SAMPLE PREPARATION and SUBMISSION INFORMATION ...
- Sample effectively and try to minimize contamination with clean containers and good technique.
- Filter samples with 0.2- or 0.45-micron filters when possible. Syringe filters work best.
- Refrigerate or freeze samples to be analyzed for nutrients or organic acids during storage before shipping.
- Take care in packing your shipping containers. Make sure all caps are tight and all bottles are properly labeled.
- No tape on the caps!
- If desired, acidify cation samples to pH 2 or less with ACS grade hydrochloric acid.
- Use plastic bags to separate samples and prevent cross contamination in case of leaks.
- Do not send samples in coolers unless you don't want them back or are willing to pick them up.
- Do not use cold packs in your shipping containers. It's a waste of time and money.
- If you have conductivity data for your samples, please include that in your shipping container or e-mail me a file containing that information. This will help me in assessing samples for possible dilution before analysis.
I will not be held responsible for samples lost in the mail or by your carrier. Please e-mail me using the contact page to let me know that your samples have been shipped, and I will then acknowledge their receipt when they arrive.
Shipping Address ... PLEASE, before submitting samples, read the shipping Summary above!
Rick Knurr
Ion Chrom Analytical
1395 5th St E
Saint Paul, MN 55106
MORE DETAILED INFORMATION ...
The analysis of samples in the lab by ion chromatography is fairly straightforward. The ionic species of interest are separated on an ion exchange column with the proper mobile phase (eluent) and detected by conductivity. The resulting chromatographic peaks are integrated and compared to the results of certified calibration standards to determine the unknown concentrations. The procedure produces very accurate and reproducible results if good analytical equipment and lab practices are used. Like any analytical procedure, however, the ultimate accuracy of the concentrations produced depends also on the sample itself. The instrument can only analyze what is in the sample that it sees. If the sample is not truly representative of the source, is contaminated, mislabeled, or allowed to change chemistry after sampling, the customer will get very precise but inaccurate results. It is, therefore, very important for the customer to make sure that the sample is collected properly, prepared properly, stored properly, and submitted properly to help get the right answers at the end.
Make sure that you first know what ions you are looking for and that you are sampling in a manner to properly represent those ions in the sample. When collecting samples use only clean polypropylene or polyethylene bottles. They are relatively cheap and easy to clean. Don't bother using Teflon unless you don't mind paying for me to send them back to you. I will, however, "gratefully" accept Teflon bottle donations. Do not use glass. Save the glass bottles for gas analyses. If possible, rinse the container several times with the sample before capping. If you are analyzing for nutrients (nitrate, nitrite, phosphate, thiosulfate) or organic acids (lactate, acetate, formate) and you want accurate results, you must filter the sample through a 0.2- or 0.45-micron filter first. I do not filter samples for customers here in the lab. If there is particulate matter visible in the samples, I will allow the samples to sit at room temperature until the particulates have settled to the bottom of the bottle. I will then sample the bottle without further mixing. This applies to both cation and anion samples. Nutrient, and particularly organic acid samples, may be sent frozen as a further precaution.
Do not send samples in containers that you want back, and don't bother sticking cold packs in the shipping container. They don't work long enough to be effective and then I'm stuck with their disposal. I have the facility to refrigerate samples once I receive them, but I will not keep samples frozen until analysis. Do not tape your bottle caps. That is a waste of your time putting it on and my time taking it off. Simply tighten the caps firmly and place all bottles in a sealed plastic bag before shipping. If you want to avoid any possibility of cross contamination during shipping, consider putting each bottle in a separate small Ziploc bag. If you are sending frozen samples, you should insulate the shipping container with Styrofoam and individually pack the samples in separate bags. Ship these samples overnight so that I can get them in a refrigerator as soon as possible. Cation samples do not need to be acidified unless you think that they are supersaturated on sampling (not very common). The cation species that I analyze for do not oxidize to form insoluble precipitates. I still highly recommend that you filter the sample, and if you wish to acidify, use ACS grade or better hydrochloric (recommended) or nitric acid. Acidify to pH 2 or less. Remember, acidified samples can not be analyzed for any anions other than sulfate, and maybe phosphate. If you want to analyze for both anions and cations from the same bottle, you should filter only, do not acidify!
Samples are run on a first come, first served basis. There are no "rush samples". PLAN ACCORDINGLY.