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| LIQUID CHROMATOGRAPHY |
20.9 |
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| Introducing Discovery Zr: HPLC Method Development at pH and Temperature Extremes |
| In Volume 20.9 of The Reporter we introduce Supelco’s newest addition to the Discovery family – Discovery Zr. Discovery Zr comprises four different phase chemistries: Discovery Zr-PBD (polybutadiene), Discovery Zr-PS (polystyrene), Discovery Zr-Carbon (carbon-clad zirconia), and Discovery Zr-CarbonC18 (octadecyl-modified, carbon-clad zirconia). This new product line augments the overall Discovery message of “Rediscover Method Development” by expanding the allowable pH and temperature ranges of the Discovery family. The Discovery Zr line comprises four different stationary phases bonded to highly efficient, 3 and 5 micron zirconia particles. Because of the greater chemical stability of zirconia compared to silica and polymer particles, mobile phases from pH 1 to 14 and temperatures up to 200°C are now possible. All of the articles in The Reporter revolve around the theme of how temperature and pH can be used to improve some aspect of the separation: decreased analysis time, better peak spacing, retention where there was none, etc. In many cases, separations not achievable on silica-based columns can be performed successfully on Discovery Zr zirconia-based columns by leveraging the selective power of pH and the increased speed provided by elevated temperatures. In the Lead Article, we introduce the Discovery Zr line and show some examples of RP-HPLC separations run at pH and temperature extremes not possible with silica-based particles. In the Case Study, we discuss the advantages of running HPLC methods at elevated temperature. An example shows the dramatically reduced run time by increasing the temperature from 30°C to 65°C. At these elevated temperatures, silica- and polymer-based particles have limited stability and lifetime. Discovery Zr phases can be run up to 100°C in standard hardware, and up to 200°C in special all-steel hardware. In the Application, we surprised even the skeptics by showing the RP-HPLC separation of two quaternary ammonium compounds without ion-pairing. Paraquat and diquat are retained and resolved on Discovery Zr-PS (polystyrene-modified zirconia particles) using simple mobile phases. Without ion-pair agents, these compounds elute unretained on a silica-based C18 column. In the Performance Tip we discuss the proper preparation of buffers for HPLC to maximize the reliability and reproducibility of the method. |
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| For Durability and Low Bleed, Equity Meets the Challenge! |
| This issue of The Reporter examines the needs of today’s laboratories to increase sample throughput while achieving lower detection limits. For most GC analyses, this requires running an increased number of samples daily and using a highly sensitive detector such as an MSD. These demands require that the analytical column chosen be durable and exhibit low bleed. The new Equity capillary GC columns offers the durable, consistent column life you demand for increased column throughput, and the low bleed you expect for great sensitivity and reliable identification. In this issue, a case study examines the use of a split injection method for improved volatile analyses when working with purge and trap.
The new product section highlights Supelco’s new line of improved non-polar capillary GC columns discussed in the main article. Our new column line now offers 67 column dimensions to fit most needs. We also present our new CAP Kits for Agilent, PerkinElmer, and Varian. Our performance tip discusses how to reduce the effects of water and methanol in purge and trap analyses. The literature section describes the applications that can be found in our newly updated Equity capillary GC column brochure and the recently updated SPME application note 147 on analysis of trace odors. |
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| LIQUID CHROMATOGRAPHY |
20.7 |
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| Looking Beyond C18 Bonded Phase Chemistry when Developing HPLC Methods |
| In Volume 20.7 of The Reporter, we share with you the benefits of using reversed-phases other than C18 to alter chromatographic resolution. The vast majority of modern HPLC separations of small molecules are performed on C18-bonded silica. Given enough time and mobile phase variation, it is likely that a C18 column will perform nearly all separations. However, there are practical limits to mobile phases and the time necessary to change and re-equilibrate in new mobile phases can be excessive. In the lead article, a separation of two small molecules shows the simultaneous problems of too much and too little retention on a C18 column. By replacing the C18 with a Discovery HS F5 column, both problems are overcome. In the case study, we show how efficient method development can be when you systematically employ different functionalized reversed-phases. The performance tip expands on the systematic method development and gives step-by-step approach to multiple column screening. In the new applications section, we show how the unique bonded phase chemistry of the Discovery HS F5 was able to pull apart a critical impurity from a pharmaceutical active ingredient that a C18 did not. The best HPLC methods can be ruined by a fouled column. In the new products section, we describe Supelco’s mobile phase filtration apparatus. This product was designed to maximize column lifetime and reduce system wear by removing particles and dissolved gasses from mobile phases. |
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New Equity
Capillary GC Columns:
The Resolution You Need and the Analyte Response You Require |
| This issue of The Reporter discusses the demanding resolution and analyte response requirements GC chemists must meet when analyzing environmental samples using US EPA method 8270. While mass spectrometry can resolve co-eluting pairs based on spectral differences, compounds with the same or similar spectra still require chromatographic resolution for proper analysis. In addition, the method’s acidic and basic compounds require you to choose an extremely inert capillary column to achieve the desired analyte responses. The new Equity capillary GC columns offer the resolution you need and the response you require to achieve the demanding performance this method requires. In this issue, a case study looks at detecting trace levels of organic compounds using Solid Phase Microextraction (SPME) and the new low bleed, Equity-5 capillary column. The new product section highlights Supelco’s new line of improved non-polar capillary GC columns discussed in the main article. We also present our new line of Hamilton syringes for CTC/Leap Technologies autosamplers. Our performance tip discusses how to choose the correct splitless liner for optimum performance. The seminar and literature sections describe the benefits of the new Equity-1 and Equity-5 columns and the newly updated SPME application note 147 on analysis of trace odors. |
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| LIQUID CHROMATOGRAPHY |
20.5 |
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| Ionic Additives and LC/MS Conditions for Polypeptide
Analysis |
| In issue 20.5 of The Reporter we continue
our objective of providing relevant information about the analysis
of biomolecules by RP-HPLC. All articles revolve around the theme
of how using the right RP-HPLC column can maximize the sensitivity
of your separation by eliminating the need for TFA in the mobile phase.
