Sunday, 28 February 2016

Checklist SNI ISO/IEC 17025:2008

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Bagi pembaca yang akan melakukan audit internal (atau eksternal) dengan menggunakan standar SNI ISO/IEC 17025:2008 (ISO/IEC 17025:2005, IDT) - Persyaratan umum kompetensi laboratorium pengujian dan laboratorium kalibrasi), pada postingan ini saya memberikan checklist penting bagi anda.

Checklist yang tersedia cukup lengkap dan mencakup semua klausul standar ISO/IEC 17025 sebagai berikut;

4         Persyaratan manajemen
4.1      Organisasi
4.2      Sistem manajemen
4.3      Pengendalian dokumen .
4.3.1   Umum
4.3.2   Pengesahan dan penerbitan dokumen
4.3.3   Perubahan dokumen
4.4      Kaji ulang permintaan, tender dan kontrak
4.5      Subkontrak pengujian dan kalibrasi
4.6      Pembelian jasa dan perbekalan
4.7      Pelayanan kepada pelanggan
4.8      Pengaduan
4.9      Pengendalian pekerjaan pengujian dan/atau kalibrasi yang tidak sesuai
4.10     Peningkatan
4.11     Tindakan perbaikan
4.11.1  Umum
4.11.2  Analisis penyebab
4.11.3  Pemilihan dan pelaksanaan tindakan perbaikan
4.11.4  Pemantauan tindakan perbaikan
4.11.5  Audit tambahan
4.12     Tindakan pencegahan
4.13     Pengendalian rekaman
4.13.1  Umum
4.13.2  Rekaman teknis
4.14     Audit Internal
4.15     Kaji ulang manajemen

5         Persyaratan Teknis
5.1      Umum
5.2      Personel
5.3      Kondisi akomodasi dan kondisi lingkungan
5.4      Metode pengujian, metode kalibrasi dan validasi metode
5.4.1   Umum
5.4.2   Pemilihan metode
5.4.3   Metode yang dikembangkan oleh laboratorium
5.4.4   Metode tidak baku
5.4.5   Validasi metode
5.4.6   Estimasi ketidakpastian pengukuran
5.4.7   Pengendalian data
5.5      Peralatan
5.6      Ketertelusuran pengukuran
5.6.1   Umum
5.6.2   Persyaratan khusus
5.6.3   Standar acuan dan bahan acuan
5.7      Pengambilan contoh (sample)
5.8      Penanganan barang yang diuji dan dikalibrasi
5.9      Jaminan mutu hasil pengujian dan hasil kalibrasi
5.10     Pelaporan hasil
5.10.1  Umum
5.10.2  Laporan pengujian dan sertifikat kalibrasi
5.10.3  Laporan pengujian
5.10.4  Sertifikat kalibrasi
5.10.5  Opini dan interpretasi
5.10.6  Hasil pengujian dan hasil kalibrasi dari subkontraktor
5.10.7  Pengiriman hasil secara elektronik
5.10.8  Format laporan dan sertifikat
5.10.9  Amandemen laporan pengujian dan sertifikat kalibrasi

Silahkan unduh checklist di bawah, apabila ingin bertukar fikiran lebih jauh tentang persyaratan standar ISO/IEC 17025 ini, silahkan tinggalkan pesan, mudah-mudahan bisa membantu anda.

Sunday, 21 February 2016

Determination Of Dissolved Oxygen

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1. SCOPE

This method is an adaptation from the APHA 20th edition, 4500-O A, C and G, pp. 4 - 129-136. This method covers the determination of dissolved oxygen in natural waters and wastewaters.

A limit of reporting of 0.1 mg/L for waters is achieved by this method.

2. PRINCIPLE

An oxygen meter with probe is used to routinely determine dissolved oxygen. The DO meter is calibrated on use against the Winkler titration method.

The membrane electrode procedure is based on the rate of diffusion of molecular oxygen across a membrane. Oxygen-sensitive membrane electrodes are composed of two solid metal electrodes in contact with supporting electrolyte separated from the test solution by a selective membrane. The ‘diffusion current’ is linearly proportional to the concentration of molecular oxygen. The current is converted to concentration units by a number of calibration procedures.

The DO meter is calibrated against the Winkler titration method. DO rapidly oxidises an equivalent amount of the dispersed divalent manganous hydroxide precipitate to hydroxides of higher valency states. In the presence of iodide ions in an acidic solution, the oxidised manganese reverts to the divalent state, with the liberation of iodine equivalent to the original DO content. The iodine is then titrated with a standard thiosulfate solution using Vitex as an indicator.

MnSO4 + 2NaOH  -->  Mn(OH)2 + Na2SO4

2Mn2+ + O2 +4OH-  -->  2MnO(OH)2
                 acid
Mn4+ + 2I-  ---->  Mn2+ + I2

I2 + 2S2O32-  -->  2I- + S4O62-


3. INTERFERENCES

Plastic films used with membrane electrode systems are permeable to a variety of gases besides oxygen, although none are depolarised easily at the indicator electrode. Prolonged use of membrane electrodes in waters containing such gases as hydrogen sulfide (H2S) tends to lower cell sensitivity. Eliminate this interference by frequently changing the membrane and calibrating the membrane electrode.

DO measurements should ideally be conducted immediately on site upon collection. Any agitation after sample collection will lead to an erroneous estimation of field conditions. In the event that field measurement is not possible, samples should be fixed on site using steps 8.1.1.1 to 8.1.1.4. Steps 8.1.1.5 to 8.1.1.8 may be conducted at the laboratory for field preserved samples.

4. REFERENCES

APHA 20 th ed. Standard Methods - For the Examination of Water and Wastewater
Operating Manual for YSI-5100 Oxygen Meter
Operating Manual for TPS 90-D Oxygen Meter
Operating Manual for YSI-5010 BOD Probe

5. APPARATUS

5.1 DO meter, TPS oxygen / salinity meter, Model 2052A or equivalent

5.2 Probe, YSI oxygen probe, Model 5739 or equivalent

5.3 Balance (0.0001 g accuracy)

5.4 Volumetric flasks, A-grade; 1000 mL

5.5 Erlenmeyer flasks, 250 mL

5.6 Burette; 25 mL, 0.1 mL increments

5.7 300 mL glass bottle having a ground-glass stopper.

5.8 Measuring cylinder, 200 mL

5.9 Volumetric pipettes, 1 mL

6. SAFETY

SAFETY GLASSES, GLOVES AND LABORATORY COAT MUST BE WORN WHEN PREPARING THE FOLLOWING REAGENTS. SULPHURIC ACID AND SODIUM HYDROXIDE ARE HIGHLY CORROSIVE. SODIUM AZIDE IS TOXIC WHEN ABSORBED THROUGH THE SKIN. THE MATERIAL SAFETY DATA SHEETS FOR SULPHURIC ACID, SODIUM HYDROXIDE AND SODIUM AZIDE NEED TO BE READ BEFORE COMMENCING THE PROCEDURE.

