Bureau of Mines Report of Investigations/l975 

Use of Vacutainers for Collection 

of Mine Atmosphere Samples 

UNITED STATES DEPARTMENT OF THE INTERIOR 
UNITED STATES DEPARTMENT OF THE INTERIOR 

Rogers C. B. Morton, Secretary 

Jack W. Carlsom, As~istant Secretary-Energy and Minepals 

BUREAU OF MINES 

Thomas V. Falkie, Director 
CONTENTS 

Page 

Abstract ... ............................................................ 1 

Introduction ............................................................. 1 

Experimental work ....................................................... 2 

Apparatus .........................,..,............................. 3 

Evacuation and sampling ............................................ 4 

Results and discussion ... ........................,....................... 5 

Conclusions .. ........................................................... 7 

ILLUSTRATION 

1 . Evacuation vessel ................................................... 3 

TABLES 

1 . Comparison of vacuum bottles with Vacutainers at Mount Hope. W . Va .. 5 

2 . Effect of storage of gas for 41days (20 samples) ................... 6 

3 . Effect of storage time on gas concentration for evacuated 

Vacutainers stored in the laboratory at Pittsburgh ................ 7 
USE OF VACUTAINERS FOR COLLECTION OF MINE 

ATMOSPHERE SAMPLES 

Robert W. Freedrnan,l Will iorn G. Humphrey, and Robert L. Craft 

ABSTRACT 

As part of a continuing effort to reduce the weight and bulk of equipment 

that mining personnel must carry underground, the Bureau of Mines and the 

Mining Enforcement and Safety Administration (MESA) investigated accurate and 

convenient gas samplers for use by mine inspectors in sampling mine atmospheres. The samplers are septum-stoppered glass vials commonly used for 

routine blood sampling. These lightweight, compact samplers yield results 

comparable with those obtained with conventional bottle samplers of 250-ml 

nominal capacity. 

INTRODUCTION 

Over the past several years, the amount of equipment mining personnel are 

required to carry has continued to increase. Mine air samples have been 

collected for analysis with several types of glass and metal containers, as 3 reported in a previous publication. The Bureau formerly employed vacuum 

bottles with a nominal capacity of 250 ml for most of the sampling done by 

inspectors and mining personnel. These are large and cumbersome, and thus 

limit the sampling capability. Hypodermic syringes satisfy most of the 

requirements, but their use is limited mainly to research work because storage 

time after sampling and prior to analysis, if it is more than a few days, 

presents problems. Gases such as carbon dioxide are lost relatively rapidly 

from the syringes by permeation. Thus, there was a need to develop more convienent and efficient samplers. 

In 1971, the Mount Hope, W. Va., office tested 10-ml Vacutainers4 made by 

Becton-Dickenson as sample collectors. These are glass vials stoppered by 

0.25-inch-thick butyl rubber septums. Since these units are routinely 

1 Supervisory research chemist . 2 Supervisory chemist. 

3 Lang, H. W. , and R. W. Freedman. The Use of Disposal Hypodermic Syringes for 

Collection of Mine Atmosphere Samples. Am. Ind. Hyg. Assoc. J, v. 30, 

a Sep tember-October 1969, pp. 523-526. 

Reference to a specific trade name does not imply endorsement by the Bureau 

of Mines. 
employed for blood sampling, they are evacuated to only about 250 m. 

~~ver theless, the Mount Hope investigators found that consistent results could 

be obtained for mine air samples if they were compared with gas standards 

sampled in Vacutainers . 

5 

Mine inspectors found samplers of this type to be very convenient, and 

the results were comparable with those obtained with 250-ml vacuum bottles, 

even after storage periods of 1 to 2 weeks after sampling. Consequently, they 

were officially adopted for use by the Bureau in 1972. 

However, there are uncertainties inherent in the use of the Vacutainers. 

In addition to the loss of certain gases mentioned earlier, experience at both 

the Mount Hope, W. Va., office of MESA and the Pittsburgh Mining and Safety 

Research Center of the Bureau indicated that storage of either partially or 

completely evacuated Vacutainers produced levels of carbon monoxide of up to 

50 ppm. 

