Product Overview
Providing precise measurement of Chloride in numerous sample types: the M926S Chloride Analyser is intended for general laboratory use and calibrated to give results in mmol/l Chloride. The Select Button allows the Operator to choose to work with 20µl or 100µl sample volumes. . The M926S is widely used for Chloride determination in Sweat samples
Highlights
- Principle coulometric method of operation is very robust, tried and tested
- Analyser is ergonomically designed, easy to use and maintain
- Sherwood Chloride Analyser Buffer enables outstanding performance for precision
- Low cost per test
- Low after test costs (reagent disposal)
Further information about the product
The M926S Chloride Analyser method of operation is based on a coulometric titration wherein the reagent (Silver ions) is precisely and quantitatively generated at the time of analysis by passing a constant current between electrodes. The endpoint is determined when excess Silver ions cause a change in conductivity; detected by the detector electrodes.
| Instrument Model | M926S |
| Application | Chloride measurement in mmol/l |
| Units | mmol/l |
| Calibrated Sample Size | 20µl and 100µl |
| Readout Range | 10 – 299 mmol/l |
| Limit of Detection | 4mmol/l for 20µl & 100ul sample |
| Accuracy | ± 2mmol/l at the 100 mmol/l level |
| Reproducibility/Precision | CV <1% for 100µl samples and CV <1.5% for 20 µl samples @100mmol/l (excluding pipetting errors) |
| Measurement Time | 26 seconds to 100mol/l |
| Voltage (Mains Adapter Input) | 100 – 240V, 50 – 60 Hz, 0.6A |
| Size | 315 x 200 x 250mm |
| Packed Size | 385 x 370 x 450mm |
| Net Weight | 1.9 Kg |
| Gross Weight | 5.4 Kg |
| Packed Unit Contents | M926S Chloride Analyser, Printer Cable 9 way RS232, Buffer (500ml), 100 mmol/l Chloride Standard Solution (100ml), 1 Pack of Anodes, 1 Pack of Electrodes, 2 Marked Beakers, Silver Electrode Polish, Stirrer, Operator Manual, Universal Mains Adapter and USB lead A(M) – B(M) |
Analytical Performance:
Precision/Reproducibility:
Using guidelines as per CLSI EP5A2, repeatability testing was performed using one M926S Chloride Analyser and one Batch of Chloride Analyser Buffer.
Within run precision was obtained for both selectable titration volumes by performing 2 runs per day, two measurements per run for 1 standard (100mmol/l) and three concentrations of control material (Low, Medium , and High), using one M926S Chloride Analyser and Buffer from one batch (n = 80) for 20 days using both the 20µl and 100µl settings The results were:
For the 20µl Setting (n=80)
| Sample | Mean(mmol/l) | SD | %CV |
| 0mmol/l | 0.13 | 0.56 | 430.77 |
| 3mmol/l | 2.54 | 1.30 | 51.18 |
| 23mmol/l | 22.70 | 1.00 | 4.41 |
| 50mmol/l | 49.2 | 0.95 | 1.93 |
| 98mmol/l | 95.63 | 1.55 | 1.62 |
| 100mmol/l | 100.16 | 1.11 | 1.11 |
For the 100µl Setting (n=80)
| Sample | Mean(mmol/l) | SD | %CV |
| 0mmol/l | 0.00 | 0.00 | 0 |
| 3mmol/l | 2.55 | 0.78 | 30.59 |
| 23mmol/l | 22.81 | 0.55 | 2.41 |
| 50mmol/l | 49.80 | 0.62 | 1.24 |
| 98mmol/l | 96.90 | 0.56 | 0.58 |
| 100mmol/l | 100.56 | 0.57 | 0.57 |
Total precision study was performed using two M926S Chloride Analysers, buffer from two different batches and three operators. Three levels of control materials and two Standard Solutions were analysed covering the measuring range of the device. Controls were analysed in duplicate twice per day for consecutive 10 days (n= 240). Summarised results are below:
For the 20µl Setting
| Instrument 1 | Instrument 2 | |||||
| Sample | Mean | SD | n | Mean | SD | n |
| 100mmol/l | 99.72 | 1.2 | 180 | 99.67 | 1.11 | 180 |
| 0mmol/l | 0.00 | 0.00 | 120 | 0.01 | 0.09 | 120 |
| 3mmol/l | 3.03 | 0.76 | 120 | 2.62 | 1.34 | 120 |
| 10mmol/l | 10.09 | 0.59 | 120 | 10.19 | 0.71 | 120 |
| 23mmol/l | 22.71 | 0.76 | 120 | 22.87 | 0.84 | 120 |
| 50mmol/l | 49.59 | 0.76 | 120 | 49.56 | 1.02 | 120 |
| 98mmol/l | 97.00 | 1.64 | 120 | 96.78 | 1.14 | 120 |
