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61 I see a strange sawtooth pattern in the UV baseline using my Cogent TYPE-C Silica HPLC Column. What is it and how can I fix it?

This may be due to the presence of an immiscible solvent remaining in the column. Even trace amounts of these solvents can cause issues. The immiscibility manifests as an unstable baseline, such as the…

62 I use Normal Phase HPLC, which Syringe Filter do you recommend?

PTFE is the best for use with non polar, organic solvents required for normal phase chromatography. Click HERE for AQ Brand Syringe Filter Ordering Information. © Copyright MicroSolv Technology Corporation,…

63 I want to use the post column photochemical reactor for Aflotxins analysis. Which knitted reactor coil (KRC) do you recommend? What other accessories would I need?

The recommended KRC for Aflatoxin analysis is the 49900-KRC2525, 1.25ml void volume. The uv lamp supplied in the Photochemical Reactor is a low pressure mercury with 254nm light and is purchased with…

64 I was analyzing maleic and fumaric acids in biological extract using a Cogent Diamond Hydride column. After 10 perfect injections (%RSD of retention times around 0.5), I noticed that the peaks intensity diminished about 10 times, however the peaks still have the same retention time. What happened to the column?

Most likely, nothing happened to the column. Your mass spectrometer probably needs some attention. I would clean the ion source and check the nebulizer. © Copyright MicroSolv Technology Corporation,…

65 If I use one syringe filter for many samples will I get sample carry over?

You will most likely get some kind of carry over. It is not recommended to use one filter for more than one sample. Reusing the same syringe filters for multiple samples is never recommended due to carry…

66 Improve or obtain flat baselines in HPLC-UV gradient applications. A simple and easy technique.

Due to differences in UV absorbance between two solvents at a particular monitored wavelength, you will generally observe a sloped baseline when performing gradient methods with HPLC-UV. As the solvent…

67 Improving peak shape in an HPLC method in Aqueous Normal Phase (ANP).

Try the following tips: 1. It is generally better to have the sample solvent strength stronger that the mobile phase solvent, especially at the beginning of a gradient. In addition, Cogent TYPE-C™ silica…

68 Inconsistent peak heights obtained for glucosamine in HPLC: Tips for Resolving.

Issue: I am running an HPLC method for glucosamine. However, my peak heights are inconsistent from run to run. What is causing this? Solution: One possibility that could account for this behavior is chelation…

69 Injection technique for aqueous samples using Cogent TYPE-C HPLC columns in Aqueous Normal Phase (ANP).

Although it is preferable to use a high organic content diluent for your sample, we have observed excellent peak shapes using entirely aqueous samples in many applications. This application featuring…

70 Injection volume suggestions for Cogent TYPE-C HPLC columns

When using an analytical column it is recommended to inject 1 uL to 10 uL of the biological sample which is prepared either in DI water or 50% solvent A/50% solvent B of the mobile phase. When a 100 uL…

71 Is formic acid compatible with borosilicate glass?

Formic acid is generally compatible with borosilicate glass. There are two aspects that one needs to be mindful of when storing formic acid in glass vials or inserts. Formic acid gradually decomposes…

72 Is methanol or acetonitrile more suitable as an HPLC solvent?

Each solvent has its advantages and disadvantages. Methanol is less toxic than acetonitrile and so appeals to green chemistry incentives. It is also generally less expensive than acetonitrile. On the…

73 KRC - Knitted Reactor Coil Void Volumes

Knitted Reactor Coil Information Page © Copyright MicroSolv Technology Corporation, all rights reserved.

74 KRC - Knitted Reactor Coil Void Volumes.

Click HERE for Post Column Reactor Ordering Information including Knitted Coils. © Copyright MicroSolv Technology Corporation, all rights reserved.

75 Limits of Detection LOD and Limits of Quantification LOQ definitions.

The limits of detection (LOD) and quantification (LOQ) are evaluated using the following equations [1-4]: LOD=3.3 S0/b LOQ=10 S0/b where S0 is the standard deviation of the calibration line's y-intercept…

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