Experimental programs were initiated independently by MESA at Mount Hope 

and the Bureau at Pittsburgh to compare Vacutainers with vacuum bottles. The 

following objectives were undertaken: 

1. Devise a unit that will evacuate several dozen Vacutainers simultaneously to a level lower than that of the commercial Vacutainers. 6 

2. Measure gas leakage from the atmosphere into evacuated vessels as a 

7 function of time prior to sampling. 

3. Determine safe storage periods (after sampling and prior to analysis) 

by checking sample stability. 8 

EXPERIMENTAL WORK 

Vacutainers were evacuated at Mount Hope, W. Va., to less than 4 mm and 

were allowed to stand for measured time periods. Some were then filled to 

atmospheric pressure with pure carrier gas and analyzed to check composition. 

Others were filled to atmospheric pressure with standard gas mixtures. Several were compared immediately with similar standards collected in 250-1111 

vacuum bottles to check for sampling error. Others were compared with vacuumbottle standards, as a function of time comparable with in-use handling 

requirements. 

SVacutainers of 10-ml nominal capacity actually contain about 13 ml. The 

10 ml is sufficient for quantitative flushing and filling of a 1-ml gas 

chromatograph sample loop. 6 Completely evacuated vessels were unavailable from Becton-Dickinson, the 

manufacturer. Also, time of evacuation can be documented by using an inhouse system. 7 In the Mount Hope mine inspection program, storage of evacuated Vacutainers 

for weeks or even months was difficult to avoid. 8 In routine mine sampling, delays of 1 to 2 weeks prior to analysis at a 

distant laboratory are common. 
Top p1ate,/4 in. thick x 12 in. in diam 

Plexiglass cylinder, 10 in. in diam 

7in.long and 1/4in. thick 

2b2 -in, diam holes 

Plexiglass pressure plate, 

314 in. thick x 9 1/2 in. in diam 

Plexiglass guide plate, 1/4 in. thick 

9 in, in diam 

Bolts, 114 in. in diam 

Wooden base plate, 1/2 in. thick 

9 in. in diarn 

ooden bocking plate, 1/4 in. thick 

9 1/2 in. in diam 

'~ip~le attached to internal tube 
The Vacutainers used have a nominal capacity (draw) of 10 ml. The 

~acutainers are glass vials 16 mm ID by 10 cm long, stoppered by a butyl 

rubber septum, and are obtainable from most laboratory supply houses. Luer 

needles, numbers 21-25, are employed for injecting samples into Vacutainers. 

This operation is carried out safely by employing a Vacutainer needle holder, 

which is also available from supply houses, The gas chromatographic equipment 

used was similar to that used in previous work for rapid mine air analysis. 9 

Evacuation and Sampling 

Vacutainers are inserted into the holes in the rack with the stoppers 

10 positioned gently on top of them (without inserting them in place). The top 

compression unit is then positioned in contact with the rubber gasket and 

vacuum applied for 3 to 4 minutes. Stoppers are then inserted by forcing the 

pressure plate downward. 

Samples are introduced into the evacuated samplers by needle injection or 

by removing the stopper manually in the atmosphere being tested. For laboratory evaluation with standard gases, the sample is injected into the 

Vacutainer with a needle. Sample pressure is measured with a manometer 

attached to a second needle inserted through the stopper. 

Samples are introduced into the chromatograph by mercury displacement 

into a sample loop. At the Mount Hope laboratories, two parallel needles 

mounted to a rack-and-pinion device were simultaneously inserted through the 

Vacutainer stopper. Mercury was introduced by a reservoir and leveling bulb 

through one needle; the other needle, extending slightly through the stopper, 

was connected to the sample loop inlet. At Pittsburgh, the same system was 

employed using manual insertion of the needles, but samples were withdrawn 

from Vacutainers with a 50-ml gas-tight syringe containing a shut-off valve 

between the needle and syringe body. After withdrawal of the needle, the 

syringe plunger moves inward of itself to yield an atmospheric pressure sample 

of about 9 ml. This is sufficient for filling a 1-ml chromatograph sample 

loop. 

