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The feed and fertilizer lab is responsible for the analysis of manufactured fertilizers and animal feeds in North Dakota to verify that the stated claims on the package are accurate and meet the regulatory specifications--essentially that the consumer is getting what they pay for. Analyses include protein, moisture, fat, and minerals such as calcium and salt in feeds; and Nitrogen, Phosphorus, potassium, and micro nutrients such as copper and zinc.
Products in both areas are picked up by inspectors that are employed by the Department of Agriculture. The inspectors go to elevators around the state and collect samples either as they are manufactured for sale or from bags stored in the warehouse. Inspectors also go to local stores in their areas and buy products that are packaged. These packages range in size from small, such as fish food packages that contain only a few ounces, to that of the larger pet food bags.
Instrumentation in this laboratory includes balances, computers and a combustion analyzer. The combustion analyzer is used to test products for their nitrogen content. This nitrogen content is either used as a strict percentage in the case of fertilizers, or is converted to equivalent protein through the use of a conversion factor for feed analysis.
In the feed area, a wide variety of samples are tested. These range from cattle feed to turtle food. The manufacturer of the product guarantees certain levels of protein, fat, fiber, moisture, ash, and various minerals.
This lab checks the products for these guaranteed levels, also referred to as claims. These claims either appear on the label that is given to the consumer at the manufactured site, such as elevators or feed stores, or are stated on the bags, such as pet foods.
The analysis performed in this lab is used by the North Dakota Department of Agriculture for the regulation of these products to ensure that the consumer is getting what they pay for.
Some of the techniques used in this lab range from the simplest, such as gravimetric analysis for claims such as moisture, fat and ash to the more complex, such as Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analysis for minerals such as calcium and salt.
The fertilizer section of this lab follows the same criteria as does the feeds, however, they look for other types of claims such as nitrogen, phosphorus, and potash, also known as potassium. There are also micro nutrients that are tested for. An example of these micro nutrients are copper and zinc.
Again, the analysis techniques used in here range from the more pedestrian gravimetric techniques or titrations to the more advanced atomic absorption. As an example of the types of tests and their uses, gravimetric tests are used to determine phosphorus levels, titrations to determine potash levels and atomic absorption is used to determine micronutrient levels.
While as the feed section receives samples year round, the fertilizer section has two main heavy seasons: midwinter and early spring. Midwinter is when the elevators are filling bins with straight fertilizers that will be used to make blended fertilizer in early spring. These blends are then tested for accuracy. Straight fertilizers are made up of one constituent while blended fertilizers are made up of more than one constituent. The blended products are sampled as they are loaded into the farmers truck. The inspector takes the farmers name and address so that he may receive a copy of the analysis. This ensures that the farmer knows whether or not he received the product he purchased.
The mineral lab tests samples such as drinking water, ground water, surface water and sediments. In most instances the samples are collected by department personnel who are trying to determine such things as environmental impact, fitness of water supply, general water quality, and possible sources of contamination. Examples include hardness/softness of water, sodium level, calcium, nitrates, sulfates, etc.
Depending on the parameter of interest, the
laboratory will utilize differing instrumentation. Instrumentation in the laboratory
The organic residue laboratory is responsible for testing samples for trace amounts of organic compounds, usually insecticides and herbicides. Samples include drinking water, lake and river waters, soil, sediment, fish, milk, vegetation etc. Some of the residues we look for include Round-Up, Treflan, Tordon, Far-Go, PCB's (polychlorinated biphenyl), and 2,4-D. Many of these coumpounds are regulated by the Environmental Protection Agency (EPA). These chemicals are used by farmers and you may have used them yourself in your garden or around your house.
Organic compounds are compounds that contain carbon. Trace means that we look for very small amounts of the chemicals. For example, we look at the part per million level for chemicals. That means that 1 part of 1 million parts is what we look for. If we assume that North Dakota has about 600,000 residents, then each of us is about 1.7 ppm of the North Dakota population.
Our samples are most commonly water, which means that we look for the chemicals in water. We also get soils, sediments, foliage, and fish as samples. We have in the past tested birds and one time got a t-shirt to analyze. No matter what the sample is, there is usually some type of sample preparation to be done and this usually means concentration of the chemicals that we are looking for. We extract most of our samples by liquid/liquid extraction, starting with 1 liter of water in a seperatory funnel/EP Tox jar. The extractions are performed by shaking the separatory funnels or rotating the EPTox jars on the rotator with the water sample and a solvent, usually an organic solvent called dichloromethane. The basis for extraction is that the chemicals we look for would rather be in the organic solvent that in the water, so when the funnel is shaken, the chemicals are pulled from the water to the dichloromethane. This step is repeated twice and the extracts are collected. This takes care of the extraction part of sample preparation. The next step is to concentrate the chemicals that we are looking for and we do that by evaporation. Evaporation of organic solvents is much faster than evaporation of water. By the time evaporation is done, the sample volume will be reduced to 1 milliliter from 1 liter which is a thousand-fold concentration. At this point, the samples are ready to be analyzed. There are other ways to extract samples that utilize automation, but for now the EPA requires us to do the liquid/liquid extraction.
