Derk Bakker

6 Questions 6 Answers 0 Followers

Questions related from Derk Bakker

Chromic Sulphate (Cr2(SO4)3.6H2O is ment to be soluble in water, however the product (UniChem) we have is not at all. How can that be?

We want to use Chromic Sulphate (Cr2(SO4)3.6H2O) to contaminate soil, however we found it not to be soluble in water while according the literature and tanning practices this should be soluble in...

01 January 2019 6,170 3 View

A large range of Cr content on the same soil sample was measured with the AAS. Why could this be?

We've been digesting the same soil in a number of different ways and measuring the Cr content of the filtrate using an AAS. The results are highly variable, and only remotely reflected the levels...

12 December 2018 5,700 9 View

Analysing digested filtrate using the UV spectro-photometer and DPC is difficult due to strong discolouration of the filtrate. How can we avoid that?

We've been digesting soil samples with heated NaCO3 and NaOH mixtures. The brown discolouration of the filtrate makes it difficult to use DPC under acid conditions to detect Cr6+. Yet people use...

12 December 2018 637 1 View

How to quickly acidify a loamy soil?

I'm working with some loamy soil with a pH(1:5) of about 8. I would like get it down to pH of 6 AND grow some crops on the acidified soil. What would be the quickest and reliable way of achieving...

01 January 2018 796 1 View

Why does the pH need to be lowered to 2 when measuring CrVI with diphenylcarbazide in a spectrophotometer?

We found a good and consistent calibration over a range of 0-350ppm of CrVI from K2Cr2O7 in a spectrophotometer after adding diphenylcarbazide to the samples at a pH of about 7. Would this be...

11 November 2017 1,784 2 View

Why is the light spectrum distribution of white (6000K) LED tubes similar to warm (3000K) LED tubes?

I have been measuring the light spectrum (about 10 different wave lengths: 504 to about 1000 nm) and intensity at each of those wave lengths of two different 18W LED tubes: cool white, and warm...

01 January 1970 10,000 8 View