170135_inorganicventures_flipping

4:5 Sample Preparation

Preliminary Issues (cont.)

The following checklist should be considered prior to selec5ng a method:

✔ The iden5ty of the analytes and poten5al chemical forms. ✔ The concentra5on range(s) of the analyte(s) and the detec5on limit requirement(s). ✔ The chemical and physical composi5on of the sample matrix. ✔ The availability of apparatus and equipment. ✔ The sample size that is available or required. ✔ The poten5al for contamina5on during some part of the sample prepara5on process. Using the above informa5on, the analyst is in a posi5on to select the prepara5on technique. This involves choosing the mode of aCack (acid diges5on, ashing, fusion), the specific chemical reagents, and the container(s) materials needed to carry out the prepara5on. The analyst must keep in mind that contamina5on issues, plus any difficul5es within the final sample solu5on matrix, will have an impact upon the ICP-OES and/or ICP-MS measurement techniques

5:1 Container Material Proper2es

Materials Laboratories use many different container materials for handling samples during sample prepara7on. Some materials are more advantageous to use than others. In sec7on 5, we'll look at the proper7es of borosilicate glass, porcelain, quartz, pla7num, graphite, and plas7cs.

Borosilicate Glass:

• Borosilicate glass is used extensively. • It is resistant to most acids, but should not be used with HF or boiling H3PO4. • As a general rule alkaline solu7ons should not be heated or stored in borosilicate glass. • Borosilicate glass can contribute a variety of contaminants [Ca(1760), Si(170), Na(130), Fe(3), K(30), B(60), Mg(53), Al(50), Mn(1.2), Zn(22), Sr(1.3), Sn(0.8), Sb(0.4), Ba(17) -values are (ppb) obtained by leaching new borosilicate glass with 1 % HNO 3 for 7 days at 60 0 C]. • It should not be heated over temperatures achievable using a hot plate (500 ̍C). For example, if you need to ash a sample using a muffle furnace, do not use borosilicate glass.