How hard is CG to get a handle on

[MichaelVW]

Hi Ben,

First off... I'm kind of shocked that no one even spot checks produce for pests... Really?

I wanted to ask a bit more about your goal and what resources are at your disposal. I'm curious, on the one hand, about much money, how much time, how many people, and how much space are to be devoted to this. On the other, I'd like to know how many samples you want to be able to run in a given amount of time, and what you want to be able to run them for.

You might want to look around for environmental contract labs. I don't know what is available in NZ, and how much it would cost to have someone else run your samples, but it's worth considering. At *least* do a pilot run where you send a batch of samples to a contract lab. You don't want to set up your own GC/MS just to find out that there really aren't any interesting results to report.

I don't know what kind of extraction and sample prep you need to do on food, but maybe you could try to convince an environmental lab to allow you to do those steps on your own and just have them run and analyze your extract. They might give you a break that way, and that would give you an idea of the workload involved in doing the extraction. Of course... I'm not sure I'd inject something into my GC that was prepared by a stranger off the street. Then again, some people get tattoos in the back of vans, so I donno. Maybe you can convince someone, especially if you have a lab background. (Keep in mind that if you prep the samples, the lab's certifications aren't really going to apply to them). If you can, and you find after some months that you like preparing samples yourself and you want to take a plunge into the instrumentation (supposing it's worth your time and you'll pass the economic break-even point by getting your own instrument) then let that be the next step.

Of course, if you're independently wealthy and bored, what you need to do is buy a GC/MS and fly me down first class to help you set it up. We'll end up back on this forum asking Peter, Don, et al. for help when we run into trouble but I swear I'll consider it a success regardless. I've been to NZ once before and I've never seen anywhere so beautiful, nor tasted anything as nice as a gas station meat pie, lol.

[NZBen]

I think products do get spot checked in NZ, but I believe its few and far between. The guy I knew who grew tomatoes never knew one grower who got checked. What I'm trying to accomplish, is not to make sure the goods fall within a certain "safe" guideline which may or may not be correct. But just give consumers the power of informed choice.

I havent got a big budget or finances, I could scrap together enough coin for a second hand machine plus a little extra for setup, consumables etc.

My apologies, the first class seat wont quite fit in the budget, will keep it in mind tho.

Since my last post I visited a lab with about 5 CG/MS and 2 HPLG/MS machines and learned quite a lot. The lab manager was very helpful and accommodating to my persistent and probably annoying question asking. It was interesting, however they mainly do just urine and not food. The manager seemed to much prefer the GC to the LC machines - but as I learned earlier the LC does have its place for degrading chemicals. However I've just read a paper on different setup parameters for heat degrading compounds, if anyone is interested I can try find the link and post it.

The compounds I'd like to look for obviously will depend on the product, for example if I do eggs I'll likely want to look for antibiotics, glyphosate (think GM corn). Fruit and veggies will want to look for things like pesticides, herbicides, fungicides, rodenticides. Canned foods I will look for the above where relevant plus things like BPA from the can lining, as with meat - over here meat comes on polystyrene trays - which apparently leach styrene - vinyl benzene.

There will only be me, and I would like to start off doing one food group per week, and for this I'm willing to dedicate a day. I will likely buy a machine with an autoloader for convenience plus repeatability. For sample prep I've found there are a cpl of quick methods available - pre-prepared kits many suppliers seem to be selling or quechers. I personally wouldnt feel comfortable asking someone to run my samples through their machines just in case... I suppose I might aim to do 6 samples on a day, so we are certainly not talking big numbers here.

Good suggestion about getting someone else to do some first, I'm going to talk with SGS tomorrow who do a lot of food testing here, get a price and a feel for what they typically find.

The other thing... even if the whole concept is not a particularly clever one, I love learning new things, plus I've always had an interest in analyzing materials. Some people like to build model boats in bottles. I could consider this to be an unusual hobby.

I'll let you know what I find out from SGS - what would a best guess $$$ be for food testing say 4 samples?

[Don_Hilton]

I don’t want to rain on a parade, but you have a wide range of potential analytes – and, therefore many analytical methods. Each method has to be set up and proven. If you just focus on a single analytical method, you need to establish that you can get good results – we are not talking a regulatory requirement here, but just to demonstrate to yourself and to anyone who would want to look at your results, that you can analyze samples and get correct answers and do so reproducibly. Without having run a single sample from the market place, you will already have spent a considerable sum on analyzing samples. And this takes a lot of time.

Do some digging and look up the methods you want to run and be sure the expected limits of detection are low enough to be meaningful. Calculate the quantities of reagents you will need to run a hundred samples. In setting up a method, it is not unreasonable that you might run even more than this number as you set things up and try things out. Include the cost of standards and disposal of the waste solvents. Also include consumables like GC inlet liners, septa, GC vials, sample vials or tubes (it is probably better to use disposable glassware than to have to ensure that you have properly cleaned glassware for reuse in a trace analytical method.), and any other supplies. You need volumetric glassware for diluting standards – if it does not say “Class A” you are probably looking at the wrong devices. You will note that the GC is quickly becoming not the major cost in an analytical laboratory.

Also, look at the facility in which you intend to work. The basement at home is not a good idea. A laboratory fire in the home with tens of liters of solvent stored there may result in the fire insurance claim being denied. And, be sure that you have checked to be sure that you have appropriate permits for operating a laboratory. It would not be a good day if law enforcement were to get you confused with an illicit drug lab. You need adequate ventilation for the use of solvents – probably a fume hood. And the use of solvents requires proper storage - in solvent cabinets or by other approved means of storage.

Note that if you intend to extract vegetable material in a blender, the type of blender available at the store will not do the job. Solvent vapors can enter the motor of such a blender and the extraction is over in a flash. You need explosion proof laboratory equipment for use around solvents.

Running an analytical laboratory is an expensive proposition – and one reason that monitoring by government agencies and watchdog groups is as few and far between as it is.

[MichaelVW]

I'll let you know what I find out from SGS - what would a best guess $$$ be for food testing say 4 samples?

Well, I send wastewater samples to a qualified lab for analysis, and pay about $90 USD per sample, depending on the test.