7. REAGENTS

Use reagent grade water for all solutions.

7.1 Manganous sulfate, MnSO4.H2O, AR

7.2 Manganous sulfate solution: Dissolve 364 g MnSO4.H2O (7.1) in reagent grade water, filter, and dilute to 1L.

The MnSO4 solution should not give a colour with starch when added to an acidified potassium iodide solution.

7.3 Sodium Hydroxide, NaOH, AR

7.4 Sodium Iodide, NaI, AR

7.5 Sodium azide, NaN3, AR

7.6 Alkali-iodide-azide reagent: Dissolve 500 g NaOH (7.3) and 135 g NaI in water and dilute to 1 L. Add 10 g NaN3 (7.5) dissolved in 40 mL of water.

7.7 This reagent should not give a colour with vitex solution when diluted and acidified.

7.8 Sulphuric acid (H2SO4), 98 %, AR


7.9 Vitex, AR

7.10 Sodium thiosulfate, Na2S2O3.5H2O, AR

7.11 Standard sodium thiosulfate titrant, 0.025 M: Dissolve 6.205 g Na2S2O3.5H2O (7.10) in water and add 0.4 g NaOH (7.3) and dilute to 1 L. Standardise as per QWI-EN/48.

8. PROCEDURE

8.1 Calibration DO Meter

8.1.1 Determination DO of Water (reagent grade or other, as long as same water is carried through both Winkler titration and probe reading) by Winkler Titration

8.1.1.1 Fill a 300 mL glass bottle with reagent grade water. Add 1 mL MnSO4 solution (7.2), followed by 1 mL alkali-iodide-azide reagent (7.6). Hold pipette tips just above liquid surface when adding reagents.

8.1.1.2 Stopper carefully to exclude air bubbles and mix by inverting the bottle a few times.

8.1.1.3 When the precipitate has settled sufficiently to leave clear supernatant above the manganese hydroxide floc, add 1.0 mL Conc. H2SO4 (7.7).

8.1.1.4 Restopper and mix by inverting several times until dissolution is complete.

8.1.1.5 Transfer 200 mL sample from 8.1.1.4 to a 250 mL Erlenmeyer flask.

8.1.1.6 Titrate with 0.025 M Na2S2O3 solution (7.9) to a pale straw colour. Add 0.3 g vitex and continue titration until the first disappearance of blue colour.

8.1.1.7 Repeat 8.1.1.1 – 8.1.1.6 two more times. Record on work book.

8.1.1.8 Calculation: When a 200 mL sample aliquot is used:
1 mL of 0.025 M Na2S2O3 = 1 mg DO/L

8.1.2 Calibration of DO Meter

8.1.2.1 Calibration of TPS 90-D DO Meter

8.1.2.1.1 To calibrate the DO meter, use the Span by Air Calibration procedure. Refer to Section 3.1 (b1) of the Instruction Manual for the TPS 90-D Oxygen Meter.

8.1.2.1.2 The DO reading of a water (reagent grade or other, as long as same water is carried through both tests) sample is checked against that of a Winkler titration (procedure 8.1.1).

8.1.2.1.3 If the variation between the DO meter reading and the Winkler titration is < 1.0, the DO meter is then calibrated using the Alternate Oxygen Span Calibration procedure (Section 3.1 (b2) of the Instruction Manual for the TPS 90-D Oxygen Meter). The value of the Winkler titration is keyed into the DO meter. 8.1.2.1.4 If the variation between DO reading and Winkler titration is > 1.0, initiate the following steps:

• Change the filling solution, and replace membrane
• Repeat steps 8.1.2.1.1 – 8.1.2.1.3.

8.1.2.2 Calibration of YSI-5100 Oxygen Meter

8.1.2.2.1 To calibrate the DO meter, use the manual Calibration procedure. Refer to pages 20 –21 of Calibration Instructions for YSI-5100 Oxygen Meter. Calibrate in mg/L.

8.2 Sample measurement

8.2.1 Determine sample DO. If the sample bottle is full with no headspace, carefully insert the DO probe and hold in place with a clamp and stand. Leave probe in place until a stable DO reading is obtained. If a full bottle was not received, accurate DO measurements are not possible.

8.2.2 Record both DO and temperature in DO work sheet. Rinse DO electrode between determinations to prevent cross-contamination of samples.

Wednesday, 17 February 2016

Cara Uji Total Reduced Sulfur (TRS) dalam emisi sumber tidak bergerak

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1. Prinsip

    Gas buang yang mengandung oksida-oksida sulfur ditangkap dengan larutan bufer sitrat,
    TRS yang tidak terjerap dioksidasi menggunakan tungku oksidasi (oxidation furnace)
    menjadi SO2. Gas SO2 yang terbentuk dijerap dalam larutan H2O2 membentuk asam sulfat
    (H2SO4). H2SO4 yang terbentuk direaksikan dengan barium klorida membentuk barium sulfat.
    Kadar sulfat ditentukan secara turbidimetri pada panjang gelombang 420 nm.

Sunday, 14 February 2016

Toxicity Characteristic Leaching Procedure (TCLP)

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SECTION A - BOTTLE EXTRACTION PROCEDURE


1. SCOPE AND APPLICATION

    The TCLP is designed to determine the mobility of both organic and inorganic analytes
    present in liquid, solid and multiphasic wastes. The bottle extraction method applies only
    to non-volatile analytes.


2. APPARATUS AND MATERIALS

2.1 Agitation Apparatus

      2.1.1 Tumbler to meet specifications listed in USEPA 1311.



2.2 Extraction Vessels

      2.2.1 2 litre glass TCLP bottles

      2.2.2 Teflon lined lids
      2.2.3 White plumbers tape.

2.3 Filtration Devices

      2.3.1 Millipore Vacuum filtration apparatus

2.4 Filters

      2.4.1 0.6 - 0.8 µm TCLP glass fibre filter paper (142 mm)

2.5 pH Meter

      2.5.1 The meter should be accurate to ± 0.05 units at 25 oC

2.6 Analytical Balance

      2.6.1 Any balance accurate to within ± 0.01 g may be used (all weight measurements are to
               be within ± 0.1 g).

2.7 Beaker or similar container

      2.7.1 Glass or plastic, 100 mL

2.8 Watchglass (suitable size to cover beaker or similar container)

2.9 Magnetic Stirrer


3. REAGENTS

3.1 Hydrochloric acid (HCl), 32 %, AR

3.2 Hydrochloric acid, 1 M: Add 100 mL of 32 % HCl (3.1) to 800 mL of DI water, mix well, then
      bulk up to 1 L.

3.3 Deionised (DI) Water

3.4 Glacial Acetic Acid, AR. Use in a fume cupboard. Where this is not possible keep sealed as
      much as possible when using on the bench.

