Vibrating Ball Mills

If an analyte is definitely insoluble or only soluble in solvents that are not acceptable for the standard MALDI sample preparation technique, it can alternatively be ground together with the solid matrix, preferably in a vibrating ball mill. The resulting fine powder is then spread onto the target. To avoid contamination, nonadherent material should be gently blown away from the target before insertion into the ion source. [103,108,109]... 

The pellet (pressed-disk) technique depends on the fact that dry, powdered potassium bromide (or other alkali metal halides) can be compacted under pressure in vacuo to form transparent disks. The sample (0.5-1.0 mg) is intimately mixed with approximately 100 mg of dry, powdered KBr. Mixing can be effected by thorough grinding in a smooth agate mortar or, more efficiently, with a small vibrating ball mill, or by lyophili-... 

In order to obtain absolute measurements of spin concentrations, a series of standards was made up, which consisted of known weights of diphenyl-picrylhydrazyl (DDPH) diluted with potassium chloride (the mixtures were mended in a vibrating ball mill). A suitable standard was run immediately after each unknown at identical settings of instrument gain so that recorder traces of standard and unknown could be directly compared. 

The pellet (pressed-disk) technique depends on the fact that dry, powdered potassium bromide (or other alkali metal halides) can be compacted under pressure to form transparent disks. The sample (0.5-1.0 mg) is intimately mixed with approximately 100 mg of dry, powdered KBr. Mixing can be effected by thorough grinding in a smooth agate mortar or, more efficiently, with a small vibrating ball mill, or by lyophilization. The mixture is pressed with special dies under a pressure of 10,000-15,000 psi into a transparent disk. The quality of the spectrum depends on the intimacy of mixing and the reduction of the suspended particles to 2 gm or less. Microdisks, 0.5-1.5 mm in diameter, can be used with a beam condenser. The microdisk technique permits examination of samples as small as 1 fxg. Bands near 3448 and 1639 cm-1, resulting from moisture, frequently appear in spectra obtained by the pressed-disk technique. 

Villiers MM, Tiedt LR. An analysis of fine grinding and aggregation of poorly solubile drug powders in a vibrating ball mill. Pharmazie 1996 51 564-567. 

Crushing. Byrskii et al. (8) used a vibration ball mill to study the volatile compounds released from a series of crushed polymers. They chose this method to intensify the mechanical degradation process and thus to increase the rate of volatile evolution from the polymer. For polymers such as polyethylene (PE) and polytetrafluoroethylene (FIFE), compound evolution rates are low from other methods of mechanical deformation hence, it is difficult to obtain mass spectra. Byl skii et al. used this technique to successfully obtain mass spectra of compounds from PE and PTFE and demonstrated the feasibility of the vibration ball mill for performing kinetic studies of mechanical degradation as a function of the amplitude of the vibration and duration of the grinding. 

Home-made high-speed vibrational ball mill, 3500rpm, chalcone.ethyl acetoacetate K2CO3 1 1 0.1mol. 

By building their own vibration ball mill, Shayesteh and coworkers obtained 100% conversion in just 12 min at 30 Hz for cross-dehydrogenative coupling (CDC) of 2-naphthol [62]. In comparison, the Toda s mortar grinding and above described method by Rasmussen et al. needed 2 and 1 h, respectively. On operation condition of 30 Hz vibration ball mill gives better performance in comparison to other commonly used methods such as ball mill and mortar and pestle, due to higher mechanical... 

The first account on 1,2-dione/diamine condensation carried out mechanochemically was given by Zefirov, who investigated solid-phase synthesis of benzo[Mphenazme 3 by reaction of phenylenediamine 1 with 2,3-naphthoquinone 2 (Scheme 3.1) [1]. Synthesis was carried out in an SVM-0.4 vibrational ball mill (120mL chamber volume). Cascade reaction mechanism consists of the four reactions substitution, elimination, cyclization, and elimination. 

Retsch MM400 vibrational ball mill, stainless steel capsule (25mL), one ball (15mm, 13.6g),... 

Li Z, Jiang Z, Su W. Fast, solvent-free, highly enantioselective three-component coupling of aldehydes, alkynes, and amines catalysed by the copper(II)pybox complex under high-vibration ball-milling. Green Chem 2015 17 2330-4. 

Table 21.1 Samples prepared by vibrational ball milling for 90 min at 30 Hz, their molar and weight ratio, success in amorphization, glass transition temperature (Tg), presence of molecular interactions in the co-amorphous mixtures, their physical stability at 40 °C under dry storage conditions, and intrinsic dissolution rate...

Vibro-energy Mill. Trade-name a VIBRATING BALL MILL (q.v.) designed to oscillate both horizontally and vertically, the vertical motion being of small but sufficient amplitude to prevent the charge from becoming tightly packed. 

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