use R&D spectrometer for all test

[THIEN LE]

Happy Sunday everyone.
I hope this is the right forum to post questions that relate to testing reef's parameters. I wonder if anyone is using lab grade spectrometer for all of your tests. A brief search on spectrometers and methods of converting wavelengths of known/unknown solutions to concentrations make me think it is possible. If the answer is YES then I think we can eliminate alot of head scratching, save some money, and obtain more accuracy results.
Thank you all in advance.

 

[EMeyer]

Hi,
I am using this

Visible Spectrophotometer 721 Lab Equipment 350-1020nm 220v Tungsten Lamp for sale online | eBay

Find many great new & used options and get the best deals for Visible Spectrophotometer 721 Lab Equipment 350-1020nm 220v Tungsten Lamp at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Its not cheap for a hobbyist instrument, but very cheap for a research or teaching grade instrument. After using this for a few months I would say it is a very solid teaching grade instrument and a good tool for hobbyists. For comparison, this costs about the same as buying ~4 of the Hanna Checkers... but this one tool can do any number of different tests.

I took a gamble on this instrument and have been pleasantly surprised. I havent found any detectable problems. It identifies peak absorbance at the right wavelengths, suggesting the wavelength selection is reasonably accurate. It gives linear relationships with concentration in the expected ranges.

I've used this so far for NO2, NO3, and NH4 but really any colorimetric test should work. I could discuss these in more detail if there is interest.

This has been great because now I can do proper blanks and standard curves, and get objective readings. No more "is this closer to the 0.5 color or the 1.0 color"... the spec is objective; human eyes are terribly subjective.

 

[taricha]

I use this one (for educational use)

Go Direct® SpectroVis® Plus Spectrophotometer - Vernier

The Go Direct SpectroVis Plus Spectrophotometer quickly measures a full wavelength spectrum. It connects via Bluetooth® wireless technology or via USB to your device.

www.vernier.com

@Dan_P uses a similar one by pasco I think. He's done some creative stuff with chemical tests not all of which are used in the hobby.

I've mostly used mine to investigate pigments in organisms in a reef tank. And to detect some pigmented/fluorescent agents in tank water.
thread here:

A Spectrophotometer view of Photosynthetic Organisms in our Tanks

Recently I got my hands on a spectrophotometer. I wanted to take a peek at absorption spectra of organisms that grow in our tanks and see if I could identify pigments other than Chlorophyll A - the accessory pigments - to start to drill down on possible differences between the ways they use...

www.reef2reef.com

I've also looked a little bit at some color change test kits. But mostly I find that with a proper regression figured out, Most color change test kits can be analyzed really accurately by a hanna checker. But a spectrophotometer is useful to see exactly what the end color absorbance looks like to know which checker wavelengths can work well.

 

[Dan_P]

I use this one (for educational use)

Go Direct® SpectroVis® Plus Spectrophotometer - Vernier

The Go Direct SpectroVis Plus Spectrophotometer quickly measures a full wavelength spectrum. It connects via Bluetooth® wireless technology or via USB to your device.

www.vernier.com

@Dan_P uses a similar one by pasco I think. He's done some creative stuff with chemical tests not all of which are used in the hobby.

I've mostly used mine to investigate pigments in organisms in a reef tank. And to detect some pigmented/fluorescent agents in tank water.
thread here:

A Spectrophotometer view of Photosynthetic Organisms in our Tanks

Recently I got my hands on a spectrophotometer. I wanted to take a peek at absorption spectra of organisms that grow in our tanks and see if I could identify pigments other than Chlorophyll A - the accessory pigments - to start to drill down on possible differences between the ways they use...

www.reef2reef.com

I've also looked a little bit at some color change test kits. But mostly I find that with a proper regression figured out, Most color change test kits can be analyzed really accurately by a hanna checker. But a spectrophotometer is useful to see exactly what the end color absorbance looks like to know which checker wavelengths can work well.

I do use the Pasco visible spectrometer, but the largest number of tests are performed with the Hanna Checker. I routinely use the PO4 Checker for nitrates. Right now the spectrometer is used to record the color of cyanobacteria films and the relative light intensity of the culture illumination.

The spectrometer might provide a small increase in sensitivity, but I have not performed enough work to prove it does much better than the Hanna Checkers.

@Rick Mathew has done quite a bit of work understanding the precision and accuracy of Hanna Checkers. For the average aquarists that is willing to use these hand held photometers “carefully”, very good results can be obtained.