RESULTS AND DISCUSSION 

A standard mixture at Mount Hope containing 0.25% CQ and 0.25% C02 in 

air was stored in 250-ml vacuum bottles and 10-ml Vacutainers for 7 days at 

1-atm internal pressure. Precision expressed in percent standard deviation of 

integrator counts1' for the bottles was 4, 0.34%; N,, 0.25%; CQ, 1.28%; and 

C02, 2.17%. The corresponding values for Vacutainers were 02, 0 45%; 

N2, 0.32%; CQ, 1,68%, and CO,, 2.27%. Thus, sampling and storage errors were 

'Lang, H. W., ,and R. W. Freedman, Three-Minute Gas chromatographic Analysis 

of the Main Constituents of Mine Atmospheres. BuMines RI 7696, 1972, 7 pp. 10 The stoppers supplied by Becton-Dickinson are notched at the bottom. This 

permits air to be withdrawn from the vials prior to inserting the stoppers 

11 fully in place. 

Statistical comparison based upon counts (peak integrands) is more accurate 

than comparison using the percentage values calculated from counts. 
small. Percentages of Cb and COZ were-calculated from each set of counts 

(table 1). The mean values for the two types of samplers were very close for 

each gas. If the individual percentages are calculated to three decimal 

places, and the t-test applied for the difference in means,12 values of t are 

0.75 and 0.44 for CO, and CQ, respectively. This is well within the twotailed critical value to.s7s,z6 = 2.06, and indicates insignificant difference 

due to sampling or storage. 

TABLE 1. - Comparison of vacuum bottles with Vacutainers 

at Mount Ho~e. W. Va. 

To examine the effect of longer storage, 20 samples of a gas mixture were 

allowed to stand for 41 days at the Pittsburgh laboratory. Results are given 

in table 2. Precision is only fair (up to -t4% standard deviation) for CH4, 

CO. and C02. In addition, C02 shows substantial change in concentration over 

the 41-day period. The loss of 16.1% of the initial level in the standard is 

12Spiege1, M. R. Theory and Problems of Statistics. Schaum Publishing Co., 

New York, 1961, 359 pp. 

Sample 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

Mean 

% 

Difference 

0.00 

+.01 

+.01 

+.01 

. 00 

. 00 

.OO 

+.01 

+.01 

.OO 

+.01 

.OO 

-. 01 

-.01 

-.01 

.OO 

+.01 

. 00 

-.01 

-. 03 

. 00 

.OO 

. 00 

.OO 

-.01 

-. 01 

-. 01 

- 

Carbon 

10-ml 

Vacutainer 

0.26 

-25 

-24 

.24 

.25 

.25 

.25 

.24 

.24 

.26 

.24 

-25 

.26 

.26 

.25 

.25 

.24 

.24 

.25 

.26 

.25 

.25 

.25 

.25 

.26 

.26 

.26 

.250 

dioxide, 

250-ml 

bottle 

0.26 

.26 

.25 

.25 

.25 

.25 

.25 

.25 

.25 

.26 

.25 

.25 

.25 

-25 

.24 

.25 

.25 

.24 

.24 

.23 

.25 

.25 

.25 

.25 

.25 

.25 

.25 

.249 

% 

Difference 

-0.01 

-. 01 

.OO 

.OO 

.OO 

.OO 

. 00 

.OO 

. 00 

.OO 

. 00 

+.01 

. 00 

-.01 

. 00 

.OO 

. 00 

. 00 

. 00 

-.01 

+. 01 

.OO 

.OO 

.OO 

.OO 

.OO 

+.01 

- 

10-ml 

Vacutainer 

0.25 

.25 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.23 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.25 

.23 

.24 

.24 

.24 

.24 

.24 

.24 

.250 

Methane, 

250-ml 

bottle 

0.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.23 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.24 

.25 

.249 
2.6% per week on a linear basis. These findings indicate that storage periods 

of longer than 1 week should be avoided if accurate C02 levels are important. 13 It can be presumed that C02 is lost by permeation rather than by diffusion 

through small orifices. The difference between the two types of flow are 

14 described in a previous publication. 

TABLE 2. - Effect of storage of gas for 41 days (20 sam~les) 

A problem noted at Mount Hope was the gradual concentration of carbon 

monoxide when evacuated units (either factory-supplied or completely evacuated) 

were stored for extended periods in the laboratory. Levels as high as 50 ppm 

were measured when the Vacutainers were filled with CO-free air or helium. 