| Buffer Batch 1 | Buffer Batch 2 | |||||
| Sample | Mean | SD | n | Mean | SD | n |
| 100mmol/l | 99.86 | 1.15 | 180 | 99.53 | 1.13 | 180 |
| 0mmol/l | 0.01 | 0.09 | 120 | 0.00 | 0.00 | 120 |
| 3mmol/l | 2.92 | 1.09 | 120 | 2.73 | 1.10 | 120 |
| 10mmol/l | 10.16 | 0.62 | 120 | 10.13 | 0.68 | 120 |
| 23mmol/l | 22.77 | 0.72 | 120 | 22.81 | 0.88 | 120 |
| 50mmol/l | 49.66 | 0.69 | 120 | 49.49 | 1.06 | 120 |
| 98mmol/l | 97.04 | 1.32 | 120 | 96.74 | 1.49 | 120 |
| Overall | |||
| Sample | Mean | SD | n |
| 100mmol/l | 99.69 | 1.15 | 360 |
| 0mmol/l | 0.00 | 0.00 | 240 |
| 3mmol/l | 2.83 | 1.10 | 240 |
| 10mmol/l | 10.14 | 0.65 | 240 |
| 23mmol/l | 22.79 | 0.80 | 240 |
| 50mmol/l | 49.58 | 0.90 | 240 |
| 98mmol/l | 96.89 | 1.41 | 240 |
Total precision study was performed using two M926S Chloride Analysers, two Buffer lots and three operators. Three levels of control materials and two Standard Solutions were analysed covering the measuring range of the device. Controls were analysed in duplicate twice per day for consecutive 10 days (n= 240). Summarised results are below:
For the 100µl Setting
| Instrument 1 | Instrument 2 | |||||
| Sample | Mean | SD | n | Mean | SD | n |
| 100mmol/l | 100.65 | 0.74 | 180 | 100.36 | 0.78 | 180 |
| 0mmol/l | 0.00 | 0.00 | 120 | 0.00 | 0.00 | 120 |
| 3mmol/l | 2.75 | 0.69 | 120 | 2.52 | 0.99 | 120 |
| 10mmol/l | 9.94 | 0.42 | 120 | 9.91 | 0.37 | 120 |
| 23mmol/l | 22.94 | 0.37 | 120 | 22.88 | 0.48 | 120 |
| 50mmol/l | 50.19 | 0.47 | 120 | 50.01 | 0.54 | 120 |
| 98mmol/l | 98.23 | 0.76 | 120 | 97.92 | 0.68 | 120 |
| Buffer 1 | Buffer 2 | |||||
| Sample | Mean | SD | n | Mean | SD | n |
| 100mmol/l | 100.60 | 0.76 | 180 | 100.41 | 0.77 | 180 |
| 0mmol/l | 0.00 | 0.00 | 120 | 0.00 | 0.00 | 120 |
| 3mmol/l | 2.66 | 0.76 | 120 | 2.61 | 0.95 | 120 |
| 10mmol/l | 9.95 | 0.36 | 120 | 9.90 | 0.42 | 120 |
| 23mmol/l | 22.89 | 0.44 | 120 | 22.92 | 0.42 | 120 |
| 50mmol/l | 50.10 | 0.35 | 120 | 50.10 | 0.65 | 120 |
| 98mmol/l | 98.21 | 0.73 | 120 | 97.93 | 0.72 | 120 |
| Sample | Mean | SD | n |
| 100mmol/l | 100.51 | 0.77 | 360 |
| 0mmol/l | 0.00 | 0.00 | 240 |
| 3mmol/l | 2.63 | 0.86 | 240 |
| 10mmol/l | 9.93 | 0.39 | 240 |
| 23mmol/l | 22.91 | 0.43 | 240 |
| 50mmol/l | 50.10 | 0.52 | 240 |
| 98mmol/l | 98.08 | 0.74 | 240 |
Linearity/assay reportable range:
The linearity study was based on CLSI EP6-A. Eleven samples covering the measuring range of the Chloride Analyser system were formulated and analysed in triplicate on one instrument (Factory calibrated with a NIST traceable Chloride Standard Solution) with one reagent lot at both titration volume settings. Results were analysed using 1st, 2nd and 3rd order least-squared regression to obtain the linear and non-linear regression coefficients. Results were as follows:
For the 20µl Setting
| Dilution | Mean | Expected values mmol/l | Difference observed – Expected |
| 0% | 0.0 | -0.08 | 0.08 |
| 3% | 9.00 | 8.08 | 0.92 |
| 10% | 27.33 | 27.12 | 0.21 |
| 20% | 54.00 | 54.32 | -0.32 |
| 30% | 80.67 | 81.53 | -0.86 |
| 40% | 108.33 | 108.73 | -0.40 |
| 50% | 136.00 | 135.94 | 0.06 |
| 60% | 164.00 | 163.14 | 0.86 |
| 70% | 191.00 | 190.34 | 0.66 |
| 80% | 217.67 | 217.55 | 0.12 |
| 90% | 244.33 | 244.75 | -0.42 |
| 100% | 271.67 | 271.96 | -0.29 |
y = 0.9716x –0.0848, R2 = 1.0000
For the 100µl Setting
| Dilution | Mean | Expected values mmol/l | Difference observed – Expected |
| 0% | 0.00 | -0.33 | 0.33 |
| 3% | 8.00 | 7.99 | 0.01 |
| 10% | 27.33 | 27.40 | -0.07 |
| 20% | 55.00 | 55.13 | -0.13 |
| 30% | 82.67 | 82.86 | -0.19 |
| 40% | 110.33 | 110.59 | -0.26 |
| 50% | 138.33 | 138.32 | 0.01 |
| 60% | 166.33 | 166.06 | 0.28 |
| 70% | 193.67 | 193.79 | -0.12 |
| 80% | 222.00 | 221.52 | 0.48 |
| 90% | 249.67 | 249.25 | 0.42 |
| 100% | 276.33 | 276.98 | -0.65 |
y = 0.9904x –0.3326, R2 = 1.0000
The linearity study supports the claimed measuring range of 10 – 299 mmol/l for the M926S Chloride Analyser system.