 

[ReefLab]

Hi,
I am using this

Visible Spectrophotometer 721 Lab Equipment 350-1020nm 220v Tungsten Lamp for sale online | eBay

Find many great new & used options and get the best deals for Visible Spectrophotometer 721 Lab Equipment 350-1020nm 220v Tungsten Lamp at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Its not cheap for a hobbyist instrument, but very cheap for a research or teaching grade instrument. After using this for a few months I would say it is a very solid teaching grade instrument and a good tool for hobbyists. For comparison, this costs about the same as buying ~4 of the Hanna Checkers... but this one tool can do any number of different tests.

I took a gamble on this instrument and have been pleasantly surprised. I havent found any detectable problems. It identifies peak absorbance at the right wavelengths, suggesting the wavelength selection is reasonably accurate. It gives linear relationships with concentration in the expected ranges.

I've used this so far for NO2, NO3, and NH4 but really any colorimetric test should work. I could discuss these in more detail if there is interest.

This has been great because now I can do proper blanks and standard curves, and get objective readings. No more "is this closer to the 0.5 color or the 1.0 color"... the spec is objective; human eyes are terribly subjective.

how do you set up a standard curve??

 

[THIEN LE]

Hi,
I am using this

Visible Spectrophotometer 721 Lab Equipment 350-1020nm 220v Tungsten Lamp for sale online | eBay

Find many great new & used options and get the best deals for Visible Spectrophotometer 721 Lab Equipment 350-1020nm 220v Tungsten Lamp at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Its not cheap for a hobbyist instrument, but very cheap for a research or teaching grade instrument. After using this for a few months I would say it is a very solid teaching grade instrument and a good tool for hobbyists. For comparison, this costs about the same as buying ~4 of the Hanna Checkers... but this one tool can do any number of different tests.

I took a gamble on this instrument and have been pleasantly surprised. I havent found any detectable problems. It identifies peak absorbance at the right wavelengths, suggesting the wavelength selection is reasonably accurate. It gives linear relationships with concentration in the expected ranges.

I've used this so far for NO2, NO3, and NH4 but really any colorimetric test should work. I could discuss these in more detail if there is interest.

This has been great because now I can do proper blanks and standard curves, and get objective readings. No more "is this closer to the 0.5 color or the 1.0 color"... the spec is objective; human eyes are terribly subjective.

Sound great. Your personal experience gives me a GO. The cheapest one is aboit $215 and has many positive review. Thank you Emeyer.

 

[Dana Riddle]

I use a Hach DR890 colorimeter that delivered results comparable to a $4,000 Hach spectrometer. The Hanna Checkers are good as well.

 

[THIEN LE]

Are all those models come with solfware cd ? The one Emeyer is using doesn't come with a CD as I checked on Ebay.

 

[EMeyer]

how do you set up a standard curve??

Using an analytical grade balance, I prepare a stock solution of known concentration. Then from that stock solution, I prepare a series of dilutions to produce a range of known concentrations. I use NaCl in RODI at seawater equivalent concentrations since some tests are sodium dependent. (For ammonia, I use instead an artificial seawater blank, but thats another discussion)

For any hobbyist test, I first run the test as directed using a solution of known concentration. This identifies the wavelength of peak absorbance.

I then prepare a series of tests again as directed using this time the dilution series of known concentrations, and read their absorbance at the peak wavelength.

From these data one can calculate the regression equation (y=mx+b) *. You then run your test as usual, read the absorbance, and calculate the concentration as x=(y-b)/m.
[Note that in theory if your blank is perfect and your readings have no error, in theory b=0. In the real world it is wise to measure and account for b]

All more or less standard procedures as I understand them. Probably more detail than you wanted, but there it is!

 

[EMeyer]

Are all those models come with solfware cd ? The one Emeyer is using doesn't come with a CD as I checked on Ebay.

Correct, this instrument does not connect to a computer at all. There are theoretically ways to do that but it doesnt appear plug and play. So no need for drivers because it cant connect to a computer anyway! :)

Its old school and really reminds me of undergrad chem classes, you put the cuvette in the machine then read the number off the digital screen.

It is so no-frills that even a simple USB connection was considered too much of a frill. But honestly, for $200ish I couldnt be happier. It appears to be a solid education grade instrument for the cost of a few Hanna checkers.

But it does require manual data entry on spreadsheets, or in a calculator, to use. There are no shiny apps.

 

[taricha]

All more or less standard procedures as I understand them. Probably more detail than you wanted, but there it is!

It's also same procedure people have used to figure out how to measure other color forming tests in Hanna checkers.

$200 is a nice find for a general purpose spectrophotometer. Very cool.

 

[ReefLab]

Correct, this instrument does not connect to a computer at all. There are theoretically ways to do that but it doesnt appear plug and play. So no need for drivers because it cant connect to a computer anyway! :)

Its old school and really reminds me of undergrad chem classes, you put the cuvette in the machine then read the number off the digital screen.

