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LC Reversed Phase Test Mix #1 (4 components)

...LC Reversed Phase Test Mix #1...

Resprep SPE Cartridges (Bonded Reversed Phases)

...Sample Handling , Solid Phase Extraction , Cartridges...

Force FluoroPhenyl LC Columns (USP L43)

...'s FluoroPhenyl phase offers chromatographers the ability to run in reversed-phase or HILIC mode .Properties: Capable of both reversed-phase and HILIC separations. Ideal for increasing ... Capable of both reversed-phase and HILIC separations. Ideal for increasing...

Ultra Quat Columns

...A retentive, high-purity, base-deactivated, reversed-phase packing for the analysis...

Raptor FluoroPhenyl LC Columns (USP L43)

... the ability to run in reversed-phase or HILIC mode for a variety of compounds. The Restek Raptor Fluoro reversed-phase and HILIC separations. Ideal for increasing sensitivity and selectivity in LC ... Capable of both reversed-phase and HILIC separations. Ideal for increasing...

Ultra C1 Columns (USP L13)

... phase features our least-retentive reversed-phase hydrocarbon packing.Stationary Phase Category The Ultra line represents Restek’s broadest selection of stationary phases on a single silica ... Stationary Phase Category: trimethylsilane (L13)Ligand Type: monomeric C1Particle: 3...

Pinnacle DB Cyano Columns (USP L10)

..., or confirmation, to a C18 or C8 column is desired. It can be used in normal-phase, reversed-phase (best of phases to give chromatographers a stable and selective column. Get the most out of your UHPLC system ... Stationary Phase Category: cyano (L10)Ligand Type: cyanopropylsilaneParticle: 5 µm...

Ultra Cyano HPLC Prep Columns

... selectivity, or confirmation, to a C18 or C8 column is desired. It can be used in normal-phase, reversed-phase Easy scale-up from Restek analytical columns. Popular bonded phases ... Our broadest selection of stationary phases, including unique phases. High-density bondings...

Pinnacle DB IBD UHPLC Columns (USP L68)

... phases and can be used under reversed-phase or HILIC conditions to retain very polar, ionic compounds of phases to give chromatographers a stable and selective column. Get the most out of your UHPLC system ... Stationary Phase Category: polar-embedded alkyl (L68)Ligand Type: proprietary polar...

Ultra IBD HPLC Prep Columns

... mobile phases and can be used under reversed-phase or HILIC conditions to retain very polar, ionic Easy scale-up from Restek analytical columns. Popular bonded phases ... Our broadest selection of stationary phases, including unique phases. High-density bondings...

Roc Cyano HPLC Columns (USP L10)

... be used in normal-phase, reversed-phase (best with mobile phase pH between 5 and 7), and HILIC modes . It is an excellent choice for the analysis of protonated bases.Stationary Phase Category: Cyano (L10 ... -volume workflows—high-purity, fully porous silica backed by quality manufacturing features a variety of phases phases cover 98% of USP methods. ...

Ultra Cyano Columns (USP L10)

..., to a C18 or C8 column is desired. It can be used in normal-phase, reversed-phase (best with mobile phase The Ultra line represents Restek’s broadest selection of stationary phases on a single silica ... Stationary Phase Category: cyano (L10)Ligand Type: cyanopropylsilaneParticle: 3 µm...

Ultra IBD Columns (USP L68)

Specialized Columns for Mixed Polar and Nonpolar Compounds

... under reversed-phase or HILIC conditions to retain very polar, ionic compounds in highly organic mobile The Ultra line represents Restek’s broadest selection of stationary phases on a single silica ... Stationary Phase Category: polar-embedded alkyl (L68)Ligand Type: proprietary polar...

Ultra Aromax Columns (USP L11)

..., these columns are designed for selective and reliable HPLC applications.Ultra Aromax is a unique reversed-phase The Ultra line represents Restek’s broadest selection of stationary phases on a single silica ... Stationary Phase Category: phenyl (L11)Ligand Type: proprietary phenyl ligand...

Raptor C18 LC Columns (USP L1)

..., this phase offers consistently excellent data quality in less time across myriad reversed-phase applications to a C18 when: You need a general-purpose column for reversed-phase chromatography ... A traditional end-capped C18 ideal for general-purpose use in reversed-phase , and compounds. Offers the highest hydrophobic retention of any Raptor phase. Part of Restek...

Ultra Aqueous C18 Columns (USP L1)

... is a rugged, reversed-phase column with a well-balanced retention profile. It can effectively retain more The Ultra line represents Restek’s broadest selection of stationary phases on a single silica ... Stationary Phase Category: modified C18 (L1)Ligand Type: proprietary polar modified...

