Small seeds, testing

The second scheme deals with larger types, like pea and bean seed, for which germination is much more laborious and critical For these seeds, dry homogenization has shown to be most efficient The following examples illustrate the procedures and problems in testing small seeds and larger seeds ... 

Prior to World War II the Forage Crop Division of the Experimental Farm Services, Canada Department of Agriculture, had obtained seed of both forage and oil rapeseeds and had distributed them for small plot tests at experimental farms and research stations across the country. These research plots indicated that rapeseed could be successfully grown in both Eastern and Western Canada. 

In order to obtain a representative test portion, the laboratory sample is rasped or ground to a fine meal (maximum dimensions of the grains 2-3 mm). The sample should not be reduced to an impalpable powder, generate heat or lose too much moisture. Small seeds (e.g. linseed, rapeseed) can be sampled without prior mechanical grinding. 

In the case of small seeds, the test portion should be ground taking care not to leave any seeds intact. The ground sample is transferred to an extraction thimble, which is placed in a suitable extraction apparatus provided with 250 ml flasks and an electrical heating bath. 

As a general rule flasks and similar vessels should be heated in an air bath (compare Fig. II, 5, 3). A glycerol bath may be employed for temperatures up to 140° the glycerol is subsequently removed from the outside of the vessel by washing with water. Medicinal liquid paraffin may be used for temperatures up to about 220° hard hydrogenated cotton seed oil, Silicone fluids or fusible metal may be employed when higher temperatures are required. Small test-tubes and centrifuge tubes... 

Once a suitable strain is available, the prachce is to grow, often ftom a single organism, a sizeable culture which is distributed in small amounts in a large number of ampoules and then stored at 70°C or freeze-dried. This is the seed lot. From this seed lot, one or more ampoules are taken and used as the seed to originate a limited number of batches of vaccine which are first examined exhaustively in the laboratory and then, if found to be satisfactory, tested for safety and efficacy in clinical trials. Satisfactory results in the clinical trials validate the seed lot as the seed from which batches of vaccine for routine use can subsequently be produced. 

Both materials were tested as catalysts in the anisole acylation (Scheme 1). The conventional Beta sample showed a slightly higher activity than the Beta (PHAPTMS). At 3 hours, the conversions were 26.8 and 22.8 % for the conventional and seed silanized catalysts, respectively. This behavior is explained as a consequence of the relatively small size of the anisole molecule, which allows this compound to diffuse without significant hindrances through the zeolitic micropores, and of the slightly weaker acidity of the Beta (PHAPTMS) sample. In both cases, p-methoxyacetophenone (p-MAP) was the main reaction product, being obtained with a high selectivity (> 97%). 

Early on in the drug development program, only small amoimts of material are available for crystallization studies. Parallel crystallization technique in test tubes allows for the identification of many solvent systems using small amoimts of material. On a small scale, it is not easy to control the rate of cooling or the rate of evaporation to achieve supersaturation. However, the antisolvent addition strategy to achieve supersaturation in combination with seeding, allows rapid identification of several crystallization systems using a minimum amount of compound. 

Some legal products actually contain small amounts of illegal chemicals. All tests, including the GC/MS, will test you positive because the metabolites derived from the true positive are identical to the metabolites of the illegal drugs. One exception poppy seeds will not cause a positive GC/MS (explained below). 

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