Pre-packed

The bare foot completion, which leaves an open hole section below the previous casing, is cheap, simple and suitable for consolidated formations which have little tendency to collapse. The slotted liner s an uncemented section of casing with small intermittent slots cut along its length, which prevents the hole from collapsing, but allows no selectivity of the interval which will be produced. The cased and cemented horizontal completion does allow a choice of which intervals will be perforated and produced. None of these examples provides any effective sand exclusion it this is required a gravel pack or a pre-packed liner can be used. 

Bearings pre-packed with grease will function for extended periods without attention. Another advantage is the almost complete elimination of drip or splash, which can be a problem in certain applications. Grease is also able to operate effectively over a wider range of temperatures than any single oil. 

Another modern trend is the increased sale of filled rolls and prepacked sandwiches. The sale of filled rolls provides many small bakers with a very satisfactory source of profit. The manufacture of pre-packed sandwiches is now a large industry, consuming large quantities of bread. Such sales growth is obviously caused by a population that is short of time rather than money. 

Partisil PXS 10/25 PAC pre-packed Magnum 9 column with a mobile phase of methanol pH 3 0,1 M citrate buffer 85 15 with a flow rate of 1.6 ml/min. The retention time of the dicarboxylic acid was 12 minutes. 

Use calendar packages or dosing aid equipments. In some countries pharmacy pre-packed multi-dose bags (one for each scheduled time) are available. 

A fourth factor is the flow rate of the eluent (mobile phase). A too high rate decreases resolution because there is no time for molecules to diffuse into the pores of the matrix. In contrast, a very slow migration of solvent decreases the resolution by remixing the components by diffusion. The effect of diffusion is minimized if the chromatography is done at low temperature. If short separation times are necessary, pre-packed columns, elevated pressure, or HPLC columns are indispensable. 

Scalia S (1990) Group separation of free and conjugated bile acids by pre-packed anion-ex-change cartridges. J Pharm Biomed Anal 8 235-241... 

Many packing materials are available only in pre-packed columns and, in this respect, packing can be avoided altogether. However, the cost of pre-packed columns is extremely high, and this is one of the most undesirable features of HPLC at present. 

The handling of solid sorbents, often used in pre-packed tubes, is more convenient than the use of organic solvents to trap VOCs from the air, especially for sampling in the field. The typical laboratory safety procedures required for the handling of organic solvents are not required for solid sorbent samples. 

To a solution of 5 (30 mg, 0.114 mmol) in dry degassed CH2C12 (25 mL) was added, via syringe, a solution of ruthenium alkylidene catalyst G1 (5 mg, 0.006 mmol) predissolved in CH2C12 (6mL). The resulting purple solution was heated to 45 °C for 21 h and then concentrated under reduced pressure to afford an oily brown residue. Purification by MPLC [pre-packed silica gel column 2 x 50 cm, eluent ethyl... 

Preparative HPLC can be carried out in pre-packed HPLC columns or self-pack systems (e.g. DAC columns). The conditions used to slurry pack various self-pack hardware is discussed in Chapter 4. 

Hibar 250-4 pre-packed with 5 micron NH2. It has been found that frequently a single 250 mm column does not give adequate separation tissue substances. Normally the chromatography is done using two 5 micron NH2 columns such as Lichrosorb 50376. 

When concentration data for the chemical(s) of concern are considered it is necessary to relate them to their actual relevance. For example, do we use values at the highest level permitted, highest reported, mean or median or, most importantly, in the foodstuffs consumed In addition if the consumer purchases one or more pre-packed foodstuffs and then prepares a meal from them how are any potential migrants from the processing considered ... 

For some very non-polar compounds, even small quantities of dichloromethane may cause elution problems and an alternative method of loading can be used. Thus, a solution of the sample is added to a small amount of silica in a round bottom flask and the mixture is evaporated to dryness. The dry impregnated silica is then added to the top of the pre-packed column. 

Injectable drag products are often pre-packed into vials that are inserted into syringe barrels for delivery into the patient. In some cases, the vials contain contaminants. In one instance, the drag in this vial was found to contain acetophenone, dibutyl phthalate, stearic acid, and myristic acid, none of which are components of the drag formulation. These substances each have negative health implications and are regulated for various applications. 

Use pre-packed columns of Sephadex G-25 gel filtration media, for rapid sample clean-up at laboratory scale, as shown in Table 2. 

Pre-packed column Sample volume loading per run Sample volume recovery per run Code No. 

Xlf a purification is not intended for scale up (i.e. only milligram quantities of product are needed), use high performance, pre-packed media such as Sepharose High Performance (IEX, HIC), SOURCE (IEX, HIC), MonoBeads (IEX), or Superdex (GF) for all steps. 

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