Pinnacle DB Aqueous C18 Columns (USP L1)

... is a rugged, reversed-phase column with a well-balanced retention profile. It can effectively retain more of phases to give chromatographers a stable and selective column. Get the most out of your UHPLC system ... Stationary Phase Category: modified C18 (L1)Ligand Type: proprietary polar modified...

Ultra Aqueous C18 HPLC Prep Columns

...—please call and inquire. The Restek Aqueous C18 is a rugged, reversed-phase column with a well Easy scale-up from Restek analytical columns. Popular bonded phases ... Our broadest selection of stationary phases, including unique phases. High-density bondings...

USLC Columns: Choose Columns Fast. Develop Methods Faster. (PDF 1815kB)

.... Through our extensive study of reversed phase chromatography Restek created the widest range robust methods. While numerous bonded phases are available for reversed phase chromatography, many (e ... , method development, UHPLC, HPLC, USLC, reversed phase...

USLC Columns—Ultra Selective Liquid Chromatography

Selectivity is the most influential factor affecting peak separation, or resolution. Restek Ultra Selective Liquid Chromatography (USLC) technology i...

HPLC Analysis of Glucosinolates in Vegetable Extracts without Ion Pairing Using an Ultra Aqueous C18 Column (PDF 675kB)

... of the least polar glucosinolates, making it relatively easy to retain by reversed-phase, high , such as 3-methylsulfinylpropyl glucosinolate, that are very difficult to retain by conventional reversed-phase...

Single-Column Method for HPLC Analysis of Organic Acids in Fruit Juices, Using an Allure Organic Acids Column (PDF 636kB)

.... Analysis of polar organic acids can be difficult on conventional reversed phase columns. A highly aqueous and apple juice, can be determined using AOAC method 986.13.2 In this procedure, reversed phase HPLC...

USLC Columns Put the Right Tools in Your LC Method Development Toolbox (PDF 1474kB)

... Understanding Selectivity in Reversed Phase Separations – A Simplified Approach to HPLC and UHPLC Column by instead focusing on column choice. In this article, we discuss column selection for reversed phase ... , reversed phase, H-S Model, method development, UHPLC, HPLC...

ChromaBLOGraphy: How to decrease run time for reversed phase LC

There are several ways to accomplish this, although it boils down to roughly 4 possibilities. Use a shorter column length. This may be appropriate if you have plenty of retention for your analyte(s), if you only have one or a few analytes AND if you do not have interference peaks in your chromatogram. It does, […]

USLC Column Selection & Mobile Phase Adjustment Guide (PDF 1682kB)

... is often amenable to the hydrophobic interactions of reversed phase analysis. If your molecule contains . • Capable of reversed phase and HILIC separations. Switch to an IBD when: • You need improved retention...

Raptor FluoroPhenyl LC Columns Brochure (PDF 3042kB)

... to run in reversed-phase or HILIC mode for a variety of compounds. The Restek Raptor FluoroPhenyl column . Switch to a Raptor FluoroPhenyl LC column for reliable performance in both reversed-phase and HILIC modes...

Reliable HILIC LC-MS/MS Analysis of 4-Methylimidazole (4-MEI) on Raptor FluoroPhenyl Columns (PDF 1191kB)

... compared to a C18. • Flexible Raptor FluoroPhenyl columns can be used in both HILIC and reversed-phase compound, 4-MEI is difficult to retain using typical reversed-phase conditions and C18 columns. As shown...

How to Avoid Common Problems with HILIC Methods (PDF 563kB)

... to those employed in reversed-phase LC (e.g., water, methanol, and acetonitrile) and volatile buffers for the analysis of polar molecules that have limited or no retention on typical reversed phases like C8 and C18...

Raptor FluoroPhenyl LC Columns Sales Sheet (PDF 1816kB)

...Stationary Phase: FluoroPhenyl Get the Power of HILIC and RP Modes in One LC Column Reversed-phase reversed-phase and HILIC separations. • Ideal for increasing sensitivity and selectivity in LC-MS analyses...

The Role of Selectivity in Liquid Chromatography Method Development (PDF 1332kB)

... interact with the stationary phase. While different separation modes (e.g., reversed phase [RP that there are other stationary phases available to impart additional selectivity in reversed-phase separations...

Resprep Sample Preparation by Solid Phase Extraction (SPE) Instruction Sheet (PDF 368kB)

...(S) ELUTION SOLUTION reversed phase C18, carbon packing & analyte are nonpolar polar, often aqueous Resprep Sample Preparation by Solid Phase Extraction (SPE) Solid Phase Extraction: 1. Choose...

ChromaBLOGraphy: Do reverse phase HPLC columns really need conditioning?