3.5 Sodium Hydroxide (NaOH), AR

3.6 Nitric Acid, AR

3.7 Extraction Fluid #1: Prepare by mixing 4 L (using a measuring cylinder) of DI water, 22.8 mL
      (using burette) glacial acetic acid (3.4) and 10.25 - 10.30 g of NaOH (3.5). If required, this
      solution must be adjusted to a pH of 4.88 - 4.98 using either NaOH (3.5) or acetic acid (3.4).
      Record this pH.

3.8 Extraction Fluid #2: Prepare by mixing 4 L (using a measuring cylinder) of DI water with 22.8
      mL (using burette) of glacial acetic acid (3.4). The pH of the solution must be 2.83 - 2.93.
      Adjust pH if necessary with NaOH (3.5) or acetic acid (3.4). Record this pH.


4. PRELIMINARY EVALUATIONS

4.1 Determination of Percent Solid

      The percent solid is defined as that fraction of a waste sample from which no liquid may be
      forced out.

      4.1.1 If the waste will obviously yield no liquid when subjected to pressure (that is: it is
               100 % solid) proceed to section 4.2.

      4.1.2 Record the following information in the Miscellaneous Workbook. If the sample is
               liquid or liquid/solid a percent solid determination is required. This is achieved using
               a vacuum filtration device. The first step is to preweigh the filter paper and the
               container which will receive the filtrate. A subsample of the waste is then weighed
               out (a minimum of 100 g) and the weight recorded. This subsample is then
               quantitatively transferred to the filtration device and vacuum applied gradually.
               When continued vacuum does not result in any additional filtrate within any 2 minute
               period, stop the filtration.


      4.1.3 Record the weight of the liquid and solid phases. Calculate the percent solids as
               follows:

                                             weight of solid
               Percent solids = ----------------------------- x 100 %
                                             total weight of waste

               Retain both liquid and solid obtained from this determination.

      4.1.4 If the percent solids is equal to or greater than 0.5 %, the liquid if any, is separated
               from the solid phase and stored for later analysis (see 7.4.). Proceed to section 4.2
               for the solid phase. If the percent of solids is less than 0.5 %, the liquid phase, after
               filtration through a 0.6 - 0.8 µm glass fibre filter, is defined as the TCLP extract.

4.2 Determination of Particle Size Reduction

      Particle size reduction is required unless the solid is smaller than 1 cm in its narrowest
      dimension. If the particle size is larger than described above, prepare the solid portion for
      extraction by crushing, cutting or grinding the waste to a suitable particle size.


5. DETERMINATION AND PREPARATION OF APPROPRIATE EXTRACTION FLUID

5.1 Transfer 5.0 g of the solid phase (after particle size reduction, if required) to a beaker. Add
      96.5 mL of DI water and record the pH of the solution whilst stirring vigorously. If the pH is
      < 5 use extraction fluid #1. If the pH is > 5, proceed to section 5.2.

5.2 Add 3.5 mL, using a 10 mL graduated dispensing pipette, of 1 M HCl to the solution, cover       with a watchglass and heat at 50 oC ± 5ÂșC (on a water bath) for 10 minutes. Allow to cool
      and record the pH again. If the pH is < 5 use extraction fluid #1. If the pH is > 5 use
      extraction fluid #2.

      Note: Discard this solution - do not use in extraction procedure.


6. EXTRACTION PROCEDURE

6.1 Procedure with regard to percentage of solid

      6.1.1 If the waste is 100 % solid: Weigh out 100 g of prepared waste. Transfer quantitatively
               to a glass TCLP bottle (2 litre capacity) and fill bottle with 2 L (using a measuring
               cylinder) of the appropriate extraction fluid. If less than 100 grams of sample is
               available, then the amount of soil that is available is used, and the volume of
               extraction fluid used is scaled down accordingly. e.g.: if 80 grams of soil is used, then
               1.6 L of extraction fluid is used. This information is recorded in the TCLP workbook.


      6.1.2 If the waste has a mixture of solid and liquid but has more than 0.5 % solid, take the
               filtered and prepared sample (from 4.1 and 4.2) and the filter used to separate the
               liquid from the solid phase (from 4.1), and place into a TCLP bottle.

      Determine the amount of extraction fluid to add to the extraction vessel as follows:

                                                       20 x percent solids (4.1.3) x weight of waste filtered (4.1.2)
Volume of extraction fluid (mL) = -------------------------------------------------------------------
                                                                                          100

      Slowly add this amount of extraction fluid to the TCLP bottle.

      NOTE 1: Ensure that the amount of extraction fluid is going to be sufficient to undertake
      the analysis. If not, use more filtered sample.

      NOTE 2: For further explanation and details, see USEPA 1311, Section 7.2.

6.2 Seal bottle using a Teflon-lined lid and white plumbers tape.

6.3 A blank (containing only extraction fluid) must be run with each batch.

6.4 Waste is extracted by tumbling at 30 ± 2 rpm, for 18 ± 2 hours on the tumbler, at 19 - 25 OC.
      The temperature of the room must be monitored, using a max. - min. thermometer. If the
      temperature falls outside this range then a comment should be made when reporting the
      results.


7. FINAL FILTRATION PROCEDURE

7.1 After tumbling, the waste should be allowed to settle (while standing upright) for at least
      2 hours.

7.2 The supernatant is poured onto the TCLP filter and gravity filtered until no additional liquid
      passes through the filter in any 2 minute interval. A gentle pressure of 10 psi is then
      applied until air moves through the filter. If this does not occur, and no additional liquid
      passes through the filter in any 2 minute interval, the pressure is increased in 10-psi
      increments. This continues until air flows through the filter, or liquid ceases to flow (in a
      2 minute period) at 50 psi.
      Note: Instantaneous application of high pressure can degrade the glass filter and may cause
      premature plugging.


7.3 If the waste contained no initial liquid phase, the filtered liquid material obtained from 7.2
      is defined as the TCLP extract.

7.4 If compatible (multiphases will not result on combination), combine the filtered liquid       resulting from section 7.2 with the initial liquid phase of the waste obtained in section       4.1.2. This combined liquid is defined as the TCLP extract.

7.5 If the initial liquid phase of the waste obtained from section 4.1.2 is not or may not be       compatible with the filtered liquid resulting from section 7.2, do not combine these
      liquids. Analyse the liquids, collectively defined as the TCLP extract, and combine
      the results mathematically. For further explanation see USEPA 1311, section 7.2.14.

7.6 The filtrate is collected in an amber solvent washed glass bottle if organic analysis is       required, a nitric preserved plastic bottle if metals are required, or a natural plastic bottle
      for other analytes. The extracts are stored in the cold room for further analysis.

