productivity Tools Applications > Return to Table of Contents > Search entire document Integrated Second Peristaltic Pump for Improved Sample Throughput and Reduced Matrix Effects Technical Overview Introduction Second Peristaltic Pump Option As a simpler, less expensive alternative to Agilent’s Based on the input of dozens of ISIS users, Agilent Integrated Sample Introduction System (ISIS), the decided to introduce a simplified, more economi- Second Peripump Option permits both rapid cal solution for rapid sample uptake and constant sample uptake and constant flow nebulization for flow nebulization: a computer-controlled second improved throughput and matrix tolerance and is peristaltic pump that is fully compatible with fully compatible with all the most recent hardware recent software and hardware enhancements to and software improvements on the 7500 Series improve matrix tolerance and productivity. ICP-MS. The second peristaltic pump option works seam- Uncoupling Sample Uptake from Sample Nebulization lessly with both Pre-emptive and Intelligent Rinse functions, as well as with the new High Matrix With the introduction of its ISIS in 1999, Agilent Sample Introduction (HMI) accessory. The result is pioneered the use of constant flow nebulization in simple, fully integrated, high sample throughput ICP-MS. By uncoupling the sample uptake rate for even the most difficult samples, with no danger (using a separate, high-capacity peristaltic pump) of plasma overloading or sample carryover. from the nebulizer flow rate (using a small, close- coupled peristaltic pump), very high sample throughput could be achieved without the concur- Nebulizer Nebulizer rent overloading of the sample introduction system pump and plasma. Total matrix load on the plasma could be reduced by a factor of 5x or more over a conven- tional single pump system with the added benefit Second of significantly higher sample throughput. While peristaltic Waste ISIS supported many other functions, including Tee pump autodilution and matrix elimination, for many users, constant flow nebulization was the primary advantage. Sample Figure 1. Schematic of the second peristaltic pump arrangement. www.agilent.com/chem Figure 2. The second peristaltic pump option allows completely independent control of both the sample uptake pump (left) and the nebulizer pump (right) and fully supports all intelligent and pre-emptive rinse functions. Operation of the second peristaltic pump is simple Ordering Information and fully controlled by the ChemStation software. The second peristaltic pump is used to rapidly pull Order Agilent product number G3146B to add a the sample to the Tee shown on Figure 1. After the second three-channel peristaltic pump integrated sample reaches the Tee, the nebulizer pump trans- into the mainframe. ISIS tubing kit G3138-65006 is ports it to the nebulizer at a constant flow, without recommended with G3146B. It is preconfigured for the need to alter the pump speed. This constant easy set up. Please note that G3146B is not com- flow eliminates extended stabilization time and patible with G3148B (ISIS). the introduction of excessive sample into the plasma, interface, and mass spectrometer. For More Information The ChemStation pre-emptive rinse feature will move the autosampler probe to the rinse station to For more information on our products and services, begin cleaning the probe and sample line while the visit our Web site at www.agilent.com/chem. nebulizer pump delivers the remaining sample to complete the analysis. In addition, Intelligent Rinse will ensure that rinse time is sufficient by monitoring up to 10 predefined element signals, but avoid excessive rinse times when they are not Agilent shall not be liable for errors contained herein or for incidental or consequential needed (for example, after a blank). A significant damages in connection with the furnishing, performance, or use of this material. advantage to this system is that high throughput is Information, descriptions, and specifications in this publication are subject to change accomplished without the need to use a six-port without notice. valve or additional vacuum pumps. © Agilent Technologies, Inc. 2008 Printed in the USA April 30, 2008 5989-8543EN Eliminate the Dilution Step from ICP-MS Sample Prep with the Agilent High Matrix Introduction System Introduction HMI w/o HMI Agilent has developed the High Matrix Introduction (HMI) Element (Mass) MDL MDL (1/10 dil.) accessory for ICP-MS as an alternative to conventional mg/kg mg/kg dilution. The HMI modifies the sample introduction system of the Agilent 7500 Octopole Reaction System (ORS) ICP-MS, Al (27) 4.1 5.8 making it possible to directly measure sample solutions with Sb (121) 0.026 0.031 total dissolved solids (TDS) exceeding 1%. As (75) 0.03 0.15 Ba (137) 0.053 0.17 Analytical Challenges Be (9) 0.021 0.018 Analysts at TestAmerica Savannah labs in the USA tested