  Well, it’s partly a matter of semantics sometimes, but there is usually nothing drastic that you need to do to get your HPLC column going if it is new.  There is no baking at high temperatures involved like you might do for GC or that sort of thing. You do, however, need to equilibrate […]

Raptor HILIC-Si: Simplify the Switch to HILIC (PDF 2013kB)

... is the strong (or eluting) solvent versus the more familiar reversed-phase mode, where elution is the result -interaction chromatography (HILIC) (1) is an increasingly popular alternative to reversed-phase LC for challenging polar...

Method Development and Column Selection: How the FluoroPhenyl Phase Provides the Power of HILIC and Reversed-Phase Modes in One Column (PDF 2146kB)

... retention mechanisms and can be used in both reversed-phase (RP) and hydrophilic interaction liquid , resulting in hydrophobic retention. This single retention mechanism is the foundation for many reversed-phase...

Featured Application: LC Analysis of 4-MEI on Raptor FluoroPhenyl Columns Reliable HILIC LC-MS/MS Analysis of 4-Methylimidazole (4-MEI) on Raptor FluoroPhenyl Columns

... HILIC and reversed-phase modes. Exceptional reproducibility assures accurate results analysis typical reversed-phase conditions and C18 columns. As shown below, LC analysis of 4-MEI ... Raptor FluoroPhenyl columns perform well in both HILIC and reversed phase modes, giving method ). This approach provides more retention than reversed phase mode and can be applied to determining 4-MEI levels...

News: Understanding Selectivity in Reversed Phase Separations – A Simplified Approach to HPLC and UHPLC Column Selection

Author(s): Rick Lake, Ty Kahler Published By: Restek Corporation Year of Publication: 2011 Link: http://www.restek.com/Technical-Resources/Technical-Library/Pharmaceutical/general_PHAN1348 Abstract: Column selectivity has the most significant influence on chromatographic peak separation, or resolution, so choosing the right column can greatly speed up HPLC and UHPLC method … Continue reading

ChromaBLOGraphy: Resurrecting an old reverse phase LC column- should I, could I, how would I???

Well, if we had an Easter egg hunt and you found an egg that was from last year or the year before, you could probably tell the difference and you would know pretty quickly if it had gone bad.  Let’s just say that is not so easy with HPLC columns. If you’ve dealt with this […]

Rapid and Accurate LC-MS/MS Analysis of Nicotine and Related Compounds in Urine Using Raptor Biphenyl LC Columns and MS-Friendly Mobile Phases (PDF 1244kB)

... with the Raptor Biphenyl column using standard low-pH, reversed-phase LC-MS mobile phases that are compatible when used with standard low-pH, reversed-phase mobile phases. The clinical applicability of this method...

Direct Analysis of Morphine, M3G and M6G Metabolites, and Related Compounds in Urine by LC-MS/MS (PDF 778kB)

... to traditional reversed-phase chromatography. However, both hydrolysis procedures cost an analyst time and result polar and, therefore, more amenable to traditional reversed-phase chromatography. While either acid...

How to Avoid Common Problems with HILIC Methods

... the Raptor FluoroPhenyl column. The solvents used in HILIC methods are similar to those employed in reversed-phase molecules that have limited or no retention on typical reversed phases like C8 and C18. HILIC ... , there are significant differences between reversed-phase and HILIC methods that must be considered. This article...

High-Throughput Analysis of Mycotoxins in Cannabis CBD Oil Pairs Simplified Cleanup with LC-MS/MS Sensitivity (PDF 1230kB)

... was transferred to a conditioned (1 mL 45:55 water:methanol) Resprep bonded reversed phase SPE cartridge (Restek Cartridges (Bonded Reversed Phases) Hydrophobic (nonpolar) silica-based adsorbents; used to extract...

Increase Data Quality for Sulfonamide Antibiotics Analysis by HPLC and UHPLC (PDF 975kB)

... suppression in reversed phase mode often occurs with early eluting compounds, so it is good practice to retain with better selectivity and retention. • Biphenyl column and MS-friendly mobile phases allow easy transfer...

Tech Tip — Why do I Lose Retention on my C18 in Highly Aqueous Mobile Phases?

...When analyzing polar compounds by conventional reversed phase chromatography on a C18 column phase than for the hydrophobic C18 stationary phase. However, using a low organic mobile phase ... de-wetting, Aqueous C18, polar compounds, reversed phase, RPLC...

Fast, Accurate LC-MS/MS Method for Folate Deficiency Biomarkers in Plasma (PDF 513kB)

... are not retained well on traditional reversed-phase LC columns. Retention can be improved using a HILIC method :20) containing 10 mg/mL 2-mercaptoethanol; Inj. Vol.: 5 μL; Mobile Phase; A: 50:50 Water:acetonitrile, 20 m...