7.7 The TCLP filter must be washed and the filter paper changed between each sample. If       metals are being analysed for, the filters and filter paper must be rinsed with 10 % nitric
      acid before use.

7.8 The pH of the final extract is recorded.




SECTION B - ZERO - HEADSPACE EXTRACTION PROCEDURE


1. SCOPE AND APPLICATION

    This method applies only to waste being tested for volatile analytes. This procedure is
    applicable to the extraction of WAD and total cyanide and those volatile organic compounds
    listed in Table 1 of USEPA 1311.

    The Zero-Headspace Vessel (ZHE) allows for the initial liquid / solid separation, extraction,
    and final filtration to occur without opening of the vessel.


2. APPARATUS AND MATERIALS

2.1 Zero-Headspace Extraction Vessel (ZHE).

      2.1.1 To meet specifications listed in USEPA 1311.

2.2 ZHE Extract Collection Devices: TEDLAR bags or glass, stainless steel or PTFE gas tight       syringes.

2.3 ZHE Extraction Fluid Transfer Devices; Any device capable of transferring the extraction       fluid into the ZHE without changing the nature of the extraction fluid is acceptable.
      e.g. a positive displacement or peristaltic pump, a gas tight syringe, pressure filtration
      unit, or other ZHE device.

2.4 Filters

      2.4.1 0.6 - 0.8 µm TCLP glass fibre filter paper (142 mm)

2.5 pH Meter
      2.5.1 The meter should be accurate to + 0.05 units at 25 oC

2.6 Analytical Balance

      2.6.1 Any balance accurate to within + 0.01 g may be used (all weight measurements are to
               be within ± 0.1 g).

2.7 Beaker or similar container

      2.7.1 Glass or plastic, 100 mL

2.8 Watchglass (suitable size to cover beaker or similar container)

2.9 Magnetic Stirrer



3. REAGENTS

3.1 Ultra High Purity (UHP) Water

3.2 Glacial Acetic Acid, AR. Use in a fume cupboard. Where this is not possible keep sealed       as much as possible when using on the bench.

3.3 Sodium Hydroxide (NaOH), AR

3.4 Extraction Fluid #1: Prepare by mixing 4 L (using a measuring cylinder) of DI water, 22.8 mL
      (using burette) glacial acetic acid and 10.25 - 10.30 g of NaOH. If required, this solution
      must be adjusted to a pH of 4.88 - 4.98 using either NaOH or acetic acid. Record this pH.


4. PRELIMINARY EVALUATIONS

4.1 Determination of Percent Solid

      TAKE ANY SUBSAMPLES FOR TOTAL SOLIDS DETERMINATION RAPIDLY FROM A COLD SAMPLE
      TO AVOID THE LOSS OF VOLATILES.

      THE SAMPLE USED FOR THE SOLIDS DETERMINATION IS NOT TO BE USED FOR ZHE ANALYSIS.

      The percent solid is defined as that fraction of a waste sample from which no liquid may be
      forced out.

      4.1.1 If the waste will obviously yield no liquid when subjected to pressure (that is: it is
               100 % solid) proceed to section 4.2.

      4.1.2 Record the following information in the Miscellaneous Workbook. If the sample is
               liquid or liquid/solid a percent solid determination is required. This is achieved using
               a vacuum filtration device. The first step is to preweigh the filter paper and the
               container which will receive the filtrate. A subsample of the waste is then weighed
               out (a minimum of 100 g) and the weight recorded. This subsample is then
               quantitatively transferred to the filtration device and vacuum applied gradually.
               When continued vacuum does not result in any additional filtrate within any 2 minute
               period, stop the filtration.

      4.1.3 Record the weight of the liquid and solid phases. Calculate the percent solids
               as follows:

                                             weight of solid
               Percent solids = ----------------------------- x 100 %
                                             total weight of waste


4.2 Determination of Particle Size Reduction

      Particle size reduction is required unless the solid is smaller than 1 cm in its narrowest
      dimension. If the particle size is larger than described above, prepare the solid portion for
      extraction by crushing, cutting or grinding the waste to a suitable particle size.

      IF PARTICLE SIZE REDUCTION IS REQUIRED, THIS IS TO BE CARRIED OUT ON THE SAMPLE
      IMMEDIATELY PRIOR TO EXTRACTION.


5. EXTRACTION PROCEDURE

5.1 Pre-weigh the evacuated filtrate collection container and set aside.

5.2 Place the ZHE piston within the body of the ZHE. Adjust the piston within the ZHE body to
      a height that will minimise the distance the piston will have to move once the ZHE is
      charged with sample. Secure the gas inlet / outlet flange (bottom flange) onto the ZHE
      body in accordance with the manufacturer’s instructions. Secure the glass fibre filter
      between the support screens and set aside. Set the liquid inlet / outlet flange (top flange)
      aside.

5.3 If the waste is 100 % solid, weigh out 25 g of the waste.

5.4 If the percent of solids is less than 0.5 %, the liquid phase, after filtration, is defined as
      the TCLP extract. Filter enough sample so that that the amount of filtrate will support all
      the volatile analysis required. For wastes containing ≥ 0.5 % dry solids (ref 4.1.3), use the
      % solids information to determine the optimum sample size to charge into the ZHE.

5.5 For wastes containing < 5 % solids, weigh out a 500 g subsample and record the weight. 5.6 For wastes containing ≥ 0.5 % solids, determine the amount of waste to charge into the ZHE       as follows:                                                                      25       Weight of waste to charge to ZHE = --------------- x 100                                                              percent solids 5.7 Weigh out a subsample (cold) of the waste of the appropriate size and record the weight. 5.8 Carry out any particle size reduction. 5.9 Transfer quantitatively, as quickly as possible the entire sample to the ZHE. Secure the        filter and support screens onto the top flange of the device and secure the top flange to        the ZHE body in accordance with the manufacturers instructions. Tighten all ZHE fittings        and place the device in the vertical position (gas inlet / outlet flange on the bottom).        Do not attach the extraction collection device to the top plate.        NOTE: If > 1 % of waste material has adhered to the container used to transfer the sample,
       determine the weight of the residue and subtract it from the initial weight.

5.10 Attach a gas line to the gas inlet / outlet valve (bottom flange) and with the liquid inlet        / outlet valve (top flange) open, begin applying gentle pressure of 1 -10 psi (or more if
       necessary) to force all the headspace slowly out of the ZHE device. At the first appearance
       of liquid from the liquid inlet / outlet valve, quickly close the valve and discontinue
       pressure. If filtration of the waste at 4 OC reduces the amount of expressed liquid over
       what would be expressed at room temperature, then allow the sample to warm to room
       temperature in the device before filtering.
       If the waste is 100 % solid, slowly increase the pressure to a maximum of 50 psi to force
       most of the headspace out of the devise. Proceed to 5.15.