B (11) 0.33 1.3 the HMI for the analysis of soil and Toxicity Characteristic Cd (111) 0.029 0.031 Leaching Procedure (TCLP) samples. For ICP-MS analysis in Ca (40) 5.7 8.4 the Savannah Labs, these types of samples are typically diluted Cr (52) 0.031 0.13 by a factor of 1:5 for liquids and 1:10 for soils. The dilution Co (59) 0.0064 0.0094 steps reduce the matrix effects contributed by both the acids Cu (63) 0.078 0.14 used in the preparation and the samples themselves. There Fe (56) 1.7 4.6 are several disadvantages associated with this practice: Pb (208) 0.055 0.03 •Possibility of introducing contamination from the pipette Mg (24) 1.3 1.9 tips or the diluent Mn (55) 0.037 0.11 • Chance of “human” error of simply preparing an inaccurate Mo (95) 0.036 0.058 dilution Ni (60) 0.024 0.036 •Sample prep time and cost of reagents K (39) 3.8 6.5 •Increased waste disposal volume Se (78) 0.13 0.044 Ag (107) 0.005 0.0071 HMI Methodology Na (23) 1.8 15 With the HMI unit installed on the 7500ce, TestAmerica Sr (88) 0.051 0.066 analysts are now able to introduce most typical Tl (205) 0.026 0.015 environmental samples to the ICP-MS directly, without a Sn (118) 0.105 0.24 dilution step, and thus eliminate the disadvantages Ti (47) 0.17 0.12 associated with conventional dilution. V (51) 0.041 0.096 High Acid Matrices Zn (66) 0.84 0.64 A significant hurdle to running undiluted environmental Table 1. Comparison of MDL for a suite of elements using HMI and normal samples is related to the final acid concentration specified in dilution. USEPA method 3050B for soils and wastes using the "hot- plate" procedure, which includes 10% HCl. Method 3010A for Conclusions liquids specifies a final concentration of 5% HCl. Prior to The addition of the High Matrix Introduction system to the using the HMI, matrix matching during the dilution step was Agilent 7500ce ICP-MS allows the analysis of soils without used to reduce and normalize the acid concentration in the complications of a dilution step and with slightly impro- standards and both types of samples. Not only does the ved Method Detection Limits (MDL). This ensures that soils HMI eliminate the matrix effects from varying acid analyzed according to USEPA methodologies can now be concentrations, it also removes the need for expensive done so with significantly improved productivity and redu- platinum cones when analyzing high acid concentrations. ced costs. TestAmerica now uses 5% HNO3 /5% HCl for standards and blanks with all sample types run using HMI. Acknowledgements The HMI was set-up for typical “ultra-robust” analysis. Table Cliff Eaton & Ernie Walton, TestAmerica Inc. Savannah, 1 shows comparison Method Detection Limit (MDL) data Ga., USA (mg/kg) for soils with and without the HMI. With the HMI, the digestates were analyzed directly (undiluted); without the More Information www.agilent.com/chem/hmi HMI, the digestates were diluted 1/10. The results highlight an improvement in MDLs for the majority of elements when the HMI is used. www.agilent.com/chem/icpms © Agilent Technologies, Inc. May 21 2008, 5989-8573EN Retention Time Locking with the MSD Productivity ChemStation Technical Overview Introduction mance. The ability to correct for degrading chro- matographic performance, optimize lab resources, A retention time is the fundamental qualitative and still provide the correct answer saves time, measurement of chromatography. Most peak identi- money, and results in significant productivity fication is performed by comparing the retention gains. time of the unknown peak to that of a standard. It is much easier to identify peaks and validate meth- Using GC/MS, it is also possible to screen samples ods if there is no variation in the retention time of for the presence of target compounds using a mass each analyte. spectral database of RTL spectra. The RTL mass spectral database provides additional confirma- However, shifts in retention time occur frequently. tory information in spite of changes to the chro- Routine maintenance procedures such as column matographic system. One such database is the trimming alter retention times. In a multi-instru- G1672AA Pesticide RTL Library. This database ment laboratory running duplicate methods, the allows for quick and easy screening of pesticide retention times for each instrument will differ from samples. each other, even when run under nominally identi- cal conditions. These differences in retention times mean that each instrument must have a separate When Should I Lock My Methods? calibration and integration event table, making it Locking or relocking your methods should be done time-consuming to transfer methods from one whenever you make any changes to the chromato- instrument to another. Differences in retention graphic system or move methods from one system time also complicate comparison of data between to another (GC or GC/MS).
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