Page 76 - Modern Analytical Chemistry

1400-CH04 9/8/99 3:53 PM Page 59

Chapter 4 Evaluating Analytical Data 59

4
Table .2 Measurement Errors for Selected Glassware a
Measurement Errors for
Volume Class A Glassware Class B Glassware
Glassware (mL) (±mL) (±mL)
Transfer Pipets 1 0.006 0.012
2 0.006 0.012
5 0.01 0.02
10 0.02 0.04
20 0.03 0.06
25 0.03 0.06
50 0.05 0.10

Volumetric Flasks 5 0.02 0.04
10 0.02 0.04
25 0.03 0.06
50 0.05 0.10
100 0.08 0.16
250 0.12 0.24
500 0.20 0.40
1000 0.30 0.60
2000 0.50 1.0
Burets 10 0.02 0.04
25 0.03 0.06
50 0.05 0.10

a Specifications for class A and class B glassware are taken from American Society for Testing and
Materials E288, E542 and E694 standards.

Table 4.3 Measurement Errors Table . Measurement Errors
4 4
for Selected Balances for Selected Digital Pipets
Capacity Measurement Volume Measurement Error
Balance (g) Error Pipet Range (mL or mL) a (±%)
Precisa 160M 160 ±1 mg 10–100 mL b 10 1.0
A & D ER 120M 120 ±0.1 mg 50 0.6
Metler H54 160 ±0.01 mg 100 0.6

200–1000 mL c 200 1.5
1000 0.8

1–10 mL d 1 0.6
5 0.4
10 0.3

a Units for volume same as for pipet range.
b Data for Eppendorf Digital Pipet 4710.
c Data for Oxford Benchmate.
d Data for Eppendorf Maxipetter 4720 with Maxitip P.