Determination

Container

Sample size mL

Preservation

Storage recommended/ Regulatory (1)

Acidity

P, G(B)

100

Refrigerate

24 h / 14 d

Alkalinity

P, G

200

Refrigerate

24 h / 14 d

BOD

P, G

1000

Refrigerate

6 h / 48 h

Boron

P

100

None required

28 d / 6 months

Bromide

P, G

-

None required

28 d / 28 d

Carbon, organic, total

G

100

Analyze immediately or refrigerate and add HCl to pH<2

7 d / 28 d

Carbon dioxide

P, G

100

Analyze immediately

Stat/ N.S.

COD

P, G

100

Analyze as soon as possible or add H₂SO₄ to pH<2, refrigerate

7 d / 28 d

Chlorine, residual

P, G

500

Analyze immediately

0.5 h / Stat

Chlorine dioxide

P, G

500

Analyze immediately

0.5 h / N.S.

Chlorophyll

P, G

500

30 d in dark

30 d / N.S.

Color

P, G

500

Refrigerate

48 h / 48 h

Conductivity

P, G

500

Refrigerate

28 d / 28 d

Cyanide

Total

P, G

500

Add NaOH to pH>12, refrigerate in dark

24 h / 14 d (24 hIf sulfide present

Amenable to chlorination

P, G

500

Add 100 mg Na₂S₂O₃/ L

Stat / 14 d (24 hIf sulfide present

Fluoride

P

300

None required

28 d / 28 d

Hardness

P, G

100

Add HNO₃ to pH<2

6 months / 6months

Iodine

P, G

500

Analyze immediately

0.5 h / N.S.

Metals, general

P(A), G(A)

-

For dissolved metals filter immediately, add HNO₃ to pH<2

6 months / 6months

Chromium VI

P(A), G(A)

300

Refrigerate

24 h / 24 h

Copper by colorimetry

Mercury

P(A), G(A)

500

Add HNO₃ to pH<2, 4ºC, refrigerate

28 d / 28 d

Nitrogen

Ammonia

P, G

500

Analyze as soon as possible or add H₂SO₄ to pH<2, refrigerate

7 d / 28 d

Nitrate

P, G

100

Analyze as soon as possible or refrigerate

48 h / 48 h (28 d for chlorinated samples)

Nitrate + nitrite

P, G

200

Add H₂SO₄ to pH<2, refrigerate

None / 28 d

Nitrite

P, G

100

Analyze as soon as possible or refrigerate

None / 48 h

Organic Kjeldahl

P, G

300

Refrigerate, add H₂SO₄ to pH<2

7 d / 28 d

Oil

G

500

Analyze as soon as possible, refrigerate

6h / N.S.

Oil and grease

G, wide-mouth calibrated

1000

Add H₂SO₄ to pH<2, refrigerate

28 d / 28 d

Organic compounds

Pesticides

G (S), TFE-lined cap

-

Refrigerate; 1000 mg ascorbic acid/ L if residual chlorine present

7 d / 7 d until , 40 d after extraction

Phenols

P, G

500

Refrigerate, add H₂SO₄ to pH<2

7 d / 28 d

Purgeables by purge and trap

G, TFE-lined cap

50

Refrigerate, add HCl to pH<2, 1000 mg ascorbic acid/ L if residual chlorine present

7 d / 14 d

Oxygen, dissolved:

G, BOD bottle

300

Electrode

Analyze immediately

0.5 h / Stat.

Winkler

Titration may be delayed after acidification

8 h / 8 h

Ozone

G

1000

Analyze immediately

0.5 h / N.S.

pH

P, G

-

Analyze immediately

2 h / Stat.

Phosphate

G(A)

100

For dissolved phosphate filter immediately; refrigerate

48 h / N.S.

Salinity

G, wax seal

240

Analyze immediately or use wax seal

6 months / N.S.

Silica

P

-

Refrigerate, do not freeze

28 d / 28 d

Sludge digester gas

G,gas bottle

-

-

N.S.

Solids

P, G

-

Refrigerate

7 d / 2-7 d see cited reference

Sulfate

P, G

-

Refrigerate

28 d / 28 d

Sulfide

P, G

100

Refrigerate, add 4 drops 2N zinc acetate/100 mL, add NaOH to pH>9

28 d / 7 d

Taste

G

500

Analyze as soon as possible, refrigerate

24 h / N.S.

Temperature

P, G

-

Analyze immediately

Stat. / Stat.

Turbidity

P, G

-

Analyze same day; store in dark up to 24 h, refrigerate

24 h / 48 h