5.11 Attach the evacuated pre-weighed filtrate collection container to the liquid inlet / outlet        valve and open the valve. Begin applying gentle pressure of 1 - 10 psi to force the liquid
       phase of the sample into the filtrate collection container. If no additional liquid has
       passed through the filter in any 2 minute interval, slowly increase the pressure in 10-psi
       increments to a maximum of 50 psi. After each incremental increase of 10 psi, if no
       additional liquid has passed through the filter in any 2 minute interval, proceed to the
       next 10-psi increment. When liquid flow has ceased such that continued pressure filtration
       at 50 psi does not result in any additional filtrate within a 2 minute period stop the
       filtration. Close the liquid inlet / outlet valve, discontinue pressure to the piston, and
       disconnect and weigh the filtrate collection container.

       Note: Instantaneous application of high pressure can degrade the glass filter and may
       cause premature plugging.

5.12 The material in the ZHE is defined as the solid phase of the waste and the filtrate is        defined as the liquid phase.

       Note: Some wastes, such as oily wastes and some paint wastes, will obviously contain
       some material that appears to be a liquid. Even after applying pressure filtration, this
       material will not filter. In this case, the material within the filtration device is defined as
       a solid and is carried through the TCLP extraction as a solid.

5.13 If the original waste contained < 0.5 % dry solids, this filtrate is defined as the TCLP        extract and is analysed directly.

5.14 The liquid phase may now be either analysed immediately or stored at 4 OC under minimal        headspace conditions until time of analysis. Determine the weight of solid to add to the
       ZHE as follows:
                                                               100 x 500 mL (Volume of extraction fluid)
       weight of waste filtered (4.1.2) = -----------------------------------------------------
                                                                             20 x percent solids (4.1.3)


5.15 With the ZHE in the vertical position, attach a line from the extraction fluid reservoir to        the liquid inlet / outlet valve. The line used shall contain fresh extractant fluid and should
       be preflushed with fluid to eliminate any air pockets in the line. Release the gas pressure
       on the ZHE piston (from the gas inlet /outlet valve), open the liquid inlet / outlet valve,
       and begin transferring extraction fluid (by pumping or similar means) into the ZHE.
       Continue pumping extraction fluid into the ZHE until the appropriate amount of fluid has
       been introduced into the device.

5.16 After the extraction fluid has been added, immediately close the liquid inlet / outlet
       valve and disconnect the extraction fluid line. Check the ZHE to ensure that all the valves
       are in their closed positions. Manually rotate the device in an end over end fashion 2 or
       3 times. Reposition the ZHE in the vertical position with the liquid inlet / outlet valve on
       top. Pressurise the ZHE to 5-10 psi (if necessary) and slowly open the liquid inlet / outlet
       valve to bleed out any headspace that may have been introduced due to the addition of
       extraction fluid. This bleeding shall be done quickly and shall be stopped at the first
       appearance of liquid from the valve. Re-pressurise the ZHE with 5 -10 psi and check all ZHE
       fittings to ensure that they are closed.

5.17 Place the ZHE in the rotary agitation apparatus (if it is not already there) and rotate at        30 ± 2 rpm for 18 ± 2 hours at 21 - 25 OC.

5.18 After the 18  2 hour agitation period, check the pressure behind the ZHE piston by
       quickly opening and closing the gas inlet / outlet valve and noting the escape of gas. If the
       pressure has not been maintained (i.e. no gas release observed), the device is leaking.
       Check the ZHE for leaking as specified in Appendix 1 - Sect 4.2.1, and perform the
       extraction again with a new sample of waste. If the pressure within the device has been
       maintained, the material in the extractor vessel is once again separated into its
       component liquid and solid phases. If the waste contained an initial liquid phase, the
       liquid may be filtered directly into the same filtrate collection container holding the
       initial liquid phase of the waste. A separate filtrate collection container must be used if
       combining would create multiple phases, or there is not enough volume left within
       the filtrate
       collection container. Filter through the glass fibre filter, using the ZHE device as discussed
       in Sect 5.15. All extract shall be filtered and collected if the extract is multiphasic,
       or if the waste contained an initial liquid phase.

       NOTE: An in-line glass fibre filter may be used to filter the material within the ZHE if it is
       suspected that the glass fibre filter has been ruptured.

5.19 If the waste contained no initial liquid phase, the filtered liquid material obtained from        5.18 is defined as the TCLP extract.

5.20 If compatible (multiphases will not result on combination), combine the filtered liquid        resulting from section 5.18 with the initial liquid phase of the waste obtained in section
       5.12. This combined liquid is defined as the TCLP extract.

5.21 If the initial liquid phase of the waste obtained from section 5.12 is not or may not be        compatible with the filtered liquid resulting from section 5.18, do not combine these
       liquids. Analyse the liquids, collectively defined as the TCLP extract, and combine the
       results mathematically. For further explanation see Appendix 1, section 7.2.14.

5.22 Following the collection of the TCLP extract, the sample is prepared for analysis. Store        extract with minimal headspace at 4 OC.


6. REFERENCE

USEPA Method 1311

Thursday, 11 February 2016

Holding Times, Preservasi & Jenis Wadah Sampel Lingkungan

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Sampel hanya refresentatif untuk jangka waktu tertentu sebelum persiapan sampel atau analisis dimulai. Ini didefinisikan sebagai "holding time". Batas penyimpanan maksimum sangat tergantung pada karakteristik matrik sampel lingkungan, sifat parameter uji, dan teknik pengawetan.

Aturan umum untuk penanganan Sampel lingkungan adalah sebagai berikut;

Jenis Wadah - Gunakan jenis wadah yang sesuai, plastik atau gelas, dan sudah dilakukan pencucian sesuai "EPA wash procedure".