This fact was verified at Pittsburgh (table 3). 

It is postulated that change in relative concentrations of the gases is 

due in part to external permeation from the atmosphere through the septum. 

However, the high CO levels attained are as yet unexplained, since ambient 

levels generally do not exceed 5 ppm. The results in table 3 indicate that, 

for a 1-week storage period, gaseous inflow is insignificant. After 6 months 

(25 weeks), average values for all the gases tended to reach a plateau, 

indicating attainment of equilibrium. The ambient conditions in the 

Pittsburgh laboratory were not controlled. Although the N2:02 ratio of 4:l in 

air did not vary, there probably was some variation in C& and C02 levels. In 

addition, permeation rates increase significantly with temperature, and the 

laboratory temperature ranged from 20" to 30° C. Permeation rates also depend 

linearly upon pressure differences (inside and outside the container). 

However, these are small on a relative scale, and would not be expected to 

produce significantly large variations in permeation rates. The effects of 

variations in septum geometry and composition did not appear significant over 

the short periods recommended for storage of Vacutainers. 

Percent in standard gas 

mixture.. .................... Sample mean................... 

Standard deviation. ........... Percent of standard deviation. 

Change, sample mean minus 

percent in standard gas 

mixture.. .................... Percentage of change (based 

on standard gas mixture) ..... 

13scaringelli, F. P., S. A. Frey, and B. E. Saltzman. Evaluation of Teflon 

Permeation Tubes for Use With Sulfur Dioxide. Am. Ind. Hyg. Assoc. J., 

V. 28, May-June 1967, pp. 260-266. 

14 Work cited in footnote 3. 

02 

9.80 

10.135 

.2345 

2.31 

-335 

3.31 

N2 

83.75 

84.26 

.3234 

.384 

.510 

-61 

CEh 

1.05 

1.0105 

.0481 

4.76 

-0040 

-3.96 

CO 

0.45 

.446 

.0193 

4.33 

-. 004 

-. 90 

GO2 

5.00 

4.195 

-2038 

4.86 

-. 805 

-16.1 
TABLE 3. - Effect of storage time on gas concentration for evacuated 

Vacutainers stored in the laboratory at Pittsburgh 

CONCLUSIONS 

Sample 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

Based upon this experimental work, it can be concluded that samples of 

mine gases can be collected rapidly and conveniently in 10-ml Vacutainers for 

subsequent gas chromatographic analysis. Storage of evacuated Vacutainers 

prior to analysis should not exceed 1 to 2 months if they are used for analysis of low levels of carbon monoxide. Better control over storage time can 

be accomplished by in-house evacuation. In-house evacuation also removes more 

of the air within the Vacutainer, thus eliminating a possible source of variation in results. 

Analysis of samples taken in Vacutainers provides results comparable with 

those obtained with 250-ml vacuum bottles. However, if precise values for C02 

are required, this analysis should be accomplished within 1 week after taking 

samples because some C02 may be 10s t by permeation. 

COY ppm 

0.6 

.1 

.6 

.1 

.1 

13 

29 

39 

36 

28 

35 

40 

41 

21 

19 

31 

44 

Storage period, 

weeks 

1 

1 

1 

1 

1 

25 

25 

25 

25 

52 

52 

52 

78 

78 

78 

78 

78 

O,, % 

0.07 

.06 

.07 

.05 

.06 

-37 

1.36 

-53 

.65 

- 

- 

a 

- 

.79 

.84 

-55 

.65 

N,, % 

0.12 

.09 

.10 

-10 

.09 

1.07 

2.87 

1.77 

2.01 

- 

- 

- 

- 

.92 

.93 

.85 

1.11 

C02, % 

0.0172 

.0116 

.0085 

.0212 

.0200 

.04 

.07 

.09 

.10 

- 

- 

- 

.06 

.03 

.03 

.06 

.07 

CQ, ppm 

<1 

<1 

<1 

<1 

<1 

7 

10 

6 

7 

a 

- 

- 

5 

5 

5 

5 

5