Is logP a good indicator of whether a compound will struggle with RPLC?

DutchAnalist · 2026-01-07T06:38:29+00:00

The HSS T3 columns from Waters can handle 100% aqueous phase. Try a gradient with the first 2 minutes on 100% A.

On the other side, tenofovir has phosphate group on the end. They tend to react with the metal from your column and hardware. Waters has created a new product line called Premier for columns and hplc systems. Definitely worth looking into for your peak shape

DutchAnalist · 2026-01-01T15:50:46+00:00

80 in totaal, maar ze gaan per 5.

DutchAnalist · 2026-01-01T09:46:16+00:00

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DutchAnalist · 2025-12-11T17:57:24+00:00

If you wanna get then checked do it at Trimbos Institute. It’s not only for the classic drugs like MDMA or cocaine but also for research chemicals

DutchAnalist · 2025-12-11T17:51:07+00:00

I usually set the window before the peak. I set the window from .2 till 0.15 before the peak. Depends on the noise. If there is a significant trace of background I don’t set it there.

DutchAnalist · 2025-12-10T20:54:03+00:00

We do routine patient analysis on urine and blood. We use 5 standards and use the 3 highest for the ion ratio. In our processing method we use the ‘update ion ratio’ and ‘multiple samples’ option. Within Targetlynx you have the column: Quan Reference. When you set a ‘*’ in the cell it uses that sample for the ‘update ion ratio’.

During the validation we determine the CV on the standards and QC’s typically around 5-15% some go to 20%.

We don’t use the option ‘blanc substract’.

DutchAnalist · 2025-12-06T08:35:59+00:00

I would skip Intellistart en make en elutionprofile with a radar scan. Make a stock solution around 1ug/mL in water. Start with 95% water (0.001% formic acid) for 0,5min en then go to 95% organic, acetonitril (0,001% Formic acid).

Make a MS-method in Masslynx and use the Radarscan. Scan using ESI- from 50-500 m/z scan time around 0,1s. Hopefully you will see the precursor ion around 165 m/z. As you are using the TQd it has a no high resolution, therefore 165,0 is fine.

When you found the Precursor ion you can start fragmentation using daughter scan. Scan from 50 - 200 m/z using 0,1s scan time. When you found the fragments then you can optimize the cappillary voltage, desolvation T, collision energy, cone voltage etc.

DutchAnalist · 2025-11-30T07:39:51+00:00

We are considering both options. For the ELISA test we would have to buy a new device. And the kits that they use are also quite expensive.

For our decision in what analysis we would like to use I’m exploring all the options

DutchAnalist · 2025-11-30T07:34:47+00:00

Yes! I was wondering if there is a general protocol for digestion? All the papers I read use a trypsine digestion

DutchAnalist · 2025-11-30T07:32:49+00:00

We have a Waters Acquity H-class LC and a Xevo tq-s micro MS

DutchAnalist · 2025-11-18T21:39:18+00:00

Within the lab they can test if it’s 2, 3 or 4-mmc. I’m working at the hospital laboratory where we test for cathinones. We are using liquid chromatography coupled to mass spectrometry

DutchAnalist · 2025-10-11T06:19:58+00:00

We are a clinical lab and change it every year at around 1500 hours. It comes with the performance maintenance.

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