Low preparation

Prepare calibration standards of 1.0,2.0,3.0, and 4.0 ppm iron from the 100 ppm stock in 50-mL volumetric flasks, but do not dilute to the mark until step 6. Also prepare a flask for the blank (no iron). If real water samples are being analyzed and you expect the iron content to be low, prepare two additional standards that are 0.1 and 0.5 ppm. 

C.E. Lowe, Preparation of high molecular weight polyhydroxyacetic ester, US Patent 2668162, assigned to DuPont, February 2,1954. 

The application of CE for preparative separations of peptides and proteins is limited due to the low preparative capacity of capillary columns. In addition, adaptation of an analytical capillary system to a preparative one is not straightforward and requires certain modifications of CE instruments [2,22], Several procedures for fraction collection from a capillary have been developed recently, as reviewed in Ref. 22. For continuous fraction collection in CE it is necessary to modify the capillary outlet to complete the electrical circuit. Karger and coworkers achieved this by using a coaxial sheath liquid interface to transport the sample components leaving the capillary exit into the collection microcapillary... 

While aromatic cyanates in their pure state tend to be quite stable compounds, their aliphatic counterparts very often prove to be extremely unstable molecules with an accordingly low preparative value. 

The PIC emulsification method for preparation of microemulsions enjoys many advantages, such as low preparation cost, absence of organic solvents, good production feasibility, long stability, and thermodynamic stability." ... 

Due to the low preparation cost, monolayer polymeric membranes have been widely used as separators for LIBs. However, limited by the relatively single function of mono-layer polymeric membranes with relatively poor puncture strength and thermal stability, monolayer polymeric membranes may not be able to meet many application demands. 

Although direct drying has many advantages, such as simple operation, low preparation cost, and equipment investtnent, it is difficult to obtain high-grade nanomaterials by this method due to excessive agglomeration. 

Advantage of this method Very low preparation tolerance. Independent from pressure, temperature and compressibility. This method is supported by standards (e.g. ISO 6142) [9.14]. 

If a low recovery factor (less than 95 %) occurs, prepare fresh standards. If the recovery factor remains low, prepare new electrolyte, or new electrode solutions, or both. If the recovery factor still does not fall in the proper range, review the procedural details. 

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