Dinginkan 4 ° C - Gunakan ice pack ketika pengiriman melalui udara dan jarak jauh dan ditempatkan dalam cooler box

Preservasi - Jika sampling untuk suatu analit membutuhkan preservasi, jenis pengawet yang diperlukan dimasukkan ke dalam botol (jangan lakukan pembilasan dengan sampel), atau pengawet dimasukkan ke dalam vial yang diberi label dengan tepat. Masukkan pengawet setelah sampel dimasukkan ke dalam botol

Berikut adalah pedoman teknis handling sampel lingkungan yang dipersyaratkan sebagai salah satu syarat untuk mendapatkan hasil uji yang valid dan reliable

Determination Matrix Container Preservation Max Holding Time
Bacterial Tests
Coliform, Colilert W, DW P, Bottle or Bag Cool, 4°C, 0.008% Na2S2O3 6-24 hours
Coliform, Fecal and Total W, DW P,G Cool, 4°C, 0.008% Na2S2O3 6-24 hours
Fecal Streptococci W P,G Cool, 4°C, 0.008% Na2S2O3 6-24 hours
Inorganic Tests
Acidity W P,G Cool, 4°C 14 daysEPA
Alkalinity W, DW P,G Cool, 4°C 14 daysEPA
Ammonia W, DW P,G Cool, 4°C, H2SO4 to pH<2 28 days
Biochemical Oxygen Demand (BOD) W P,G Cool, 4°C 48 hours
Bromate W, DW P,G 50mg/L EDA, cool to 4°C 28 days
Bromide W, DW P,G None Required 28 days
Chemical Oxygen Demand (COD) W P,G Cool, 4°C, H2SO4 to pH<2 28 days
Chloride – Method 300.0 W, DW P,G None Required 28 days
Chloride – Method 9056 W, S P,G Cool, 4°C Analyze immediately
Chlorine, Total Residual W, DW P,G None Required 15 minutes
Chlorite W, DW P,G 50mg/L EDA, cool to 4°C 14 days
Chlorophyll-A W G Amber Cool, 4°C Analyze immediately
Chromium VI – Method 7196A W P,G Cool, 4°C 24 hours
Color W, DW P,G Cool, 4°C 48 hours
Cyanide, Total and Amenable to Chlorination W, DW P,G Cool, 4°C, NaOH to pH>12, plus 0.6 g Ascorbic Acid 14 days
Cyanide, Weak Acid Dissociable W P,G Cool, 4°C, NaOH to pH >12 14 days
Ferrous Iron W, DW G Amber Cool, 4°C 24 hours
Fluoride – Method 300.0 W, DW P,G None Required 28 days
Fluoride – Method 9056 W, S P,G Cool, 4°C Analyze immediately
Hardness W, DW P,G HNO3 to pH<2 6 months
Hydrogen Ion (pH) W, DW, S P,G None Required Analyze immediately
Ignitability W G None Required 14 days
Kjeldahl and Organic Nitrogen W P,G Cool, 4°C, H2SO4 to pH<2 28 days
Nitrate – Method 300.0 W, DW P,G Cool, 4°C 48 hours
Nitrate – Method 353.2 W, DW P,G Cool, 4°C, H2SO4 to pH<2 48 hours
Nitrate – Method 9056 W, S P,G Cool, 4°C Analyze immediately
Nitrate-Nitrite – Method 353.2 W, DW P,G Cool, 4°C, H2SO4 to pH<2 28 days
Nitrite W P,G Cool, 4°C 48 hours
Orthophosphate – Method 365.3 W, DW P,G Cool, 4°C Analyze immediately
Oxygen, Dissolved (Probe) W, DW G, Bottle and Top None Required Analyze immediately
Oxygen, Dissolved (Winkler) W, DW G, Bottle and Top Fix on Site and Store in Dark 8 hours
Perchlorate W, DW P,G Protect from temp. extremes 28 days
Phenolics, Total W G Only Cool, 4°C, H2SO4 to pH<2 28 days
Phosphorus, Elemental W G Only Cool, 4°C 48 hours
Phosphorus, Total W P,G Cool, 4°C, H2SO4 to pH<2 28 days
Residue, Total W P,G Cool, 4°C 7 days
Residue, Filterable (TDS) W P,G Cool, 4°C 7 days
Residue, Nonfilterable (TSS) W P,G Cool, 4°C 7 days
Residue, Settleable W P,G Cool, 4°C 48 hours
Residue, Volatile W P,G Cool, 4°C 7 days
Silica W P Only Cool, 4°C 28 days
Specific Conductance W, DW P,G Cool, 4°C 28 days
Sulfate – Method 300.0 W, DW P,G Cool, 4°C 28 days
Sulfate – Method 9056 W P,G Cool, 4°C Analyze immediately
Sulfide W P,G Cool, 4°C, Add Zinc Acetate plus Sodium Hydroxide to pH>9 7 days
Sulfite W P,G None Required 24 hours
Surfactants (MBAS) W P,G Cool, 4°C 48 hours
Tannin and Lignin W P,G Cool, 4°C 28 days
Temperature W P,G None Required Analyze immediately
Turbidity W, DW P,G Cool, 4°C 48 hours
Metals
Metals, except CrVI and Mercury W, DW P,G HNO3 to pH<2 6 months
S G, Teflon-Lined Cap Cool, 4°C 6 months
Chromium VI – Method 7195 W P,G Cool, 4°C 24 hours
Mercury W P,G HNO3 to pH<2 28 days
Mercury S P,G Cool, 4°C 28 days
Organic Tests
Oil and Grease, Hexane Extractable Material (EPA 1664) W G, Teflon-Lined Cap Cool, 4°C, H2SO4 to pH<2 28 days
Organic Carbon, Total (TOC) W P,G Cool, 4°C, H2SO4 to pH<2 28 days
Organic Halogens, Total (TOX) W G, Teflon-Lined Cap Cool, 4°C, H2SO4 to pH<2, No headspace 28 days
Organic Halogens, Adsorbable (AOX) W G, Teflon-Lined Cap Cool, 4°C, HNO3 to pH<2 6 months
Petroleum Hydrocarbons, Total Recoverable W G, Teflon-Lined Cap Cool, 4°C, HCl or H2SO4 to pH<2 28 days
Petroleum Hydrocarbons, Total W G, Teflon-Lined Cap Cool, 4°C, HCl or H2SO4 to pH<2 7 days until extraction; 40 days after extraction
Petroleum Hydrocarbons, Total S G, Teflon-Lined Cap Cool, 4°C 14 days until extraction; 40 days after extraction
Volatile Organics
Petroleum Hydrocarbons, Volatile (Gasoline-Range Organics) W G, Teflon-Lined Septum Cap Cool, 4°C, HCl to pH<2, No Headspace 14 days
Petroleum Hydrocarbons, Volatile (Gasoline-Range Organics) S G, Teflon-Lined Cap Cool, 4°C, Minimize Headspace 14 days
Purgeable Halocarbons W G, Teflon-Lined, Septum Cap No Residual Chlorine Present: HCl to pH<2, Cool, 4°C, No Headspace

Residual Chlorine Present: 10% Na2S2O3, HCl to pH<2, Cool, 4°Cn No Headspace
14 days
Purgeable Halocarbons S G, Teflon-Lined Cap Cool, 4°C, Minimize Headspace 14 days
Purgeable Halocarbons S Method 5035A, G. Teflon-Lined, Septum Cap Freeze at -20°C on site in vial 14 days
Frozen in coring tool on site 48 hours
Cool 4°C, freeze at lab within 48 hours 14 days
Cool 4°C, methanol preserved within 48 hours 14 days
Cool 4°C in vial 48 hours
Cool 4°C in coring tool 48 hours
Cool 4°C, Sodium Bisulfate 14 days
Purgeable Aromatic Hydrocarbons (including BTEX and MTBE) W G, Teflon-Lined, Septum Cap No Residual Chlorine Present: HCl to pH<2, Cool, 4°C, No Headspace