The lead article shows
the dramatic improvement in LC-MS response using low TFA concentrations;
conditions under which Supelco’s Discovery BIO Wide Pore columns
excel. In the case study,
we show what happens to retention of basic peptides when TFA concentration
is varied from 0 to 0.1%. The performance
tip shows several C18 columns without TFA in the mobile phase,
and proves the importance of column inertness. In the application,
we show the use of Discovery BIO Wide Pore in 0.32mm ID capillaries
as another technique to improve sensitivity. These capillaries along
with 0.5mm ID and the microbore (1mm) dimensions are described in
the new product section. |
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New Equity
Capillary GC Columns:
The Performance You Demand for Your Non-Polar Applications |
| The
Reporter introduces our new line of improved non-polar capillary
GC columns. Equity-1 and Equity-5 columns deliver the capillary GC
column performance you demand for your nonpolar applications. Significant
improvements in the polymer chemistry are at the heart of the enhanced
performance you will receive with our new Equity columns. The polymer
improvements result in better bonding, higher thermal stability, and
superior product reproducibility. In this issue, a case
study describes how a customer solved a problem with inconsistent
and high GC/MS bleed by switching to the new low bleed, Equity-5 capillary
column. We also feature Supelco's line of Capillary Injector Products
for Agilent Technologies. Our performance
tip discusses how to ensure proper capillary column installation
in the GC injector for optimum performance. The literature
section describes the benefits of the new Equity-1 and Equity-5 improved
non-polar capillary GC columns. |
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| LIQUID CHROMATOGRAPHY |
20.3 |
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| The Effect of Ion Pair Reagent on Reversed-Phase
Selectivity of Polypeptide Separations |
| In TheReporter issue 19.8
we introduced Discovery BIO Wide Pore--our new line of reversed-phase
HPLC columns for peptide and protein separation. In this issue (TheReporter
20.3) we take up the subject of bioseparations in further detail.
The lead article discusses
choice of ion pair reagent and demonstrates that it can be an important
tool to alter selectivity. In the application,
our new Discovery BIO Wide Pore C5 phase shows the high resolving
power of reversed-phase HPLC by separating six cytochrome c isozymes
that differ by only one or two amino acids. The case
study looks at resolution of angiotensins I, II, and III at neutral
pH, demonstrating the valid use of Discovery silica-based products
for this application which is typically done at high pH on polymeric
supports. The performance
tip highlights the importance of proper sample and mobile phase
preparation prior to doing any HPLC separation. Finally, our new
product section announces the new Discovery BIO Wide Pore microbore
(1mm ID) and capillary (0.32 and 0.5mm ID) dimensions. |
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| A Tool for Selecting an Adsorbent for Thermal Desorption
Applications |
| The Reporter addresses a common question
asked by gas chromatography users doing thermal desorption, "Which
adsorbents trap what analytes?" To assist customers in selecting
the appropriate adsorbents for their applications, Supelco embarked
on a study to evaluate 24 adsorbents for trapping and releasing a
targeted list of 43 analytes. The results of this effort lead to the
development of a color-coded selection chart system that simplifies
the decision of which adsorbents trap what analytes. The entire report
is contained in T402025. In this issue, a case
study describes how Supelco's Technical Service helped solve a
customer's air monitoring problem through the proper selection of
a multi-bed thermal desorption tube. The Reporter also discusses Supelco's
new role as the authorized supplier of packed
GC columns for Agilent Technologies and for Agilent Technologies
customers. We also feature Supelco's line of Thermal
Desorption Tubes for GERSTEL®, PerkinElmer, Tekmar, and CDS/Dynatherm
instruments. Our performance
tip discusses the importance of proper conditioning of thermal
desorption tubes to prevent carryover and improve sensitivity and
product performance. The seminar
section describes a new presentation on the characterization of
adsorbents for sample preparation processes. |
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| LIQUID CHROMATOGRAPHY |
20.1 |
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Solute Functionality Provides Clues to Effective
Choice of Polar Reversed Phase
HPLC Columns |
| In Reporter 19.8
we introduced two new polar reversed phases as alternatives for C18.
Reporter 20.1 discusses these phases in greater detail. The lead
article reports on the retention and selectivity of the F5 and
PEG columns . In the case
study the use of high concentrations of TFA with elevated temperatures
on the Discovery BIO Wide Pore C18 column is discussed. The new
applications section highlights the separation of 8 Flavones on
the PEG column. This application shows a faster separation with unique
selectivity when compared to C18. The performance
tip offers some insight into the importance of sample, mobile
phase and wash solvent compatibility. And finally, the new
products page describes all of our new HPLC phases. In order to
better service the diverse needs of today’s researcher, each
phase chemistry is available in three different particle sizes. We
are now offering Discovery BIO for biomolecule analysis and purification.
These wide pore (300Å) columns are available in three different
phase chemistries: C18, C8, and C5. In addition to BIO, the HS (120Å)
line of columns has grown to include two new unique phases in addition
to time tested C18. The entire HS line is now available in the following
bonded phase chemistries: C18, PEG, and F5. |
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