Environmental Express StirBase - Manual (Page 6)

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StirBaseTM: Operation and Instruction Manual EPA Method 3060A
1.0 Scope and Application
1.1 The following procedures have been written as an aid to EPA Method
3060A for use with the Environmental Express HotBlock TM and StirBase TM .
EPA Method 3060A is an alkaline digestion procedure for extracting
hexavalent chromium [Cr(6+)] from soluble, adsorbed, and precipitated
forms of chromium compounds in soils, sludges, sediments, and similar
waste materials. Use EPA Method 3060A for reference while following
the sample preparation steps outlined below. The quantification of Cr6+
in Method 3060A digests should be performed using a suitable technique
with appropriate accuracy and precision.
2.0 Apparatus and Materials
2.1 HotBlock TM for sample digestion – Model Numbers SC100, SC154, SC150,
or SC151
2.2 StirBase TM stirring device – Catalog Number SC160
2.3 Polypropylene Digestion Vessels – Catalog Number SC475 (or SC490 for
use with the SC150 or SC151 HotBlocks TM )
2.4 Ribbed Watch Glasses – Catalog Number SC505 (or SC610 for use with the
SC150 or SC151 HotBlocks)
2.5 Reflux Caps – Catalog Number SC506 (used as an alternative to the SC505
only)
2.6 Stir Bars – Catalog Number SC168 10/pk (each StirBase TM comes standard
with 6 packs of 10)
2.7 FilterMate TM – Catalog Number SC0407 (or appropriate FilterMate TM ) for
sample filtration if necessary
2.8 FlipMate TM – Catalog Number SC0301 (or appropriate FlipMate TM ) for
sample filtration if necessary
3.0 Procedure, Solid Sample Preparation
3.1 Place 2.5 +/- 0.10 g of the field-moist sample into a clean and labeled
digestion vessel. Mix the sample thoroughly before the aliquot is
removed.
3.2 For the specific sample aliquot being spiked, the spike material should
be added directly to the sample aliquot at this point.
3.3 Add 50 mL +/- 1 mL of digestion solution to each sample using a
graduated cylinder, and also add approximately 400 mg of magnesium
chloride and 0.5 mL of 1.0M phosphate buffer. For analytical techniques
that can correct for oxidation/reduction of Cr, the addition of Mg(2+) is
optional. Cover all samples with watch glasses or reflux caps.
3.4 Stir the samples continuously (unheated) for at least five minutes using
the StirBase TM .
3.5 Heat the samples to 90 - 95ºC, then maintain the samples at 90 - 95ºC for
at least 60 minutes with continuous stirring.
Adaptation for EPA Method 3060A for use with the
Environmental Express HotBlock
TM and StirBase TM Digestion System