Novel Column Chemistry—High Impact, Low Cost Technology

... Reversed-phase liquid chromatography (RPLC) is arguably the most common analytical tool in pharmaceutical needed to make column stationary phase obsolete. At this juncture, the column is still an integral part ... reversed phase, biphenyl, RPLC, UHPLC...

USLC Columns Put the Right Tools in Your LC Method Development Toolbox Understanding Selectivity in Reversed Phase Separations – A Simplified Approach to HPLC and UHPLC Column Selection

.... In this article, we discuss column selection for reversed phase separations and, using the hydrophobic can begin to compare and quantify stationary phase selectivity in reversed phase separations ... set—that encompasses the widest range of reversed phase selectivity available today. . In this article, we discuss column choice and identify a set of just 4 stationary phases—Restek’s USLC column...

Malachite Green and Leucomalachite Green Analysis

... General Chromatographic Methodology Often reversed phase HPLC, typically on an octadecylsilane column with a guard column with the same stationary phase, is used to analyze for MG and LMG ... , where it is easily absorbed by fish tissue, and thus enters the human food supply. Reversed phase HPLC...

Restek Liquid Chromatography (LC) Columns - Usage & Care (PDF 143kB)

... mobile phase minus any buffered, acidic, or basic components. For long-term storage, reversed phase for complete instructions on installing the column. Mobile Phase When shipped, the column contains...

Restek Advantage, 2011.1 (PDF 3826kB)

... reversed phase selectivity to providepracticing chromatographers with the most effective and widest range for reversed phase chromatography, many aresimilar and offer only moderate changes in retention (e.g. C8 and C...

Viva Wide Pore HPLC Columns Brochure (PDF 1015kB)

... reversed phase HPLC packing materials with 60-150 Å pore sizes are not generally suitable for large -pore packing exhibits excellent peak shape for a wide range of compounds. Less retention in reversed-phase...

Analysis of d- and l-Amphetamine and Methamphetamine Enantiomers for High-Throughput Labs (PDF 568kB)

... chiral column, we developed the LC-MS/MS method shown here on a standard reversed-phase Raptor C18 .: 10 μL; Mobile Phase: A: 0.1% Formic acid in water; B: 0.1% Formic acid in methanol; Gradient (%B): 0...

Restek LC Columns and Accessories (PDF 17555kB)

..., and rugged reversed-phase separations of drugs and metabolites. By bringing the speed of SPP to the Biphenyl —with industry-leading stationary phases have been designed and built to address the needs of not only today...

Rapid and Accurate LC-MS/MS Analysis of Nicotine and Related Compounds in Urine Using Raptor Biphenyl LC Columns and MS-Friendly Mobile Phases

... standard low-pH, reversed-phase LC-MS mobile phases that are compatible with a variety of LC when used with standard low-pH, reversed-phase mobile phases. The clinical applicability of this method ... column using standard, low pH, reversed-phase LC-MS mobile phases which are compatible with a variety...

Method Development and Column Selection: How the FluoroPhenyl Phase Provides the Power of HILIC and Reversed-Phase Modes in One Column

... reversed-phase (RP) and hydrophilic interaction liquid chromatography (HILIC) modes. This paper explores , resulting in hydrophobic retention. This single retention mechanism is the foundation for many reversed-phase ... they incorporate multiple retention mechanisms and can be used in both reversed-phase (RP) and HILIC modes...

Trace-Level Analysis of Metanephrines in Plasma by HILIC LC-MS/MS (PDF 712kB)

... monitoring. Trace-level analysis of metanephrines in plasma using typical reversed-phase LC can be difficult reversed-phase chromatography. Accurate results were consistently obtained without matrix interference even...

Simultaneous Analysis of Catecholamines and Metanephrines in Urine by LC-MS/MS (PDF 1289kB)

...-methoxytyramine) in urine. Analysis of these polar compounds using reversed-phase LC can be difficult due ), normetanephrine (NMN), and 3-methoxytyramine (3-MT) (Figure 1). Although reversed-phase LC-MS/MS has been...

Simultaneous Analysis of Catecholamines and Metanephrines in Urine by LC-MS/MS

..., normetanephrine, 3-methoxytyramine) in urine. Analysis of these polar compounds using reversed-phase LC can ) (Figure 1). Although reversed-phase LC-MS/MS has been the method of choice for this analysis, challenges ... -methoxytyramine) in urine. Analysis of these polar compounds using reversed-phase LC can be difficult due matrix interferences. This method overcomes these problems by combining a simple solid phase extraction...

Force LC Columns Sales Sheet (PDF 3547kB)

...: • You need a general-purpose column for reversed-phase chromatography. • You need to increase Dipolar Acidic Basic 0 2 4 6 8 10 Properties: • Capable of both reversed-phase and HILIC separations...