Residual Chlorine Present: 10% Na2S2O3, HCl to pH<2, Cool 4°C
14 days
Purgeable Aromatic Hydrocarbons (including BTEX and MTBE) S G, Teflon-Lined Cap Cool, 4°C, Minimize Headspace 14 days
Purgeable Aromatic Hydrocarbons (including BTEX and MTBE) S Method 5035A, G. Teflon-Lined, Septum Cap Freeze at -20°C on site in vial 14 days
Frozen in coring tool on site 48 hours
Cool 4°C, freeze at lab within 48 hours 14 days
Cool 4°C, methanol preserved within 48 hours 14 days
Cool 4°C in vial 48 hours
Cool 4°C in coring tool 48 hours
Cool 4°C, Sodium Bisulfate 14 days
Acrolein, Acrylonitrile, Acetonitrile W G, Teflon-Lined, Septum Cap Adjust pH to 4-5, Cool, 4°C, No Headspace 14 days
EDB and DBCP W,S G, Teflon-Lined Cap Cool, 4°C, 3 mg Na2S2O3, No Headspace 28 days
Semivolatile Organics
Dioxins/Furans by 8290/8280 W G Amber Cool, 4°C 30 days
Dioxins/Furans by 8290/8280 S G Cool, 4°C 30 days, if frozen 1 year
Dioxins/Furans by 1613B W G Amber Cool, 4°C 1 year
Dioxins/Furans by 1613B S G Frozen 1 year
Coplanar PCBs by 1668A W G Amber Cool, 4°C 1 year
Coplanar PCBs by 1668A S G Cool, 4°C 1 year
Petroleum Hydrocarbons, Extractable (Diesel-Range Organics) W,S G, Teflon-Lined Cap Cool, 4°C 7 days until extraction;f 40 days after extraction
Alcohols and Glycols W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Phenols W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Phthalate Esters W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Nitrosamines W,S G, Teflon-Lined Cap Cool, 4°C 7 days until extraction;f 40 days after extraction
Organochlorine Pesticides and PCBs W,S G, Teflon-Lined Cap Cool, 4°C 7 days until extraction;f 40 days after extraction
Nitroaromatics and Cyclic Ketones W,S G, Teflon-Lined Cap Cool, 4°C 7 days until extraction;f 40 days after extraction
Polynuclear Aromatic Hydrocarbons W,S G, Teflon-Lined Cap Cool, 4°C 7 days until extraction;f 40 days after extraction
Haloethers W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Chlorinated Hydrocarbons W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Organophosphorus Pesticides W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Nitrogen- and Phosphorus-Containing Pesticides W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Carbonyl Compounds (formaldehyde) W G, Teflon-Lined Cap Cool, 4°Ca 3 days until extraction; 3 days after extraction
Chlorinated Herbicides W,S G, Teflon-Lined Cap Cool, 4°Ca 7 days until extraction;f 40 days after extraction
Chlorinated Phenolics W G, Teflon-Lined Cap H2SO4 to pH<2, Cool, 4°Ca 30 days until extraction; 30 days after extraction
Resin and Fatty Acids W G, Teflon-Lined Cap NaOH to pH >10, Cool, 4°Ca 30 days until extraction; 30 days after extraction
Drinking Water Organics
Purgeable Organics DW G, Teflon-Lined, Septum Cap Ascorbic Acid, HCl to pH<2, Cool, 4°C, No Headspace 14 days
EDB, DBCP, and TCP DW G, Teflon-Lined Septum Cap Cool, 4°C, 3 mg Na2S2O3, No Headspace 14 days
Carbamates, Carbamoyloximes DW G, Amber, Teflon-Lined Cap 1.8 mL monochloroacetic acid to pH<3; 80 mg/L Na2S2O3 if Res.Cl.; Cool, 4°C 28 days
Chlorinated Herbicides DW G, Amber, Teflon-Lined Cap If Res.Cl, 2mg/40mL NaS; Cool, <6°C 14 days until extraction; 21 days after extraction
Chlorinated Pesticides DW G, Amber, Teflon-Lined Cap 50 mg/L NaS, HCl to pH< 2; Cool, 4°C 14 days until extraction; 30 days after extraction
Diquat and Paraquat DW HDPE, Amber, Teflon-Lined Cap 100 mg/L Na2S2O3 if Res.Cl., Cool, 4°C 7days until extraction; 21 days after extraction
Endothall DW G, Amber, Teflon-Lined Cap Cool, 4°C 7 days until extraction; 14 days after extraction
Glyphosate DW G, Amber, Teflon-Lined Cap 100 mg/L Na2S2O3, Cool, 4°C 14 days
Haloacetic Acids DW G, Amber, Teflon-Lined Cap 100 mg/L NH4Cl, Cool, 4°C 14 days until extraction; 7 days after extraction
Semivolatile Organics DW G, Amber, Teflon-Lined Cap 50 mg/L NaS, HCl to pH< 2; Cool, 4°C 14 days until extraction; 30 days after extraction
Toxicity Characteristic Leaching Procedure (TCLP)
Mercury HW P,G Sample: Cool, 4°C 28 days until extraction;
TCLP extract: HNO3 to pH<2 28 days after extraction
Metals, except Mercury HW P,G Sample: Cool, 4°C 180 days until extraction;
TCLP extract: HNO3 to pH<2 180 days after extraction
Volatile Organics HW G, Teflon-Lined Cap Sample: Cool, 4°C , Minimize Headspace 14 days until extraction;
TCLP extract: Cool, 4°C, HCl to pH<2, No Headspace 14 days after extraction
Semivolatile Organics HW G, Teflon-Lined Cap Sample: Cool, 4°C, Store in Darka 14 days to prepare leachate;
TCLP extract: Cool, 4°C, Store in Darka 7 days to extract
40 days after extraction to analyze
Organochlorine Pesticides HW G, Teflon-Lined Cap Sample: Cool, 4°C 14 days until TCLP ext'n;
TCLP extract: Cool, 4°C 7 days until extraction; 40 days after extraction
Chlorinated Herbicides HW G, Teflon-Lined Cap Sample: Cool, 4°C 14 days until TCLP ext'n;
TCLP extract: Cool, 4°C 7 days until extraction; 40 days after extraction

Notes:

DW = Drinking Water; W = Water; S = Soil or Sediment; HW = Hazardous Waste; A = Air

P = Polyethylene; G = Glass

Wednesday, 10 February 2016

Cara Uji Krom Total (Cr-T) secara AAS - nyala

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1. Prinsip Analisis

    Analit logam krom dalam nyala udara-asetilen diubah menjadi bentuk atomnya, menyerap
    energi radiasi elektromagnetik yang berasal dari lampu katoda dan besarnya serapan
    berbanding lurus dengan kadar analit.