It is so no-frills that even a simple USB connection was considered too much of a frill. But honestly, for $200ish I couldnt be happier. It appears to be a solid education grade instrument for the cost of a few Hanna checkers.

But it does require manual data entry on spreadsheets, or in a calculator, to use. There are no shiny apps.

No that's great. Thank you. Wouldn't you just use the sample without the color-changing chemicals to zero the spectrometer before a test?
I figure creating the scale could become difficult when testing things like copper or other things that may be difficult to get ahold of reagents & the raw material to create known standards.

 

[EMeyer]

The blank in principle should be identical to the test solution, but with exactly zero of the compound being tested for. It should include the dyes etc from the test kit.

As far as getting your hands on chemicals, all I can say is I love the age of Amazon. You can order stuff that was previously only available through purchase accounts at scientific supply companies. And have it delivered in 1-2 days for free.

 

[Dana Riddle]

Just my opinion. Mixing standards from ACS raw chemicals is time consuming and can be expensive. Sure, it can be done if you've got a fully functional lab (analytical balance for instance.) So unnecessary when pre-programmed colorimeters and spectrophtometers are available but if extensive lab work is your thing, go for it!
Here's an article I wrote on a couple of Hanna Checkers.

Product Review: Inexpensive Analytical Devices: Hanna Instruments’ Checkers: Alkalinity and Phosphate

In many cases, results from colorimeters are superior to visually judging colored samples. Will an inexpensive device deliver results comparable to an expensive spectrophotometer? Dana tests the Hanna Checkers to find out.

www.advancedaquarist.com

 

[jordlr]

Isnt this the whole point of ICP tests done by Triton, ATI, Reef Colours etc...... I applaud you if you want to do it at home but these places have proper labs and high end equipment and surely by the time you buy all the chemicals, reagents, plot graphs, figure out if they are accurate etc it would just be cheaper and easier to do the simple tests yourself and ICP for the things you cant test for now and then?

 

[EMeyer]

I want to be clear that I'm not advocating this as something everyone needs to do. I had other reasons for needing a fully stocked lab. It just happened to come in handy for reefing too. Someone asked about using a spec so I thought I'd share this surprisingly cheap one.

Not everyone needs to be a huge lab geek :)

 

[EMeyer]

Just my opinion. Mixing standards from ACS raw chemicals is time consuming and can be expensive. Sure, it can be done if you've got a fully functional lab (analytical balance for instance.) So unnecessary when pre-programmed colorimeters and spectrophtometers are available but if extensive lab work is your thing, go for it!
Here's an article I wrote on a couple of Hanna Checkers.

Product Review: Inexpensive Analytical Devices: Hanna Instruments’ Checkers: Alkalinity and Phosphate

In many cases, results from colorimeters are superior to visually judging colored samples. Will an inexpensive device deliver results comparable to an expensive spectrophotometer? Dana tests the Hanna Checkers to find out.

www.advancedaquarist.com

I considered buying a selection of Hanna checkers instead to cover a few wavelengths but the interface turned me off. It wasnt clear to me that these units allowed basic operations like reading the raw absorbance of a blank or a standard... it looked like they are hard coded to do the calculations using built in coefficients and return calculated concentrations.

Many ways to get to the same end, though, and the Hanna checkers are a great option. Especially if one only wants to measure a couple different things, which is probably true for most reefers.

 

[LadyTang2]

I considered buying a selection of Hanna checkers instead to cover a few wavelengths but the interface turned me off. It wasnt clear to me that these units allowed basic operations like reading the raw absorbance of a blank or a standard... it looked like they are hard coded to do the calculations using built in coefficients and return calculated concentrations.

Many ways to get to the same end, though, and the Hanna checkers are a great option. Especially if one only wants to measure a couple different things, which is probably true for most reefers.

How closely do you think the hannah checkers come a spectrophotometer in terms of accuracy? I see Dana's article with the 2 (phos and alk) comparisons but am wondering if you have any experience or ideas as to how accurate the hannah checkers are.

 

[EMeyer]

I dont have direct experience with the Hanna checkers. I have no reason to suspect any problems with the hardware.

I chose a spectrophotometer because (a) it's one instrument for all tests, and (b) as I understand it, the Hanna checkers don't allow setting a blank or reading raw absorbance values.

Assuming the Hanna hardware is fine (which I assume), it should be possible to do the same thing with some workarounds using Hanna checkers, assuming you buy one for each wavelength you need.

 

[taricha]

@EMeyer does this mean you've worked out a concentration vs absorbance linear regression for multiple test kits that would work for any other spectrometer capable of measuring absorbance at those wavelengths?