Force LC Columns Brochure (PDF 4515kB)

.... Switch to a C18 when: • You need a general-purpose column for reversed-phase chromatography. • You ™ FluoroPhenyl Hydrophobic Dipolar Acidic Basic 0 2 4 6 8 10 Properties: • Capable of both reversed-phase...

Simple, Reliable HPLC Analyses of Organic Acids Using Water-Compatible Allure or Ultra C18 Columns

... and authenticity. Reversed phase HPLC coupled with UV-Vis detection is a popular technique reversed phase HPLC using two C18 stationary phase columns in series. Because organic acids are low ... Commonly used organic acid methods (e.g. AOAC method 986.13) depend on reversed phase HPLC and C18 columns, however these columns are vulnerable to phase collapse when used with the aqueous mobile phases...

The Effects of LC Particle Choice on Column Performance: Switching from 3 and 5 µm Fully Porous Particles (FPP) to 5 µm Superficially Porous Particles (SPP) (PDF 559kB)

... Column Temp.: 30 °C Sample LC Reversed Phase Test Mix #1 (cat.# 35005) Diluent: Methanol:water (75 : Dimensions: 150 mm x 4.6 mm ID; Temp.: 30 °C; Mobile Phase: Water:Acetonitrile (45:55). 0501001502002503000...

Restek Liquid Chromatography (LC) Columns — Cleaning Recommendations

...: Reversed Phase: Normal Phase: Biphenyl Amino . Reversed Phase Columns Normal Phase Columns 1. Water...

Raptor Biphenyl LC Columns Brochure (PDF 6071kB)

... and comparison of commercially available reversed-phase liquid chromatographic columns containing phenyl for clinical testing because of its ability to provide highly retentive, selective, and rugged reversed-phase...

Direct Analysis of Morphine, M3G and M6G Metabolites, and Related Compounds in Urine by LC-MS/MS

..., therefore, more amenable to traditional reversed-phase chromatography. However, both hydrolysis procedures reversed-phase chromatography. While either acid or enzymatic hydrolysis can improve analyte ... to traditional reversed-phase chromatography than the metabolites are. However, both hydrolysis procedures cost...

Roc HPLC Columns: The Reliable Cornerstone for Your LC Lab (PDF 2233kB)

... columns provide results you can trust time and time again. Reversed Phase Normal Phase Roc Chromatography www.restek.com 2 www.restek.com C18 C8 Phenyl-Hexyl Cyano Silica USP Phase Code L1 L7 L11 L10 L...

News: New Advice on an Old Topic: Buffers in Reversed-Phase HPLC

Author: Sharon Lupo and Ty Kahler Published By: LC-GC (chromatographyonline.com) Year of Publication: 2017 Link: http://www.chromatographyonline.com/new-advice-old-topic-buffers-reversed-phase-hplc Abstract: Buffers are commonly used in reversed-phase liquid chromatography (LC) to control the ionization state of analytes. However, the addition of buffers is much more complex than simple … Continue reading

Raptor C18 LC Columns Brochure (PDF 2375kB)

... consistently excellent data quality in less time across myriad reversed-phase applications, matrices -purpose column for reversed-phase chromatography. • You need to increase retention of hydrophobic compounds...

News: How to Avoid Common Problems with HILIC Methods

Author: Restek Corporation Published By: Restek Corporation Year of Publication: 2017 Link: www.restek.com/Technical-Resources/Technical-Library/General-Interest/general_GNAR2716-UNV Abstract: Whether you’ve run HILIC methods before or are attempting to for the first time, there are significant differences between reversed-phase and HILIC methods that must be considered. This article addresses … Continue reading

Influencing Selectivity in LC-MS Peptides Analysis on the Raptor ARC-18 Column (PDF 989kB)

..., respectively. Reversed-phase separations were performed using water and acetonitrile mobile phases modified Abstract Methods for LC-MS peptide analysis often use acidified mobile phases, which can alter...

ChromaBLOGraphy: Is it OK to use THF (tetrahydrofuran) on my HPLC?

Well, it might be. In the early days of HPLC, THF was commonly used as a mobile phase solvent. It has eluting strength similar to acetonitrile, but just slightly stronger. Since it technically is an ether and is very miscible with water, it is sometimes useful with reverse phase HPLC. It also provides additional options […]

Method Evaluation: Analysis of Phosphatidylethanol (PEth) in Human Whole Blood by LC-MS/MS (PDF 874kB)

...: • Capable of both reversed-phase and HILIC separations. • Ideal for increasing sensitivity and selectivity , 50 mm x 2.1 mm (cat.#. 9319A52) Mobile phase A: Water, 5 mM ammonium acetate Mobile phase B: 9...