Most of our samples are analyzed by a technique called gas chromatography, or GC for short. It's called gas chromatography because it uses a gas, usually helium or hydrogen, to separate compounds. A gas chromatograph is basically a fancy oven with a GC column inside. A GC column is a long, very narrow glass tube with a special coating on the inside of the column. The autosampler will take a very small portion of the sample and inject onto the GC. The sample is vaporized by high temperatures. The gas (helium or hydrogen) then gets involved. The gas will start to move the compounds down the column. The compounds have different affinities for the coating on the inside of the column. Some compounds will stick to the column for a short time while some will stick for longer times. At the end of a column is a device that can measure a change in current caused by the release of electrons from the compounds of interest. These devices are called detectors and the one just described is an electron capture detector. The result is called a chromatogram where each peak is an individual compound and the time it takes to come out can be used to identify and quantify the chemicals. We also inject known chemicals at known amounts, called standards, and compare our samples to them. From the standards, we can calculate how much is present in our samples. We also use a technique called liquid chromatography, which uses liquids to separate chemicals. In this case a metal column is filled with particles that have a special coating on them. The liquid is pumped through the column and the chemicals alternate time between the liquid phase and the solid phase(coating). The more time in the liquid phase, the faster the chemical will come out of the column and be detected by UV absorbance or fluorescence.
The petroleum laboratory is responsible for testing gasoline and diesel taken from the same pumps where you buy your petroleum product. Basically we test the petroleum to guarantee that the consumer is buying a product that will keep their vehicles running. The samples are tested to guarantee the quality of the gas/diesel by nationally established criteria set forth by American Standards Testing Methods. Examples of the testing in this laboratory include octane rating of gasoline and ethanol percentage in the gasohol.
This is the petroleum laboratory, in the organic chemistry section. This lab is a regulatory section. Inspectors go out to all the gas stations in the state, and all the pipeline terminals. They randomly pick up samples of gas and diesel throughout the state. The gas samples are processed on a gas chromatogram through simulated distillation and if the sample fails the parameters allowed on this instrument, a manual distillation is done on a manual distillation unit.. The distillation determines the quality of the gasoline and diesel. It also indicates the tendency for vapor lock in the engine. Two laboratory engines determine what the octane is on each gas sample, one is the motor engine and the other is the research engine. The octane is the number which is posted on the pump at the gas station. We make sure that the simulated distillation and the octane on each sample are what the claim says they are supposed to be. We also check for ethanol and water and sediment on each sample. In diesel we again do a distillation, check for water and sediment, and do specific gravity. Again these must meet state specifications. Sometimes samples are right along the border of the state, meaning, some come from South Dakota, Minnesota, and even Canada. However, if they sell them in North Dakota, they must meet our specifications.
The radiation area primarily is utilized for the
analysis of radium 226 in drinking water and radon in air. We have also been involved in
some special projects in the past including:
Instrumentation in this area includes:
The spectroscopy laboratory consists of two distinct areas, the demands area and the metals area. The demands area tests water from lagoons or sewage treatment facilities for the biochemical oxygen demand and total suspended solids. This information is used to determine whether the lagoon can be discharged into the natural environment without contaminating or polluting the ecosystem. The metals area tests samples for metals. Samples include drinking water, lake and river waters, soils, sediments, fish, and paint. Some of the analyses include mercury in fish, lead in paint, lead and copper in drinking water, metals such as chromium and cadmium in landfill samples.
Instrumentation in this laboratory includes balances, pH meters, and four different instruments which measure metals in varying amounts and with varying amounts of productivity:
FlAAS: Flame Atomic Absorption Spectrometer
The metals area receives samples for testing from various sources, i.e. drinking water, river and lake water, sediments, fish, TCLP extracts, and paints. In most instances the samples are collected by department personnel who are trying to determine such things as environmental impact, fitness of water supply, possible sources of contamination, etc.
Depending on the sample matrix and the expected level of the parameter of interest, the laboratory will utilize differing instrumentation. The uses of the varied instruments is outlined above.
Some special projects which have been performed
in the metals area include:
The demands area receives samples from various municipalities around the state in addition to samples which were collected by department staff. Typically the sample is taken from a sewage lagoon or other water treatment facility. It is this area's responsibility to determine such parameters as biochemical oxygen demand and total suspended solids. The results of these tests are used to determine the effect on the environment if the water was to be discharged from the lagoon. If the wastewater is determined to be at a safe level, the water may then be discharged to the natural environment. This evaluation of whether or not to allow a municipality to discharge is handled by the permits area of the Water Quality Division. Typically the sample needs to be at or below a 5-day biochemical oxygen demand level of 25 mg/L.
Special projects in this area include the analysis of both the Red River and the James River to determine the impact of water treatment plant upgrades on the receiving stream. A test known as an ultimate biochemical oxygen demand is utilized in these instances.
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