Product Name:	Chromium Release Assay (BA0019)
SKU:	BA0019
Detection Method:	Colorimetric (OD 480 nm)
Detection Range:	20 - 2000 µg/L Chromium; detection limit 20 µg/L
Sample Type:	['Serum', 'Plasma', 'Water', 'Soil', 'Food', 'Beverages']
Species Reactivity:	All
Assay Time:	20 minutes
Kit Size:	250 Assays
Equipment Required:	Microplate reader
Storage:	Reagent A at -20°C; all other reagents at 2-8°C
Shelf Life:	6 months after receipt
Shipping:	Room Temperature

Chromium is widely used in various industries such as electroplating, leather tanning, chrome paint, dyeing, hardened steel, ceramic and glass. Chromium exists in two stable oxidation states, hexavalent Cr(VI) and trivalent Cr(III). Cr(VI) is produced solely by industrial processes, whereas in nature chromium exists in its trivalent form. Cr(III) is generally regarded as non-toxic due to poor absorption, whereas Cr(VI) is considered a pulmonary carcinogen, has tested positive in genotoxicity tests and is one of the most serious pollutants in many water streams. This kit provides a simple one-step colorimetric means to directly measure Cr(VI) in a sample, in which Cr(VI) forms a stable complex with a specific chromogenic dye and the optical density at 480 nm is directly proportional to the Cr(VI) concentration. Cr(III) can be converted to Cr(VI) with nitric acid/hydrochloric acid, allowing the determination of Cr(III) or total Cr. The assay is sensitive with a detection limit of 20 µg/L Cr.

Sensitive and accurate. Linear detection range of 20 - 2000 µg/L Chromium.
Convenient and high-throughput. Homogeneous mix-incubate-measure type assay with no wash or reagent transfer steps that can be readily automated for processing thousands of samples per day.

Determination of chromium in biological (serum, plasma etc.), environmental (water, soil etc.), food and beverage samples.

Note: The below protocol is a sample protocol. Protocols are specific to each batch/lot. For the correct instructions please follow the protocol included in your kit.

Step	Procedure
1	Bring all reagents to room temperature and use clear flat-bottom plates. Ensure samples are clear, colourless and free from particles or precipitates; substances that may interfere include azide, Ba2+, Pb2+, Fe3+, gold(III), Sn(II) and Ti(IV). If necessary, concentrate water samples by evaporation, and refer to the general sample treatment procedure to determine Cr(III) or total chromium.
2	Prepare standards: make 600 µL of 2000 µg/L Cr(VI) Standard Premix by mixing 30 µL Standard and 570 µL deionised water, then dilute as described in the standard curve table. Transfer 250 µL standards into separate wells of the plate.
3	Transfer 250 µL of each sample into separate wells of the plate.
4	Prepare enough Working Reagent by mixing, for each well, 1 µL Reagent A and 55 µL Reagent B. Add 50 µL Working Reagent to each well and tap the plate to mix. Incubate for 20 min at room temperature.
5	Read the optical density at 480 nm (usable range 430-505 nm).

Subtract the blank control OD (#4) from the OD values of the standards, plot the standard curve and determine its Slope. [Cr(VI)] = [(OD_Sample - OD_Blank) / Slope] x n (µg/L), where OD_Sample and OD_Blank are the OD_480nm values of the sample and blank control (#4) and n is the dilution factor. If the sample Cr(VI) concentration exceeds 2000 µg/L, dilute the sample in deionised water and repeat, multiplying by n. Conversion factor: 1000 µg/L chromium is equivalent to 19.2 µM or 1 ppm.