Raptor ARC-18 LC Columns Brochure (PDF 4942kB)

... these difficult compounds using reversed-phased chromatography (RPC) in less time than traditional columns Stationary Phase: ARC-18 Si O Selectivity Accelerated Pure Chromatography www...

Restek Advantage, 2012.1 (PDF 14846kB)

... Liquid Chromatography (USLC) column set represents the widest range of reversed phase selectivity analyses by lowering method sensitivity through suppressing ionization. Ion suppression in reversed phase...

News: Method Development and Column Selection: How the FluoroPhenyl Phase Provides the Power of HILIC and Reversed-Phase Modes in One Column

Author: Sharon Lupo, Frances Carroll Restek Corporation Published By: Restek Corporation Year of Publication: 2017 Link: http://www.restek.com/Technical-Resources/Technical-Library/General-Interest/gen_GNAR2613 Abstract: Column selection is an important part of method development, as the quality of critical separations is determined in large part by the retention and selectivity of … Continue reading

News: The New USLC® Toolbox Gives You All the Right Tools—All in One Box

Restek’s USLC® column set represents the widest range of reversed phase selectivity available with just 4 stationary phases: Aqueous C18, IBD, Biphenyl, and PFP Propyl. It simplifies column choice for fast, effective method development—and new USLC® toolboxes make things even … Continue reading

Definitive EtG/EtS LC-MS/MS Analysis: A Rugged 4-min Method for High-Throughput Labs (PDF 631kB)

... them difficult to retain via reversed-phase chromatography. Both compounds are also very sensitive was developed and stringently tested on a Raptor EtG/EtS column, which features a novel stationary phase...

Featured Application: Folate Deficiency Biomarkers in Plasma on Raptor HILIC-Si Fast, Accurate LC-MS/MS Method for Folate Deficiency Biomarkers in Plasma

... challenging because these small, polar compounds are not retained well on traditional reversed-phase LC ... of matrix phospholipids and lysophospholipids. These interferences are problematic with reversed-phase LC...

The Role of Selectivity in Liquid Chromatography Method Development

.... While different separation modes (e.g., reversed phase (RP), hydrophilic interaction (HILIC), aqueous available to impart additional selectivity in reversed phase separations. Recent moves to alter support...

ChromaBLOGraphy: When should you use a buffer for HPLC, how does it work and which one to use?

As many of you know, buffers are usually used in mobile phases to hold the pH constant. They are composed of a weak acid or weak base, combined with its conjugate base or acid in solution that is at least partially aqueous (at least 50%).  This pair of compounds exists in equilibrium, so that when […]

News: Rapid and Accurate LC-MS/MS Analysis of Nicotine and Related Compounds in Urine Using Raptor™ Biphenyl LC Columns and MS-Friendly Mobile Phases

Author(s): Shun-Hsin Liang Restek Corporation Published By: Restek Corporation Year of Publication: 2015 Link: http://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFAN2216-UNV Abstract: A rapid, accurate, and reproducible method was developed for high-throughput testing of nicotine, cotinine, trans-3’-hydroxycotinine, nornicotine, norcotinine, and anabasine in urine. Data show that … Continue reading

News: New Raptor™ FluoroPhenyl Phase: the Power of HILIC and RP Modes in One LC Column

Restek has now extended the speed and reliability of Raptor™ column technology into the HILIC realm with the addition of Raptor™ FluoroPhenyl columns. Restek’s Raptor™ FluoroPhenyl phase offers chromatographers the ability to run in reversed-phase or HILIC mode for a … Continue reading

News: Simultaneous Analysis of Catecholamines and Metanephrines in Urine by LC-MS/MS

Author: Shun-Hsin Liang and Frances Carroll Published By: Restek Corporation Year of Publication: 2017 Link: http://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFAN2800-UNV Abstract:  Clinical diagnosis of pheochromocytoma and paraganglioma is often based on the analysis of catecholamines (epinephrine, norepinephrine, dopamine) and metanephrines (metanephrine, normetanephrine, 3-methoxytyramine) in urine. Analysis of these … Continue reading

Featured Application: Amphetamine and Methamphetamine on Raptor C18 Analysis of d- and l-Amphetamine and Methamphetamine Enantiomers for
High-Throughput Labs

... and specialized chiral column, we developed the LC-MS/MS method shown here on a standard reversed-phase Raptor C18...

ChromaBLOGraphy: Which LC Phase Do I Need?

So you’re thinking about doing HPLC (or UHPLC) and don’t have a method? You’ve never even seen a method for anything remotely similar. You might have even searched our HPLC chromatogram database for the application and haven’t found anything.  (After all, that’s the quickest and easiest way to get some ideas.) What to do… Let’s [...]

