Hap Mo Flashcards
GC/MS stands for
Gas chromatograph/ Mass spectrometer
What functions are performed by the MS part of hapsite?
- Detection
- Ionisation
- Filtering of ions
The GC separates compounds using what criteria
Boiling point
What is the scan range on the Hapsite using default methods?
45-300 AMU
Atomic Mass Units
From cold how long does it take to get a hapsite up and running?
20 mins +
What is the 2 function of the internal standard?
To be injected as a standard in Analyze methods and for tuning
Is the hapsite intrinsically safe?
No
Liquids can and should be drawn up the probe.
True or false?
False
What is the ambient temp range of the hapsite?
0-45c
What % of a battery is used to start the hapsite from cold?
40%
How long does it take to re-charge a flat battery
15-20 hours
What is the normal battery life
2-3 hours
How many batteries do u need to do a hot swap?
3
What does the Neg do?
Helps maintain the vacuum in the mass spectrometer
At what pressure should the Neg be replaced
6e -03
For a chemical to be detected by the hapsite what should it’s boiling point be?
> 250c
Less than
What range of PH is safe for the hapsite?
2-11
The hapsite detects compounds that are?
Organic
Which best describes the type of compound detectable by the hapsite?
Volatile
What is the max number of carbons a chemical can have to be detected by the hapsite?
12
What are the names of the library’s used by hapsite?
NIST and AMDIS
What must be the concentration of a chemical to be detected using survey mode.
Great than 10ppm
What must be the concentration of a chemical to be detected using GC/MS loop method?
Low ppm to high ppb
What method can be used as a quick screening tool?
Survey
The proper sampling technique when running a survey is:
Background for 1 min then sample for voc
What must u do when loop fill is in progress?
Hold the probe over the sample
The NIST library is?
A very large library >190,000 of chemicals with a known mass spectrum
The AMDIS library is:
A small focused library of EPA chemicals and cwa
Contains approximately 750 chemicals
How long does it take to fill a loop ?
1 min
What time would you expect to see the air peak
1:20 min
+/-10
What time would you expect to see TRIS peak
2:30 min
+/-10
What time would you expect to see BPFB
8 min
+/-10
Ratio of TRIS to BPFB
1/3 to 1/2 the peak hight
Tic max of BPFB
1-3 million
How long between tunes
12 hours
What time would you expect to see “the bump”
12 min
Min pressure for nitrogen
Colour of tin
Min pressure for reservoir
Known as?
- 172 KPA
- Purple stripe
- 380 KPA
- Known as the “carrier” gas
Min pressure for internal standard
Colour of tin
- 104 KPA
* Yellow stripe
Possible wifi range
300 m in line of sight
Tic max saturation
60 million
How long does it take the sample to travel the length of the probe
6-7 sec
Describe survey mode:
- Draws air sample directly into MS
- Identifies pure chemicals well
- More difficult to identify mixtures
- Looking for an increase in TIC of greater than 2-3 times background level
Describe GC/MS mode:
- GC adds separation to MS identification
- Each sample takes 15mins
- More sensitive
- Better identification when sampling mixtures
- When the data from the survey method is inconclusive and further investigation is desired
- To confirm survey
What should you run before use and why?
•A “blank” run
- A background blank provides:
- Data on the environmental background
- Verification that it is working correctly, the internal pressures are acceptable and the gas flow rate are in acceptable range
What are you looking for in a good “blank” run?
- Only 3 peaks are present
- The peaks are the correct ratios
- Correct retention times
- The tic max of BPFB is 1-3 million
- The baseline is <10%
What is the temperature of the Neg?
400c
When should a new Neg be ordered?
4E-03
Explain why there may be no identification or response whilst operating in survey mode:
- Compound not in library
- Sample is a mixture
- A low net fit
- Sample concentration <10ppm
- Sample not volatile
- Sample not in AMU range (45-300)
- Sample does not contain Carbon
What other tools do we have if we have to work in lower temperatures?
Pizza bag and probe cover
What are the detection requirements?
- Volatile Organic Compound
- A boiling point below 250c
- Have a ph of 2-11
What is the weight of the Hapsite?
20 kg
Why is it important to measure ph of unknowns prior to analyses?
Too acidic or alkaline samples can corrode internal mechanisms
What are the two types of concentrator tubes?
- Tenax
* Tri-bed
Sensitivity tree
Survey >10ppm
Air GC/MS Loop
Low ppm - High ppb
Air GC/MS Concentrator
Low ppb - High ppt
