Syringe needle

Schematic of a liquid-liquid microextraction showing syringe needle with attached 1-pL droplet.

Solid-phase microextractions also have been developed. In one approach, a fused silica fiber is placed inside a syringe needle. The fiber, which is coated with a thin organic film, such as poly(dimethyl siloxane), is lowered into the sample by depressing a plunger and exposed to the sample for a predetermined time. The fiber is then withdrawn into the needle and transferred to a gas chromatograph for analysis. 

A solid-phase extraction in which the solid adsorbent is coated on a fused-silica fiber held within a syringe needle. 

Catalytic hydrogenation. Aqueous solution of FMN (50 pM) containing a small amount of platinized asbestos is babbled with hydrogen gas for 10-20 minutes, until the yellow color and green fluorescence of FMN completely disappear. A suitable setup for this purpose can easily be constructed using a small flask, a rubber septum and two syringe needles (used as the inlet and outlet of H2 gas). 

A syringe pump was used for the addition of acid chloride in order to achieve a steady flow rate. The tip of the syringe needle (gauge 20) was submerged in the reaction mixture. Dropwise addition of trimethylacetyl chloride at 0-5°C resulted in the immediate formation of a precipitate. 

Nitrogen is introduced via a syringe needle that pierces the septum. A positive pressure of nitrogen is maintained in the apparatus during the following operations. 

In radiation sterilization of disposable supplies such as hypodermic syringes, needles, catheters, and sterile dressings in medicine. 

Simons FER. Chan ES. Gu X. Simons KJ Epinephrine for the out-of-hospital (first aid) treatment of anaphylaxis in infants is the ampule/ syringe/needle method practical J Allergy Clin Immunol 2001 108 1040-1044. 

Adsorption or catalytic decomposition of labile substances by the syringe needle can be a problem for some compounds using hot vaporizing injectors [25]. For open tubular columns deactivated fused silica syringe needles and cold on-column Injection techniques are used to minimize this problem. Alternatively, syringes fitted with a needle shroud for cold-needle injection can be used [26]. 

Maximum amount of sample enters the column %rhen the sample is released near the inlet of the column. This will depend on the design of the injector and the length of the syringe needle. 

Distance between syringe needle tip and capillary inlet... 

Reproduce penetration length of syringe needle into injector precisely. 

Filled needle Sample is taken up into the syringe needle without entering the barrel. Injection is made by placing the syringe needle into the injection zone. No mechanical movement of the plunger is involved and the sample leaves the needle by evaporation. 

Cold needle Sample is drawn into the syringe barrel so that an empty syringe needle is inserted into the injection zone. Immediately the sample is Injected by depressing the plunger. Sample remaining in the syringe needle leaves by evaporation. 

Silvery, shiny, and hard. Unique metal, gives off an odor as it forms volatile 0s04 on the surface (oxidation states 81). Osmium is the densest element (22.6 g cm3 record ). Was replaced in filaments (Osram) by the cheaper tungsten. Used in platinum alloys and as a catalyst. Haber s first catalyst in ammonia synthesis was osmium, which fortunately could be replaced by doped iron. The addition of as little as 1 to 2 % of this expensive metal increases the strength of steel (e.g. fountain-pen tips, early gramophone needles, syringe needles). 

Figure 26. EXAFS spectroelectrochemical cell (A) front view, (B) top view, (C) side view, (D) assembly (a) auxiliary electrode compartment, (b) working electrode well, (c) reference electrode compartment, (d) X-ray window, (e) inlet port, (f) auxiliary electrode lead, (g) RVC working electrode, (h) Pt syringe needle inlet and electrical contact, (i) Pt wire auxiliary electrode, (j) Ag/AgCl(3M NaCl) reference electrode. (From Ref. 98, with permission.)...

A syringe needle equipped with an argon-filled balloon should be inserted through the rubber septum on the reflux condenser. In addition, while the mixture is refluxing, the apparatus should be checked frequently for leaks. 

---