Mitigating Matrix Effects: Examination of Dilution, QuEChERS, and Calibration Strategies for LC-MS/MS Analysis of Pesticide Residues in Diverse Food Types (PDF 1561kB)

... matrix effects at the end of a reverse phase chromatographic analysis indicate that hydrophobic that late eluting matrix compounds in a reverse phase HPLC analysis can cause significant ion suppression [2...

How do intrinsically base-deactivated phases work?

... analytes often exhibit tailing on these hydrophobic, reversed phase packings. This is mainly due Analyzing basic compounds can be somewhat troublesome on traditional alkyl stationary phases ... Analyzing basic compounds can be somewhat troublesome on traditional alkyl stationary phases analyte selectivities through a wide variety of bonded stationary phases....

News: Direct Analysis of Morphine, M3G and M6G Metabolites, and Related Compounds in Urine by LC-MS/MS

Author: Justin Steimling and Frances Carroll Restek Corporation Published By: Restek Corporation Year of Publication: 2017 Link: www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFAN2665-UNV Abstract: The analysis of total morphine is typically conducted by first subjecting urine samples to acid or enzymatic hydrolysis in order to cleave the glucuronide … Continue reading

ChromaBLOGraphy: Fluorophenyl LC Phases- what you should know

They may be called PFP, PFPP, pentafluorophenyl, fluorophenyl or F5 phases. What they all have in common is the structure shown above (the pentafluorophenyl  group) attached to the silica particles. Most modern phases contain a propyl spacer between the above group and the silica, so that the phase looks something like this:     A […]

How do small particle size columns increase sample throughput? Learning Links

... Injection: 2µL Reversed Phase Test Mix the mobile and stationary phases. Through this type of diffusion, increased flows have been observed to widen...

ChromaBLOGraphy: What does the certificate for my new LC column tell me? Why should I keep it?

You know those pieces of paper that you sometimes run across when you open a box containing a new column? Maybe you don’t have much time to look at it or it sometimes gets lost along the way. Let’s stop for a minute and look at what that information is and how it pertains to […]

ChromaBLOGraphy: Shifting Analyte Retention Times or Matrix Interferences?

Occasionally, we will get a Technical Service call about peak retention times moving during a customer analysis.  Early eluting compounds are especially prone to this shifting, but the issue can often be attributed to matrix interferences that are also not well retained.    Pregabalin and Gabapentin are two antiepileptic drugs typically analyzed by LC-MS/MS.  Because of […]

ChromaBLOGraphy: Analysis of Nicotine and Related Compounds in Urine Using Raptor™ Biphenyl

As Applications Chemists in the LC lab, one of the most exciting parts of our jobs is the variety of analyses we are exposed to. One day you are developing a method for potency analysis in cannabis samples, the next you are looking at anti-epileptic drugs in urine.    We’re regularly challenged to think outside the […]

News: Raptor™ Speed, Efficiency, and Ruggedness is Now Available in C18

Every LC lab has a cache of C18s, but every C18 is not created equal. Because the chemistry tends to be similar, the silica support that carries this ubiquitous octadecylsilane phase becomes vitally important. When you need a general-purpose LC … Continue reading

News: Restek at ISCC & GCxGC 2017

Going to ISCC & GCxGC in Fort Worth this year? Don’t miss these presentations by Restek’s expert chromatographers. Stop by our booth or attend a presentation—we’re excited to share our research and discuss solutions to your toughest chromatography challenges!   … Continue reading

Trace-Level Analysis of Metanephrines in Plasma by HILIC LC-MS/MS

... of metanephrines in plasma using typical reversed-phase LC can be difficult due to limited chromatographic at low detection limits using reversed-phase chromatography. Accurate results were consistently obtained ... because this approach provides retention of all target compounds in highly organic mobile phases, thus...

ChromaBLOGraphy: Live Long and Prosper-How to make your HPLC columns last longer

We frequently get questions about how long an HPLC or UHPLC column should last. To borrow a phrase from my colleagues, “Your mileage may vary.”  Columns are like cars, so their lifetime depends how they are used and how well they are maintained. That being said, some phases are known to be more rugged than [...]

Optimized RP-HPLC Method for Hydroxybenzoic Acids Balanced Retention for a Range of Polarities, Using an Ultra Aqueous C18 Column

... Retention by Reversed Phase (RP) HPLC Many types of alkyl phases column is compatible with 100% aqueous mobile phases. Ideal for samples that encompass ... C18 phase assures high resolving power, the best separations across a broad range of analyte polarity, and compatibility with 100% aqueous mobile phases....

Increase Data Quality for Sulfonamide Residue Analysis by HPLC and UHPLC Using Unique Biphenyl Column Selectivity

... suppressing ionization. Ion suppression in reversed phase mode often occurs with early eluting compounds, so column and MS-friendly mobile phases allow easy transfer between UV and MS detection. Maximize...