2. Pereaksi

a) Air bebas mineral.
b) Asam nitrat (HNO3) pekat p.a.
c) Krom trioksida (CrO3) atau kalium dikromat (K2Cr2O7).
d) Gas asetilen (C2H2) HP dengan tekanan minimum 100 psi.
e) Larutan pengencer HNO3 0,05 M.
    Larutkan 3,5 mL HNO3 pekat ke dalam 1000 mL air bebas mineral dalam gelas piala.
f) Larutan pencuci HNO3 5 % (v/v).
    Tambahkan 50 mL asam nitrat pekat ke dalam 800 mL air bebas mineral ke dalam gelas
    piala 1000 mL, lalu tambahkan air bebas mineral hingga 1000 mL dan homogenkan.
g) Udara tekan HP atau udara tekan dari kompresor.


3. Peralatan

a) Spektrofotometer Serapan Atom (AAS)- nyala.
b) Lampu katoda berongga (Hollow Cathode Lamp/HCL) krom.
c) Gelas piala 100 mL dan 250 mL.
d) Pipet volumetrik 10,0 mL dan 50,0 mL.
e) Labu ukur 50,0 mL; 100,0 mL dan 1000,0 mL.
f) Erlenmeyer 100 mL.
g) Corong gelas.
h) Kaca arloji.
i) Pemanas listrik.
j) Saringan membran dengan ukuran pori 0,45 um.
k) Timbangan analitik dengan ketelitian 0,0001 g.
l) Labu semprot.



4. Persiapan pengujian

    Siapkan contoh uji untuk dengan tahapan sebagai berikut:

    a) Homogenkan contoh uji, pipet 50,0 mL contoh uji dan masukkan ke dalam gelas piala
        100 mL atau Erlenmeyer 100 mL.
    b) Tambahkan 5 mL HNO3 pekat, bila menggunakan gelas piala, tutup dengan kaca arloji
        dan bila dengan Erlenmeyer gunakan corong sebagai penutup.
    c) Panaskan perlahan-lahan sampai sisa volumenya 15 mL sampai dengan 20 mL.
    d) Jika destruksi belum sempurna (tidak jernih), maka tambahkan lagi 5 mL HNO3 pekat,
        kemudian tutup gelas piala dengan kaca arloji atau tutup Erlenmeyer dengan corong dan
        panaskan lagi (tidak mendidih). Lakukan proses ini secara berulang sampai semua
        logam larut, yang terlihat dari warna endapan dalam contoh uji menjadi agak putih atau
        contoh uji menjadi jernih.

        CATATAN Jika destruksi tidak sempurna, lihat tabel di bawah

AsamDisarankan untuk analisisBisa berguna untuk contoh ujiTidak disarankan untuk analisis
HCl AgSb, Ru, SnTh, Pb
H2SO4 Ti-Ag, Pb, Ba
HClO4 -mengandung bahan organik-
HF -mengandung silika-

    e) Bilas kaca arloji dan masukkan air bilasannya ke dalam gelas piala.
    f) Pindahkan contoh uji ke dalam labu ukur 50,0 mL (saring bila perlu) dan tambahkan air
        bebas mineral sampai tepat tanda tera dan dihomogenkan.
    g) Contoh uji siap diukur serapannya.


4.1 Pembuatan larutan baku logam krom 100 mg Cr/L

    a) Larutkan ± 0,192 g CrO3 atau ± 0,282 g K2Cr2O7 dengan air bebas mineral dalam labu
        ukur 1000,0 mL ( 100 mg Cr/L).
    b) Tambahkan 10 mL HNO3 pekat dan encerkan dengan air bebas mineral hingga tanda
        tera, lalu homogenkan.
    c) Hitung kadar krom berdasarkan hasil penimbangan.

        CATATAN Larutan ini dapat dibuat dari larutan standar 1000 mg Cr/L siap pakai.

4.2 Pembuatan larutan baku logam krom 10 mg Cr/L

    a) Pipet 10,0 mL larutan standar logam krom 100 mg/L ke dalam labu ukur 100,0 mL.
    b) Tepatkan dengan larutan pengencer sampai tanda tera dan homogenkan.

4.3 Pembuatan larutan kerja logam krom

    Buat deret larutan kerja dengan 1 (satu) blanko dan minimal 3 (tiga) kadar yang berbeda
    secara proporsional dan berada pada rentang pengukuran.



5. Prosedur dan pembuatan kurva kalibrasi

    5.1 Pembuatan kurva kalibrasi

          Kurva kalibrasi dibuat dengan tahapan sebagai berikut:
          a) Operasikan alat dan optimasikan sesuai dengan petunjuk penggunaan alat untuk
              pengukuran krom total.

              CATATAN 1 Salah satu cara optimasi alat dengan uji sensitifitas.

              CATATAN 2 Tambahkan matrix modifier dan/atau atasi gangguan pengukuran sesuai
              dengan AAS yang digunakan.

              CATATAN 3 Pengukuran dilakukan pada nyala reduksi.

              CATATAN 4 Bila diperlukan tambahkan 0,5 mL larutan hidrogen peroksida (H2O2) 30%
              (v/v) ke dalam 50 mL contoh uji dan larutan standar untuk meningkatkan sensitifitas.

          b) Aspirasikan larutan blanko ke dalam AAS-nyala kemudian atur serapan hingga nol.
          c) Aspirasikan larutan kerja satu persatu ke dalam AAS-nyala, lalu ukur serapannya pada
              panjang gelombang 357,9 nm, kemudian catat.
          d) Lakukan pembilasan pada selang aspirator dengan larutan pengencer.
          e) Buat kurva kalibrasi dari data pada butir 5.1.c) di atas, dan tentukan persamaan garis
              lurusnya.
          f) Jika koefisien korelasi regresi linier (r) < 0,995, periksa kondisi alat dan ulangi langkah
              pada butir 5.1 b) sampai dengan c) hingga diperoleh nilai koefisien r ≥ 0,995.


    5.2 Cara uji

          Uji kadar krom total dengan tahapan sebagai berikut:
          a) Aspirasikan contoh uji ke dalam AAS-nyala lalu ukur serapannya pada panjang
              gelombang 357,9 nm. Bila diperlukan, lakukan pengenceran.
          b) Catat hasil pengukuran.



6. Perhitungan

Kadar logam krom total (Cr-T)

Cr-T (mg/L)  =  C x fp

Keterangan:
C  adalah kadar yang didapat hasil pengukuran (mg/L).
fp adalah faktor pengenceran.



Referensi

SNI 6989.17:2009

 

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