Hi Lee! I still have some old kits-- I can send a tube to you and you could send them to a gemologist for evaluation. Let me know via PM. Cheers, Erik.

I was told by thre qiagen r&d that the mine that produced them stopped.

I was told the same - the garnet obviously was a natural product with unstable properties and the mine (probably in India) was exhausted, which is why they looked for alternatives. I do not think the beads is the main problem of the new kit´s poor performance (although it may be for specific soils I admit). Qiagen changed not only the beads but also the buffers which messed the new kit completely making it really poorly performing for most soils. And changing the buffers is something they did not want to admit for a long time at all.

To be honest, we're getting much higher DNA concentration (x4-5) with the new DNeasy PowerSoil Pro kit compared to the previous one. For others, did switching to he new kit reduce the quantity or quality of DNA?

We are doing a lot of qPCR with our samples, for which we need good quality (i.e., PCR-compatible) as well as reasonable quantity of DNA. To measure whether we extract reasonable quality of DNA, we developed spike-in internal standard. We measure the recovery of this standard and if at least 20% of the spike is recovered, we consider the extraction acceptable. For most soils the old kit gave values 30-50% internal DNA standard recovery. At the same time, we could conducte PCR with the samples (inhibitors were effectively removed) The new kit worked for about half of our samples pretty comparably with the old kit in our hands, and for the other half of samples the recovery was well below 1%. Quality is still good for (end-point) PCR but the quantity is simply not there. And if you are loosing more than 99% of your DNA, it is worrisome for someone interested in quantity... And one asks what is the reason behind. Seems to be organic C (preliminary observations)

Jan Jansa thank you for reply, I agree with you regarding the recovery of DNA. To share my experience: I've made a similar comparisson of the kits (with a spike-in) and the new kit worked better, with higher percentage of recovery so that's really interesting. For example with the old kit, we reached up to ~120 ng/uL while with the new one we're reaching 300+ ng/uL - talking for arable soil (for grassland even +500 ng/uL) - all from 250 mg soil in 50-60 uL extract. That said, I only tested recovery effifciency on one type of soil. We extracted also forest soil with good quantity and it worked well on a qPCR. However I usually dilute samples in the range between 1-5 ng/uL final concentration, which for new kit means around 150x (I use 2-8 ng DNA per qPCR reaction). I also tested 16S abundance from the same sample extracted with old and the new kit and the trends seemed comparable, however with higher numbers by the new kit. Inhibition was always tested by spiking reactions with external standard and comparing it to the positive control (only external standard) and seemed ok. What kind of soil are you working with? Which genes do you analyze by qPCR?

Hi, Anton, we work with a range of cropped and grasslands soils and various functional guilds of soil microbes - mycorrhizal and other fungi, bacteria, protists, AOA, AOB, for instance. We never get as much DNA as you describe though - usually not above 20 ng/uL. Maybe the soil, maybe another batch of the kit too?

I see we work in similar fields :), we're also analyzing nitrification/denitrification genes together with general community (16S, ITS) in the soil. Could be, would be interesting maybe to make a cross comparisson :).

Yes, it would certainly be interesting, Anton, but I feel this is the duty of the company to do such tests and I am not ready to serve as a (free) test rabbit for their products... So whereas I would be interested to see results of such cross-comparison of different kits and materials, I am not ready to use my limited resources and workpower to do that myself. Already spend 2 years and thousands of Euro to find out that their new product did not work for me. Eventually, the Qiagen confirmed that the new kit does not work with my samples, but they did not offer any compensation for the lost money and workpower to test the different kits and batches in our labs... Not very friendly indeed.

True that, I agree Jan. That's certainly the duty of the company, especially for such a renowned company as Qiagen. Anyway, good luck with your future research!

You too, Anton, all the best. And happy to hear it works at least for some people.