ChromaBLOGraphy: Here’s to HILIC: tailor-made for the MS analysis of polar analytes and highly water-soluble species

There is much discussion these days about Hydrophilic Interaction Chromatography (HILIC) and the options it provides today’s analysts. And there should be.  It’s powerful for analysts working with polar metabolites or highly water-soluble compounds, namely when using MS/MS techniques. Since phase chemistry is Restek’s specialty, and we have designed our Raptor SPP LC column line for […]

ChromaBLOGraphy: Calculating pH

I’m guessing that most of us that work in the lab would find it more convenient to measure a pH rather than to calculate a theoretical value.  But, at times, it can be very useful to make that calculation and get an idea of what to expect.  As far as chromatography is concerned, all columns […]

Analysis of Brominated Flame Retardants by Liquid Chromatography Mass Spectrometry

... response factors. A further convoluting factor is the limited solubility of BFRs in typical reversed phase stationary phases. HBCD is one of the most widely used BFRs with production globally in excess of 20,000 tons...

Separating NSAIDs through Aromatic Selectivity Improve Retention by Using An Allure Biphenyl HPLC Column

... and, therefore, historically have been separated through reversed phase HPLC on C18 columns , for better separations. Orthogonal separations with simple mobile phase changes ... Non-steroidal anti-inflammatory drugs (NSAIDs) are typically separated on C18 phases. Separations and selectivity. Increased retention requires higher organic content in the mobile phase, increasing desolvation...

ISC 2018

Here’s a sneak peek at what we’ll be up to during this year’s show.

ChromaBLOGraphy: Can I use a 100% aqueous mobile phase with my LC column?

You might be asking this because you have read that not all columns are OK to use with highly aqueous content (>95%) in the mobile phase.  Or maybe the caption caught your eye because you have recently encountered some difficulty with using highly aqueous mobile phase. There is a phenomenon called “phase dewetting” that can […]

ChromaBLOGraphy: What is the pressure limit for my LC column?

This is a question we get in Tech Services fairly often.  Unfortunately, we are not able to provide a published limit for every column that we produce, but here are a few of them that we have specified: For 3 and 5 um fully porous particle ROC LC columns, the maximum operating pressure is 400 […]

Frequently Asked Questions: HPLC and UHPLC

... for reverse phase)? How do I address an increase in backpressure and other signs %water for reverse phase)? In this scenario, the sample is initially concentrated onto the head...

Influencing Selectivity in LC-MS Peptides Analysis on the Raptor ARC-18 Column

... ionization in positive ion mode was used for UV and MS detection, respectively. Reversed-phase separations Abstract Methods for LC-MS peptide analysis often use acidified mobile phases, which ... Methods for LC-MS peptide analysis often use acidified mobile phases, which can alter retention...

ChromaBLOGraphy: [4]Troubleshooting HPLC- Fronting Peaks

Patterns in your HPLC chromatography can exhibit telltale signs that point toward probable sources of error.  In this brief series of posts, we have looked at possible scenarios that you may encounter in the laboratory and how you might approach resolving those difficulties. Any time you have difficulty with poor peak shape, it is also […]

SOFT

Learn more about what Restek will be doing at the Society of Forensic Toxicologists (SOFT) annual meeting.

Rapid, Reproducible HPLC Analysis for Flavonoids in Cocoa Using a LECO Unique LC-TOFMS System and an Ultra Aqueous C18 Column

... reversed phase separations well and reproducibly when the mobile phase has a high aqueous content. Using phase: A: 0.1% formic acid in water; B: acetonitrile:methanol, 50:50 (v ... mobile phase composition in 15 minutes. For compounds common to both samples, retention times were equal...

Definitive EtG/EtS LC-MS/MS Analysis: A Rugged 4-Min Method for High-Throughput Labs

... makes them difficult to retain via reversed-phase chromatography. Both compounds are also very sensitive phase that was developed specifically for this critical application. This column was selected because...

Mitigating Matrix Effects: Examination of Dilution, QuEChERS, and Calibration Strategies for LC-MS/MS Analysis of Pesticide Residues in Diverse Food Types

...-liquid extraction, solid phase extraction, and the QuEChERS approach. QuEChERS has extraction and cleanup steps EChERS extraction and dispersive solid phase extraction (dSPE) tubes, as well as QuEChERS internal and quality...

For advanced chromatogram searching, please check out our Chromatogram Library Search Tool.

Antibiotic Cephaloridine on Ultra IBD (Reversed Phase)

LC_0102

Column: Ultra IBD (cat.# 9175565), Dimensions:150 mm x 4.6 mm ID, Particle Size: 5 µm, Pore Size: 100 Å, Temperature: 27 °C
Detector: UV/Vis

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