IOM Sampler

Basically, the name IOM came from the developer, the UK Institute of Occupational Medicine.

Various studies were undertaken in past using different samplers, out of all IOM sampler has shown the best results for the inhalable dust criteria to ISO under wide range of working conditions and it is considered to be the best method of inhalable dust sample assessment nowadays. IOM sampler and its’ use consists of:

• A calibration adapter for the IOM

• Sampling cassettes and transport clips

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• Constant flow personal sampling pump, capable of a flow rate of 2L/min

• Calibrator such as a piston calibrator or bubble meter

• Flow adjusting screw driver

• Tube to connect pump to sampler

• Disposable gloves

The whole body of the IOM sampling head basically comprises of the following components as shown in the following figure.

• Cassette cover/Cover cap

• O-ring

• Front cover

• Cassette Top/Cassette front

• Filter paper- We used filter mixed cellulose esters membrane- filter type – 0.8µm AAWP (made in Ireland) for sampling

• Cassette rare/cassette bottom, in which filter paper is adjusted

• Housing body of sampler, where all the components are fitted.

• Sampling trains: The sampling device, sample pump and filter collectively when connected together give rise to a train like structure known as sampling train.

Figure 3.1: IOM Sampler Figure 3.2: Components of IOM Sampler

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3.3.1.1 Procedure of sampling using IOM sampler

The procedure adopted for sampling is explained as follows:

a) Weighing of filter

Weighing was performed in a weighing room in which the temperature (°C) and humidity (%) were controlled. All weighing was carried out with a Mettler–Toledo ME22 balance (Greifensee, Switzerland), with a resolution of 1 µg. At the beginning of each weighing session the balance was calibrated using a 100 mg weight supplied by the manufacturer. During the sessions, the balance was tared when necessary. In order to reduce the static electrical charge on the filter or cassette being weighed, a radioactive α-source [0.5 mCi ²¹⁰Po, NRD Inc., Grand Island (NY), USA] was placed above the weighing pan. Continue weighing filter until the difference between two consecutive reading comes out to be <0.002.

b) Steps:

As we have to measure inhalable dust exposure, so we connected sampling train with worker to measure the content of inhalable dust. The procedure adopted for sampling of inhalable dust is given below: I,

1. Put on a pair of gloves, without using skin oils, lotions, hand sanitizers since they can contaminate samples

2. Removed the face plate of IOM sampler and examined the inside the covering is intact 3. Removed the cassette from its transport clip and put the clip back in the same bag for later, and also labelled the bag of the IOM sampling head to ensure cassettes are not mixed up after sampling as it is essential after sampling that of the transport clip or bag has a barcode, the sample cassette must be matched back to the correct barcode.

4. Removed the protected cap and placed the cassette into the IOM sampler and replaced the face plate

5. Screwed it down firmly for secure seal

6. Clipped the sampling pump securely on to the belt of the employee, minimizing interference with work activities. It is better to clamp IOM Sampler near the employee breathing zone. After clamping, turned on the pump noting the start time. Once the sampling is complete, turned off the pump and recorded the end time. Immediately capped the IOM sampler remove the pump and sampler from the individual and transported it to clean area. Using new gloves between samples to avoid cross

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contamination. Opened the face plate of the sampler. Obtained the correct original barcoded transport clip for that cassette and returned it to the original clip and bag.

7. Note: For gravimetric, total inhalable particulate analysis in a low-dust environment, maximize the total air volume, sampling up to a full working shift. For active pharmaceutical ingredients or APIs and other sensitive tests, a lower air volume may suffice.

c) Calibration Procedure:

Basically, it is good to select a representative sampler for the post calibration, but make sure that it is not used to collect the sample. We adopted following procedure for calibration: I,

1. Allowed the pump to run for ten minutes before start and inserted the IOM sampler through the hinged bracket of the adopter with the inner link of the sampler against the adopter firm ring.

2. Clamped the IOM sampler in place with the clamping screws

3. One end of the IOM Sampler was connected to the pump and the other end with soap calibrator the mini BUCK CALLIBRATOR) outlet with a piece of flexible tubing.

4. After this, I removed the dust cap from the sampler outlet and connect the sampler outlet to the sampling pump and soap calibrator.

5. TURNED ON the pump and soap calibrator then noted at least five readings of the flow rate from soap calibrator. The flow rate carried forward for the pump was the average of all the readings taken before. When finished, TURNED OFF the pump. Disconnected the IOM cassette and adopter and set it aside for field study

6. Again, installed a new IOM cassette into an IOM sampler body and collected a new sample at various sampling location selected for field study

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Figure 3.3: Buck Calibrator (soap calibrator) d) Post Calibration Procedure:

To finish, use the calibration adopter, the flow rate of the pump. Post calibration flow rate should be within 5% of the pre-calibration. If not, assess whether the variance can still meet your data objectives or if it’s better to resample. Complete the laboratory request form, also called a chain of custody. Package your shipment for laboratory, following any required shipping specifications for your analyses.

e) Precautions:

1. If requesting gravimetric analyses for total inhalable dust, make sure to order Pre-weight media

2. Pre-weighed IOM cassettes are made to order and should be used ASAP (<30 days after pre-weighing)

3. A field blank is always recommended, if you are requesting gravimetric dust analysis 4. Always use disposable gloves when handling IOM sampling cassettes

5. Return all IOM cassettes to the laboratory, used or not used, to avoid replacement charges.

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